Body mass index, weight change, and cancer prognosis: a meta-analysis and systematic review of 73 cohort studies

BACKGROUND

Identifying the association between body mass index (BMI) or weight change and cancer prognosis is essential for the development of effective cancer treatments. We aimed to assess the strength and validity of the evidence of the association between BMI or weight change and cancer prognosis by a systematic evaluation and meta-analysis of relevant cohort studies.

METHODS

We systematically searched the PubMed, Web of Science, EconLit, Embase, Food Sciences and Technology Abstracts, PsycINFO, and Cochrane databases for literature published up to July 2023. Inclusion criteria were cohort studies with BMI or weight change as an exposure factor, cancer as a diagnostic outcome, and data type as an unadjusted hazard ratio (HR) or headcount ratio. Random- or fixed-effects models were used to calculate the pooled HR along with the 95% confidence interval (CI).

RESULTS

Seventy-three cohort studies were included in the meta-analysis. Compared with normal weight, overweight or obesity was a risk factor for overall survival (OS) in patients with breast cancer (HR 1.37, 95% CI 1.22-1.53; P < 0.0001), while obesity was a protective factor for OS in patients with gastrointestinal tumors (HR 0.67, 95% CI 0.56-0.80; P < 0.0001) and lung cancer (HR 0.67, 95% CI 0.48-0.92; P = 0.01) compared with patients without obesity. Compared with normal weight, underweight was a risk factor for OS in patients with breast cancer (HR 1.15, 95% CI 0.98-1.35; P = 0.08), gastrointestinal tumors (HR 1.54, 95% CI 1.32-1.80; P < 0.0001), and lung cancer (HR 1.28, 95% CI 1.22-1.35; P < 0.0001). Compared with nonweight change, weight loss was a risk factor for OS in patients with gastrointestinal cancer.

CONCLUSIONS

Based on the results of the meta-analysis, we concluded that BMI, weight change, and tumor prognosis were significantly correlated. These findings may provide a more reliable argument for the development of more effective oncology treatment protocols.

Anti-CD38 monoclonal antibody interference with blood compatibility testing: Differentiating isatuximab and daratumumab via functional epitope mapping

BACKGROUND

There are two FDA-approved anti-CD38 monoclonal antibodies for treatment of multiple myeloma: isatuximab and daratumumab. Owing to expression of CD38 on reagent red blood cells (RBCs), these antibodies interfere with indirect antiglobulin tests (IATs). We sought to understand differences in such interference by performing binding experiments.

STUDY DESIGN AND METHODS

In vitro experiments to compare the binding to RBCs of isatuximab and daratumumab alone or in the presence of a mouse anti-human CD38 antibody (HB-7 or AT13/5) or a nicotinamide adenine dinucleotide-analog CD38 inhibitor were performed and quantified by flow cytometry, imaging, mass spectrometry, surface plasmon resonance, and LigandTracer technologies. Serologic testing was performed on plasma samples spiked with isatuximab or daratumumab.

RESULTS

CD38 expressed on RBCs can be directly bound by daratumumab, whereas isatuximab requires a co-factor, such as HB-7, AT13/5, or a CD38 inhibitor, suggesting that the isatuximab epitope on RBCs is masked in vitro. Daratumumab samples more frequently showed interference and had stronger reactions than isatuximab samples. Dithiothreitol treatment was equally effective in mitigating the interference caused by either drug.

DISCUSSION

Both isatuximab and daratumumab interfere with IATs but at different magnitudes, reflecting distinct binding to CD38 on RBCs. From the binding studies, we conclude that the isatuximab epitope on RBCs is masked in vitro and binding requires a certain CD38 conformation or co-factor. This circumstance may explain why interference is seen only in a subset of patients receiving isatuximab when compared with interference seen in most patients on daratumumab therapy.

[Talin1 is highly expressed in the fallopian tube and chorionic villi to promote trophoblast invasion in tubal pregnancy]

OBJECTIVE

To investigate the expression of Talin1 in the fallopian tube and chorionic villi in patients with tubal pregnancy and its role in regulating invasion and migration of trophoblasts.

METHODS

Immunohistochemistry and Western blotting were used to detect the localization and expression level of Talin1 in the fallopian tube and chorionic villi in patients with tubal pregnancy and in women with normal pregnancy. In the cell experiment, HTR-8/SVneo cells was transfected with Talin1 siRNA and the changes in cell invasion and migration were assessed using scratch assay and Transwell assay. The expressions of MMP-2, MMP-9, N-cadherin and Snail in the transfected cells were detected by qRT-PCR and Western blotting.

RESULTS

Positive expression of Talin1 was detected in both normal fallopian tube tissues and tissues from women tubal pregnancy, and its expression was localized mainly in the cytoplasm of cilia cells. The expression level of Talin1 was significantly higher in both the fallopian tube and chorionic villi in women with tubal pregnancy than in normal fallopian tube and chorionic villi samples (P < 0.01). In HTR-8/SVneo cells, transfection with Talin1 siRNA significantly inhibited cell invasion (P < 0.01) and migration (P < 0.05), down-regulated the expression of N-cadherin, MMP-2 and Snail (P < 0.05), and up-regulated the expression of MMP-9 in the cells (P < 0.05).

CONCLUSION

The expression of Talin1 in the fallopian tube and chorionic villi is significantly increased in women with tubal pregnancy, suggesting the association of Talin1-regulated trophoblast cell invasion with the occurrence of tubal pregnancy.

A trispecific antibody targeting HER2 and T cells inhibits breast cancer growth via CD4 cells

Effective antitumour immunity depends on the orchestration of potent T cell responses against malignancies¹. Regression of human cancers has been induced by immune checkpoint inhibitors, T cell engagers or chimeric antigen receptor T cell therapies^2-4. Although CD8 T cells function as key effectors of these responses, the role of CD4 T cells beyond their helper function has not been defined. Here we demonstrate that a trispecific antibody to HER2, CD3 and CD28 stimulates regression of breast cancers in a humanized mouse model through a mechanism involving CD4-dependent inhibition of tumour cell cycle progression. Although CD8 T cells directly mediated tumour lysis in vitro, CD4 T cells exerted antiproliferative effects by blocking cancer cell cycle progression at G1/S. Furthermore, when T cell subsets were adoptively transferred into a humanized breast cancer tumour mouse model, CD4 T cells alone inhibited HER2⁺ breast cancer growth in vivo. RNA microarray analysis revealed that CD4 T cells markedly decreased tumour cell cycle progression and proliferation, and also increased pro-inflammatory signalling pathways. Collectively, the trispecific antibody to HER2 induced T cell-dependent tumour regression through direct antitumour and indirect pro-inflammatory/immune effects driven by CD4 T cells.

The combination of sucrose dilaurate and sucrose laurate suppresses HMGB1: an enhancer of melanocyte dendricity and melanosome transfer to keratinocytes

BACKGROUND

Hyperpigmented spots are common issues in all ethnicities, involving multiple intrinsic and extrinsic factors such as UVB exposure, hormone balance, inflammatory status and ageing.

OBJECTIVES

To determine (i) melanocyte dendricity in multiple facial spot types, (ii) impact of High Mobility Group Box 1 (HMGB1), and the combination of sucrose dilaurate and sucrose laurate (SDL) on melanogenesis and melanocyte dendricity, and (iii) SDL effect on facial spots in a human use test.

