7-O-tyrosyl Silybin Derivatives as a Novel Set of Anti-Prostate Cancer Compounds

Silybin is a natural compound extensively studied for its hepatoprotective, neuroprotective and anticancer properties. Envisioning the enhancement of silybin potential by suitable modifications in its chemical structure, here, a series of new 7-O-alkyl silybins derivatives were synthesized by the Mitsunobu reaction starting from the silybins and tyrosol-based phenols, such as tyrosol (TYR, 3), 3-methoxytyrosol (MTYR, 4), and 3-hydroxytyrosol (HTYR, 5). This research sought to explore the antioxidant and anticancer properties of eighteen new derivatives and their mechanisms. In particular, the antioxidant properties of new derivatives outlined by the DPPH assay showed a very pronounced activity depending on the tyrosyl moiety (HTYR > MTYR >> TYR). A significant contribution of the HTYR moiety was observed for silybins and 2,3-dehydro-silybin-based derivatives. According to the very potent antioxidant activity, 2,3-dehydro-silybin derivatives 15ab, 15a, and 15b exerted the most potent anticancer activity in human prostate cancer PC-3 cells. Furthermore, flow cytometric analysis for cell cycle and apoptosis revealed that 15ab, 15a, and 15b induce strong G1 phase arrest and increase late apoptotic population in PC-3 cells. Additionally, Western blotting for apoptotic marker cleaved caspase-3 confirmed apoptosis induction by these silybin derivatives in PC-3 cells. These findings hold significant importance in the investigation of anticancer properties of silybin derivatives and strongly encourage swift investigation in pre-clinical models and clinical trials.

Effect of nonsteroidal anti-inflammatory drugs (aspirin and naproxen) on inflammation-associated proteomic profiles in mouse plasma and prostate during TMPRSS2-ERG (fusion)-driven prostate carcinogenesis

Recent preclinical studies have shown that the intake of nonsteroidal anti-inflammatory drugs (NSAIDs) aspirin and naproxen could be an effective intervention strategy against TMPRSS2-ERG fusion-driven prostate tumorigenesis. Herein, as a follow-up mechanistic study, employing TMPRSS2-ERG (fusion) positive tumors and plasma from TMPRSS2-ERG. Ptenflox/flox mice, we profiled the stage specific proteomic changes (focused on inflammatory circulating and prostate tissue/tumor-specific cytokines, chemokines, and growth factors/growth signaling-associated molecules) that contribute to prostate cancer (PCa) growth and progression in the TMPRSS2-ERG fusion-driven mouse model of tumorigenesis. In addition, the association of the protective effects of NSAIDs (aspirin 1400 ppm and naproxen 400 ppm) with the modulation of these specific molecular pathways was determined. A sandwich Elisa based membrane array-proteome profiler identifying 111 distinct signaling molecules was employed. Overall, the plasma and prostate tissue sample analyses identified 54 significant and differentially expressed cytokines, chemokines, and growth factors/growth signaling-associated molecules between PCa afflicted mice (TMPRSS2-ERG. Ptenflox/flox , age-matched noncancerous controls, NSAIDs-supplemented and no-drug controls). Bioinformatic analysis of the array outcomes indicated that the protective effect of NSAIDs was associated with reduced expression of (a) tumor promoting inflammatory molecules (M-CSF, IL-33, CCL22, CCL12, CX3CL1, CHI3L1, and CD93), (b) growth factors- growth signaling-associated molecules (Chemerin, FGF acidic, Flt-3 ligand, IGFBP-5, and PEDF), and (c) tumor microenvironment/stromal remodeling proteins MMP2 and MMP9. Overall, our findings corroborate the pathological findings that protective effects of NSAIDs in TMPSS2-ERG fusion-driven prostate tumorigenesis are associated with antiproliferative and anti-inflammatory effects and possible modulation of the immune cell enriched microenvironment.

Dexamethasone targets actin cytoskeleton signaling and inflammatory mediators to reverse sulfur mustard-induced toxicity in rabbit corneas

PURPOSE

Sulfur mustard (SM), a bi-functional alkylating agent, was used during World War I and the Iran-Iraq war. SM toxicity is ten times higher in eyes than in other tissues. Cornea is exceptionally susceptible to SM-injuries due to its anterior positioning and mucous-aqueous interphase. Ocular SM exposure induces blepharitis, photosensitivity, dry eye, epithelial defects, limbal ischemia and stem cell deficiency, and mustard gas keratopathy leading to temporary or permanent vision impairments. We demonstrated that dexamethasone (Dex) is a potent therapeutic intervention against SM-induced corneal injuries; however, its mechanism of action is not well known. Investigations employing proteomic profiling (LC-MS/MS) to understand molecular mechanisms behind SM-induced corneal injury and Dex efficacy were performed in the rabbit cornea exposed to SM and then received Dex treatment. PEAKS studio was used to extract, search, and summarize peptide identity. Ingenuity Pathway Analysis was used for pathway identification. Validation was performed using immunofluorescence. One-Way ANOVA (FDR < 0.05; p < 0.005) and Student's t-test (p < 0.05) were utilized for analyzing proteomics and IF data, respectively. Proteomic analysis revealed that SM-exposure upregulated tissue repair pathways, particularly actin cytoskeleton signaling and inflammation. Prominently dysregulated proteins included lipocalin2, coronin1A, actin-related protein2, actin-related protein2/3 complex subunit2, actin-related protein2/3 complex subunit4, cell division cycle42, ezrin, bradykinin/kininogen1, moesin, and profilin. Upregulated actin cytoskeleton signaling increases F-actin formation, dysregulating cell shape and motility. Dex reversed SM-induced increases in the aforementioned proteins levels to near control expression profiles. Dex aids corneal wound healing and improves corneal integrity via actin cytoskeletal signaling and anti-inflammatory effects following SM-induced injuries.

Nitrogen Mustard-Induced Ex Vivo Human Cornea Injury Model and Therapeutic Intervention by Dexamethasone

Sulfur mustard (SM), a vesicating agent first used during World War I, remains a potent threat as a chemical weapon to cause intentional/accidental chemical emergencies. Eyes are extremely susceptible to SM toxicity. Nitrogen mustard (NM), a bifunctional alkylating agent and potent analog of SM, is used in laboratories to study mustard vesicant-induced ocular toxicity. Previously, we showed that SM-/NM-induced injuries (in vivo and ex vivo rabbit corneas) are reversed upon treatment with dexamethasone (DEX), a US Food and Drug Administration-approved, steroidal anti-inflammatory drug. Here, we optimized NM injuries in ex vivo human corneas and assessed DEX efficacy. For injury optimization, one cornea (randomly selected from paired eyes) was exposed to NM: 100 nmoles for 2 hours or 4 hours, and 200 nmoles for 2 hours, and the other cornea served as a control. Injuries were assessed 24 hours post NM-exposure. NM 100 nmoles exposure for 2 hours was found to cause optimal corneal injury (epithelial thinning [∼69%]; epithelial-stromal separation [6-fold increase]). In protein arrays studies, 24 proteins displayed ≥40% change in their expression in NM exposed corneas compared with controls. DEX administration initiated 2 hours post NM exposure and every 8 hours thereafter until 24 hours post-exposure reversed NM-induced corneal epithelial-stromal separation [2-fold decrease]). Of the 24 proteins dysregulated upon NM exposure, six proteins (delta-like canonical Notch ligand 1, FGFbasic, CD54, CCL7, endostatin, receptor tyrosine-protein kinase erbB-4) associated with angiogenesis, immune/inflammatory responses, and cell differentiation/proliferation, showed significant reversal upon DEX treatment (Student's t test; P ≤ 0.05). Complementing our animal model studies, DEX was shown to mitigate vesicant-induced toxicities in ex vivo human corneas. SIGNIFICANCE STATEMENT: Nitrogen mustard (NM) exposure-induced injuries were optimized in an ex vivo human cornea culture model and studies were carried out at 24 h post 100 nmoles NM exposure. Dexamethasone (DEX) administration (started 2 h post NM exposure and every 8 h thereafter) reversed NM-induced corneal injuries. Molecular mediators of DEX action were associated with angiogenesis, immune/inflammatory responses, and cell differentiation/proliferation, indicating DEX aids wound healing via reversing vesicant-induced neovascularization (delta-like canonical Notch ligand 1 and FGF basic) and leukocyte infiltration (CD54 and CCL7).

Establishing a Dexamethasone Treatment Regimen To Alleviate Sulfur Mustard-Induced Corneal Injuries in a Rabbit Model

Sulfur mustard (SM) is an ominous chemical warfare agent. Eyes are extremely susceptible to SM toxicity; injuries include inflammation, fibrosis, neovascularization (NV), and vision impairment/blindness, depending on the exposure dosage. Effective countermeasures against ocular SM toxicity remain elusive and are warranted during conflicts/terrorist activities and accidental exposures. We previously determined that dexamethasone (DEX) effectively counters corneal nitrogen mustard toxicity and that the 2-hour postexposure therapeutic window is most beneficial. Here, the efficacy of two DEX dosing frequencies [i.e., every 8 or 12 hours (initiated, as previously established, 2 hours after exposure)] until 28 days after SM exposure was assessed. Furthermore, sustained effects of DEX treatments were observed up to day 56 after SM exposure. Corneal clinical assessments (thickness, opacity, ulceration, and NV) were performed at the day 14, 28, 42, and 56 post-SM exposure time points. Histopathological assessments of corneal injuries (corneal thickness, epithelial degradation, epithelial-stromal separation, inflammatory cell, and blood vessel counts) using H&E staining and molecular assessments (COX-2, MMP-9, VEGF, and SPARC expressions) were performed at days 28, 42, and 56 after SM exposure. Statistical significance was assessed using two-way ANOVA, with Holm-Sidak post hoc pairwise multiple comparisons; significance was established if P < 0.05 (data represented as the mean ± S.E.M.). DEX administration every 8 hours was more potent than every 12 hours in reversing ocular SM injury, with the most pronounced effects observed at days 28 and 42 after SM exposure. These comprehensive results are novel and provide a comprehensive DEX treatment regimen (therapeutic-window and dosing-frequency) for counteracting SM-induced corneal injuries. SIGNIFICANCE STATEMENT: The study aims to establish a dexamethasone (DEX) treatment regimen by comparing the efficacy of DEX administration at 12 versus 8 hours initiated 2 hours after exposure. DEX administration every 8 hours was more effective in reversing sulfur mustard (SM)-induced corneal injuries. SM injury reversal during DEX administration (initial 28 days after exposure) and sustained [further 28 days after cessation of DEX administration (i.e., up to 56 days after exposure)] effects were assessed using clinical, pathophysiological, and molecular biomarkers.

Phenylarsine oxide induced corneal injury involves oxidative stress mediated unfolded protein response and ferroptotic cell death: Amelioration by NAC

Phenylarsine oxide (PAO), an analog of lewisite, is a highly toxic trivalent arsenical and a potential chemical warfare agent. PAO-induced toxicity has been studied in lung, liver, and skin tissues. Nevertheless, very few studies have been published to comprehend the impact of PAO-induced toxicity on ocular tissues, even though eyes are uniquely vulnerable to injury by vesicants. Notably, arsenical vesicants such as lewisite have been shown to cause edema of eyelids, inflammation, massive corneal necrosis, and blindness. Accordingly, human corneal epithelial cells were used to study the effects of PAO exposure. PAO (100 and 200 nM) induced significant oxidative stress in corneal epithelial cells. Simultaneous treatment with N-acetyl-l-cysteine (NAC), an FDA-approved antioxidant, reversed the PAO-induced toxicity in human corneal epithelial cells. Furthermore, oxidative stress induction by PAO was accompanied by unfolded protein response (UPR) signaling activation and ferroptotic cell death. Further, to validate the findings of our in vitro studies, we optimized injury biomarkers and developed an ex vivo rabbit corneal culture model of PAO exposure. Investigations using PAO in ex vivo rabbit corneas revealed similar results. PAO (5 or 10 μg) for 3, 5, and 10 min caused moderate to extensive corneal epithelial layer degradation and reduced the epithelial layer thickness in a concentration- and time-dependent manner. Similar to human corneal cells, injuries by PAO in ex vivo cultured rabbit corneas were also associated with elevated oxidative stress, UPR signaling, and ferroptosis induction. NAC mitigated PAO-induced corneal injuries in rabbit ex vivo cornea culture as well. The reversal of PAO toxicity upon NAC treatment observed in our studies could be attributed to its antioxidant properties. These findings suggest that PAO exposure can cause significant corneal injury and highlight the need for further mechanistic studies to better understand the pathobiology of different arsenical vesicants, including PAO and lewisite.

