A DERL3-associated defect in the degradation of SLC2A1 mediates the Warburg effect

Cancer cells possess aberrant proteomes that can arise by the disruption of genes involved in physiological protein degradation. Here we demonstrate the presence of promoter CpG island hypermethylation-linked inactivation of DERL3 (Derlin-3), a key gene in the endoplasmic reticulum-associated protein degradation pathway, in human tumours. The restoration of in vitro and in vivo DERL3 activity highlights the tumour suppressor features of the gene. Using the stable isotopic labelling of amino acids in cell culture workflow for differential proteome analysis, we identify SLC2A1 (glucose transporter 1, GLUT1) as a downstream target of DERL3. Most importantly, SLC2A1 overexpression mediated by DERL3 epigenetic loss contributes to the Warburg effect in the studied cells and pinpoints a subset of human tumours with greater vulnerability to drugs targeting glycolysis.Seventh Framework Programme (European Commission) (Grant HEALTH-F5-2010-258236-SYSCOL)Seventh Framework Programme (European Commission) (Grant HEALTH-F2-2011-259015-COLTHERES)Cellex FoundationOlga Torres FoundationEuropean Research Council (EPINORC Project Grant Agreement 268626)Spain. Ministerio de Economia y Competividad (MINECO Project SAF2011-22803)Institute of Health Carlos III (RTICC Grant RD12/0036/0039

Vitamin D deficiency causes inward hypertrophic remodeling and alters vascular reactivity of rat cerebral arterioles

BACKGROUND AND PURPOSE: Vitamin D deficiency (VDD) is a global health problem, which can lead to several pathophysiological consequences including cardiovascular diseases. Its impact on the cerebrovascular system is not well understood. The goal of the present work was to examine the effects of VDD on the morphological, biomechanical and functional properties of cerebral arterioles. METHODS: Four-week-old male Wistar rats (n = 11 per group) were either fed with vitamin D deficient diet or received conventional rat chow with per os vitamin D supplementation. Cardiovascular parameters and hormone levels (testosterone, androstenedione, progesterone and 25-hydroxyvitamin D) were measured during the study. After 8 weeks of treatment anterior cerebral artery segments were prepared and their morphological, biomechanical and functional properties were examined using pressure microangiometry. Resorcin-fuchsin and smooth muscle actin staining were used to detect elastic fiber density and smooth muscle cell counts in the vessel wall, respectively. Sections were immunostained for eNOS and COX-2 as well. RESULTS: VDD markedly increased the wall thickness, the wall-to-lumen ratio and the wall cross-sectional area of arterioles as well as the number of smooth muscle cells in the tunica media. As a consequence, tangential wall stress was significantly lower in the VDD group. In addition, VDD increased the myogenic as well as the uridine 5'-triphosphate-induced tone and impaired bradykinin-induced relaxation. Decreased eNOS and increased COX-2 expression were also observed in the endothelium of VDD animals. CONCLUSIONS: VDD causes inward hypertrophic remodeling due to vascular smooth muscle cell proliferation and enhances the vessel tone probably because of increased vasoconstrictor prostanoid levels in young adult rats. In addition, the decreased eNOS expression results in endothelial dysfunction. These morphological and functional alterations can potentially compromise the cerebral circulation and lead to cerebrovascular disorders in VDD

Epigenetic inactivation of the putative DNA/RNA helicase SLFN11 in human cancer confers resistance to platinum drugs

Platinum-derived drugs such as cisplatin and carboplatin are among the most commonly used cancer chemotherapy drugs, but very few specific molecular and cellular markers predicting differential sensitivity to these agents in a given tumor type have been clearly identified. Epigenetic gene silencing is increasingly being recognized as a factor conferring distinct tumoral drug sensitivity, so we have used a comprehensive DNA methylation microarray platform to interrogate the widely characterized NCI60 panel of human cancer cell lines with respect to CpG methylation status and cisplatin/carboplatin sensitivity. Using this approach, we have found promoter CpG island hypermethylation-associated silencing of the putative DNA/RNA helicase Schlafen-11 (SLFN11) to be associated with increased resistance to platinum compounds. We have also experimentally validated these findings in vitro. In this setting, we also identified the BRCA1 interacting DHX9 RNA helicase (also known as RHA) as a protein partner for SLFN11, suggesting a mechanistic pathway for the observed chemoresistance effect. Most importantly, we have been able to extend these findings clinically, following the observation that those patients with ovarian and non-small cell lung cancer carrying SLFN11 hypermethylation had a poor response to both cisplatin and carboplatin treatments. Overall, these results identify SLFN11 epigenetic inactivation as a predictor of resistance to platinum drugs in human cancer