METHODS

Facial spot and adjacent non-spot skin biopsies were collected from Chinese women (age 20-70). Histological assessment of melanocyte dendricity was performed for 3 spot types (solar lentigo, melasma and postinflammatory hyperpigmentation) by immunofluorescent staining for c-kit/MITF. Keratinocyte, melanocyte and melanocyte-keratinocyte co-culture models were used to assess HMGB1 release by UVB radiation, the effects of HMGB1 and SDL on melanin production, melanocyte dendricity and melanosome transfer. The effect of an SDL-containing moisturizer on appearance of facial hyperpigmented spots was assessed against a vehicle control in an 8-week human use test.

RESULTS

Melanocytes in spot areas are more dendritic than melanocytes in adjacent non-spot skin across three investigated spot types. In cell culture models, a moderate UVB-radiation exposure caused release of HMGB1 from keratinocytes. HMGB1 did not alter melanin production in melanocytes, but enhanced melanocyte dendricity and melanosome transfer. SDL reduced HMGB1 release from keratinocytes, inhibited melanin production, reversibly suppressed melanocyte dendricity and reduced melanosome transfer. In the human use test, SDL-containing moisturizer reduced appearance of spots versus vehicle.

CONCLUSION

Increased melanocyte dendricity was observed in multiple types of facial spots. Addition of HMGB1 protein increased melanocyte dendricity and melanosome transfer in cell cultures, implicating potential involvement in spot formation. SDL suppressed melanin production, melanocyte dendricity and melanosome transfer in vitro and reduced appearance of spots in the use test, suggesting SDL is an effective solution to address hyperpigmented spot concerns.

Automating inventorying of blood stations: A system based on ultrahigh-frequency radio-frequency identification (UHF RFID) technology

Inventorying blood products is an essential process in blood station management. Traditional methods need to integrate barcodes with refrigerators, which suffer from low time efficiency, high error rate and high labour cost. Several methods have been proposed to automate this process in blood stations. However, none of them is ideal enough. In this paper, we analyse the difficulties of automation in blood inventory, and propose an automated blood inventory system based on UHF RFID technology. Comparisons over our method with manual inventory and handheld RFID inventory are conducted. The result shows that our method is nearly 10 times higher than manual inventory in time efficiency while increases the accuracy to 100%.

Abstract 1888: Anti-CD38 interference with blood compatibility testing: Differentiating isatuximab and daratumumab via functional epitope mapping

Introduction: Two anti-CD38 monoclonal antibodies (mAb) are approved for the treatment of multiple myeloma: isatuximab (Isa) and daratumumab (Dara); binding to CD38 on red blood cells (RBCs) results in false positive agglutination on indirect antiglobulin tests (IATs). Compared to Dara, which interferes with IATs in nearly 100% of patients, Isa interfered in 67/99 (67%) patients in the Phase 3 ICARIA-MM (NCT02990338) study and 95/150 (63%) patients in the Phase 3 IKEMA (NCT0327585) study. We sought to understand differences between the binding abilities of Isa and Dara to CD38 on RBCs.

Experimental Procedures: In vitro binding experiments in RBCs were performed following pretreatment of RBCs isolated from healthy donors +/- a mouse anti-human CD38 mAb (clone HB-7 or AT13/5) or a nicotinamide adenine dinucleotide (NAD) analog (irreversible CD38 inhibitor) before incubation with Isa, Dara, or control human IgG (hIgG). RBC surface bound CD38 antibodies were detected with fluorophore conjugated secondary antibodies and quantified by flow cytometry, imaging or mass spectrometry. Binding of Isa to recombinant human CD38 (rhCD38) pretreated with HB-7 or an NAD analog was quantified by Surface Plasmon Resonance (SPR). Ex vivo IAT was performed on plasma samples spiked with Isa or Dara.

Results: In vitro testing in the absence of human plasma showed that incubation of RBCs with Dara but not Isa resulted in a dose-dependent increase in RBC binding. The binding specificity of Dara was demonstrated by treatment with HB-7, an anti-CD38 mAb that recognizes epitopes that overlap with Dara but not Isa binding. Flow cytometry, confocal microscopy, SPR and mass spectrometry showed HB-7 had a competitive effect on Dara binding and induced Isa to bind to CD38 without competition. Pretreatment of RBCs with another anti-CD38 mAb AT13/5 or an NAD analog also induced Isa binding to RBCs. The NAD analog is an irreversible CD38 inhibitor that stabilizes CD38 dimer conformation. SPR demonstrated that pretreatment with HB-7 or the NAD analog may enhance dimer formation increasing Isa binding affinity to rhCD38. These results indicate that CD38 conformational changes caused by anti-CD38 antibodies or the NAD analog may facilitate Isa-binding to RBC-expressing CD38. In the ex vivo IAT, except for gel testing in which both Isa and Dara were panreactive, including all other IAT methods Dara reacted with many more cells, and reactions were stronger than Isa at all concentrations tested.

Conclusions: In this study, we confirmed that both Isa and Dara interfere with IATs but at different magnitudes. This reflects distinct mechanisms of CD38 binding. In the absence of human plasma, CD38 on RBCs can be directly recognized by Dara while Isa requires a cofactor, such as an anti-CD38 antibody or an NAD analog. Future studies are essential to characterize the impact of human plasma on Isa binding to RBCs-expressing CD38.

Citation Format: Zhili Song, Olivier Bedel, Bailin Zhang, Joern Hopke, Gejing Deng, Sandrine Macé, Marielle Chiron, Francisco Adrian, Taro Fukao, Frank Basile, France Pirenne, Makoto Okuda, Morvarid Moayeri, Btissam Chami, Yoko Hidaka, Ashok Nambiar, Thomas Martin, Chen Zhu. Anti-CD38 interference with blood compatibility testing: Differentiating isatuximab and daratumumab via functional epitope mapping [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2021; 2021 Apr 10-15 and May 17-21. Philadelphia (PA): AACR; Cancer Res 2021;81(13_Suppl):Abstract nr 1888.

Autophagy activators stimulate the removal of advanced glycation end products in human keratinocytes

BACKGROUND

The accumulation of advanced glycation end products (AGEs) can impact cellular homoeostasis and protein structure, thus is implicated in numerous skin conditions including yellow, dull appearance. AGE formation is irreversible; thus, understanding of the recycling process of AGEs in the skin is critical for addressing skin appearance conditions.

OBJECTIVE

To determine whether (i) accumulation of AGEs occurs in dull appearance group among young population (age 20-29) (ii) in vitro autophagy stimulation results in reduction of AGEs in keratinocytes.

METHODS

Facial cheek biopsies were collected from Chinese women (age 20-50) exhibiting either dull or non-dull appearing skin. Histological assessment of glycation was performed for representative subjects among the 20-29 years sub-group by immunofluorescence staining of AGEs. LC-MS methods and keratinocyte cell culture were used to assess impact of autophagy modulators and skin care materials on carboxymethyl lysine (CML) amount, a representative AGE.

RESULTS

Notable amounts of AGEs were observed in the epidermal samples among young females. Interestingly, the amount of AGEs was significantly higher among the dull skin appearance group. Treatment of keratinocytes with glyceraldehyde (GLA) enhanced CML in the cells, and postglycation treatment with autophagy activators reduced CML. Two skin care materials, Nymphaea alba flower extract (a.k.a. white water lily extract) and sucrose dilaurate, were identified based from in vitro autophagy activation and found to reduce CML in keratinocytes.