Metabolomics for identifying pathways involved in vesicating agent lewisite-induced corneal injury

Lewisite (LEW) is an arsenical vesicant that can be a potentially dangerous chemical warfare agent (CWA). Eyes are particularly susceptible to vesicant induced injuries and ocular LEW exposure can act swiftly, causing burning of eyes, edema, inflammation, cell death and even blindness. In our previous studies, we developed a LEW exposure-induced corneal injury model in rabbit and showed increased inflammation, neovascularization, cell death, and structural damage to rabbit corneas upon LEW exposure. In the present study, we further assessed the metabolomic changes to delineate the possible mechanisms underlying the LEW-induced corneal injuries. This information is vital and could help in the development of effective targeted therapies against ocular LEW injuries. Thus, the metabolomic changes associated with LEW exposures in rabbit corneas were assessed as a function of time, to delineate pathways from molecular perturbations at the genomic and proteomic levels. New Zealand white rabbit corneas (n = 3-6) were exposed to LEW vapor (0.2 mg/L; flow rate: 300 ml/min) for 2.5 min (short exposure; low dose) or 7.5 min (long-exposure; high dose) and then collected at 1, 3, 7, or 14 days post LEW exposure. Samples were prepared using the automated MicroLab STAR® system, and proteins precipitated to recover the chemically diverse metabolites. Metabolomic analysis was carried out by reverse phase UPLC-MS/MS and gas chromatography (GC)-MS. The data obtained were analyzed using Metabolon's software. The results showed that LEW exposures at high doses were more toxic, particularly at the day 7 post exposure time point. LEW exposure was shown to dysregulate metabolites associated with all the integral functions of the cornea and cause increased inflammation and immune response, as well as generate oxidative stress. Additionally, all important metabolic functions of the cells were also affected: lipid and nucleotide metabolism, and energetics. The high dose LEW exposures were more toxic, particularly at day 7 post LEW exposure (>10-fold increased levels of histamine, quinolinate, N-acetyl-β-alanine, GMP, and UPM). LEW exposure dysregulated integral functions of the cornea, caused inflammation and heightened immune response, and generated oxidative stress. Lipid and nucleotide metabolism, and energetics were also affected. The novel information about altered metabolic profile of rabbit cornea following LEW exposure could assist in delineating complex molecular events; thus, aid in identifying therapeutic targets to effectively ameliorate ocular trauma.

Differential Effect of Non-Steroidal Anti-Inflammatory Drugs Aspirin and Naproxen against TMPRSS2-ERG (Fusion)-Driven and Non-Fusion-Driven Prostate Cancer

The consumption of the non-steroidal anti-inflammatory drug (NSAID) aspirin is associated with a significant reduction in the risk of developing TMPRSS2-ERG (fusion)-positive prostate cancer (PCa) compared to fusion-negative PCa in population-based case-control studies; however, no extensive preclinical studies have been conducted to investigate and confirm these protective benefits. Thus, the focus of this study was to determine the potential usefulness of aspirin and another NSAID, naproxen, in PCa prevention, employing preclinical models of both TMPRSS2-ERG (fusion)-driven (with conditional deletion of Pten) and non-TMPRSS2-ERG-driven (Hi-Myc+/- mice) PCa. Male mice (n = 25 mice/group) were fed aspirin- (700 and 1400 ppm) and naproxen- (200 and 400 ppm) supplemented diets from (a) 6 weeks until 32 weeks of Hi-Myc+/- mice age; and (b) 1 week until 20 weeks post-Cre induction in the fusion model. In all NSAID-fed groups, compared to no-drug controls, there was a significant decrease in higher-grade adenocarcinoma incidence in the TMPRSS2-ERG (fusion)-driven PCa model. Notably, there were no moderately differentiated (MD) adenocarcinomas in the dorsolateral prostate of naproxen groups, and its incidence also decreased by ~79-91% in the aspirin cohorts. In contrast, NSAIDs showed little protective effect against prostate tumorigenesis in Hi-Myc+/- mice, suggesting that NSAIDs exert a specific protective effect against TMPRSS2-ERG (fusion)-driven PCa.

Abstract 5270: Silibinin modulates migration and survival pathways in bone marrow mast cells via RAC2: Implications in its anti-cancer activity in basal cell carcinoma growth and progression

Most of the non-melanoma skin cancers are basal cell carcinoma (BCC); thus, extensive efforts to discover chemopreventive agents against BCC are ongoing. Recently, we showed that silibinin (SB) exerts strong efficacy against ultraviolet B radiation (UVB)-induced BCC growth/progression, and mast cells (MCs) are one of the targets of its efficacy. Notably, 30 days of UVB exposure in patched (Ptch)+/- mouse model of UVB-induced BCC formation increased MC numbers by ~50% that was completely inhibited by SB. Hence, understanding pathways associated with MC regulation by SB seems valuable for its efficacy against BCC and other cancers. We generated bone marrow MCs (BMMCs) in presence of interleukin (IL)-3 and stem cell factor from C57BL/6 mice (confirmed using flow cytometry dual staining: cKit/Fc€RI). They were treated with two concentrations of SB (25 µM; SB 25 and 100 µM; SB 100) or untreated (control), and proteomics was performed (liquid chromatography mass spectrometry on Fusion Lumos mass spectrometer). Total 3575 proteins were identified and 166 were found to be statistically significant (ANOVA, Fisher’s posthoc analysis, p&lt;0.05, FDR&lt;0.01) amongst the three groups (n=4/group). Proteins with highest differential expression among the groups (greatest fold change expression; n=50), greatest contribution to the selection (variable importance; n=15), and common expression profiles in both SB 25 and SB 100 compared to control (n=21) were selected for further pathway analysis. Important nodes found for SB regulation of MCs were tumor necrosis factor, interferon-gamma, and IL-13; IL-13 also emerged as a key regulatory node in normal BMMCs. Furthermore, to determine the effect of SB in BCC associated MCs, a subset of proteins implicated with skin-associated MC activity (determined using IPA) was generated. Most important molecules implicated included IL-13 and Rac Family Small GTPase2 (RAC2; regulates all myeloid lineages). RAC2 was found to modulate the expression of mast cell protease4 (MCPT4), mast cell transcriptase1 (TPSAB1), and macrophage migration inhibition factor. RAC2 also activates MC proteases via JNK signaling cascade. Together, via the regulation of MCPT4, TPSAB1, and JNK signaling, RAC2 regulates inflammatory responses, and controls MC migration via actin cytoskeleton reorganization and lamellipodia formation. Phagosome maturation was also an important pathway implicated in our analysis; MCs lyse engulfed pathogens/debris via phagosome maturation and fusion with lysosomes. In conclusion, our findings demonstrate that SB increases RAC2 expression in BMMCs, which can regulate MC migration into the tumors and effectively increase the MC protease gene expression. Thus, SB treatment shifts BMMCs towards anti-tumorigenic pathways and RAC2 can be a novel therapeutic target in BCC and other cancers as well.

Citation Format: Neha Mishra, Sandeep Paudel, Chapla Agarwal, Rajesh Agarwal. Silibinin modulates migration and survival pathways in bone marrow mast cells via RAC2: Implications in its anti-cancer activity in basal cell carcinoma growth and progression. [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2023; Part 1 (Regular and Invited Abstracts); 2023 Apr 14-19; Orlando, FL. Philadelphia (PA): AACR; Cancer Res 2023;83(7_Suppl):Abstract nr 5270.

Fractional flow reserve versus angiography guided revascularization for patients with multivessel coronary artery disease: a systematic review and meta-analysis of randomized controlled trials

Background

Recently published randomized controlled trials (RCT) have questioned the utility of Fraction Flow Reserve (FFR) to guide revascularization in patients with multivessel coronary artery disease (CAD) as compared to Angiography

Purpose

This current analysis aimed to compare the clinical outcomes associated with FFR guided versus standard angiography-guided revascularization for patients with multivessel CAD using a large number of randomized patients with stable CAD and acute coronary syndrome (ACS)

Methods

We conducted an electronic database search of all published data for RCT that compared FFR versus Angiography for patients with multivessel CAD and reported on subsequent mortality, cardiac death, myocardial infarction, revascularization, and other outcomes of interest. Event rates were compared using a forest plot of odds ratios using a fixed-effects model assuming interstudy heterogeneity.

Results

Eleven RCT (n=6052; FFR = 3043, Angiography = 3027) were included in the final analysis. Mean follow-up period was 1.7 years. In our analysis, FFR guided revascularization as compared to angiography guided revascularization alone was not associated with any significant reduction in overall mortality (OR = 1.10, 95% CI = 0.83–1.47, P=0.47, I2=0), cardiac mortality (OR = 0.95, 95% CI = 0.63–1.45, P=0.42, I2=0), all revascularization (OR = 0.96, 95% CI = 0.80–1.14, P=0.17, I2=31%) or myocardial infarction (OR = 0.99, 95% CI = 0.79–1.23, P=0.33, I2=12%). There was also no difference between two groups in terms of major adverse cardiac or cerebrovascular event [MACCE] (OR = 1.13, 95% CI = 0.90–1.42, P=0.39, I2=5%), major adverse cardiac event [MACE] (OR = 0.86, 95% CI = 0.70–1.07, P=0.55, I2=0), stroke/TIA (OR = 1.61, 95% CI = 0.92–2.82, P=0.36, I2=8%) or target lesion revascularization [TLR] (OR = 0.86, 95% CI = 0.44–1.67, P=0.71, I2=0). Furthermore, sensitivity analysis was conducted to include only studies with ACS patients and studies which used CABG only for revascularization. However, there was no difference between the two groups for any of the above outcomes

Conclusion

There is no difference in clinical outcomes in patients undergoing FFR-guided versus angiography guided revascularization for multivessel CAD

Funding Acknowledgement

Type of funding sources: None.

Stage-Specific Effect of Inositol Hexaphosphate on Cancer Stem Cell Pool during Growth and Progression of Prostate Tumorigenesis in TRAMP Model

Herein, we assessed the stage-specific efficacy of inositol hexaphosphate (IP6, phytic acid), a bioactive food component, on prostate cancer (PCa) growth and progression in a transgenic mouse model of prostate cancer (TRAMP). Starting at 4, 12, 20, and 30 weeks of age, male TRAMP mice were fed either regular drinking water or 2% IP6 in water for ~8–15 weeks. Pathological assessments at study endpoint indicated that tumor grade is arrested at earlier stages by IP6 treatment; IP6 also prevented progression to more advanced forms of the disease (~55–70% decrease in moderately and poorly differentiated adenocarcinoma incidence was observed in advanced stage TRAMP cohorts). Next, we determined whether the protective effects of IP6 are mediated via its effect on the expansion of the cancer stem cells (CSCs) pool; results indicated that the anti-PCa effects of IP6 are associated with its potential to eradicate the PCa CSC pool in TRAMP prostate tumors. Furthermore, in vitro assays corroborated the above findings as IP6 decreased the % of floating PC-3 prostaspheres (self-renewal of CSCs) by ~90%. Together, these findings suggest the multifaceted chemopreventive-translational potential of IP6 intervention in suppressing the growth and progression of PCa and controlling this malignancy at an early stage.

Characterization of stage-specific tumor progression in TMPRSS2-ERG (fusion)-driven and non-fusion-driven prostate cancer in GEM models

In the present study, we performed a comparative stage-specific pathological and molecular marker evaluation of TMPRSS2-ERG fusion and PTEN loss-driven (TMPRSS2-ERG. Pten^flox/flox ) versus non-fusion-driven prostate tumorigenesis (Hi-Myc) in mice. Anterior, ventral, and dorsolateral prostates were collected from mice at different ages (or time points post-Cre induction). Results indicated that growth and progression of prostatic intraepithelial lesions to adenocarcinoma stages occurred in both mice models albeit at different rates. In the TMPRSS2-ERG. Pten^flox/flox mice, the initiation of tumorigenesis was slow, but subsequent progression through different stages became increasingly faster. Adenocarcinoma stage was reached early on; however, no high-grade undifferentiated tumors were observed. Conversely, in the Hi-Myc^+/- mice, tumorigenesis initiation was rapid; however, progression through different stages was relatively slower and it took a while to reach the more aggressive phenotype stage. Nevertheless, at the advanced stages in the Hi-Myc^+/- mice, high-grade undifferentiated tumors were observed compared to the later stage tumors observed in the fusion-driven TMPRSS2-ERG. Pten^flox/flox mice. These results were corroborated by the stage specific-pattern in the molecular expression of proliferation markers (PCNA and c-Myc); androgen receptor (AR); fusion-resultant overexpression of ERG; Prostein (SLC45-A3); and angiogenesis marker (CD-31). Importantly, there was a significant increase in immune cell infiltrations, which increased with the stage of tumorigenesis, in the TMPRSS2-ERG fusion-positive tumors relative to fusion negative tumors. Together, these findings are both novel and highly significant in establishing a working preclinical model for evaluating the efficacy of interventions during different stages of tumorigenesis in TMPRSS2-ERG fusion-driven PCa.

