Improvement of a predictive model in ovarian cancer patients submitted to platinum-based chemotherapy: implications of a GST activity profile

Up-regulation of GSTT1 in serous ovarian cancer associated with resistance to TAXOL / carboplatin

Serous ovarian cancer (SOC) is the most common women cancer and the leading cause of cancer-related mortality among the gynaecological malignancies. Although effective chemotherapeutics combined with surgery are developed for the treatment, the five-year survival rate is unsatisfactory due to chemoresistance. To overcome this shortcoming of chemotherapy, we established taxol and carboplatin resistant SOC cell lines for the understandings of the molecular and cellular mechanisms of chemoresistance. Here, we found that these chemoresistant cell lines showed less viability and proliferation, due to more cells arrested at G0/G1 phase. Glutathione-S-transferases-theta1 (GSTT1) was significantly upregulated in these chemoresistant cells, along with other chemoresistant genes. Meanwhile, GSTT1 expression was also significantly upregulated in the SOC patient tissues after taxol treatment, indicating this upregulation was physiologically relevant to chemotherapy. Further, suppression of GSTT1 expression by shRNA in SOC cell lines led to more sensitivity to drug treatment, through increasing divided cells and promoting cell death. Moreover, the expression of DNA topoisomerase 1 (Topo I) was in synergy with that of GSTT1 in the chemoresistant cells, and GSTT1 can bind to Topo I in vitro, which suggested GSTT1 could function through DNA repair mechanism during chemoresistance. In summary, our data imply that GSTT1 may be a potential biomarker or indicator of drug resistance in serous ovarian cancer.

GSTZ1 sensitizes hepatocellular carcinoma cells to sorafenib-induced ferroptosis via inhibition of NRF2/GPX4 axis

Increasing evidence supports that ferroptosis plays an important role in tumor growth inhibition. Sorafenib, originally identified as an inhibitor of multiple oncogenic kinases, has been shown to induce ferroptosis in hepatocellular carcinoma (HCC). However, some hepatoma cell lines are less sensitive to sorafenib-induced ferroptotic cell death. Glutathione S-transferase zeta 1 (GSTZ1), an enzyme in the catabolism of phenylalanine, suppresses the expression of the master regulator of cellular redox homeostasis nuclear factor erythroid 2-related factor 2 (NRF2). This study aimed to investigate the role and underlying molecular mechanisms of GSTZ1 in sorafenib-induced ferroptosis in HCC. GSTZ1 was significantly downregulated in sorafenib-resistant hepatoma cells. Mechanistically, GSTZ1 depletion enhanced the activation of the NRF2 pathway and increased the glutathione peroxidase 4 (GPX4) level, thereby suppressing sorafenib-induced ferroptosis. The combination of sorafenib and RSL3, a GPX4 inhibitor, significantly inhibited GSTZ1-deficient cell viability and promoted ferroptosis and increased ectopic iron and lipid peroxides. In vivo, the combination of sorafenib and RSL3 had a synergic therapeutic effect on HCC progression in Gstz1^-/- mice. In conclusion, this finding demonstrates that GSTZ1 enhanced sorafenib-induced ferroptosis by inhibiting the NRF2/GPX4 axis in HCC cells. Combination therapy of sorafenib and GPX4 inhibitor RSL3 may be a promising strategy in HCC treatment.

Genetic Polymorphisms and the Efficacy of Platinum-Based Chemotherapy: Review

Previous studies have indicated that genetic variations in individuals may result in changes in gene expression and amino acids. The effect of these changes may lead to different responses to platinum-based chemotherapy. A vast response rate interval and a short survival rate indicate that the efficacy and efficiency of the selection of chemotherapy have not been optimized. This article aims to illustrate the potential relationship of various genetic polymorphisms in response to platinum-based chemotherapy for several types of cancer. This review was conducted using articles from the last three- and five-year periods (2014-2019) that use gene polymorphism and its relationship to the efficacy of platinum-based chemotherapy as their theme. A total of 26 out of 488 relevant articles were included based on specific criteria. Through various mechanisms, genes, including ERCC1, ERCC2/XPD, XPC, XPA, XRCC1, APE-1, PARP1, OGG1, ABCC2, MRP, GSTP1, GSTM1, GSTT1, MATE1, and OCT2, have been associated with patient response to platinum-based chemotherapy. We conclude that genetic polymorphism analysis is recommended for the management of cancer so that each patient can be administered therapy based on his or her genetic profile to achieve an effective and efficient outcome.