CONCLUSION

We found AGEs accumulate in the facial epidermis even among young people, correlating to a yellow and dull appearance. We also demonstrated in vitro activation of autophagy can reduce AGEs in keratinocytes, and autophagy activating skin care materials, N. alba flower extract and sucrose dilaurate, also reduce AGEs in the keratinocyte in vitro model. These data suggest epidermal AGEs contribute to the dull skin appearance, and autophagy activators may provide an effective solution to improve dull appearance by removing and recycling the accumulated glycation in the skin.

[Analysis of the effect of percutaneous vertebroplasty combined with (125)I seed implantation in the treatment of spinal metastatic epidural spinal cord compression]

Objective: To investigate the clinical efficacy of percutaneous vertebroplasty (PVP) combined with iodine-125 ((125)I) seed brachytherapy in the treatment of spinal metastatic epidural spinal cord compression (MESCC) and toassess the changes inthe grade of epidural spinal cord compression (ESCC) by magnetic resonance imaging (MRI). Methods: A total of 37 MESCC patients treated with PVP combined with (125)I seed brachytherapy in the interventional and vascular surgery department of Zhongda Hospital affiliated to Southeast University from January 2014 to June 2019 were retrospectively analyzed, including 23 cases of bilateral lower limbs paralysis. Total diseased vertebrae are 39 segments. Visual analogue scale (VAS) and paralysis of lower extremities were evaluated regularly before and after treatment, and VAS values at different follow-up time points were compared. At the same time, MRI was used to evaluate the changes of ESCC grade in the spinal canal and calculate the local lesion efficiency after operation. The postoperative local lesion efficiency at different follow-up times was compared. Results: PVP combined with (125)I seed implantation in all diseased vertebral bodies was successful. The average injection volume of polymethylmethacrylate (PMMA) was (3.2±1.3) ml/segment, the average number of (125)I seed implanted was (25.0±8.6) seeds/segment and the average radiation dose was (15.0±5.1) mCi/segment. The VAS before operation was 8.5, and postoperative VAS were respectively 3.6±1.3, 3.8±1.5, 3.4±1.4, 5.5±1.0, 5.9±1.4 at 5 days, 1 month, 3 months, 6 months, and 1 year after operation. The differences between all follow-up time points and preoperative VAS values were statistically significant (all P<0.001). Compared with 5 days, 1 month and 3 months after operation, VAS increased significantly at 6 months and 1 year after operation, and the difference was statistically significant (all P<0.001); there was no significant difference between the VAS value at 6 months after operation and 1 year after operation (P=0.405). At a follow-up of 3 months, 22 of 23 patients with paralysis of bilateral lower limbs regained the functions of autonomous walking and voiding; the effective rates of MESCC local lesions evaluated by MRI at 1 month, 3 months, 6 months, and>1 year were 89.7%, 91.9%, 90.6%, and 94.7%, respectively, and there was no statistically significant differences among those follow-up time points (all P>0.05). Conclusions: PVP combined with (125)I seed brachytherapy in the treatment of MESCC has significant improvement in immediate pain relief and spinal cord function. After combined treatment, MRI showed that the tumors around the spinal cord regressed dramatically, which could considerably reduce the MESCC grade and remain stable for a long time.

Infrared attenuated total reflection spectroscopic analysis and quantitative detection of forage spectral features in ruminant systems

This study aimed to (1) access protein molecular structure profile and metabolic characteristics of model forages [Foreign sourced-origin (coded as: "FSO", n = 7 vs. Chinese sourced-origin alfalfa hay "CSO", n = 5] in ruminant systems; (2) Quantify the relationship between forage protein molecular structures and protein utilization and availability. Advanced non-invasive vibrational molecular spectroscopic technique (ATR-FTIR: Attenuated Total Reflection Fourier Transform Infrared spectroscopy) with chemometrics was applied to reveal forage protein molecular structure. Both univariate and multivariate molecular spectral analyses were applied to study molecular structure features in model forages. The molecular structure study provided the detailed protein structure profiles of Amide I and Amide II areas and height, total Amide I and II area ratios, Amide I to II height ratio as well as Amide I to II area ratio using ATR-FTIR spectroscopy. The results showed FSO and CSO had similar (P > 0.05) protein rumen degradation kinetics. However, FSO had superior quality than CSO in intestinal (IDP) and total digestible protein (TDP) and truly absorbed nutrient supply (P < 0.05). As intestinal digestion of protein, FSO was higher (P < 0.05) in protein digestion in terms of: intestinal digestibility of rumen undegraded protein (dIDP: 47.5 vs. 38.3 %RUP); Intestinal digestible protein (IDP: 17.6 vs. 13.7 %CP). As truly absorbed nutrient supply, FSO contained higher (P < 0.05) truly absorbed rumen synthesized microbial protein, absorbable rumen undegradable feed protein in the small intestine, total truly digested protein in the small intestine, metabolizable protein and Feed Milk Value (FMV^DVE: 1.2 vs. 1.1 g/kg DM). The molecular structure-nutrition interactive relationship study showed that protein molecular structure profiles were highly associated to protein rumen degradation kinetics, significantly correlated to protein subfractions, protein intestinal digestion, and truly absorbed nutrient supply in ruminant systems.

FoxP3 in Treg cell biology: a molecular and structural perspective

Regulatory T cells (T_regs) are specialized in immune suppression and play a dominant role in peripheral immune tolerance. T_reg cell lineage development and function maintenance is determined by the forkhead box protein 3 (FoxP3) transcriptional factor, whose activity is fine‐tuned by its post‐translational modifications (PTMs) and interaction partners. In this review, we summarize current studies in the crystal structures, the PTMs and interaction partners of FoxP3 protein, and discuss how these insights may provide a roadmap for new approaches to modulate T_reg suppression, and new therapies to enhance immune tolerance in autoimmune diseases.

Single dose of 17β-estradiol provides transient neuroprotection in female juvenile mice after cardiac-arrest and cardiopulmonary resuscitation

Each year there are approximately 7000 out of hospital cardiac arrests in the pediatric population, with 30% resuscitation rate and a 6-10% rate of survival to hospital discharge. Survivors of cardiac arrest exhibit learning and memory deficits that are devastating during the school years. Delayed neuronal cell death occurs in the hippocampus following cardiac arrest and likely contributes to memory impairments. Circulating endogenous estrogen in young adult females has been shown to provide protection against ischemic cell death, as does chronic exogenous administration of 17β-estradiol (E2). Chronic estrogen benefit can have undesirable feminizing effects, particularly in pre-adolescents. Here, we tested if a single-dose of E2 is neuroprotective in our pediatric cardiac arrest mouse model performed in juvenile mice. We subjected P21P25 C57Blk6 male and female mice to 8 min of cardiac arrest followed by cardiopulmonary resuscitation (CA/CPR). This developmental stage preceded the hormonal onset and serum estradiol and testosterone levels were not different in males and females. A single dose of E2 (100μg/kg) or vehicle was administered 30 min after resuscitation. Neuronal cell death measured 3 days after CA/CPR showed reduced hippocampal cell death in E2-treated females, but not males. Benefit of E2 in females was blocked by the P38 MAPK inhibitor, SB203580. Hippocampal-dependent memory function was equally impaired in E2-and vehicle-treated females measured in the contextual fear conditioning task at 7 days. Our findings demonstrate female-specific transient neuroprotection with E2 that does not provide sustained functional benefit.

