The IL6/JAK/STAT3 signaling axis is a therapeutic vulnerability in SMARCB1-deficient bladder cancer

SMARCB1 loss has long been observed in many solid tumors. However, there is a need to elucidate targetable pathways driving growth and metastasis in SMARCB1-deficient tumors. Here, we demonstrate that SMARCB1 deficiency, defined as genomic SMARCB1 copy number loss associated with reduced mRNA, drives disease progression in patients with bladder cancer by engaging STAT3. SMARCB1 loss increases the chromatin accessibility of the STAT3 locus in vitro. Orthotopically implanted SMARCB1 knockout (KO) cell lines exhibit increased tumor growth and metastasis. SMARCB1-deficient tumors show an increased IL6/JAK/STAT3 signaling axis in in vivo models and patients. Furthermore, a pSTAT3 selective inhibitor, TTI-101, reduces tumor growth in SMARCB1 KO orthotopic cell line-derived xenografts and a SMARCB1-deficient patient derived xenograft model. We have identified a gene signature generated from SMARCB1 KO tumors that predicts SMARCB1 deficiency in patients. Overall, these findings support the clinical evaluation of STAT3 inhibitors for the treatment of SMARCB1-deficient bladder cancer.

Dimethylarginine Dimethylaminohydrolase - 1 expression is increased under tBHP-induced oxidative stress regulates nitric oxide production in PCa cells attenuates mitochondrial ROS-mediated apoptosis

Dimethylarginine dimethylaminohydrolase-1 (DDAH1) expression is frequently elevated in different cancers including prostate cancer (PCa) and enhances nitric oxide (NO) production in tumor cells by metabolising endogenous nitric oxide synthase (NOS) inhibitors. DDAH1 protects the PCa cells from cell death and promotes survival. In this study, we have investigated the cytoprotective role of DDAH1 and determined the mechanism of DDAH1 in protecting the cells in tumor microenvironment. Proteomic analysis of PCa cells with stable overexpression of DDAH1 has identified that oxidative stress-related activity is altered. Oxidative stress promotes cancer cell proliferation, survival and causes chemoresistance. A known inducer of oxidative stress, tert-Butyl Hydroperoxide (tBHP) treatment to PCa cells led to elevated DDAH1 level that is actively involved in protecting the PCa cells from oxidative stress induced cell damage. In PC3-DDAH1- cells, tBHP treatment led to higher mROS levels indicating that the loss of DDAH1 increases the oxidative stress and eventually leads to cell death. Under oxidative stress, nuclear Nrf2 controlled by SIRT1 positively regulates DDAH1 expression in PC3 cells. In PC3-DDAH1+ cells, tBHP induced DNA damage is well tolerated compared to wild-type cells while PC3-DDAH1- became sensitive to tBHP. In PC3 cells, tBHPexposure has increased the production of NO and GSH which may be acting as an antioxidant defence to overcome oxidative stress. Furthermore, in tBHP treated PCa cells, DDAH1 is controlling the expression of Bcl2, active PARP and caspase 3. Taken together, these results confirm that DDAH1 is involved in the antioxidant defence system and promotes cell survival.

Abstract 2379: Gender-specific metabolome in bladder cancer: Role of EPHX2 in bladder cancer

Bladder cancer (BLCA) is the fourth most common cancer diagnosed in American men. In the U.S., men are four times more likely to be diagnosed with bladder cancer than women. Our research group has previously identified alterations in xenobiotic metabolism in BLCA. In this study, using a metabolomics approach, we identified alterations in the arachidonic acid pathway in bladder tumors from male versus female patients. Included within this altered arachidonic acid pathway was downregulation of EPHX2, an enzyme that converts epoxyeicosatrienoic acids (EETs) to dihydroxyeicosatrienoic acids (DiHETs). Consistent with this, levels of EETs were significantly elevated in bladder tumors derived from male versus female patients. Cox proportional hazard regression analysis further revealed that reduced expression of EPHX2 was significantly associated with poor clinical outcome across multiple publicly available datasets only in male BLCA patients but not in females. Mechanistic studies revealed that EPHX2 over-expression in male-derived BLCA cell line reduced cell growth in vitro and tumor growth in vivo. Overall, these studies nominate EPHX2 as a potential tumor suppressor in male patients with BLCA.

Citation Format: Mohammed Khurshidul Hassan, Roshan Borkar, Karthik Reddy Kami Reddy, Danthasinghe Waduge Badrajee Piyarathna, Chandra Shekar Amara, Allison Bellman, ChandraShekar R. Ambati, Vasanta Putluri, Abu Hena Mostafa Kamal, Roni J. Bollag, Martha K. Terris, Leomar Y. Ballester, Yair Lotan, Cristian Coarfa, Arun Sreekumar, Nagireddy Putluri. Gender-specific metabolome in bladder cancer: Role of EPHX2 in bladder cancer [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 2379.