A Positive Feedback Loop of lncRNA DSCR8/miR-98-5p/STAT3/HIF-1α Plays a Role in the Progression of Ovarian Cancer

Background

Accumulating studies have revealed that long non-coding RNA (lncRNA) and microRNA (miRNA) contribute to ovarian cancer (OC). DSCR8 has been found to mediate hepatocellular carcinoma development, while its role in OC remains to be explored.

Methods

In this study, lncRNA DSCR8 and miR-98-5p expressions in OC tissues and adjacent non-cancer tissues were determined by reverse transcriptase polymerase chain reaction (RT-PCR). Besides, gain-of-function or loss-of-function assays of DSCR8 and miR-98-5p were conducted on OC cell lines SKOV-3 and A2780. Cell proliferation was detected with Cell Counting Kit (CCK)8 and colony formation assay, and western blot was used to test the apoptotic levels of OC cells. Transwell assay was conducted to examine cell invasion, and the epithelial–mesenchymal transition (EMT) of OC cells was tested by western blot. Moreover, luciferase activity assay and RNA immunoprecipitation (RIP) assay were conducted to verify the relationships between DSCR8 and miR-98-5p, miR-98-5p, and signal transducer and activator of transcription 3 (STAT3).

Results

DSCR8 was remarkedly increased in OC tissues and associated with poorer survival of OC patients. Overexpressing DSCR8 promoted cell proliferation, invasion, and EMT but inhibited apoptosis. On the other hand, miR-98-5p was downregulated in OC tissues and relieved the progression of OC. Moreover, overexpressed DSCR8 increased the levels of STAT3 and hypoxia inducible factor 1 alpha (HIF-1α) and dampened the functions of miR-98-5p on OC. Pharmaceutical intervention of STAT3 and HIF-1α significantly altered the expressions of DSCR8 and miR-98-5p.

Conclusion

The present results suggested a positive feedback loop of lncRNA DSCR8/miR-98-5p/STAT3/HIF-α axis in the progression of OC.

Colorectal cancer: pharmacogenetics support for the correct drug prescription

Pharmacogenetics (PGx) in clinical practice is a tool that the clinician can use to guide, in a personalized way, the most suitable treatment that will be administered to the patient. The objective of this review is to summarize in a practical and accessible rational way, the advances that currently exist for the application of PGx in colorectal cancer chemotherapy management through the study of the patients' germline polymorphisms. To define the polymorphisms that can be applied, we rely on three fundamental cornerstones: the recommendations of drug regulatory agencies; the implementation guidelines prepared by expert consortia in PGx and information from clinical annotations (the drug/polymorphism relation) according to the scientific level of evidence assigned by PharmGKB experts.

Pharmacogenomics in epithelial ovarian cancer first-line treatment outcome: validation of GWAS-associated NRG3 rs1649942 and BRE rs7572644 variants in an independent cohort

The identification of predictive biomarkers for the first-line treatment of epithelial ovarian cancer (EOC) remains a challenge. Although genome-wide association studies (GWAS) have identified several genetic polymorphisms as predictors of EOC clinical outcome, the subsequent validation has not yet been performed. This study aims to validate the influence of Neuregulin 3 (NRG3) rs1649942 and Brain and reproductive organ-expressed (TNFRSF1A modulator) (BRE) rs7572644 GWAS-identified variants in an independent cohort of EOC patients from the North region of Portugal (n = 339) submitted to first-line treatment. Polymorphism genotypes were determined by real-time PCR using validated assays. Patients carrying the NRG3 rs1649942 A allele presented a significantly longer overall survival (OS) when compared to GG-genotype patients (log-rank test, P = 0.011) in the FIGO IV stage subgroup. No impact was observed for early-stage patients or considering disease-free survival (DFS) as an outcome. For FIGO I/II stage patients, BRE rs7572644 C allele carriers exhibit a decreased OS (P = 0.014) and DFS (P = 0.032) when compared to TT-homozygous patients. Furthermore, a Multivariate Cox regression analysis revealed a three-fold increase in the risk of death (HR, 3.09; P = 0.015) and recurrence (HR, 3.33; P = 0.009) for FIGO I/II C allele carriers. No significant impact was observed for late-stage patients. The BRE rs7572644 and NRG3 rs1649942 genetic variants were validated in an independent cohort of EOC Portuguese patients, particularly in specific subgroups considering FIGO staging. Further functional post-GWAS analyses are indispensable to understand the biological mechanisms underlying the observed results.