Abstract 716: Silibinin: A novel potential therapeutic agent against UVB-induced basal cell carcinoma

Herein, we report silibinin (a natural flavonolignan from milk thistle seeds) efficacy against basal cell carcinoma (BCC), the major non-melanoma skin cancer. To determine the preventive/therapeutic activity of silibinin on the progression of UVB-induced microscopic BCC lesions to more advanced BCC, both male and female 8 weeks old Ptch1+/- mice were irradiated with 240 mJ/cm2 UVB dose 3 times/week (M, W, F) for 26 weeks, and thereafter, UVB irradiation was stopped. At this point (after initial UVB exposure for 26 weeks was stopped), these Ptch1+/- mice were randomized into 3 groups: Baseline group (mice euthanized for baseline data); Vehicle group: mice treated topically with acetone for 20 more weeks, and Silibinin group: mice treated topically with silibinin (9 mg in 200 µL acetone), once a day for five days/week for 20 more weeks i.e., till 54 weeks of mice age. Assessment of BCC and non-BCC lesion pathology was performed following β-galactosidase and H&E based histopathological analysis. Results indicated that compared to BCC-associated pathologies observed at baseline, acetone exposure for another 20 weeks resulted in a significant increase in the number (~2 folds, P&lt;0.001) and area (~3.4 folds, P&lt;0.001) covered by BCC lesions. There was also a significant increase in epidermal dysplasia, fibrosarcoma, and squamous cell carcinoma incidence. Notably, topical application of silibinin during this phase significantly decreased BCC numbers as well as area covered by BCC lesions by ~76% (P&lt;0.001) and ~88% (P&lt;0.001), respectively. This protective effect of silibinin was associated with decreased proliferation of basal cells and decreased expression of Hh signaling molecules (Smo and Gli1). To further delineate the changes associated with silibinin’ s protective effect at the transcriptomic level, RNA sequencing studies were performed in skin samples from all three groups as well as non-UVB exposed control mice. Clustering of mRNA profile by sparse Partial Least Squares - Discriminant Analysis (sPLS-DA) showed that UVB exposed tissues (not treated with silibinin) were significantly different from non-UVB controls; most notably, silibinin treatment (after UVB exposure) reversed this phenomenon and the transcriptomic profile of silibinin group was almost similar to non-UVB controls. This indicated that topical silibinin was not only able to protect against progression to advanced BCC but had the potential to even normalize the aberrant gene expression driving BCC formation. In addition, Gene ontology enrichment analysis as well as Pathway enrichment analysis of differentially expressed genes showed silibinin-associated enrichment in the calcium and CX3CR1-mediated signaling pathway, and TGF-β-mediated regulation of the extracellular matrix. Taken together, these results highlight the potential of silibinin to be an effective preventive and/or therapeutic modality against BCC growth and progression.

Citation Format: Komal Raina, Sandeep Paudel, Neha Mishra, Sushil Kumar, David J. Orlicky, Zhiying You, Rama Kant, Chapla Agarwal, Rajesh Agarwal. Silibinin: A novel potential therapeutic agent against UVB-induced basal cell carcinoma [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2022; 2022 Apr 8-13. Philadelphia (PA): AACR; Cancer Res 2022;82(12_Suppl):Abstract nr 716.

Abstract 718: Significantly strong protective efficacy of silibinin against basal cell carcinoma growth and progression

Basal cell carcinoma (BCC) is the most common skin malignancy accounting for ∼80% of non-melanoma skin cancers (NMSCs). It arises in basal cells of skin that line the deepest layer of the epidermis. The most important risk factor for BCC is solar ultraviolet B (UVB) radiation that results in DNA damage (CPDs formation) in skin epidermis, which, if not repaired, leads to fixation of mutations and initiation of skin carcinogenesis. One of the key molecular features of BCC is sustained activation of Hedgehog signaling (Hh) pathway through inactivating mutations in tumor suppressor gene Patched (Ptch) or activating mutations in Smoothened (Smo). Therefore, extensive efforts have been made to target activated Hh pathway for the treatment of BCC, though with toxic side effects. With regards to chemoprevention of BCC, the agents which target the events associated with UVB-induced DNA damage repair, together with targeting promotion/progression stages, might provide more effective broad-spectrum opportunities to intervene at the earliest. Utilizing the well-established patched (Ptch)+/- mouse model of UVB radiation-induced BCC formation, our approach in this study was to target BCC development and its prevention by employing silibinin (a natural flavonolignan from milk thistle seeds). Previously, we have extensively reported the efficacy of silibinin against UVB-induced photodamage and photo-carcinogenesis, and also recently reported silibinin efficacy against BCC growth in cell culture (including anti-BCC drug-resistant cell lines) and mouse BCC allograft tumors. In this study, both male and female (Ptch)+/- mice were irradiated with 240 mJ/cm2 UVB dose, 3 times per week (M, W, F) for 26 and 46 weeks with or without silibinin. Silibinin (9 mg/200μl of acetone) was applied topically, 30 min post and pre-UVB exposure. Our study shows that chronic UVB exposure induced BCCs in Ptch+/- mice. Treatment with silibinin post and pre-UVB exposure for 26 weeks decreased BCC lesion numbers (39-65%), and cross-sectional area (45-72%) p&lt;0.001, respectively compared to UVB alone. Furthermore, continuous UVB exposure up to 46 weeks increased the BCC lesion number by ∼6 folds and cross-sectional area by ∼3.4 folds (p&lt;0.001) respectively. Notably, silibinin (irrespective of post and pre-UVB treatment) significantly halted the progression of BCC (81-94%, p&lt;0.001), even upon prolonged UVB exposure. Histological analysis showed increased dysplasia, fibro-sarcoma, and squamous cell carcinoma upon UVB exposure, which significantly decreased upon silibinin treatment. In addition, mechanistic studies revealed that silibinin significantly decreased basal cell proliferation (Ki-67) and the expression of cytokeratins (14 and 15), and Hh signaling mediators Smo and Gli1 in the BCC lesions. Together, our findings demonstrate that silibinin has the potential to prevent the growth and progression of UVB-induced BCC.

Citation Format: Sandeep Paudel, Komal Raina, Vasundhara R. Tiku, Akhilendra Maurya, David J. Orlicky, Zhiying You, Cindy M. Rigby, Gagan Deep, Rama Kant, Bupinder Raina, Chapla Agarwal, Rajesh Agarwal. Significantly strong protective efficacy of silibinin against basal cell carcinoma growth and progression [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2022; 2022 Apr 8-13. Philadelphia (PA): AACR; Cancer Res 2022;82(12_Suppl):Abstract nr 718.

Transcriptome and metabolome changes induced by bitter melon (Momordica charantia)- intake in a high-fat diet induced obesity model

Background and aim

Metabolic syndrome (MetS) is a complex disease of physiological imbalances interrelated to abnormal metabolic conditions, such as abdominal obesity, type II diabetes, dyslipidemia and hypertension. In the present pilot study, we investigated the nutraceutical bitter melon (Momordica charantia L) -intake induced transcriptome and metabolome changes and the converging metabolic signaling networks underpinning its inhibitory effects against MetS-associated risk factors.

Experimental procedure

Metabolic effects of lyophilized bitter melon juice (BMJ) extract (oral gavage 200 mg/kg/body weight-daily for 40 days) intake were evaluated in diet-induced obese C57BL/6J male mice [fed-high fat diet (HFD), 60 kcal% fat]. Changes in a) serum levels of biochemical parameters, b) gene expression in the hepatic transcriptome (microarray analysis using Affymetrix Mouse Exon 1.0 ST arrays), and c) metabolite abundance levels in lipid-phase plasma [liquid chromatography mass spectrometry (LC-MS)-based metabolomics] after BMJ intervention were assessed.

Results and conclusion

BMJ-mediated changes showed a positive trend towards enhanced glucose homeostasis, vitamin D metabolism and suppression of glycerophospholipid metabolism. In the liver, nuclear peroxisome proliferator-activated receptor (PPAR) and circadian rhythm signaling, as well as bile acid biosynthesis and glycogen metabolism targets were modulated by BMJ (p < 0.05). Thus, our in-depth transcriptomics and metabolomics analysis suggests that BMJ-intake lowers susceptibility to the onset of high-fat diet associated MetS risk factors partly through modulation of PPAR signaling and its downstream targets in circadian rhythm processes to prevent excessive lipogenesis, maintain glucose homeostasis and modify immune responses signaling.

Chemopreventive efficacy of silibinin against basal cell carcinoma growth and progression in UVB-irradiated Ptch+/- mice

The factors (environmental and genetic) contributing to basal cell carcinoma (BCC) pathogenesis are well-established; however, effective agents for BCC prevention are marred by toxic side-effects. Herein, we assessed the efficacy of flavonolignan silibinin against ultraviolet B (UVB)-induced BCC in Ptch+/- (heterozygous patched homolog 1 gene) mouse model. Both male and female Ptch+/- mice were irradiated with a 240 mJ/cm2 UVB dose 3 times/week for 26 or 46 weeks, with or without topical application of silibinin (9 mg/200 µl in acetone, applied 30 min before or after UVB exposure). Results indicated that silibinin application either pre- or post-UVB exposure for 26 weeks significantly decreased the number of BCC lesions by 65% and 39% (P < 0.001 for both) and the area covered by BCCs (72% and 45%, P < 0.001 for both), respectively, compared to UVB alone. Furthermore, continuous UVB exposure for 46 weeks increased the BCC lesion number and the BCC area covered by ~6 and ~3.4 folds (P < 0.001), respectively. Notably, even in this 46 week prolonged UVB exposure, silibinin (irrespective of pre- or post-UVB treatment) significantly halted the growth of BCCs by 81-94% (P < 0.001) as well as other epidermal lesions; specifically, silibinin treated tissues had less epidermal dysplasia, fibrosarcoma, and squamous cell carcinoma. Immunohistochemistry and immunofluorescence studies revealed that silibinin significantly decreased basal cell proliferation (Ki-67) and the expression of cytokeratins (14 and 15), and Hedgehog signaling mediators Smo and Gli1 in the BCC lesions. Together, our findings demonstrate strong potential of silibinin to be efficacious in preventing the growth and progression of UVB-induced BCC.

Effect of dexamethasone treatment at variable therapeutic windows in reversing nitrogen mustard-induced corneal injuries in rabbit ocular in vivo model

Nitrogen mustard (NM) is an analogue of the potent vesicating agent sulfur mustard, with well-established ocular injury models in rabbit eyes to study vesicant-induced ocular toxicity. The effects of NM-exposure to eyes may include irritation, redness, inflammation, fibrosis, epithelial degradation, blurred vision, partial/complete blindness, which may be temporary or permanent, depending on the route, duration, and dosage of exposure. Effective countermeasures against vesicant exposure are presently not available and are warranted in case of any terrorist activity or accidental leakage from stockpiles. Herein, our focus was to evaluate whether dexamethasone (DEX), an FDA approved potent corticosteroid with documented anti-inflammatory activities, could be an effective treatment modality. Accordingly, utilizing NM-induced corneal injuries in rabbit ocular in vivo model, we examined and compared the efficacy of DEX treatments when administration was started at early (2 h), intermediate (4 h), and late (6 h) therapeutic windows of intervention after NM-exposure and administered every 8 h thereafter. The effects of NM-exposure and DEX treatments were evaluated on clinical (corneal opacity, ulceration, and neovascularization), biological (epithelial thickness, epithelial-stromal separation, blood vessels density, and inflammatory cell and keratocyte counts) and molecular (COX-2 and VEGF expression) parameters, at day 1, 3, 7 and 14. Results indicated that DEX treatment markedly and effectively reversed the NM-induced injury markers in rabbit corneas. Early administration of DEX at 2 h was found to be most effective in reversing NM-induced corneal injuries, followed by DEX 4 h and DEX 6 h administration initiation, indicating that DEX has best efficacy at the early therapeutic window in our study model.