[Cement augmentation for vertebral osteolytic metastatic lesions: an evaluation on postoperative CT]

Objective: To evaluate the effectiveness of cement augmentation on the osteolytic lesion in patients with vertebral metastasis. Methods: A total of consecutive 132 patients with 268 vertebral metastatic lesions treated with PVP from January 2008 to December 2016 in Zhongda Hospital were enrolled in this study. Retrospective analysis of preoperative, postoperative 3 days, 3 months, 6 months, 12 months and ≥ 18 months imaging data on CT, the local control and progression of the tumor were evaluated by MDA response criteria. The local control rates were compared between the groups with the different rate of cement filling by Chi²-test. Results: Vertebroplasty procedures were performed successfully in all 268 vertebrae under DSA guidance, and the mean volume of PMMA injected in each vertebra was 0.7-8.5(3.9±1.5)ml.The rate of local control at 3 months, 6 months, 12 months and ≥18 months after PVP was respectively 98.9%, 95.1%, 91.8%, and 85.2%, the difference was statistically significant(all P<0.05). The local control rate showed a statistically significant relationship to the groups with the rate of cement filling at 6 months, 12 months and ≥18 months after PVP, but there was no statistical difference at postoperative 3 months. The rate of local control was higher in 68 patients with lung or gastrointestinal cancer than in 17 patients with liver or kidney cancer at 3 months, 6 months and 12 months, the difference was statistically significant (P<0.05). Conclusion: Cement augmentation has a local anti-tumor effect on vertebral osteolytic metastatic lesion, and the anti-tumor effect will decrease as the follow-up time extended.

A Robust Multiplex Mass Spectrometric Assay for Screening Small-Molecule Inhibitors of CD73 with Diverse Inhibition Modalities

CD73/Ecto-5'-nucleotidase is a membrane-tethered ecto-enzyme that works in tandem with CD39 to convert extracellular adenosine triphosphate (ATP) into adenosine. CD73 is highly expressed on various types of cancer cells and on infiltrating suppressive immune cells, leading to an elevated concentration of adenosine in the tumor microenvironment, which elicits a strong immunosuppressive effect. In preclinical studies, targeting CD73 with anti-CD73 antibody results in favorable antitumor effects. Despite initial studies using antibodies, inhibition of CD73 catalytic activity using small-molecule inhibitors may be more effective in lowering extracellular adenosine due to better tumor penetration and distribution. To screen small-molecule libraries, we explored multiple approaches, including colorimetric and fluorescent biochemical assays, and due to some limitations with these assays, we developed a mass spectrometry (MS)-based assay. Only the MS-based assay offers the sensitivity and dynamic range required for screening small-molecule libraries at a substrate concentration close to the K_m value of substrate and for evaluating the mode of binding of screening hits. To achieve a throughput suitable for high-throughput screening (HTS), we developed a RapidFire-tandem mass spectrometry (RF-MS/MS)-based multiplex assay. This assay allowed a large diverse compound library to be screened at a speed of 1536 reactions per 40-50 min.

Exosomes promote cetuximab resistance via the PTEN/Akt pathway in colon cancer cells

Cetuximab is widely used in patients with metastatic colon cancer expressing wildtype KRAS. However, acquired drug resistance limits its clinical efficacy. Exosomes are nanosized vesicles secreted by various cell types. Tumor cell-derived exosomes participate in many biological processes, including tumor invasion, metastasis, and drug resistance. In this study, exosomes derived from cetuximab-resistant RKO colon cancer cells induced cetuximab resistance in cetuximab-sensitive Caco-2 cells. Meanwhile, exosomes from RKO and Caco-2 cells showed different levels of phosphatase and tensin homolog (PTEN) and phosphor-Akt. Furthermore, reduced PTEN and increased phosphorylated Akt levels were found in Caco-2 cells after exposure to RKO cell-derived exosomes. Moreover, an Akt inhibitor prevented RKO cell-derived exosome-induced drug resistance in Caco-2 cells. These findings provide novel evidence that exosomes derived from cetuximab-resistant cells could induce cetuximab resistance in cetuximab-sensitive cells, by downregulating PTEN and increasing phosphorylated Akt levels.

Glutaminase is essential for the growth of triple-negative breast cancer cells with a deregulated glutamine metabolism pathway and its suppression synergizes with mTOR inhibition

Tumor cells display fundamental changes in metabolism and nutrient uptake in order to utilize additional nutrient sources to meet their enhanced bioenergetic requirements. Glutamine (Gln) is one such nutrient that is rapidly taken up by tumor cells to fulfill this increased metabolic demand. A vital step in the catabolism of glutamine is its conversion to glutamate by the mitochondrial enzyme glutaminase (GLS). This study has identified GLS a potential therapeutic target in breast cancer, specifically in the basal subtype that exhibits a deregulated glutaminolysis pathway. Using inducible shRNA mediated gene knockdown, we discovered that loss of GLS function in triple-negative breast cancer (TNBC) cell lines with a deregulated glutaminolysis pathway led to profound tumor growth inhibition in vitro and in vivo. GLS knockdown had no effect on growth and metabolite levels in non-TNBC cell lines. We rescued the anti-tumor effect of GLS knockdown using shRNA resistant cDNAs encoding both GLS isoforms and by addition of an α-ketoglutarate (αKG) analog thus confirming the critical role of GLS in TNBC. Pharmacological inhibition of GLS with the small molecule inhibitor CB-839 reduced cell growth and led to a decrease in mammalian target of rapamycin (mTOR) activity and an increase in the stress response pathway driven by activating transcription factor 4 (ATF4). Finally, we found that GLS inhibition synergizes with mTOR inhibition, which introduces the possibility of a novel therapeutic strategy for TNBC. Our study revealed that GLS is essential for the survival of TNBC with a deregulated glutaminolysis pathway. The synergistic activity of GLS and mTOR inhibitors in TNBC cell lines suggests therapeutic potential of this combination for the treatment of vulnerable subpopulations of TNBC.

Trispecific broadly neutralizing HIV antibodies mediate potent SHIV protection in macaques

The development of an effective AIDS vaccine has been challenging because of viral genetic diversity and the difficulty of generating broadly neutralizing antibodies (bnAbs). We engineered trispecific antibodies (Abs) that allow a single molecule to interact with three independent HIV-1 envelope determinants: the CD4 binding site, the membrane-proximal external region (MPER), and the V1V2 glycan site. Trispecific Abs exhibited higher potency and breadth than any previously described single bnAb, showed pharmacokinetics similar to those of human bnAbs, and conferred complete immunity against a mixture of simian-human immunodeficiency viruses (SHIVs) in nonhuman primates, in contrast to single bnAbs. Trispecific Abs thus constitute a platform to engage multiple therapeutic targets through a single protein, and they may be applicable for treatment of diverse diseases, including infections, cancer, and autoimmunity.

Concurrent chemoradiotherapy with weekly nedaplatin versus radiotherapy alone in elderly patients with non-small-cell lung cancer

PURPOSE

We conduct this study to compare the efficacy and toxicity of intensity-modulated radiotherapy (IMRT) concurrent weekly nedaplatin (NDP) versus IMRT alone in the stage III/IV non-surgical elderly patients with non-small-cell lung cancer (NSCLC).