Role of Hydroxysteroid Dehydrogenase-Like 2 (HSDL2) in Human Ovarian Cancer

Background

Ovarian cancer is a common type of malignant neoplasm. Its prognosis is poor because the disease is not well understood. Abnormal lipometabolism in peroxisomes is involved in tumor progression and hydroxysteroid dehydrogenase-like 2 (HSDL2), localized in peroxisomes, might be a regulatory factor in lipometabolism. However, the role of HSDL2 in ovarian cancer progression remains unknown.

Material/Methods

HSDL2 expression was detected by qPCR and immunohistochemistry in ovarian tumor samples and qPCR in human ovarian cancer cell lines. Cell proliferation was measured by Celigo and MTT assay. Cell cycle distribution and apoptosis were determined using flow cytometry. Giemsa staining was used for analyzing colony formation. Cell motility was performed using Transwell migration and invasion assays. Tumorigenesis in nude mice was also detected.

Results

HSDL2 expression was upregulated in human ovarian cancer samples and in 3 human ovarian cancer cell lines: SKOV3, HO8910, and OVCAR-3. Higher expression of HSDL2 in ovarian tumor samples was associated with more progressed tumors (P=0.03) and lymphatic metastases (P=0.03). HSDL2 down-regulation by lentiviral-mediated HSDL2 knockdown suppressed cell proliferation, colony formation, and cell motility, while it promoted cell apoptosis and resulted in cell cycle arrest at the G0/G1 phase in human ovarian cancer cell lines OVCAR-3 and SKOV3. HSDL2 knockdown also inhibited tumorigenesis in mouse models.

Conclusions

This study shows that HSDL2 upregulation is associated with ovarian cancer progression. HSDL2 knockdown inhibited cell proliferation, colony formation, motility, and tumorigenesis. It induced apoptosis and cell cycle arrest and might therefore serve as a potential target for ovarian cancer therapy.

Rethinking ovarian cancer genomics: where genome-wide association studies stand?

Genome-wide association studies (GWAS) allow the finding of genetic variants associated with several traits. Regarding ovarian cancer (OC), 15 GWAS have been conducted since 2009, with the discovery of 49 SNPs associated with disease susceptibility and 46 with impact in the clinical outcome of patients (p < 5.00 × 10-2). Among them, 14 variants reached the genome-wide significance (p < 5.00 × 10−8). Despite the results obtained, they should be validated in independent sets. So far, five validation studies have been conducted which could confirm the association of 12 OC susceptibility SNPs. Consequently, post-GWAS studies are crucial unravel the biological plausibility of GWAS’ findings and the allelic spectrum of OC.

Genetic variants as ovarian cancer first-line treatment hallmarks: A systematic review and meta-analysis

BACKGROUND

The potential predictive value of genetic polymorphisms in ovarian cancer first-line treatment is inconsistently reported. We aimed to review ovarian cancer pharmacogenetic studies to update and summarize the available data and to provide directions for further research.

METHODS

A systematic review followed by a meta-analysis was conducted on cohort studies assessing the involvement of genetic polymorphisms in ovarian cancer first-line treatment response retrieved through a MEDLINE database search by November 2016. Studies were pooled and summary estimates and 95% confidence intervals (CI) were calculated using random or fixed-effects models as appropriate.