Comparative Pre-clinical Efficacy of Chinese and Indian Cultivars of Bitter Melon (Momordica charantia) against Pancreatic Cancer

Given the high rates of incidence and mortality associated with pancreatic cancer (PanC), there is a need to develop alternative strategies to target PanC. Recent studies have demonstrated that fruits of bitter melon (Momordica charantia) exhibit strong anticancer efficacy against PanC. However, the comparative effects of different bitter melon varieties have not been investigated. This has important implications, given that several bitter melon cultivars are geographically available but their differential effects are not known; and that on a global level, individuals could consume different bitter melon varieties sourced from different cultivars for anti-PanC benefits. Considering these shortcomings, in the present study, comparative pre-clinical anti-PanC studies have been conducted using lyophilized-juice and aqueous-methanolic extracts of the two most widely consumed but geographically diverse bitter melon varieties (Chinese [bitter melon juice; BMJ] and Indian [bitter melon extract; BME] variants). We observed that both BMJ and BME possess comparable efficacy against PanC growth and progression; specifically, these preparations have the potential to (a) inhibit PanC cell proliferation and induce cell death; (b) suppress PanC tumor growth, proliferation, and induce apoptosis; (c) restrict capillary tube formation by human umbilical vein endothelial cells, and decrease angiogenesis in PanC tumor xenografts. Thus, given the comparable pre-clinical anti-PanC efficacy of bitter melon cultivars, the geographical non-availability of a certain cultivar should not be a limiting factor in selecting a variant for moving forward for future clinical use/clinical trials either as a preventive or a therapeutic alternative for targeting PanC.

Pathophysiology and inflammatory biomarkers of sulfur mustard-induced corneal injury in rabbits

Sulfur mustard (SM) is a cytotoxic, vesicating, chemical warfare agent, first used in 1917; corneas are particularly vulnerable to SM exposure. They may develop inflammation, ulceration, neovascularization (NV), impaired vision, and partial/complete blindness depending upon the concentration of SM, exposure duration, and bio-physiological conditions of the eyes. Comprehensive in vivo studies have established ocular structural alterations, opacity, NV, and inflammation upon short durations (<4 min) of SM exposure. In this study, detailed analyses of histopathological alterations in corneal structure, keratocytes, inflammatory cells, blood vessels, and expressions of cyclooxygenase (COX)-2, matrix metalloproteinase (MMP)-9, vascular endothelial growth factor (VEGF), and cytokines were performed in New Zealand white rabbits, in a time-dependent manner till 28 days, post longer durations (5 and 7 min) of ocular SM exposure to establish quantifiable endpoints of injury and healing. Results indicated that SM exposure led to duration-dependent increases in corneal thickness, opacity, ulceration, epithelial-stromal separation, and epithelial degradation. Significant increases in NV, keratocyte death, blood vessels, and inflammatory markers (COX-2, MMP-9, VEGF, and interleukin-8) were also observed for both exposure durations compared to the controls. Collectively, these findings would benefit in temporal delineation of mechanisms underlying SM-induced corneal toxicity and provide models for testing therapeutic interventions.

Solid-phase synthesis of curcumin mimics and their anticancer activity against human pancreatic, prostate, and colorectal cancer cell lines

Curcumin is a bioactive natural compound with a wide range of pharmacological properties, including antitumor activity; however, its clinical application has been limited because of its low solubility, stability, and bioavailability. In this study, a solid phase approach was proposed for the combinatorial synthesis of a mini library of the mimics of curcumin in good purity and yield. The non-effective findings in pancreatic cancer cells switched to strong growth inhibition and cell death efficacy for PC3 prostate cancer cells, and mimic 9, in which tyrosol (TYR) and homovanillyl alcohol (HVA) units were linked by a phosphodiester bond, was quite effective not only in cell growth inhibition but also in causing strong cell death under the study conditions and treatments that were not effective in PANC1 cells. The results got more exciting when we also consider the findings in SW480 human colorectal carcinoma cell line, where the growth inhibitor effects were more in line with that of the PC3 cells, but the lack of cell death effect was more in line with the PANC1 cells.

Should COVID-19 patients >75 years be Ventilated? An Outcome Study

BACKGROUND

Elderly patients with COVID-19 disease are at increased risk for adverse outcomes. Current data regarding disease characteristics and outcomes in this population are limited.

AIM

To delineate the adverse factors associated with outcomes of COVID-19 patients ≥75 years of age.

DESIGN

Retrospective cohort study.

METHODS

Patients were classified into mild/moderate, severe/very severe and critical disease (intubated) based on oxygen requirements. The primary outcome was in-hospital mortality.

RESULTS

A total of 355 patients aged ≥75 years hospitalized with COVID-19 between 19 March and 25 April 2020 were included.Mean age was 84.3 years. One-third of the patients developed critical disease. Mean length of stay was 7.10 days. Vasopressors were required in 27%, with the highest frequency in the critical disease group (74.1%). Overall mortality was 57.2%, with a significant difference between severity groups (mild/moderate disease: 17.4%, severe/very severe disease: 71.3%, critical disease: 94.9%, P < 0.001).Increased age, dementia, and severe/very severe and critical disease groups were independently associated with increased odds for mortality while diarrhea was associated with decreased odds for mortality (OR: 0.12, 95% CI: 0.02-0.60, P < 0.05). None of the cardiovascular comorbidities were significantly associated with mortality.

CONCLUSION

Age and dementia are associated with increased odds for mortality in patients ≥75 years of age hospitalized with COVID-19. Those who require intubation have the greatest odds for mortality. Diarrhea as a presenting symptom was associated with lower odds for mortality.

Bitter melon juice intake with gemcitabine intervention circumvents resistance to gemcitabine in pancreatic patient-derived xenograft tumors

Chemoresistance to gemcitabine (GEM)-a frontline chemotherapeutic, resulting from its dysfunctional uptake and metabolism in cancer cells, is a major contributing factor for failed therapy in pancreatic cancer (PanC) patients. Therefore, there is an urgent need for agents that could reverse GEM resistance and allow continued chemosensitivity to the drug. We employed natural nontoxic agent (with anti-PanC potential) bitter melon juice (BMJ) and GEM to examine their combinatorial benefits against tumorigenesis of PanC patient-derived xenograft (PDX)-pancreatic ductal adenocarcinomas explants PDX272 (wild-type KRAS), PDX271 (mutant KRAS and SMAD4), and PDX266 (mutant KRAS). Anti-PanC efficacy of single agents vs combination in the three tumor explants, both at the end of active dosing regimen and following a drug-washout phase were compared. In animal studies, GEM alone treatment significantly inhibited PDX tumor growth, but effects were not sustained, as GEM-treated tumors exhibited regrowth posttreatment termination. However, combination-regimen displayed enhanced and sustained efficacy. Mechanistic assessments revealed that overcoming GEM resistance by coadministration with BMJ was possibly due to modulation of GEM transport/metabolism pathway molecules (ribonucleotide reductase regulatory subunit M1, human equilibrative nucleoside transporter 1, and deoxycytidine kinase). Study outcomes, highlighting significantly higher and sustained efficacy of GEM in combination with BMJ, make a compelling case for a clinical trial in PanC patients, wherein BMJ could be combined with GEM to target and overcome GEM resistance. In addition, given their specific effectiveness against KRAS-mutant tumors, this combination could be potentially beneficial to a broader PanC patient population.

Outcomes in patients with severe COVID-19 disease treated with tocilizumab: a case-controlled study

BACKGROUND

COVID-19 is an ongoing threat to society. Patients who develop the most severe forms of the disease have high mortality. The interleukin-6 inhibitor tocilizumab has the potential to improve outcomes in these patients by preventing the development of cytokine release storm.

AIMS

To evaluate the outcomes of patients with severe COVID-19 disease treated with the interleukin-6 inhibitor tocilizumab.

METHODS

We conducted a retrospective, case-control, single-center study in patients with severe to critical COVID-19 disease treated with tocilizumab. Disease severity was defined based on the amount of oxygen supplementation required. The primary endpoint was the overall mortality. Secondary endpoints were mortality in non-intubated patients and mortality in intubated patients.

RESULTS

A total of 193 patients were included in the study. Ninety-six patients received tocilizumab, while 97 served as the control group. The mean age was 60 years. Patients over 65 years represented 43% of the population. More patients in the tocilizumab group reported fever, cough and shortness of breath (83%, 80% and 96% vs. 73%, 69% and 71%, respectively). There was a non-statistically significant lower mortality in the treatment group (52% vs. 62.1%, P = 0.09). When excluding intubated patients, there was statistically significant lower mortality in patients treated with tocilizumab (6% vs. 27%, P = 0.024). Bacteremia was more common in the control group (24% vs. 13%, P = 0.43), while fungemia was similar for both (3% vs. 4%, P = 0.72).

CONCLUSION

Our study showed a non-statistically significant lower mortality in patients with severe to critical COVID-19 disease who received tocilizumab. When intubated patients were excluded, the use of tocilizumab was associated with lower mortality.

Toxic consequences and oxidative protein carbonylation from chloropicrin exposure in human corneal epithelial cells

Chloropicrin (CP), a warfare agent now majorly used as a soil pesticide, is a strong irritating and lacrimating compound with devastating toxic effects. To elucidate the mechanism of its ocular toxicity, toxic effects of CP (0-100 μM) were studied in primary human corneal epithelial (HCE) cells. CP exposure resulted in reduced HCE cell viability and increased apoptotic cell death with an up-regulation of cleaved caspase-3 and poly ADP ribose polymerase indicating their contribution in CP-induced apoptotic cell death. Following CP exposure, cells exhibited increased expression of heme oxygenase-1, and phosphorylation of H2A.X and p53 as well as 4-hydroxynonenal adduct formation, suggesting oxidative stress, DNA damage and lipid peroxidation. CP also caused increases in mitogen activated protein kinase-c-Jun N-terminal kinase and inflammatory mediator cyclooxygenase-2. Proteomic analysis revealed an increase in the carbonylation of 179 proteins and enrichment of pathways (including proteasome pathway and catabolic process) in HCE cells following CP exposure. CP-induced oxidative stress and lipid peroxidation can enhance protein carbonylation, prompting alterations in corneal epithelial proteins as well as perturbing signaling pathways resulting in toxic effects. Pathways and major processes identified following CP exposure could be lead-hit targets for further biochemical and molecular characterization as well as therapeutic intervention.

Exosomes secreted by prostate cancer cells under hypoxia promote matrix metalloproteinases activity at pre-metastatic niches

Approximately, 30 000 men die from prostate cancer (PCa) every year in the United States, mainly due to the metastasis. Thus, the key events associated with PCa metastasis are under rigorous investigation, with recent studies showing that preparation of pre-metastatic niches (PMN) in distant organs is an important step. However, the molecular basis for PMN preparation is still unclear. Hypoxia in primary tumors promotes aggressiveness; however, its precise role in metastasis is not clear. We recently reported that exosomes secreted by PCa cells under hypoxia promote stemness and invasiveness in naïve PCa cells; however, whether these extracellular vesicles also influence PMN remains unknown. In the present study, we isolated exosomes from human PCa PC3 cells under normoxic (21% O₂ , exosomes secreted under normoxic condition [Exo^Normoxic ]) and hypoxic (1% O₂ , exosomes secreted under hypoxic condition [Exo^Hypoxic ]) conditions, and characterized their effect (10 µg exosomes, intraperitoneal (IP) treatment every 48 hours for 4 weeks) on key biomarkers associated with PMN in nude mice. Whole animal fluorescence imaging showed that Exo^Hypoxic treatment promotes matrix metalloproteinases (MMPs) activity in several putative metastatic sites. Histological studies confirmed that Exo^Hypoxic treatment enhanced the level of MMP2, MMP9, and extracellular matrix proteins (fibronectin and collagen) as well as increased the number of CD11b+ cells at selective PMN sites. Furthermore, proteomic profiling of exosomes by liquid chromatography/mass spectrometry identified cargo proteins in Exo^Normoxic and Exo^Hypoxic as well as distinct canonical pathways targeted by them. These results suggest that exosomes secreted by PCa cells under hypoxia plausibly remodel distant PMN, and thus, could be a potential target to control metastatic PCa.