METHODS

117 patients were enrolled into our study. The patients were assigned into two different groups: radiotherapy (RT) group and chemoradiotherapy (CRT) group. Patients in RT group were treated with IMRT at a single daily dose of 2 Gy for 5 days per week, totally 52-66 Gy. The CRT group, IMRT concurrent weekly NDP at a dose of 25 mg/m².

RESULTS

In CRT group, the median survival was 11.0 months (95% confidence interval [CI], 8.894-13.106 months) and in RT group, it was 7.0 months (95% CI 5.771-8.229 months). The 1-year, 2-year, 3-year, survival rates in the combined treatment arm were higher than the radiation therapy arm (46.8 vs 25.9%, 25.1 vs 11.8%, 14.7 vs 8.0%; p < 0.001). The Cox's multiple regression analysis showed that CRT had significantly better overall survival than RT (HR 0.523; 95.0% CI 0.338-0.807; p = 0.003). The objective response rate provided that 73.3% treated with CRT compared with 51.1% (p = 0.018) received RT alone. Of the hematologic toxicities, leukocytes (35.0 vs 0%; p < 0.001), neutrophils (33.3 vs 0%; p < 0.001) were significantly more common in the CRT group than the RT group.

CONCLUSIONS

We first discovered that NDP concurrent IMRT for treating stage III/IV non-surgical elderly patients with NSCLC was good curative effect of better objective response rate and well-tolerated. However, within the low number of patients, only stage IV gained a survival benefit.

Sofosbuvir Monotherapy for Asymptomatic and Noncirrhotic Hepatitis C Infection in a Renal Retransplantation Recipient: A Case Report

Renal transplant recipients infected with hepatitis C virus (HCV) have a high risk of progressing to cirrhosis, end-stage liver diseases, and hepatocellular carcinoma. It is also considered as an independent risk for graft loss and is correlated with proteinuria, transplant glomerulopathy, HCV-associated glomerulonephritis, and chronic rejection. Previous therapy involving interferon alfa and ribavirin led to treatment complications, including toxicity, anemia, sepsis, and drug-drug interactions with calcineurin inhibitors, as well as reduced tolerability and efficacy. New direct-acting antiviral drugs simplify and shorten the treatment along with increasing tolerability and efficacy. Nevertheless, limited data and no specific regimen with direct-acting antiviral drugs have been described in the literature for renal transplant recipients with chronic HCV. We describe here the case of a 52-year-old Chinese man who diagnosed with chronic renal failure in 1997 and underwent renal transplantation the same year. In 2012, he was diagnosed with renal graft failure and again underwent hemodialysis. The patient then underwent his second renal transplantation and was administered an immunosuppressive cyclosporine-based regimen in 2015. During hemodialysis, he acquired asymptomatic genotype 1b HCV infection. Serologic test results reflecting liver cirrhosis were all negative, and ultrasound showed no abnormalities in the liver. The patient later required oral sofosbuvir monotherapy for 12 weeks after the second kidney transplantation. Curing HCV in renal transplant recipients is necessary. Although our treatment did not successfully result in a sustained virologic response, it suggests that genotype 1b HCV may have a poor response to a sofosbuvir monotherapy regimen. Specific and effective regimens for renal transplant recipients with HCV infection need to be confirmed in the future.

MicroRNA-383 located in frequently deleted chromosomal locus 8p22 regulates CD44 in prostate cancer

A major genomic alteration in prostate cancer (PCa) is frequent loss of chromosome (chr) 8p with a common region of loss of heterozygosity (LOH) at chr8p22 locus. Genomic studies implicate this locus in the initiation of clinically significant PCa and with progression to metastatic disease. However, the genes within this region have not been fully characterized to date. Here we demonstrate for the first time that a microRNA component of this region –miR-383- is frequently downregulated in prostate cancer, plays a critical role in determining tumor initiating potential and is involved in prostate cancer metastasis via direct regulation of CD44, a ubiquitous marker of PCa tumor initiating cells (TICs)/ stem cells. Expression analyses of miR-383 in PCa clinical tissues established that low miR-383 expression is associated with poor prognosis. Functional data suggests that miR-383 regulates PCa tumor initiating/ stem-like cells via CD44 regulation. Ectopic expression of miR-383 inhibited tumor initiating capacity of CD44+ PCa cells. Also, ‘anti-metastatic’ effects of ectopic miR-383 expression were observed in a PCa experimental metastasis model. In view of our results, we propose that frequent loss of miR-383 at chr8p22 region leads to tumor initiation and prostate cancer metastasis. Thus, we have identified a novel finding that associates a long observed genomic alteration to PCa stemness and metastasis. Our data suggests that restoration of miR-383 expression may be an effective therapeutic modality against PCa. Importantly, we identified miR-383 as a novel PCa tissue diagnostic biomarker with a potential that outperforms that of serum PSA.

Experimental Observation and Theoretical Description of Multisoliton Fission in Shallow Water

We observe the dispersive breaking of cosine-type long waves [Phys. Rev. Lett. 15, 240 (1965)] in shallow water, characterizing the highly nonlinear "multisoliton" fission over variable conditions. We provide new insight into the interpretation of the results by analyzing the data in terms of the periodic inverse scattering transform for the Korteweg-de Vries equation. In a wide range of dispersion and nonlinearity, the data compare favorably with our analytical estimate, based on a rigorous WKB approach, of the number of emerging solitons. We are also able to observe experimentally the universal Fermi-Pasta-Ulam recurrence in the regime of moderately weak dispersion.

Therapeutic hypothermia protects against ischemia-induced impairment of synaptic plasticity following juvenile cardiac arrest in sex-dependent manner

Pediatric cardiac arrest (CA) often leads to poor neurologic outcomes, including deficits in learning and memory. The only approved treatment for CA is therapeutic hypothermia, although its utility in the pediatric population remains unclear. This study analyzed the effect of mild therapeutic hypothermia after CA in juvenile mice on hippocampal neuronal injury and the cellular model of learning and memory, termed long-term potentiation (LTP). Juvenile mice were subjected to cardiac arrest and cardiopulmonary resuscitation (CA/CPR) followed by normothermia (37°C) and hypothermia (30°C, 32°C). Histological injury of hippocampal CA1 neurons was performed 3days after resuscitation using hematoxylin and eosin (H&E) staining. Field excitatory post-synaptic potentials (fEPSPs) were recorded from acute hippocampal slices 7days after CA/CPR to determine LTP. Synaptic function was impaired 7days after CA/CPR. Mice exposed to hypothermia showed equivalent neuroprotection, but exhibited sexually dimorphic protection against ischemia-induced impairment of LTP. Hypothermia (32°C) protects synaptic plasticity more effectively in females, with males requiring a deeper level of hypothermia (30°C) for equivalent protection. In conclusion, male and female juvenile mice exhibit equivalent neuronal injury following CA/CPR and hypothermia protects both males and females. We made the surprising finding that juvenile mice have a sexually dimorphic response to mild therapeutic hypothermia protection of synaptic function, where males may need a deeper level of hypothermia for equivalent synaptic protection.