Abstract 3771: Mitochondrial metabolism and racial disparity of bladder cancer

Potential differences and mechanism in metabolism among bladder cancer (BLCA) patients of diverse race or ethnicities remain largely unexplored. Even though the incidence rate of BLCA in African Americans (AA) is nearly half as that of European Americans (EA), but AA have the worst survival. We performed the transcriptomics and metabolomics profiling in ancestry verified patients from AA and EA BLCA and observed mitochondrial complex activities were uniquely enriched in AA tumors compared to EA tumors. In addition, in vitro assay demonstrated differences in mitochondrial complex protein and activity between AA and EA BLCA. We further confirmed the reprogramming of mitochondrial metabolism using in vitro 13C labeled tracers in both AA and EA BLCA. Integration of metabolomics and transcriptomics data reveals the enrichment of mTOR pathway in AA BLCA. Our findings indicate that an elevated mitochondrial oxphos activity through mTOR activation could be a factor for AA BLCA progression and provide the rationale to examine mitochondrial specific inhibitors along with mTOR inhibitors to target BLCA on subset of patients from the AA community.

Citation Format: Karthik Reddy Kami Reddy, Jun Hyoung Park, Roni J. Bollag, Allison Bellman, Martha Terris, Seth P. Lerner, Leomar Y. Ballester, Yair Lotan, Benny Abraham Kaipparettu, Nagireddy Putluri. Mitochondrial metabolism and racial disparity of bladder cancer [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 3771.

Lipidomic Profiling Identifies a Novel Lipid Signature Associated with Ethnicity-Specific Disparity of Bladder Cancer

Bladder Cancer (BLCA) is the ninth most frequently diagnosed cancer globally and the sixth most common cancer in the US. African Americans (AA) exhibit half the BLCA incidence compared to European Americans (EA), but they have a 70% higher risk of cancer-related death; unfortunately, this disparity in BLCA mortality remains poorly understood. In this study, we have used an ethnicity-balanced cohort for unbiased lipidomics profiling to study the changes in the lipid fingerprint for AA and EA BLCA tissues collected from similar geographical regions to determine a signature of ethnic-specific alterations. We identified 86 lipids significantly altered between self-reported AA and EA BLCA patients from Augusta University (AU) cohort. The majority of altered lipids belong to phosphatidylcholines (PCs), phosphatidylethanolamines (PEs), ly sophosphatidylcholines (lysoPCs), phosphatidylserines (PSs), and diglycerides (DGs). Interestingly, levels of four lysoPCs (lyso PCs 20:3, lyso PCs 22:1, lyso PCs 22:2, and lyso PCs 26:1) were elevated while, in contrast, the majority of the PCs were reduced in AA BLCA. Significant alterations in long-chain monounsaturated (MonoUN) and polyunsaturated (PolyUN) lipids were also observed between AA and EA BLCA tumor tissues. These first-in-field results implicate ethnic-specific lipid alterations in BLCA.

Restoration of the molecular clock is tumor suppressive in neuroblastoma

MYCN activation is a hallmark of advanced neuroblastoma (NB) and a known master regulator of metabolic reprogramming, favoring NB adaptation to its microenvironment. We found that the expression of the main regulators of the molecular clock loops is profoundly disrupted in MYCN-amplified NB patients, and this disruption independently predicts poor clinical outcome. MYCN induces the expression of clock repressors and downregulates the one of clock activators by directly binding to their promoters. Ultimately, MYCN attenuates the molecular clock by suppressing BMAL1 expression and oscillation, thereby promoting cell survival. Reestablishment of the activity of the clock activator RORα via its genetic overexpression and its stimulation through the agonist SR1078, restores BMAL1 expression and oscillation, effectively blocks MYCN-mediated tumor growth and de novo lipogenesis, and sensitizes NB tumors to conventional chemotherapy. In conclusion, reactivation of RORα could serve as a therapeutic strategy for MYCN-amplified NBs by blocking the dysregulation of molecular clock and cell metabolism mediated by MYCN.