Bitter melon juice-intake modulates glucose metabolism and lactate efflux in tumors in its efficacy against pancreatic cancer

The established role of bitter melon juice (BMJ), a natural product, in activating master metabolic regulator adenosine monophosphate-activated protein kinase in pancreatic cancer (PanC) cells served as a basis for pursuing deeper investigation into the underlying metabolic alterations leading to BMJ efficacy in PanC. We investigated the comparative metabolic profiles of PanC cells with differential KRAS mutational status on BMJ exposure. Specifically, we employed nuclear magnetic resonance (NMR) metabolomics and in vivo imaging platforms to understand the relevance of altered metabolism in PanC management by BMJ. Multinuclear NMR metabolomics was performed, as a function of time, post-BMJ treatment followed by partial least square discriminant analysis assessments on the quantitative metabolic data sets to visualize the treatment group clustering; altered glucose uptake, lactate export and energy state were identified as the key components responsible for cell death induction. We next employed PANC1 xenograft model for assessing in vivo BMJ efficacy against PanC. Positron emission tomography ([18FDG]-PET) and magnetic resonance imaging on PANC1 tumor-bearing animals reiterated the in vitro results, with BMJ-associated significant changes in tumor volumes, tumor cellularity and glucose uptake. Additional studies in BMJ-treated PanC cells and xenografts displayed a strong decrease in the expression of glucose and lactate transporters GLUT1 and MCT4, respectively, supporting their role in metabolic changes by BMJ. Collectively, these results highlight BMJ-induced modification in PanC metabolomics phenotype and establish primarily lactate efflux and glucose metabolism, specifically GLUT1 and MCT4 transporters, as the potential metabolic targets underlying BMJ efficacy in PanC.

Abstract 5088: Silibinin inhibits UVB-induced promotion and progression of microscopic basal cell carcinoma formation via targeting bone morphogenic protein 2

Non-melanoma skin cancers (NMSCs) account for about half of all malignancies diagnosed annually in the United States. Around 80% of NMSCs are basal cell carcinoma (BCC) and 20% are squamous cell carcinoma (SCC). Whereas the efficacy of several chemopreventive agents has been examined and reported against both BCC and SCC, a majority of these studies have focused on the test agent’s activity in a long-term setting to determine the amount of tumors formed. Notably, the studies evaluating the efficacy of chemopreventive agents during early stage/s of BCC development are lacking. Accordingly, utilizing the well-established patched (Ptch)+/- mouse model of UVB-induced BCC formation, we excised skin samples from UVB exposed mice prior to tumor formation to study the promotion/progression of BCC and to determine the target/s of silibinin, a well-known skin cancer (SCC) chemopreventive agent, in tumor growth inhibition. Ptch+/- and Ptch+/+ mice were irradiated with UVB 240mJ/cm2 3 times per week with or without topically applied silibinin 5 times per week. As early as one month, we found that UVB exposure significantly increased the number of mast cells in Ptch+/- mice by about 48% (P&lt;0.05), which was completely inhibited (to control levels) by silibinin topical treatments. In Ptch+/+ mice, which do not develop BCC tumors, we did not observe any increase in mast cells following UVB exposure, suggesting this could be a specific pathway in the development of BCC. To decipher the molecular mechanism of these findings, we performed a PCR profiler array analysis of several genes involved in signal transduction pathways which showed strong differences between Ptch+/+ and Ptch+/- mice that were unexposed, UVB irradiated, and silibinin treated. Most notably, following UVB exposure for 1 month, in Ptch+/- mice the expression of Bone morphogenetic protein 2 (BMP-2), Hairy/enhancer-of-split related with YRPW motif 1 (Hey1), and Inhibitor of DNA binding 1 (Id1) was significantly upregulated when compared to Ptch+/+ mice. Additional studies focusing on BMP-2 found that silibinin strongly inhibits UVB-induced expression of BMP-2 in Ptch+/- mouse skin. Consistent with these results, we also found that silibinin strongly attenuates UVB-induced BMP-2 expression and DNA damage in Ptch+/- mouse skin ex vivo. Regarding BCC formation, silibinin treatment inhibited UVB-induced microscopic BCC formation in Ptch+/- mice; microscopic tumor number and size were reduced by 73% and 84%, respectively. Together, our results suggest a possible role of BMP-2 in early stages of BCC development and that silibinin plausibly acts through BMP-2 to inhibit microscopic BCC formation. In conclusion, our previous studies in SCC models and current findings in BCC model suggest that silibinin could be a multi-target agent capable of being a chemopreventive agent for both types of NMSCs.

Citation Format: Cynthia M. Rigby, Gagan Deep, Anil K. Jain, David J. Orlicky, Chapla Agarwal, Komal Raina, Rajesh Agarwal. Silibinin inhibits UVB-induced promotion and progression of microscopic basal cell carcinoma formation via targeting bone morphogenic protein 2 [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2019; 2019 Mar 29-Apr 3; Atlanta, GA. Philadelphia (PA): AACR; Cancer Res 2019;79(13 Suppl):Abstract nr 5088.

Abstract 2123: A combinatorial approach using gemcitabine and bitter melon juice overcomes drug resistance impacting gemcitabine uptake and metabolism

Pancreatic cancer (PanC) has the lowest 5-year survival rate (&lt;3%) of all cancer types and is projected to be the second leading cause of cancer-associated mortalities by the year 2030 in the United States. Surgery alone fails to suffice in a majority of cases; the disease relapses in 70-80% of patients and is fatal without additional therapy. Currently, of all the available treatment modalities for PanC, gemcitabine (GEM) is the standard of care frontline drug, with a moderate success rate in improving the median overall PanC patient survival by about 5.7-6.8 months. Although a modest improvement is achieved using a combination therapy approach, the patient survival still remains less than 12 months, and includes a poor quality of life due to the extensive side effects. Moreover, chemoresistance to GEM is a major contributing factor for PanC patient’ morbidity and mortality resulting from dysfunctional uptake and metabolism of GEM in cancer cells. Therefore, there is an urgent need for agents that could reverse GEM resistance and allow continued chemosensitivity in PanC. Here, we employed natural agent bitter melon juice (BMJ) and GEM to examine their anticancer potential alone and in combination in PanC patient derived xenograft (PDX) - pancreatic ductal adenocarcinomas explants in nude mice. Comparing single agents versus combination in three explants PDX272, PDX261, and PDX266, both at the end of the active dosing regimen as well as following a post treatment-washout period (no drug administration) revealed enhanced efficacy of the combination treatment over failed GEM-in the post treatment termination cohort. Extensive mechanistic assessments revealed that overcoming GEM resistance was possibly due to modulation of GEM metabolism pathway molecules by the BMJ administration. While all drug exposures led to a decreased RRM1 expression during treatments in PanC-explants, at the end of treatment washout period explants displayed increased RRM1 levels in GEM-only group but a sustained decrease in BMJ and Combo groups. Investigation into hENT1 (human equilibrative nucleoside transporter 1) expression, responsible for bidirectional GEM trafficking, revealed that at the end of washout period, combination therapy was the only group that continued to express high levels of hENT1 for all three explants, whereas GEM only group showed poor hENT1 expression. Furthermore, analysis for deoxycytidine kinase (dCK), the enzyme responsible for GEM metabolism, revealed that the combination group had the most augmented dCK expression levels by study end. Taken together, the study outcomes highlight the efficacy of BMJ in combination with GEM in modifying and regulating multiple key players in GEM uptake and metabolism. These conclusions make a compelling case for future clinical investigations in PanC patients wherein BMJ is combined with GEM to target and overcome GEM resistance.

Citation Format: Deepanshi Dhar, Dileep Kumar, Komal Raina, David J. Orlicky, Chapla Agarwal, Rajesh Agarwal. A combinatorial approach using gemcitabine and bitter melon juice overcomes drug resistance impacting gemcitabine uptake and metabolism [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2019; 2019 Mar 29-Apr 3; Atlanta, GA. Philadelphia (PA): AACR; Cancer Res 2019;79(13 Suppl):Abstract nr 2123.

Abstract 5078: Modulation of glucose metabolism and lactate efflux in tumors by bitter melon juice in its efficacy against pancreatic cancer

Pancreatic cancer (PanC) is currently ranked as the fourth leading cause of cancer-related deaths across the United States. The dismal statistics for the year 2018 estimates about 55,440 new incidences and 44,330 PanC-associated fatalities in men and women combined, with a 5-year survival rate of less than 10%. PanCs possess a very intricately designed metabolic profile favoring excess aerobic glycolysis in addition to altered glutamine metabolism, contributing to tumor cell proliferation and PanC progression. Targeting metabolic phenotype in PanC with natural/diet-derived agents has immense scope for better non-toxic intervention, improved overall survival and quality of life; the major concerns with the use of frontline PanC chemotherapeutics. Herein, we utilized bitter melon juice (BMJ), a natural agent, which we recently reported to possess anticancer potential via targeting PanC stem cell and bulk cell populations and exerting a role in elevating drug sensitivity of gemcitabine resistant PanC cells. The established role of BMJ in activating master metabolic regulator APMK in PanC cells served as a basis for pursuing deeper investigation into the underlying metabolic alterations leading to BMJ efficacy in PanC. We investigated the comparative metabolic profiles of PanC cells with differential KRAS mutational status (PANC1 - mutated KRAS and BxPC3 -; wild type KRAS), on BMJ exposure. Specifically, we employed Nuclear magnetic resonance (NMR) metabolomics and in vivo imaging platforms to assess whether BMJ modulates PanC cell metabolome, together with establishing the molecular metabolomic targets to better understand the relevance of altered metabolism in PanC management by BMJ. Multinuclear NMR metabolomics was performed post 72 hours of BMJ treatment followed by PLS-DA (partial least square discriminant analysis) assessments on the quantitative metabolic data sets to visualize the treatment group clustering; altered glucose uptake, lactate export and energy state were identified as the key components responsible for cell death induction. We next employed PANC1 xenograft model for assessing in vivo BMJ efficacy against PanC. Positron Emission Tomography ([18FDG]-PET) and Magnetic Resonance Imaging (MRI) on PANC1 tumor-bearing animals reiterated the in vitro results, with BMJ-associated significant changes in tumor volumes, tumor cellularity and glucose uptake. Additional studies in BMJ-treated PanC cells and xenografts displayed a strong decrease in the expression of glucose and lactate transporters GLUT1 and MCT4, respectively, supporting their role in metabolic changes by BMJ. Collectively, these results highlight BMJ-induced modification in PanC metabolomics phenotype and establish primarily lactate efflux and glucose metabolism, specifically GLUT1 and MCT4 transporters, as the potential metabolic targets underlying BMJ efficacy in PanC.

Citation Format: Deepanshi Dhar, Rama Kant, Komal Raina, Michael F. Wempe, Natalie J. Serkova, Chapla Agarwal, Rajesh Agarwal. Modulation of glucose metabolism and lactate efflux in tumors by bitter melon juice in its efficacy against pancreatic cancer [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2019; 2019 Mar 29-Apr 3; Atlanta, GA. Philadelphia (PA): AACR; Cancer Res 2019;79(13 Suppl):Abstract nr 5078.

Silibinin inhibits ultraviolet B radiation-induced mast cells recruitment and bone morphogenetic protein 2 expression in the skin at early stages in Ptch(+/-) mouse model of basal cell carcinoma

Around 80% of nonmelanoma skin cancers (NMSCs) are basal cell carcinoma (BCC), still studies evaluating the efficacy of chemopreventive agents during early stage/s of BCC development are lacking. Accordingly, utilizing the well-established patched (Ptch)+/- mouse model of ultraviolet B (UVB) radiation-induced BCC formation, we excised skin samples from UVB exposed Ptch+/- and Ptch+/+ mice before tumor formation to study the promotion/progression of BCC and to determine the efficacy and target/s of silibinin, a well-known skin cancer chemopreventive agent. UVB exposure for 1 month increased the number of mast cells in Ptch+/- mice by ~48% (P < 0.05), which was completely inhibited by silibinin. Polymerase chain reaction profiler array analysis of skin samples showed strong molecular differences between Ptch+/+ and Ptch+/- mice which were either unexposed or UVB irradiated+/- silibinin treatment. Most notably, silibinin treatment significant decreased the expression of BMP-2, Bbc3, PUMA, and Ccnd1 in Ptch+/- mice irradiated with silibinin + UVB. Additional studies showed that silibinin targets UVB-induced expression of bone morphogenetic protein 2 (BMP-2) in Ptch+/- mouse skin. Last, our studies found that silibinin strongly attenuates UVB-induced BMP-2 expression and DNA damage in Ptch+/- mouse skin ex vivo only after single UVB exposure. Together, our results suggest a possible role of mast cell recruitment and BMP-2 activation in the early stages of BCC development; these are strongly inhibited by silibinin suggesting its possible chemopreventive efficacy against BCC formation in long-term UVB exposure regimen.