Extreme Vulnerability of IDH1 Mutant Cancers to NAD+ Depletion

Heterozygous mutation of IDH1 in cancers modifies IDH1 enzymatic activity, reprogramming metabolite flux and markedly elevating 2-hydroxyglutarate (2-HG). Here, we found that 2-HG depletion did not inhibit growth of several IDH1 mutant solid cancer types. To identify other metabolic therapeutic targets, we systematically profiled metabolites in endogenous IDH1 mutant cancer cells after mutant IDH1 inhibition and discovered a profound vulnerability to depletion of the coenzyme NAD+. Mutant IDH1 lowered NAD+ levels by downregulating the NAD+ salvage pathway enzyme nicotinate phosphoribosyltransferase (Naprt1), sensitizing to NAD+ depletion via concomitant nicotinamide phosphoribosyltransferase (NAMPT) inhibition. NAD+ depletion activated the intracellular energy sensor AMPK, triggered autophagy, and resulted in cytotoxicity. Thus, we identify NAD+ depletion as a metabolic susceptibility of IDH1 mutant cancers.

Selective inhibition of mutant isocitrate dehydrogenase 1 (IDH1) via disruption of a metal binding network by an allosteric small molecule

Cancer-associated point mutations in isocitrate dehydrogenase 1 and 2 (IDH1 and IDH2) confer a neomorphic enzymatic activity: the reduction of α-ketoglutarate to d-2-hydroxyglutaric acid, which is proposed to act as an oncogenic metabolite by inducing hypermethylation of histones and DNA. Although selective inhibitors of mutant IDH1 and IDH2 have been identified and are currently under investigation as potential cancer therapeutics, the mechanistic basis for their selectivity is not yet well understood. A high throughput screen for selective inhibitors of IDH1 bearing the oncogenic mutation R132H identified compound 1, a bis-imidazole phenol that inhibits d-2-hydroxyglutaric acid production in cells. We investigated the mode of inhibition of compound 1 and a previously published IDH1 mutant inhibitor with a different chemical scaffold. Steady-state kinetics and biophysical studies show that both of these compounds selectively inhibit mutant IDH1 by binding to an allosteric site and that inhibition is competitive with respect to Mg(2+). A crystal structure of compound 1 complexed with R132H IDH1 indicates that the inhibitor binds at the dimer interface and makes direct contact with a residue involved in binding of the catalytically essential divalent cation. These results show that targeting a divalent cation binding residue can enable selective inhibition of mutant IDH1 and suggest that differences in magnesium binding between wild-type and mutant enzymes may contribute to the inhibitors' selectivity for the mutant enzyme.

Abstract 4746: Selective inhibition of mutant IDH1 via small molecule binding to the dimer interface

Isocitrate dehydrogenases (IDHs) catalyze the oxidative decarboxylation of isocitric acid to α-ketoglutaric acid (αKG). Point mutations in IDH1 and IDH2 confer a neomorphic enzymatic activity: the reduction of αKG to D-2-hydroxyglutaric acid (2HG), which acts as an oncometabolite by inducing hypermethylation of histones and DNA. IDH1 mutations (predominantly R132H) have been found in 50-80% of grade II gliomas. To find potential IDH1-targeted therapeutics, we conducted a full small-molecule HTS and hit validation campaign using recombinant R132H IDH1. This campaign identified Compound 1, which belongs to a phenol-azole series, as a potent and selective inhibitor of mutant IDH1. We investigated the mode of inhibition of Compound 1 and a published IDH1 mutant inhibitor with a different chemical scaffold (Compound 2). Steady-state kinetics and biophysical studies showed that both inhibitors reversibly interact with both free and substrate-bound enzyme at an allosteric site. A crystal structure of Compound 1 complexed with R132H demonstrates binding of the inhibitor at the dimer interface. A competitive binding study showed that Compound 2 competes with Compound 1, suggesting that Compound 2 also binds at the dimer interface. This is contrary to a previously published statement that Compound 2 is a competitive inhibitor with respect to αKG. In cancer cell lines engineered to produce high levels of 2HG, both inhibitors penetrate cells efficiently and inhibit 2HG production with minimal cell toxicity. This study indicates that the dimer interface pocket is a druggable binding site for IDH1 inhibitors, and suggests that Compound 1 is a promising new starting point for future structure-based drug discovery efforts.

Citation Format: Gejing Deng, Stuart Licht, Junqing Shen, Ming Yin, Jessica McManus, Patricia Gee, Tim He, Giang Gao, Bailin Zhang, Magali Mathieu, Alexey Rak, Olivier Bedel, Chaomei Shi, Stefan Gross, Dietmar Hoffmann, Eamonn Rooney, Aurelie Vassort, Walter Englaro, Yi Li, Dmitri Wiederschain, Vinod Patel, Francisco Adrian, Hong Cheng. Selective inhibition of mutant IDH1 via small molecule binding to the dimer interface. [abstract]. In: Proceedings of the 105th Annual Meeting of the American Association for Cancer Research; 2014 Apr 5-9; San Diego, CA. Philadelphia (PA): AACR; Cancer Res 2014;74(19 Suppl):Abstract nr 4746. doi:10.1158/1538-7445.AM2014-4746

Increasing small conductance Ca2+-activated potassium channel activity reverses ischemia-induced impairment of long-term potentiation

Global cerebral ischemia following cardiac arrest and cardiopulmonary resuscitation (CA/CPR) causes injury to hippocampal CA1 pyramidal neurons and impairs cognition. Small conductance Ca(2+)-activated potassium channels type 2 (SK2), expressed in CA1 pyramidal neurons, have been implicated as potential protective targets. Here we showed that, in mice, hippocampal long-term potentiation (LTP) was impaired as early as 3 h after recovery from CA/CPR and LTP remained impaired for at least 30 days. Treatment with the SK2 channel agonist 1-Ethyl-2-benzimidazolinone (1-EBIO) at 30 min after CA provided sustained protection from plasticity deficits, with LTP being maintained at control levels at 30 days after recovery from CA/CPR. Minimal changes in glutamate release probability were observed at delayed times after CA/CPR, implicating post-synaptic mechanisms. Real-time quantitative reverse transcriptase-polymerase chain reaction indicated that CA/CPR did not cause a loss of N-methyl-D-aspartate (NMDA) receptor mRNA at 7 or 30 days after CA/CPR. Similarly, no change in synaptic NMDA receptor protein levels was observed at 7 or 30 days after CA/CPR. Further, patch-clamp experiments demonstrated no change in functional synaptic NMDA receptors at 7 or 30 days after CA/CPR. Electrophysiology recordings showed that synaptic SK channel activity was reduced for the duration of experiments performed (up to 30 days) and that, surprisingly, treatment with 1-EBIO did not prevent the CA/CPR-induced loss of synaptic SK channel function. We concluded that CA/CPR caused alterations in post-synaptic signaling that were prevented by treatment with the SK2 agonist 1-EBIO, indicating that activators of SK2 channels may be useful therapeutic agents to prevent ischemic injury and cognitive impairments.

Val/Leu247 polymorphism of β2-glycoprotein I and thrombosis in Chinese patients with SLE

INTRODUCTION

To determine the polymorphism at position 247 of the β2-glycoprotein I (β2GPI) gene in patients with systemic lupus erythematosus (SLE) and healthy controls in the Chinese Han Population and elucidate the relationship between β2GPI polymorphisms and anti-β2GPI levels, and furthermore investigate the correlation between β2GPI polymorphisms and thrombosis in patients with SLE.