Tumor protein D52 (isoform 3) interacts with and promotes peroxidase activity of Peroxiredoxin 1 in prostate cancer cells implicated in cell growth and migration

Tumor protein D52 (TPD52) is overexpressed in multiple cancers including prostate cancer due to gene amplification and investigations to understand its role in the pathophysiology of different cancers are continuing. GST pull-down assays and Tandem affinity purification of TPD52 as bait identified novel prey Peroxiredoxin 1 (PRDX1) in prostate cancer (PCa) cells. PRDX1 interaction with TPD52 was confirmed in immunoprecipitation and affinity interaction assays. Mapping of interaction domain indicated that PRDX1 interacts with C-terminal region of TPD52 containing PEST domain between 152 and 179 amino acids, a new binding region of TPD52. Here we show that TPD52 interaction with PRDX1 increased its peroxidase activity and ectopic expression of TPD52 induced dimerization of PRDX1 in PCa cells. Moreover, H₂O₂ exposure evoked the interaction between TPD52 and PRDX1 while depletion of both proteins led to the accumulation of H₂O₂ suggesting peroxidase activity is important to maintain oxidative capacity in PCa cells. We also observed that overexpression or downregulation of TPD52 and PRDX1 individually or together affecting PCa cells growth, survival, and migration. Altogether, our results show a novel interaction partner of TPD52 providing new insights of its functions and ascertain the role of TPD52-PRDX1 interaction in PCa progression.

Novel Cellularly Active Inhibitor Regresses DDAH1 Induced Prostate Tumor Growth by Restraining Tumor Angiogenesis through Targeting DDAH1/ADMA/NOS Pathway

Dimethylarginine dimethylaminohydrolase1 (DDAH1) inhibitors are important therapeutics by virtue of their ability to control nitric oxide (NO) production by elevating asymmetric dimethylarginine (ADMA) levels. In a screening campaign, we identified that DD1E5 (3-amino-6- tert-butyl-N-(1,3-thiazol-2-yl)-4-(trifluoromethyl)thieno[2,3- b]pyridine-2- carboxamide) inhibits the DDAH1 activity both in vitro and in cultured cells. Mechanistic studies found that DD1E5 is a competitive inhibitor (dissociation constant ( K_i) of 2.05 ± 0.15 μM). Enzyme kinetic assays showed time and concentration dependent inhibition of DDAH1 with DD1E5, which shows tight binding with an inactivation rate constant of 0.2756 ± 0.015 M^-1 S^-1. Treatment of cancer cells with DDAH1 inhibitors shows inhibition of cell proliferation and a subsequent decrease in NO production with ADMA accumulation. DD1E5 reversed the elevated VEGF, c-Myc, HIF-1α, and iNOS levels induced by exogenous DDAH1 overexpression in PCa cells. Moreover, DD1E5 significantly increased intracellular levels of ADMA and reduced NO production, suggesting its therapeutic potential for cancers in which DDAH1 is upregulated. In in vitro assays, DD1E5 abrogated the secretion of angiogenic factors (bFGF and IL-8) into conditional media, indicating its antiangiogenic potential. DD1E5 inhibited in vivo growth of xenograft tumors derived from PCa cells with DDAH1 overexpression, by reducing tumor endothelial content represented with low CD31 expression. VEGF, HIF-1α, and iNOS expression were reversed in DD1E5 treated tumors compared to respective control tumors. In this work, integrating multiple approaches shows DD1E5 is a promising tool for the study of methylarginine-mediated NO control and a potential therapeutic lead compound against pathological conditions with elevated NO production such as cancers and other diseases.

Interleukin-6 induced overexpression of valosin-containing protein (VCP)/p97 is associated with androgen-independent prostate cancer (AIPC) progression

Though Androgen deprivation therapy (ADT) is effective initially, numerous patients become resistant to it and develop castration resistant PCa (CRPC). Cytokines promotes ligand independent activation of AR. Interleukin-6 (IL-6) levels are elevated in CRPC patients and regulate AR activity. However, progression to CRPC is not fully understood. In this study, we analyzed differential protein expression in LNCaP cells treated with IL-6 using proteomics. Results revealed altered expression of 27 proteins and Valosin-containing protein (VCP)/p97 plays a predominant role in co-regulation of altered proteins. Interestingly, IL-6 induced VCP expression through Pim-1 via STAT3 is AR independent there by suggesting a role for VCP in CRPC. Transfection of LNCaP cells for VCP overexpression showed an increased cell proliferation, migration, and invasion where as its inhibition by NMS-873 showed the reverse effect causing cell death. Mechanistic studies demonstrate that cell death occurs due to apoptosis by endoplasmic reticulum (ER) stress, elevated cell cycle inhibitors p21, p27kip1, and active PARP and reduced Bcl-2. VCP promotes cell invasion and migration by altering E-cadherin and Vimentin levels inversely triggering EMT of PCa cells. VCP immunostaining revealed no staining in BPH but strong staining in PCa. This study determines VCP may play an important role in progression to CRPC and it can be a favorable target with to develop new therapies to treat ADT resistant prostate cancer.