Differential effect of grape seed extract and its active constituent procyanidin B2 3,3″-di-O-gallate against prostate cancer stem cells

The present study aimed to determine whether grape seed extract (GSE) procyanidin mix, and its active constituent procyanidin B2 3,3″-di-O-gallate (B2G2) have the potential to target cancer stem cells (CSCs) in prostate cancer (PCa). The CSC populations were isolated and purified based on CD44⁺ -α2β1^high surface markers in PCa cell lines LNCaP, C4-2B, 22Rv1, PC3, and DU145, and then subjected to prostasphere formation assays in the absence or presence of GSE or B2G2. Results indicated that at lower doses (<15 μg) , the GSE procyanidin mix produced activity in unsorted prostate cancer antigen (PCA) cells, but not in sorted; however, multiple treatments with low dose GSE over a course of time inhibited sphere formation by sorted PCA CSCs. Importantly, B2G2 demonstrated significant potential to target both unsorted and sorted CSCs at lower doses. As formation of spheroids, under specific in vitro conditions, is a measure of stemness, these results indicated the potential of both GSE and B2G2 to target the self-renewal of CSC in PCa cell lines, though B2G2 was more potent in its efficacy. Subsequent mechanistic studies revealed that both GSE procyanidins and B2G2 strongly decreased the constitutive as well as Jagged1 (Notch1 ligand)-induced activated Notch1 pathway. In totality, these in vitro studies warrant extensive dose-profiling-based assessments in vivo settings to conclusively determine the impact on CSC pool kinetics on the efficacy of both GSE and B2G2 to target PCa growth as well as tumor relapse.

Identical and Nonidentical Twins: Risk and Factors Involved in Development of Islet Autoimmunity and Type 1 Diabetes

OBJECTIVE

There are variable reports of risk of concordance for progression to islet autoantibodies and type 1 diabetes in identical twins after one twin is diagnosed. We examined development of positive autoantibodies and type 1 diabetes and the effects of genetic factors and common environment on autoantibody positivity in identical twins, nonidentical twins, and full siblings.

RESEARCH DESIGN AND METHODS

Subjects from the TrialNet Pathway to Prevention Study (N = 48,026) were screened from 2004 to 2015 for islet autoantibodies (GAD antibody [GADA], insulinoma-associated antigen 2 [IA-2A], and autoantibodies against insulin [IAA]). Of these subjects, 17,226 (157 identical twins, 283 nonidentical twins, and 16,786 full siblings) were followed for autoantibody positivity or type 1 diabetes for a median of 2.1 years.

RESULTS

At screening, identical twins were more likely to have positive GADA, IA-2A, and IAA than nonidentical twins or full siblings (all P < 0.0001). Younger age, male sex, and genetic factors were significant factors for expression of IA-2A, IAA, one or more positive autoantibodies, and two or more positive autoantibodies (all P ≤ 0.03). Initially autoantibody-positive identical twins had a 69% risk of diabetes by 3 years compared with 1.5% for initially autoantibody-negative identical twins. In nonidentical twins, type 1 diabetes risk by 3 years was 72% for initially multiple autoantibody-positive, 13% for single autoantibody-positive, and 0% for initially autoantibody-negative nonidentical twins. Full siblings had a 3-year type 1 diabetes risk of 47% for multiple autoantibody-positive, 12% for single autoantibody-positive, and 0.5% for initially autoantibody-negative subjects.

CONCLUSIONS

Risk of type 1 diabetes at 3 years is high for initially multiple and single autoantibody-positive identical twins and multiple autoantibody-positive nonidentical twins. Genetic predisposition, age, and male sex are significant risk factors for development of positive autoantibodies in twins.

Exosome proteomic analyses identify inflammatory phenotype and novel biomarkers in African American prostate cancer patients

African American men face a stark prostate cancer (PCa)-related health disparity, with the highest incidence and mortality rates compared to other races. Additional and innovative measures are warranted to reduce this health disparity. Here, we focused on the identification of a novel serum exosome-based "protein signature" for potential use in the early detection and better prognosis of PCa in African American men. Nanoparticle tracking analyses showed that compared to healthy individuals, exosome concentration (number/ml) was increased by ~3.2-fold (P ˂ 0.05) in the sera of African American men with PCa. Mass spectrometry-based proteomic analysis of serum exosomes identified seven unique and fifty-five overlapping proteins (up- or downregulated) in African Americans with PCa compared to healthy African Americans. Furthermore, ingenuity pathway analyses identified the inflammatory acute-phase response signaling as the top pathway associated with proteins loaded in exosomes from African American PCa patients. Interestingly, African American PCa E006AA-hT cells secreted exosomes strongly induced a proinflammatory M2-phenotype in macrophages and showed calcium response on sensory neurons, suggesting a neuroinflammatory response. Additionally, proteomic analyses showed that the protein Isoform 2 of Filamin A has higher loading (2.6-fold) in exosomes from African Americans with PCa, but a lesser loading (0.6-fold) was observed in exosomes from Caucasian men with PCa compared to race-matched healthy individuals. Interestingly, TCGA and Taylor's dataset as well as IHC analyses of PCa tissue showed a lower Filamin A expression in tissues of PCa patients compared with normal subjects. Overall, these results support the usefulness of serum exosomes to noninvasively detect inflammatory phenotype and to discover novel biomarkers associated with PCa in African American men.

Bitter melon juice exerts its efficacy against pancreatic cancer via targeting both bulk and cancer stem cells

Pancreatic cancer (PanC) is one of the deadliest malignancies worldwide and frontline treatment with gemcitabine becomes eventually ineffective due to increasing PanC resistance, suggesting additional approaches are needed to manage PanC. Recently, we have shown the efficacy of bitter melon juice (BMJ) against PanC cells, including those resistant to gemcitabine. As cancer stem cells (CSCs) are actively involved in PanC initiation, progression, relapse and drug-resistance, here we assessed BMJ ability in targeting pancreatic cancer-associated cancer stem cells (PanC-CSCs). We found BMJ efficacy against CD44+ /CD24+ /EpCAMhigh enriched PanC-CSCs in spheroid assays; BMJ also increased the sensitivity of gemcitabine-resistant PanC-CSCs. Exogenous addition of BMJ to PanC-CSC generated spheroids (not pre-exposed to BMJ) also significantly reduced spheroid number and size. Mechanistically, BMJ effects were associated with a decrease in the expression of genes and proteins involved in PanC-CSC renewal and proliferation. Specifically, immunofluorescence staining showed that BMJ decreases protein expression/nuclear localization of CSC-associated transcription factors SOX2, OCT4 and NANOG, and CSC marker CD44. Immunohistochemical analysis of MiaPaCa2 xenografts from BMJ treated animals also showed a significant decrease in the levels of CSC-associated transcription factors. Together, these results show BMJ potential in targeting PanC-CSC pool and associated regulatory pathways, suggesting the need for further investigation of its efficacy against PanC growth and progression including gemcitabine-resistant PanC.

A Type 1 Diabetes Genetic Risk Score Predicts Progression of Islet Autoimmunity and Development of Type 1 Diabetes in Individuals at Risk

OBJECTIVE

We tested the ability of a type 1 diabetes (T1D) genetic risk score (GRS) to predict progression of islet autoimmunity and T1D in at-risk individuals.

RESEARCH DESIGN AND METHODS

We studied the 1,244 TrialNet Pathway to Prevention study participants (T1D patients' relatives without diabetes and with one or more positive autoantibodies) who were genotyped with Illumina ImmunoChip (median [range] age at initial autoantibody determination 11.1 years [1.2-51.8], 48% male, 80.5% non-Hispanic white, median follow-up 5.4 years). Of 291 participants with a single positive autoantibody at screening, 157 converted to multiple autoantibody positivity and 55 developed diabetes. Of 953 participants with multiple positive autoantibodies at screening, 419 developed diabetes. We calculated the T1D GRS from 30 T1D-associated single nucleotide polymorphisms. We used multivariable Cox regression models, time-dependent receiver operating characteristic curves, and area under the curve (AUC) measures to evaluate prognostic utility of T1D GRS, age, sex, Diabetes Prevention Trial-Type 1 (DPT-1) Risk Score, positive autoantibody number or type, HLA DR3/DR4-DQ8 status, and race/ethnicity. We used recursive partitioning analyses to identify cut points in continuous variables.

RESULTS

Higher T1D GRS significantly increased the rate of progression to T1D adjusting for DPT-1 Risk Score, age, number of positive autoantibodies, sex, and ethnicity (hazard ratio [HR] 1.29 for a 0.05 increase, 95% CI 1.06-1.6; P = 0.011). Progression to T1D was best predicted by a combined model with GRS, number of positive autoantibodies, DPT-1 Risk Score, and age (7-year time-integrated AUC = 0.79, 5-year AUC = 0.73). Higher GRS was significantly associated with increased progression rate from single to multiple positive autoantibodies after adjusting for age, autoantibody type, ethnicity, and sex (HR 2.27 for GRS >0.295, 95% CI 1.47-3.51; P = 0.0002).

CONCLUSIONS

The T1D GRS independently predicts progression to T1D and improves prediction along T1D stages in autoantibody-positive relatives.

A novel approach to target hypoxic cancer cells via combining β-oxidation inhibitor etomoxir with radiation

Background

Hypoxia in tumors is associated with resistance towards various therapies including radiotherapy. In this study, we assessed if hypoxia in cancer spheres could be effectively reduced by adding etomoxir (a β-oxidation inhibitor) immediately after cell irradiation.

Methods

We employed cancer cells’ sphere model to target hypoxia. Confocal imaging was used to analyze hypoxia and expression of specific biomarkers in spheres following various treatments (radiation and/or etomoxir).

Results

Etomoxir (32.5 μM) treatment improved the radiation (2.5 Gy) efficacy against growth of lung adenocarcinoma H460 spheres. More importantly, radiation and etomoxir combination significantly reduced the hypoxic regions (pimonidazole+ areas) in H460 spheres compared to either treatment alone. Also, etomoxir and radiation combination treatment reduced the protein level of biomarkers for proliferation (Ki-67 and cyclin D1), stemness (CD44) and β-oxidation (CPT1A) in H460 spheres. We observed similar efficacy of etomoxir against growth of prostate cancer LNCaP cells’ spheres when combined with radiation. Further, radiation treatment strongly reduced the hypoxic regions (pimonidazole+ areas) in CPT1 knockdown LNCaP cells’ spheres.

Conclusions

Together, these results offer a unique approach to target hypoxia in solid tumors via combining etomoxir with radiation, thereby improving therapeutic efficacy.

Nintedanib inhibits growth of human prostate carcinoma cells by modulating both cell cycle and angiogenesis regulators

Prostate cancer (PCa) is the most common malignancy and second leading cause of cancer-related deaths in American men. Proliferating cells have higher need for nutrients and oxygen, triggering angiogenesis that plays a critical role in tumor growth, progression and metastasis. Consequently, immense focus has converged onto inhibitors of angiogenesis in cancer treatment, such as Nintedanib, which has shown exceptional antitumor activity via inhibiting cell proliferation and the resulting tumor growth, primarily due to its combined action on tumor cells, endothelial cells and pericytes. Accordingly, here we assessed both in vitro and in vivo efficacy of Nintedanib in PCa. The results showed that Nintedanib decreased cell viability in both androgen dependent- and -independent PCa cells, together with a decrease in cell motility and invasiveness. Nintedanib also reduced the expression of significant genes responsible for cell cycle progression. PCa PC3 xenograft-carrying nude mice treated with Nintedanib showed significantly decreased tumor volume and cell proliferation alongside diminished levels of pro-angiogenic molecules and blood vessel densities. In conclusion, we report that Nintedanib has strong efficacy against PCa in pre-clinical models via modulation of various pathways, and that it could be employed as a promising new strategy to manage PCa clinically.