Logical Imputation to Optimize Prognostic Risk Classification in Metastatic Renal Cell Cancer

BACKGROUND: Application of the MSKCC and IMDC models is recommended for prognostication in metastatic renal cell cancer (mRCC). Patient classification in MSKCC and IMDC risk groups in real-world observational studies is often hampered by missing data on required pre-treatment characteristics. OBJECTIVES: To evaluate the effect of application of easy-to-use logical, or deductive, imputation on MSKCC and IMDC risk classification in an observational study setting. PATIENTS AND METHODS: We used data on 713 mRCC patients with first-line sunitinib treatment from our observational European multi-centre study EuroTARGET. Pre-treatment characteristics and follow-up were derived from medical files. Hospital-specific cut-off values for laboratory measurements were requested. The effect of logical imputation of missing data and consensus versus hospital-specific cut-off values on patient classification and the subsequent models' predictive performance for progression-free and overall survival (OS) was evaluated. RESULTS: 45% of the patients had missing data for >= 1 pre-treatment characteristic for either model. Still, 72% of all patients could be unambiguously classified using logical imputation. Use of consensus instead of hospital-specific cut-offs led to a shift in risk group for 12% and 7% of patients for the MSKCC and IMDC model, respectively. Using logical imputation or other cut-offs did not influence the models' predictive performance. These were in line with previous reports (c-statistic similar to 0.64 for OS). CONCLUSIONS: Logical imputation leads to a substantial increase in the proportion of patients that can be correctly classified into poor and intermediate MSKCC and IMDC risk groups in observational studies and its use in the field should be advocated

Epigenetic Inactivation of the BRCA1 Interactor SRBC and Resistance to Oxaliplatin in Colorectal Cancer

BACKGROUND: A major problem in cancer chemotherapy is the existence of primary resistance and/or the acquisition of secondary resistance. Many cellular defects contribute to chemoresistance, but epigenetic changes can also be a cause. METHODS: A DNA methylation microarray was used to identify epigenetic differences in oxaliplatin-sensitive and -resistant colorectal cancer cells. The candidate gene SRBC was validated by single-locus DNA methylation and expression techniques. Transfection and short hairpin experiments were used to assess oxaliplatin sensitivity. Progression-free survival (PFS) and overall survival (OS) in metastasic colorectal cancer patients were explored with Kaplan-Meier and Cox regression analyses. All statistical tests were two-sided. RESULTS: We found that oxaliplatin resistance in colorectal cancer cells depends on the DNA methylation-associated inactivation of the BRCA1 interactor SRBC gene. SRBC overexpression or depletion gives rise to sensitivity or resistance to oxaliplatin, respectively. SRBC epigenetic inactivation occurred in primary tumors from a discovery cohort of colorectal cancer patients (29.8%; n = 39 of 131), where it predicted shorter PFS (hazard ratio [HR] = 1.83; 95% confidence interval [CI] = 1.15 to 2.92; log-rank P = .01), particularly in oxaliplatin-treated case subjects for which metastasis surgery was not indicated (HR = 1.96; 95% CI = 1.13 to 3.40; log-rank P = .01). In a validation cohort of unresectable colorectal tumors treated with oxaliplatin (n = 58), SRBC hypermethylation was also associated with shorter PFS (HR = 1.90; 95% CI = 1.01 to 3.60; log-rank P = .045). CONCLUSIONS: These results provide a basis for future clinical studies to validate SRBC hypermethylation as a predictive marker for oxaliplatin resistance in colorectal cancer

<i>hSRBC</i> promoter CpG island hypermethylation as resistant predictive biomarker of oxaliplatin based chemotherapy in metastasic colorectal cancer patients.