All-Trans-Retinoic Acid Stimulates Overexpression of Tumor Protein D52 (TPD52, Isoform 3) and Neuronal Differentiation of IMR-32 Cells

Tumor protein D52 (TPD52), a proto-oncogene is overexpressed in a variety of epithelial carcinomas and plays an important role in cell proliferation, migration, and cell death. In the present study we found that the treatment of IMR-32 neuroblastoma (NB) cells with retinoic acid (RA) stimulates an increase in expression of TPD52. TPD52 expression is detectable after 72 h, can be maintained till differentiation of NB cells suggesting that TPD52 is involved in differentiation. Here, we demonstrate that TPD52 is essential for RA to promote differentiation of NB cells. Our results show that exogenous expression of EGFP-TPD52 in IMR-32 cells resulted cell differentiation even without RA. RA by itself and with overexpression of TPD52 can increase the ability of NB cells differentiation. Interestingly, transfection of IMR-32 cells with a specific small hairpin RNA for efficient knockdown of TPD52 attenuated RA induced NB cells differentiation. Transcriptional and translational level expression of neurotropic (BDNF, NGF, Nestin) and differentiation (β III tubulin, NSE, TH) factors in NB cells with altered TPD52 expression and/or RA treatment confirmed essential function of TPD52 in cellular differentiation. Furthermore, we show that TPD52 protects cells from apoptosis and arrest cell proliferation by varying expression of p27Kip1, activation of Akt and ERK1/2 thus promoting cell differentiation. Additionally, inhibition of STAT3 activation by its specific inhibitor arrested NB cells differentiation by EGFP-TPD52 overexpression with or without RA. Taken together, our data reveal that TPD52 act through activation of JAK/STAT signaling pathway to undertake NB cells differentiation induced by RA. J. Cell. Biochem. 118: 4358-4369, 2017. © 2017 Wiley Periodicals, Inc.

Targeting chitinase gene of Helicoverpa armigera by host-induced RNA interference confers insect resistance in tobacco and tomato

Helicoverpa armigera Hübner (Lepidoptera: Noctuidae) is a devastating agricultural insect pest with broad spectrum of host range, causing million dollars crop loss annually. Limitations in the present conventional and transgenic approaches have made it crucial to develop sustainable and environmental friendly methods for crop improvement. In the present study, host-induced RNA interference (HI-RNAi) approach was used to develop H. armigera resistant tobacco and tomato plants. Chitinase (HaCHI) gene, critically required for insect molting and metamorphosis was selected as a potential target. Hair-pin RNAi construct was prepared from the conserved off-target free partial HaCHI gene sequence and was used to generate several HaCHI-RNAi tobacco and tomato plants. Northern hybridization confirmed the production of HaCHI gene-specific siRNAs in HaCHI-RNAi tobacco and tomato lines. Continuous feeding on leaves of RNAi lines drastically reduced the target gene transcripts and consequently, affected the overall growth and survival of H. armigera. Various developmental deformities were also manifested in H. armigera larvae after feeding on the leaves of RNAi lines. These results demonstrated the role of chitinase in insect development and potential of HI-RNAi for effective management of H. armigera.

Association of G>A transition in exon-1 of alpha crystallin gene in age-related cataracts

Aim

To identify the presence of a known or novel mutation/SNP in Exon-1 (ex-1) of alpha crystallin (CRYAA) gene in different types of age-related cataract (ARC) patients.

Materials and Methods

Single strand Conformation Polymorphism (SSCP) analysis was carried for the detection of single nucleotide polymorphism (SNP) in ex-1 of alpha crystallin (CRYAA) gene which was confirmed by sequencing.

Results

The SSCP analysis of ex-1 of CRYAA gene revealed mobility shift in patients and controls, which was due to G>A transition at 6^th position in exon-1 of CRYAA gene. All the three genotypes, GG, AA and GA, were detected in patients and controls indicating that G>A substitution is polymorphic. The analysis showed significant risk for heterozygotes (GA) as compared to pooled frequencies of homozygotes (GG + AA), which was 1.81 times for all the types of cataracts in general and 2.5 times for Nuclear Cataract and twice for Cortical Cataract.

Conclusion

The GA heterozygotes were at higher risk for developing NC and CC types of cataracts, where as the GG homozygotes for MT and AA homozygotes for PSC types were at risk. To our knowledge, an association of G>A transition found in ex-1 of CRYAA gene with ARC, with differential risk of genotypes for individual type of cataracts has not been reported previously.