METHODS

The β2GPI polymorphisms of 300 patients with SLE and 300 healthy controls were examined by single-specific-primer polymerase chain reaction (SSP-PCR), the efficacy of which was confirmed by sequencing technology. Anti-β2GPI antibodies were tested by enzyme-linked immunosorbent assay. β2GPI polymorphisms associated with thrombosis and the presence of anti-β2GPI antibodies were also statistically evaluated with SPSS software.

RESULTS

The genotype expressions and the allele frequencies were obtained in both patients with SLE and healthy controls. The SLE patients with thrombosis had significantly higher frequencies of the VV genotype and V allele than those without thrombosis and the controls, and there were no differences in VV genotype and V allele expression between the SLE patients without thrombosis and the controls. In contrast, the presence of anti-β2GPI antibody was related to the VV genotype of β2GPI, and the anti-β2GPI-positive patients had obviously higher frequencies of the VV genotype than the negative ones and the controls.

CONCLUSION

The study results suggested that the V/V genotype and the V-encoding allele at position 247 of the β2GPI gene had strong correlation with the occurrence of thrombosis and the production of the anti-β2GPI antibodies, showing that the Val(247) β2GPI allele may be one of the genetic risk factors for the development of thrombosis in patients with SLE.

A novel mouse model of pediatric cardiac arrest and cardiopulmonary resuscitation reveals age-dependent neuronal sensitivities to ischemic injury

BACKGROUND

Pediatric sudden cardiac arrest (CA) is an unfortunate and devastating condition, often leading to poor neurologic outcomes. However, little experimental data on the pathophysiology of pediatric CA is currently available due to the scarcity of animal models.

NEW METHOD

We developed a novel experimental model of pediatric cardiac arrest and cardiopulmonary resuscitation (CA/CPR) using postnatal day 20-25 mice. Adult (8-12 weeks) and pediatric (P20-25) mice were subjected to 6min CA/CPR. Hippocampal CA1 and striatal neuronal injury were quantified 3 days after resuscitation by hematoxylin and eosin (H&E) and Fluoro-Jade B staining, respectively.

RESULTS

Pediatric mice exhibited less neuronal injury in both CA1 hippocampal and striatal neurons compared to adult mice. Increasing ischemia time to 8 min CA/CPR resulted in an increase in hippocampal injury in pediatric mice, resulting in similar damage in adult and pediatric brains. In contrast, striatal injury in the pediatric brain following 6 or 8 min CA/CPR remained extremely low. As observed in adult mice, cardiac arrest causes delayed neuronal death in pediatric mice, with hippocampal CA1 neuronal damage maturing at 72 h after insult. Finally, mild therapeutic hypothermia reduced hippocampal CA1 neuronal injury after pediatric CA/CPR.

COMPARISON WITH EXISTING METHOD

This is the first report of a cardiac arrest and CPR model of global cerebral ischemia in mice.

CONCLUSIONS

Therefore, the mouse pediatric CA/CPR model we developed is unique and will provide an important new tool to the research community for the study of pediatric brain injury.

Evaluation of cancer dependence and druggability of PRP4 kinase using cellular, biochemical, and structural approaches

PRP4 kinase is known for its roles in regulating pre-mRNA splicing and beyond. Therefore, a wider spectrum of PRP4 kinase substrates could be expected. The role of PRP4 kinase in cancer is also yet to be fully elucidated. Attaining specific and potent PRP4 inhibitors would greatly facilitate the study of PRP4 biological function and its validation as a credible cancer target. In this report, we verified the requirement of enzymatic activity of PRP4 in regulating cancer cell growth and identified an array of potential novel substrates through orthogonal proteomics approaches. The ensuing effort in structural biology unveiled for the first time unique features of PRP4 kinase domain and its potential mode of interaction with a low molecular weight inhibitor. These results provide new and important information for further exploration of PRP4 kinase function in cancer.

Abstract 4376: Evaluation of PRP4 kinase as a potential drug target in cancer

PRP4 kinase plays a crucial role in regulating pre-mRNA splicing, cell cycle progression, proliferation, and survival. The aforementioned functions have been well documented in Schizosaccharomyces pombe, Caenorhabditis elegans, and human cancer cell lines. For example, it was demonstrated that PRP4 kinase is essential for growth in fission yeast, and disruption of C. elegans PRP4 by RNAi resulted in a highly penetrant early embryonic lethality. In experiments utilizing siRNAs to screen for kinases essential for pancreatic cancer cell survival, PRP4 knockdown was demonstrated to increase apoptosis and decrease viability. In a genome-wide pooled shRNA screen, shRNAs against PRP4 was shown to reduce the viability of DLD-1, HCT-116, and HCC1954 cancer cell lines. Similarly, PRP4 kinase was identified as a potential therapeutic target in a pooled shRNA screen designed to identify genes required for proliferation and survival of diffuse large B-cell lymphoma cell lines. Moreover, in an effort to reveal potential kinase targets to treat multidrug resistance ovarian cancer, inhibition of PRP4 activity by shRNAs was shown to re-sensitize chemo-resistant human ovarian cancer to paclitaxel treatment. Interestingly, loss of PRP4 kinase was also demonstrated to enhance paclitaxel activity in breast cancer cells. To further investigate PRP4 kinase substrate spectrum and explore the druggability of PRP4 kinase, we utilize quantitative proteomics and structural biology to help achieve these objectives. In this report, we provided evidence that the kinase domain of PRP4 is essential for regulating cell growth and survival. In addition, through a global proteomics approach, we expanded the interactome and phosphoproteome of PRP4 kinase in cancer cells and identifed novel substrates of PRP4, including oncogenic PAK4 kinase. Subsequently, these substrates were substantiated in orthogonal biochemical and cellular assays. These new biological findings not only identify suitable biomarkers to monitor PRP4 kinase activity, but also provide interesting avenues for future in-depth interrogation of PRP4 functions in cancer biology and clinical development. Finally, we solve the X-ray structure of the PRP4 kinase domain and identify several features suitable for the rational design of PRP4 kinase inhibitors. We further provided the co-crystal structure of PRP4 kinase domain in complex with a small molecule and elucidated the exploitable mechanisms to synthesize potent and specific PRP4 inhibitors. Future efforts will be focused on understanding patient stratification strategy and assessing the utility of PRP4 kinase inhibitors in relevant pre-clinical models of cancer.