e14609 Background: Resistance acquisition to chemotherapeutic agents is one of the main problems that come up during cancer treatment. hSRBC is a tumor suppressor gene whose inactivation has been associated with malignant tumor progression. In a previous work, we investigated the influence of hSRBC promoter methylation alterations in oxaliplatin (OXA) resistance acquisition by using a CRC “in vitro” model, detecting an hSRBC promoter hypermethylation in OXA–resistant derived cells when compared with the sensitive counterpart. These results were validated by functional analyses in the same model. Taking this into account, our aim in the present work is to determine the role of hSRBC methylation status as a potential biomarker of OXA resistance, in metastatic CRC patients, treated at first line with fluouropirimidines plus OXA based chemotherapy. Methods: hSRBC promoter hypermethylation was analyzed in DNA extracted from paraffin embebbed tissue of 111 metastatic CRC tumors by using Methylation Specific PCR. Methylation data was correlated to overall response (OR) and progression free survival (PFS) by using F-Fisher test and Kaplan-Meyer Survival curves respectively. A multivariate analysis was carried out by Cox regression. p-values under 0.05 were considered statistic significant. Results: Two independent cohorts of stage IV CRC tumors were included. Twenty-two out of 111 patients received radical surgery for metastasis, that became to be a positive prognostic factor (p-value = 0.04). Gene hypermethylation was detected in a 33% of cases. Although OR was not associated with hSRBC methylation, we observed a significant correlation between hypermethylation of gene and a worse PFS in patients without metastasis surgery (Log Rank; p-value = 0.04). Conclusions: Remarkably, hSRBC promoter hypermethylation is associated with worse PFS in metastatic CRC patients. We suggest hSRBC methylation status as a predictive biomarker of OXA-based treatment outcome in metastatic CRC patients. However, further studies are warranted in order to elucidate the clinical application of these findings. </jats:p

Abstract 5478: Curcumin mediates reversion to oxaliplatin-acquired resistance in colorectal cancer cell lines through modulation of nuclear factor κB (NFκB) and cyclin-dependent kinase 5 (CDK5)

Abstract Background: In previous work we have observed hyper-activation of the transcription factor (TF) NF-κB and an up-regulation of the Cyclin-dependent kinase 5 (CDK5) in human colorectal cancer cell lines with acquired resistance to oxaliplatin (OXA). Moreover, OXA treatment induced NF-κB activation. Curcumin (diferuloylmethane, CURC), the major active ingredient of turmeric (Curcuma longa), without discernable toxicity, has been shown to inhibit the growth of colon tumor cells in vitro and in vivo partly by suppressing activation of NF-κB. The aim of this study was to demonstrate whether a combined treatment with CURC and OXA could revert the acquired resistance phenotype to the latter in in vitro models and to elucidate the molecular mechanisms behind this effect. Material and Methods: HT29- and LoVo-derived OXA-resistant HTOXAR3 and LoVOXAR3 cells (p53 mutant and WT respectively) as well as HCT116 and its isogenic derivative with a targeted inactivation of p53 (HCT116 p53 null) cell lines were used in the present study. The IC50s and combination index for CURC and OXA in the six cell lines was determined by MTT assay and the data was analysed using the median effect lines and the Chou and Talalay method, respectively. Survival and clonogenic expansion of cells after OXA and CURC treatment was assessed by colony assay. Cell death was measured by flow cytometry and propidium iodide staining. Dose-response-associated phosphorylation status of P65 (S536), IκBα(S32/S36) and expression of Survivin and CDK5 was analysed by Western Blotting after oxaliplatin and CURC treatments. Nuclear translocation of p65 was assessed by inmunocytochemistry. Results: CURC had a similar effect on proliferation in all cell lines (IC50 range 7.5-14.7uM). In terms of synergism, the best combination of CURC and OXA was the 24h concomitant treatment. CURC inhibited OXA-induced activation of NF-κB, downregulated the expression of Survivin, an NF-κB-regulated gene product, and it also inhibited CDK5 expression in a dose-dependent manner. Combination of OXA and CURC resulted in an OXA resistance reversion in HTOXAR3, LoVOXAR3 and HCT116 p53 null cells but it was only synergistic in HTOXAR3 and HCT116 p53 null cells, suggesting a possible role of p53 on OXA/CURC synergism. The concomitant treatment also reduced the number of colonies formed compared with OXA or CURC alone. This was further supported by preliminary experiments showing that the combination also increased cell death. Conclusions: These results demonstrate that the OXA/CURC combination can revert OXA acquired resistance in our resistant models through the inhibition of the NFκB TF and for the first time, suggest a role of CDK5 in the CURC mechanism of action. Further experiments are ongoing in order to elucidate a possible link between CDK5 and NF-κB, and their role in acquisition of OXA resistance. Citation Format: Vicenç Ruiz de Porras, Sara Bystrup, Anna Martinez-Cardus, Alba Ginés, Laura Layos, José Luis Manzano, Cristina Bugés, Albert Abad, Eva Martinez-Balibrea. Curcumin mediates reversion to oxaliplatin-acquired resistance in colorectal cancer cell lines through modulation of nuclear factor κB (NFκB) and cyclin-dependent kinase 5 (CDK5). [abstract]. In: Proceedings of the 106th Annual Meeting of the American Association for Cancer Research; 2015 Apr 18-22; Philadelphia, PA. Philadelphia (PA): AACR; Cancer Res 2015;75(15 Suppl):Abstract nr 5478. doi:10.1158/1538-7445.AM2015-5478</jats:p