Exosomal microRNA profiling to identify hypoxia-related biomarkers in prostate cancer

Hypoxia and expression of hypoxia-related biomarkers are associated with disease progression and treatment failure in prostate cancer (PCa). We have reported that exosomes (nanovesicles of 30-150 nm in diameter) secreted by human PCa cells under hypoxia promote invasiveness and stemness in naïve PCa cells. Here, we identified the unique microRNAs (miRNAs) loaded in exosomes secreted by PCa cells under hypoxia. Using TaqMan^® array microRNA cards, we analyzed the miRNA profile in exosomes secreted by human PCa LNCaP cells under hypoxic (Exo^Hypoxic) and normoxic (Exo^Normoxic) conditions. We identified 292 miRNAs loaded in both Exo^Hypoxic and Exo^Normoxic. The top 11 miRNAs with significantly higher level in Exo^Hypoxic compared to Exo^Normoxic were miR-517a, miR-204, miR-885, miR-143, miR-335, miR-127, miR-542, miR-433, miR-451, miR-92a and miR-181a; and top nine miRNA with significantly lower expression level in Exo^Hypoxic compared to Exo^Normoxic were miR-521, miR-27a, miR-324, miR-579, miR-502, miR-222, miR-135b, miR-146a and miR-491. Importantly, the two differentially expressed miRNAs miR-885 (increased expression) and miR-521 (decreased expression) showed similar expression pattern in exosomes isolated from the serum of PCa patients compared to healthy individuals. Additionally, miR-204 and miR-222 displayed correlated expression patterns in prostate tumors (Pearson R = 0.66, p < 0.0001) by The Cancer Genome Atlas (TCGA) prostate adenocarcinoma (PRAD) genomic dataset analysis. Overall, the present study identified unique miRNAs with differential expression in exosomes secreted from hypoxic PCa cells and suggests their potential usefulness as a biomarker of hypoxia in PCa patients.

Abstract B32: Translational potential of a small-molecule silibinin in colorectal cancer: Targeting cancer stem cells and their inflammatory niche

The inflammatory milieu of colon cancer stem cell (CSC) niche is also an important growth regulator for both CSC and progenitor cell population. Inflammatory signals, e.g., cytokines arising in CSC niche, due to inflammatory cells in microenvironment, also network with other regulatory pathways to influence the expansion of both cell types. With this background, we aimed to assess whether silibinin, a nontoxic, naturally occurring chemopreventive agent with established preclinical efficacy against growth and progression of colorectal cancer (CRC), has the potential to target colon CSC and associated inflammatory niche during CRC inhibition. Our results found that silibinin strongly decreases the percentage of colonosphere formation (a stem cell characteristic) of CRC cells, and that this effect on colon CSC is mediated via blocking IL-4/6 signaling in CRC cell lines. Silibinin also strongly decreased IL-4/6 induced activation of STAT-3 and NF-kB transcriptional activity, which is associated with decreased mRNA levels of various CSC regulatory molecules, and CSC-associated markers. In other studies, silibinin significantly reduced the booster signals of macrophages towards colon CSC, resulting in decreased colonosphere numbers under both normoxic and hypoxic conditions. Furthermore, we used a colitis-related AOM/DSS-induced colon tumorigenesis model to assess the role of inflammatory conditions on colon CSC generation and expansion, and their modulation by silibinin. Our data indicated the protective effect of oral silibinin feeding in this model in terms of an absence of large macroadenomas (&gt;2-3 mm) in the colon. This effect was accompanied by minimal colonic inflammation (decrease in recruitment of inflammatory cells); tissue analysis indicated a decrease in the expression of proinflammatory cytokines, and associated transcription factors: STAT-3 and NF-kB in the colonic tissues from silibinin group. A decrease in transformed stem cell population (for CSC pool expansion) was also identified by dual staining for BMI-1 and CD44 in the colonic tissues. Together, these results highlight silibinin's potential to interfere with CSC pool expansion by targeting both colon CSC and their inflammatory niche, as well as associated signals involved with the survival and multiplication of colon CSC pool. These findings further support the translational potential and clinical usefulness of silibinin in CRC intervention and therapy. (Supported by R01 CA112304.)

Citation Format: Rajesh Agarwal, Chapla Agarwal. Translational potential of a small-molecule silibinin in colorectal cancer: Targeting cancer stem cells and their inflammatory niche [abstract]. In: Proceedings of the AACR International Conference held in cooperation with the Latin American Cooperative Oncology Group (LACOG) on Translational Cancer Medicine; May 4-6, 2017; São Paulo, Brazil. Philadelphia (PA): AACR; Clin Cancer Res 2018;24(1_Suppl):Abstract nr B32.

Procyanidin B2 3,3″-di-O-gallate induces oxidative stress-mediated cell death in prostate cancer cells via inhibiting MAP kinase phosphatase activity and activating ERK1/2 and AMPK

Neoplastic cells exhibit higher oxidative stress compared to normal cells; however, antioxidants based clinical trials have mostly failed. Another attractive therapeutic approach is to further increase the oxidative stress in cancer cells leading to cell death. Herein, we show that Procyanidin B2 3,3″-di-O-gallate (B2G2), the most active constituent of grape seed extract, treatment causes cell death in human prostate cancer (PCa) cells (LNCaP and 22Rv1) via increasing the reactive oxygen species (ROS) generation. Mechanistically, B2G2 treatment decreased the mitochondrial electron transport chain complex III activity leading to enhanced mitochondrial superoxide generation and decreased ATP production in LNCaP cells. Additional molecular studies revealed that B2G2-induced cell death was mediated mainly through ROS-induced sustained activation of ERK1/2, which was due to inhibition of MAP kinase phosphatase (MKP) activity as over-expression of MKP3 in LNCaP cells conferred significant protection against B2G2-induced cell death. Along with ERK1/2, AMP-activated protein kinase α (AMPKα) was also activated by B2G2 treatment, and pre-treatment with AMPKα inhibitor compound C significantly reversed the cytotoxic effects of B2G2 in LNCaP cells. Furthermore, pre-treatment of MKP3 over-expressing LNCaP cells with compound C further reduced the B2G2-induced cell death, suggesting the involvement of AMPKα along with MKP3 and ERK1/2 in the biological effects of B2G2. Together, these results for the first time identified that oxidative stress and MKP3 inhibition play a critical role in B2G2-induced cell death in PCa cells through sustained activation of both ERK1/2 and AMPKα. These results offer a unique opportunity to control this deadly malignancy through B2G2 use.

Abstract 1249: Procyanidin B2-3,3′-di-O-gallate targets cancer cell metabolism in its efficacy against human prostate carcinoma cells

The metabolic profile of various cancerous tissues can be correlated with cell growth and death, specific tumor type as well as the pathological stage of tumor. In recent times, prostatic tissue metabolomics using spectroscopy methods has helped to identify and establish the metabolic profiles specific to prostate cancer (PCa) malignancy. Thus, the evaluation of the anticancer efficacy of an agent can be considered incomplete without assessing its effect on the metabolic profile of the tumor tissue. With this rationale, herein, we carried out a metabolomics study on human PCa cell lines after procyanidin B2-3,3′-di-O-gallate (B2G2) exposure, which was recently identified by us as most effective agent in grape seed extract for growth inhibition and apoptotic death of human PCa cells. Specifically, we employed quantitative high-resolution nuclear magnetic resonance spectroscopy (1H-, 13C- and 31P-NMR) to assess the metabolic profile and energy state of the B2G2-treated human PCa cell lines PC3 and C42B. This approach helped us assess global metabolic profile, including glucose metabolism, energy state, and lipid metabolism in these cells after B2G2 treatment. We also studied the time-course (4-72 hrs) of B2G2 effect on glucose uptake and lactate release in the media of B2G2-treated PCa cells. Our results indicated that there was differential effect of B2G2 on mitochondrial glucose metabolism in these cells. While glucose uptake was markedly reduced as a function of time, there was also a significant decrease in extracellular lactate export with increased B2G2 exposure-time. Importantly, B2G2 preserved citrate concentration in the PCa cells as indicated by an increase in citrate levels after treatments; citrate generation is indicative of normal secretion functions of the prostate epithelial cells. The fact that the citrate was not further utilized for cholesterol synthesis was also confirmed by a decrease in cholesterol levels in these cells, indicating decreased cholesterogenesis by B2G2. Together, these results suggest that B2G2 differentially induces metabolic alterations in various PCa cell lines, which could be associated with its effects on cell growth, proliferation and death, as well as androgen dependency (or lack of it). In in vivo study examining B2G2 effect on PCa PC3 tumor xenograft growth in athymic nu/nu mice, B2G2 treatment (dose: 5mg/kg body weight of mice; given daily as intraperitoneal injections) significantly decreased tumor volume and tumor weight by ∼61% and ∼52% (both P≤ 0.01), respectively, after 5 weeks of treatments. Taken together, these studies indicate anti-PCa efficacy of B2G2 under both in vitro and in vivo scenario and warrant further extensive studies to establish its efficacy in other PCa models.

Citation Format: Chapla Agarwal, Dileep Kumar, Alpna Tyagi, Natalie Serkova, Michael Wempe, Komal Raina, Rajesh Agarwal. Procyanidin B2-3,3′-di-O-gallate targets cancer cell metabolism in its efficacy against human prostate carcinoma cells [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2017; 2017 Apr 1-5; Washington, DC. Philadelphia (PA): AACR; Cancer Res 2017;77(13 Suppl):Abstract nr 1249. doi:10.1158/1538-7445.AM2017-1249

Abstract 1268: Bitter melon efficacy against human pancreatic cancer cells: possible involvement of cellular stemness and metabolome targets

Pancreatic cancer (PanC) has a dismal 5-year survival rate of &lt; 5%. Symptomless progression, late diagnosis and rising drug resistance to leading chemotherapeutic agents like gemcitabine, add to PanC severity. Hence, there is a critical requirement for identifying alternative novel non-toxic agents (dietary/non-dietary) aimed at effective management of PanC with minimal patient distress. Bitter melon (Momordica charantia), a dietary agent, is actively being investigated for its anti-cancer potential against a variety of malignancies, including our work in PanC. Recent studies by us have shown bitter melon juice (BMJ) efficacy against a panel of human PanC cell lines in culture and tumor xenografts. For mechanistic studies, here we evaluated the efficacy of BMJ against cancer stem cells (CSCs) pool in PanC cells. Results indicated that BMJ treatment (0.25-2% v/v) significantly decreased CSC enriched (CD44+CD24+EpCAMhigh) PanC cell population. Successive immunofluorescence/ immunohistochemical analysis of BMJ exposed cells, spheroids and MiaPaCa2 xenograft tumors showed a significant reduction in CSC markers/ regulatory molecules. Since cancer cell metabolism is an important component to be targeted to control cancer growth and progression, we next assessed BMJ efficacy in that direction. Indeed, BMJ mediated its anti-PanC effect via activating the key metabolic regulator AMPK. Concomitantly, to determine whether BMJ-effects were nutrient/energy stress dependent, we next sought to determine the cellular energy profile and major metabolic changes induced by BMJ. PanC cell metabolome analysis was done, as a function of time, to determine the shift in PanC cell metabolism on BMJ exposure. 1H-, 13C- and 31P-NMR spectra of PanC cell monolayers treated with BMJ (2% v/v) at early ( 4h) and late (72h) time points showed significantly altered energy status and modulation of major metabolic pathways involved in PanC cell growth and proliferation. A significant reduction in glucose uptake and cellular energy levels (ATP/ADP) ratio was observed, but lactate export was increased. BMJ also modulated nucleotides and aromatic amino acids involved in protein precursors/synthesis for PanC growth and proliferation. Total fatty acids and phosphatidylcholine levels (a precursor of membrane lipids) were also downregulated by BMJ. Glutamine and glutamate levels were constrained by BMJ, indicating that it could potentially limit PanC cell ability for targeting an alternative energy source. Furthermore, the cellular levels and membrane localization of GLUT1 (major glucose transporter overexpressed in PanC) were also suppressed after BMJ treatment. Collectively, these results suggest that BMJ targets PanC CSCs and cellular metabolism in its efficacy against this deadly malignancy (supported by CA195708).