Citation Format: Qiang Gao, Ingrid Mechin, Nayantara Kothari, Zhuyan Guo, Gejing Deng, Anlai Wang, Dmitri Wiederschain, Jennifer Rocnik, Werngard Czechtizky, Feng Liu, Tahir Majid, Vinod Patel, Christoph Lengauer, Carlos Garcia-Echeverria, Bailin Zhang, Hong Cheng, Marion Dorsch, Shih-Min A. Huang. Evaluation of PRP4 kinase as a potential drug target in cancer. [abstract]. In: Proceedings of the 104th Annual Meeting of the American Association for Cancer Research; 2013 Apr 6-10; Washington, DC. Philadelphia (PA): AACR; Cancer Res 2013;73(8 Suppl):Abstract nr 4376. doi:10.1158/1538-7445.AM2013-4376

Molecular cloning and characterization of GbDXS and GbGGPPS gene promoters from Ginkgo biloba

Ginkgolides are key pharmaceutical components in Ginkgo biloba leaves. 1-Deoxy-D-xylulose-5-phosphate synthase (GbDXS) and geranylgeranyl pyrophosphate (GbGGPPS) genes are critical genes involved in ginkgolide biosynthesis. In this study, the promoters of GbDXS and GGPPS, with 676 and 570 bp in length, respectively, were cloned by chromosome walking. The cis-elements of GbDXS and GbGGPPS promoters were predicted and analyzed by the plant cis-acting regulatory element (CARE) database. We found some major cis-elements in the sequence of GbDXS and GbGGPPS promoters. The GbDXS promoter has 3 TATA boxes, 10 CAAT boxes, 6 GATA boxes, and 1 I box. The GbGGPPS promoter has 1 TATA box, 6 CAAT boxes, 6 GATA boxes, and 4 I boxes. Furthermore, some stress-related cis-elements in the promoters of GbDXS and GbGGPPS were found to be light-regulated elements, including sequences over-represented in light-induced promoters (SORLIP1- AT), GATA box, and I box, a gibberellin-responsive element (WRKY), salicylic acid-induced (GT-1), cold- and dehydration-responsive (MYC-Core), and copper-inducible (CURE-Core). Further analyses of these cis-elements will aid in elucidating the molecular mechanisms regulating the expression of the GbDXS and GbGGPPS genes during ginkgolide accumulation in G. biloba.

Identification of elongation factor G as the conserved cellular target of argyrin B

Argyrins, produced by myxobacteria and actinomycetes, are cyclic octapeptides with antibacterial and antitumor activity. Here, we identify elongation factor G (EF-G) as the cellular target of argyrin B in bacteria, via resistant mutant selection and whole genome sequencing, biophysical binding studies and crystallography. Argyrin B binds a novel allosteric pocket in EF-G, distinct from the known EF-G inhibitor antibiotic fusidic acid, revealing a new mode of protein synthesis inhibition. In eukaryotic cells, argyrin B was found to target mitochondrial elongation factor G1 (EF-G1), the closest homologue of bacterial EF-G. By blocking mitochondrial translation, argyrin B depletes electron transport components and inhibits the growth of yeast and tumor cells. Further supporting direct inhibition of EF-G1, expression of an argyrin B-binding deficient EF-G1 L693Q variant partially rescued argyrin B-sensitivity in tumor cells. In summary, we show that argyrin B is an antibacterial and cytotoxic agent that inhibits the evolutionarily conserved target EF-G, blocking protein synthesis in bacteria and mitochondrial translation in yeast and mammalian cells.

Discovery of LFF571: an investigational agent for Clostridium difficile infection

Clostridium difficile (C. difficile) is a Gram positive, anaerobic bacterium that infects the lumen of the large intestine and produces toxins. This results in a range of syndromes from mild diarrhea to severe toxic megacolon and death. Alarmingly, the prevalence and severity of C. difficile infection are increasing; thus, associated morbidity and mortality rates are rising. 4-Aminothiazolyl analogues of the antibiotic natural product GE2270 A (1) were designed, synthesized, and optimized for the treatment of C. difficile infection. The medicinal chemistry effort focused on enhancing aqueous solubility relative to that of the natural product and previous development candidates (2, 3) and improving antibacterial activity. Structure-activity relationships, cocrystallographic interactions, pharmacokinetics, and efficacy in animal models of infection were characterized. These studies identified a series of dicarboxylic acid derivatives, which enhanced solubility/efficacy profile by several orders of magnitude compared to previously studied compounds and led to the selection of LFF571 (4) as an investigational new drug for treating C. difficile infection.

Integrative cancer care in a US academic cancer centre: The Memorial Sloan-Kettering Experience

Various surveys show that interest in complementary and alternative medicine (cam) is high among cancer patients. Patients want to explore all options that may help their treatment. Many cam modalities offer patients an active role in their self-care, and the resulting sense of empowerment is very appealing. On the other hand, many unscrupulous marketeers promote alternative cancer “cures,” targeting cancer patients who are particularly vulnerable. Some alternative therapies can hurt patients by delaying effective treatment or by causing adverse effects or detrimental interactions with other medications. It is not in the best interest of cancer patients if they cannot get appropriate guidance on the use of cam from the health care professionals who are part of their cancer care team.

The Integrative Medicine Service at Memorial Sloan–Kettering Cancer Center in New York was established in 1999 to address patient interest in cam, to incorporate helpful complementary therapies into each patient’s overall treatment management, to guide patients in avoiding harmful alternative therapies, and to develop prospective research to evaluate the efficacy of cam modalities.

Abstract P3-03-03: DNA Mutation as a Biomarker for Tracking Circulating Tumor Cells and Disseminated Tumor Cells in Breast Cancer Metastases

Introduction: Most cancer deaths are caused by metastatic disease. Tumor cells exit the primary tumor and travel through blood and/or lymphatic channels to distant sites. Circulating tumor cells (CTCs) from blood and disseminated tumor cells (DTCs) from bone marrow may play key roles in the metastatic process. Primary tumor heterogeneity and how the metastatic process evolves over time may confound the study of metastatic biology. To better distinguish the cells of origin in metastases, we developed new methodologies to isolate single tumor cells from tissues, blood, and bone marrow for DNA and RNA analyses. We compared these analyses in individual cells from primary and metastatic tumors, CTCs and DTCs. Materials and Methods: Single tumor cell suspensions from primary and metastatic tissues were prepared from fresh human specimens or mouse xenografts. Single cells were isolated from blood, bone marrow, or single tumor cell suspensions from tissue using EpCAM-conjugated microbeads and the MagSweeper, a device invented by our group. Unbounded microbeads were removed and the single cells were placed into individual PCR tubes for further nucleic acid analyses. Live CTCs and DTCs from some breast cancer patients were cultured for further testing. Single cell DNA mutational analyses were performed by multiplex PCR sequencing. Single cell transcriptional profiling was performed by multiplex qRT-PCR. Single tumor cells with mutations were compared among multiple compartments: primary tumor, metastatic tumor, blood and bone marrow. Array CGH analysis was used to focus single cell analysis on genes in potential areas of DNA deletion or amplification. Xenograft mouse models were generated using primary or tumor tissues and single cells were compared.

Results: Single tumor cells from fresh or fixed solid tumor tissues were successfully isolated for nucleic acid analyses. CTCs and DTCs isolated by MagSweeper from breast cancer patients could be isolated live and cultured or injected for growth in xenografts. Single cell DNA mutation analysis of the PIK3CA gene was identified in 3/27 breast cancer patients, showing the mutation in only 45/178 single tumor cells. Sequential PIK3CA mutational analyses of CTCs, DTCs, and metastases showed that DTCs better reflected the mutational status of metastases at time points earlier in the metastatic process.

Discussion: Our results indicate that isolating single tumor cells from tumor tissues, blood, and bone marrow provides detailed information about different tumor compartments in individual cancer patients. Single cell DNA mutational analysis can provide a biomarker for tracking CTCs and DTCs over time during the metastatic process. Based on our initial findings, we postulate that the bone marrow serves as a tumor cell reservoir for early metastatic spread in breast cancer.

Citation Information: Cancer Res 2010;70(24 Suppl):Abstract nr P3-03-03.