RESULTS

One hundred and forty-two studies gathering 106871 patients were included. Combined data suggested that GSTM1-null genotype patients have a lower risk of death compared to GSTM1-wt carriers, specifically in advanced stages (hazard ratio (HR), 0.68; 95% CI, 0.48-0.97) and when submitted to platinum-based chemotherapy (aHR, 0.61; 95% CI, 0.39-0.94). ERCC1 rs11615 and rs3212886 might have also a significant impact in treatment outcome (aHR, 0.67; 95% CI, 0.51-0.89; aHR, 1.28; 95% CI, 1.01-1.63, respectively). Moreover, ERCC2 rs13181 and rs1799793 showed a distinct ethnic behavior (Asians: aHR, 1.41; 95% CI, 0.80-2.49; aHR, 1.07; 95% CI, 0.62-1.86; Caucasians: aHR, 0.10; 95% CI, 0.01-0.96; aHR, 0.18; 95% CI, 0.05-0.68, respectively).

CONCLUSION(S)

The definition of integrative predictive models should encompass genetic information, especially regarding GSTM1 homozygous deletion. Justifying additional pharmacogenetic investigation are variants in ERCC1 and ERCC2, which highlight the DNA Repair ability to ovarian cancer prognosis. Further knowledge could aid to understand platinum-treatment failure and to tailor chemotherapy strategies.

Unusual gastrointestinal and cutaneous toxicities by bleomycin, etoposide, and cisplatin: a case report with pharmacogenetic analysis to personalize treatment

The standard treatment of testicular germ cell tumors is based on the combination of bleomycin, etoposide, and cisplatin (PEB). However, this treatment may be associated with severe adverse reactions, such as hematological and non-hematological toxicities. Here, we report a case of a patient suffering from severe PEB-related toxicities, to whom pharmacogenetic analyses were performed, comprising a panel of genes involved in PEB metabolism. The analysis revealed the presence of a complex pattern of polymorphisms in GSTP1, UGT1A1 (TA)6/7, UGT1A7, and ABCB1. The present case shows that a pharmacogenetic approach can help in the management of adverse drug reactions in order to predict, prevent, and personalize treatments.

Pharmacogenomics in Pediatric Oncology: Review of Gene-Drug Associations for Clinical Use

During the 3rd congress of the European Society of Pharmacogenomics and Personalised Therapy (ESPT) in Budapest in 2015, a preliminary meeting was held aimed at establishing a pediatric individualized treatment in oncology and hematology committees. The main purpose was to facilitate the transfer and harmonization of pharmacogenetic testing from research into clinics, to bring together basic and translational research and to educate health professionals throughout Europe. The objective of this review was to provide the attendees of the meeting as well as the larger scientific community an insight into the compiled evidence regarding current pharmacogenomics knowledge in pediatric oncology. This preliminary evaluation will help steer the committee’s work and should give the reader an idea at which stage researchers and clinicians are, in terms of personalizing medicine for children with cancer. From the evidence presented here, future recommendations to achieve this goal will also be suggested.

Association between polymorphisms in xenobiotic detoxification-related genes with prognosis of epithelial ovarian cancer

This study aimed to evaluate whether GSTM1 and GSTT1 (presents or nulls), GSTP1 c.313A>G and NQO2 c.-102A>C polymorphisms, involved in xenobiotic detoxification pathways, alter outcomes of epithelial ovarian cancer (EOC) patients. DNA from 84 EOC patients diagnosed at the University of Campinas Academic Hospital from January 1995 and July 2007 was analyzed by polymerase chain reaction and restriction fragment length polymorphism assays. The prognostic impact of genotypes of polymorphisms on progression-free survival and overall survival (OS) of EOC patients was examined using the Kaplan-Meier probability estimates and univariate and multivariate Cox proportional hazard ratio (HR) regression analyses. The significant results of Cox analyses were validated using a bootstrap resampling study (1000 replications). At 60 months of follow-up, lower OS was seen in patients with GSTT1 null genotype (50.0 vs. 76.7 %, P = 0.02) compared with the other genotype (Kaplan-Meier estimate). This outcome remained the same in univariate Cox analysis (HR 2.22, P = 0.02). After multivariate Cox analysis, patients with GSTT1 null (HR 2.11, P = 0.04, P bootstrap = 0.04) and NQO2 AA (HR 2.13, P = 0.03, P bootstrap = 0.04) genotypes were under greater risks of progressing to death when compared with those with others genotypes. Our data suggest, for the first time, that inherited abnormalities in xenobiotic detoxification pathway related to GSTT1 and NQO2 c.-102A>C polymorphisms act as independent prognostic factors for OS of EOC patients.