Citation Format: Deepanshi Dhar, Gagan Deep, Sushil Kumar, Chapla Agarwal, Natalie Serkova, Michael Wempe, Komal Raina, Rajesh Agarwal. Bitter melon efficacy against human pancreatic cancer cells: possible involvement of cellular stemness and metabolome targets [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2017; 2017 Apr 1-5; Washington, DC. Philadelphia (PA): AACR; Cancer Res 2017;77(13 Suppl):Abstract nr 1268. doi:10.1158/1538-7445.AM2017-1268

Silibinin Treatment Inhibits the Growth of Hedgehog Inhibitor-Resistant Basal Cell Carcinoma Cells via Targeting EGFR-MAPK-Akt and Hedgehog Signaling

Basal cell carcinoma (BCC) is the most common skin malignancy. Deregulated hedgehog signaling plays a central role in BCC development; therefore, hedgehog inhibitors have been approved to treat locally advanced or metastatic BCC. However, the development of resistance to hedgehog inhibitors is the major challenge in effective treatment of this disease. Herein, we evaluated the efficacy of a natural agent silibinin to overcome resistance with hedgehog inhibitors (Sant-1 and GDC-0449) in BCC cells. Silibinin (25-100 μm) treatment for 48 h strongly inhibited growth and induced death in ASZ001, Sant-1-resistant (ASZ001-Sant-1) and GDC-0449-resistant (ASZ001-GDC-0449) BCC cells. Furthermore, colony-forming ability of ASZ001, ASZ001-Sant-1 and ASZ001-GDC-0449 cells was completely inhibited by silibinin treatment. Molecular analysis showed that silibinin treatment decreased the level of phosphorylated EGFR (Tyrosine 1173) and total EGFR in ASZ001-Sant-1 cells, key signaling molecules responsible for BCC resistance toward hedgehog inhibitors. Further, silibinin treatment decreased the phosphorylated Akt (Serine 473), phosphorylated ERK1/2 (Threonine 202/Tyrosine 204), cyclin D1 and Gli-1 level but increased the SUFU expression in ASZ001-Sant-1-resistant cells. Silibinin treatment of ASZ001-Sant-1-resistant cells also decreased bcl-2 but increased cleaved caspase 3 and PARP cleavage, suggesting induction of apoptosis. Together, these results support silibinin use to target hedgehog inhibitor-resistant BCC cells.

Role of p53 in silibinin-mediated inhibition of ultraviolet B radiation-induced DNA damage, inflammation and skin carcinogenesis

Non-melanoma skin cancers (NMSC) are a growing problem given that solar ultraviolet B (UVB) radiation exposure is increasing most likely due to depletion of the atmospheric ozone layer and lack of adequate sun protection. Better preventive methods are urgently required to reduce UV-caused photodamage and NMSC incidence. Earlier, we have reported that silibinin treatment activates p53 and reduces photodamage and NMSC, both in vitro and in vivo; but whether silibinin exerts its protective effects primarily through p53 remains unknown. To address this question, we generated p53 heterozygous (p53^+/-) and p53 knockout (p53^-/-) mice on SKH-1 hairless mouse background, and assessed silibinin efficacy in both short- and long-term UVB exposure experiments. In the chronic UVB-exposed skin tumorigenesis study, compared to p53^+/+ mice, p53^+/- mice developed skin tumors earlier and had higher tumor number, multiplicity and volume. Silibinin topical treatment significantly reduced the tumor number, multiplicity and volume in p53^+/+ mice but silibinin' protective efficacy was significantly compromised in p53^+/- mice. Additionally, silibinin treatment failed to inhibit precursor skin cancer lesions in p53^-/- mice but improved the survival of the mice. In short-term studies, silibinin application accelerated the removal of UVB-induced DNA damage in p53^+/+ mice while its efficacy was partially compromised in p53^-/- mice. Interestingly, silibinin treatment also inhibited the UVB-induced inflammatory markers in skin tissue. These results further confirmed that absence of the p53 allele predisposes mice to photodamage and photocarcinogenesis, and established that silibinin mediates its protection against UVB-induced photodamage, inflammation and photocarcinogenesis partly through p53 activation.

Silibinin enhances the repair of ultraviolet B-induced DNA damage by activating p53-dependent nucleotide excision repair mechanism in human dermal fibroblasts

Ultraviolet radiation B (UVB) is the main cause of DNA damage in epidermal cells; and if not repaired, this DNA damage leads to skin cancer. In earlier studies, we have reported that natural flavonolignan silibinin exerts strong chemopreventive efficacy against UVB-induced skin damage and carcinogenesis; however mechanistic studies are still being actively pursued. Here, we investigated the role of nucleotide excision repair (NER) pathway in silibinin's efficacy to repair UVB-induced DNA damage. Normal human dermal fibroblasts (NHDFs) were exposed to UVB (1 mJ/cm²) with pre- or post- silibinin (100 μM) treatment, and cyclobutane pyrimidine dimers (CPDs) formation/repair was measured. Results showed that post-UVB silibinin treatment accelerates DNA repair via activating the NER pathway including the expression of XPA (xeroderma pigmentosum complementation group A), XPB, XPC, and XPG. In UVB exposed fibroblasts, silibinin treatment also increased p53 and GADD45α expression; the key regulators of the NER pathway and DNA repair. Consistently, post-UVB silibinin treatment increased the mRNA transcripts of XPA and GADD45α. Importantly, silibinin showed no effect on UVB-induced DNA damage repair in XPA- and XPB-deficient human dermal fibroblasts suggesting their key role in silibinin-mediated DNA damage repair. Moreover, in the presence of pifithrin-α, an inhibitor of p53, the DNA repair efficacy of silibinin was compromised associated with a reduction in XPA and GADD45α transcripts. Together, these findings suggest that silibinin's efficacy against UVB-induced photodamage is primarily by inhibiting NER and p53; and these findings further support silibinin's usage as a potential inexpensive, effective, and non-toxic agent for skin cancer chemoprevention.

Silibinin inhibits hypoxia-induced HIF-1α-mediated signaling, angiogenesis and lipogenesis in prostate cancer cells: In vitro evidence and in vivo functional imaging and metabolomics

Hypoxia is associated with aggressive phenotype and poor prognosis in prostate cancer (PCa) patients suggesting that PCa growth and progression could be controlled via targeting hypoxia-induced signaling and biological effects. Here, we analyzed silibinin (a natural flavonoid) efficacy to target cell growth, angiogenesis, and metabolic changes in human PCa, LNCaP, and 22Rv1 cells under hypoxic condition. Silibinin treatment inhibited the proliferation, clonogenicity, and endothelial cells tube formation by hypoxic (1% O₂ ) PCa cells. Interestingly, hypoxia promoted a lipogenic phenotype in PCa cells via activating acetyl-Co A carboxylase (ACC) and fatty acid synthase (FASN) that was inhibited by silibinin treatment. Importantly, silibinin treatment strongly decreased hypoxia-induced HIF-1α expression in PCa cells together with a strong reduction in hypoxia-induced NADPH oxidase (NOX) activity. HIF-1α overexpression in LNCaP cells significantly increased the lipid accumulation and NOX activity; however, silibinin treatment reduced HIF-1α expression, lipid levels, clonogenicity, and NOX activity even in HIF-1α overexpressing LNCaP cells. In vivo, silibinin feeding (200 mg/kg body weight) to male nude mice with 22Rv1 tumors, specifically inhibited tumor vascularity (measured by dynamic contrast-enhanced MRI) resulting in tumor growth inhibition without directly inducing necrosis (as revealed by diffusion-weighted MRI). Silibinin feeding did not significantly affect tumor glucose uptake measured by FDG-PET; however, reduced the lipid synthesis measured by quantitative ¹ H-NMR metabolomics. IHC analyses of tumor tissues confirmed that silibinin feeding decreased proliferation and angiogenesis as well as reduced HIF-1α, FASN, and ACC levels. Together, these findings further support silibinin usefulness against PCa through inhibiting hypoxia-induced signaling. © 2016 Wiley Periodicals, Inc.

Hypoxia induces triglycerides accumulation in prostate cancer cells and extracellular vesicles supporting growth and invasiveness following reoxygenation

Hypoxia is an independent prognostic indicator of poor outcome in several malignancies. However, precise mechanism through which hypoxia promotes disease aggressiveness is still unclear. Here, we report that under hypoxia (1% O₂), human prostate cancer (PCA) cells, and extracellular vesicles (EVs) released by these cells, are significantly enriched in triglycerides due to the activation of lipogenesis-related enzymes and signaling molecules. This is likely a survival response to hypoxic stress as accumulated lipids could support growth following reoxygenation. Consistent with this, significantly higher proliferation was observed in hypoxic PCA cells following reoxygenation associated with rapid use of accumulated lipids. Importantly, lipid utilization inhibition by CPT1 inhibitor etomoxir and shRNA-mediated CPT1-knockdown significantly compromised hypoxic PCA cell proliferation following reoxygenation. Furthermore, COX2 inhibitor celecoxib strongly reduced growth and invasiveness following hypoxic PCA cells reoxygenation, and inhibited invasiveness induced by hypoxic PCA EVs. This establishes a role for COX2 enzymatic products in the enhanced PCA growth and invasiveness. Importantly, concentration and loading of EVs secreted by PCA cells were significantly compromised under delipidized serum condition and by lipogenesis inhibitors (fatostatin and silibinin). Overall, present study highlights the biological significance of lipid accumulation in hypoxic PCA cells and its therapeutic relevance in PCA.

Abstract 5236: Bitter melon juice causes strong efficacy towards pancreatic cancer stem cells by modulating the hedgehog signaling pathway

According to ACS estimates for year 2015, ∼48,960 new cases of pancreatic cancer (PanC) would be diagnosed with 40,560 associated deaths in the US alone. The median life of PanC patients post diagnosis is &lt;6 months and overall 5 year survival is 3-5%. Thus, there is an urgent need for newer strategies to improve the disease outcome in these patients. Recently, considerable efforts have been directed towards natural dietary/non-dietary agents for both prevention/intervention of PanC. One such dietary agent, bitter melon (Momordica charantia) from Cucurbitaceae family, is now being extensively evaluated for its efficacy against various malignancies including PanC. Recently, we have shown significant growth inhibitory effects of bitter melon juice (BMJ) against a panel of PanC cells including Mia PaCa-2 xenograft tumors. Our studies also showed BMJ activity against both gemcitabine (frontline chemotherapeutic in PanC patients) sensitive as well as resistant PanC cell lines. Since the presence of cancer stem cells (CSC) is now recognized as the main cause for initiation, promotion and drug-resistance as well as relapse of most of the cancers, including PanC, there is a possibility that BMJ was affecting the CSC population in the PanC cells. Accordingly, the present study was aimed to determine whether BMJ has the potential to target CSC in PanC. We isolated CSC enriched (CD44+CD24+EpCAMhigh) cell population from the PanC cell lines, MiaPaCa2, PANC1 and AsPC1 and subjected them as well as the unsorted cells to sphere cluster formation assays in the presence or absence (single vs. multiple time treatment) of BMJ (0.25-2% v/v). The% of floating spheroids generated in the sphere cluster assays after 1-2 weeks were determined. The results indicated a dose-dependent effect of BMJ on both number and size (volume) of spheres, with 2% BMJ showing a significant reduction in both number and size of generated spheres in all PanC cell lines; single treatment of BMJ was found to be equally effective as multiple dosing regimens. Since formation of spheroids under specific in vitro conditions is a measure of stemness, our results show that BMJ has the potential to target the self-renewal of CSCs in PanC cell lines. Subsequent studies employing real time RT-PCR and immunofluorescence showed BMJ effect to be mediated in part by a significant down regulation in the expression of CSC marker CD44, CD133, and hedgehog (Hh)-pathway members in PanC cell lines. Further studies found that BMJ also decreases the protein levels of Hh-pathway members SHH and SMO in MiaPaCa2 xenograft tumors. Together, these are significant findings as they clearly show that BMJ interferes with the kinetics of CSC pool expansion via targeting various regulatory signals associated with the survival and multiplication of CSC pool leading to effective anti-cancer efficacy against PanC cells and their resistant phenotypes.

Citation Format: Rajesh Agarwal, Deepanshi Dhar, Chapla Agarwal, Gagan Deep. Bitter melon juice causes strong efficacy towards pancreatic cancer stem cells by modulating the hedgehog signaling pathway. [abstract]. In: Proceedings of the 107th Annual Meeting of the American Association for Cancer Research; 2016 Apr 16-20; New Orleans, LA. Philadelphia (PA): AACR; Cancer Res 2016;76(14 Suppl):Abstract nr 5236.