Association of expression of p53, livin, ERCC1, BRCA1 and PARP1 in epithelial ovarian cancer tissue with drug resistance and prognosis

MUL1 identified as mitochondria-linked biomarker promoting cisplatin resistance in OC cells

Ovarian cancer (OC) ranks among the prevalent tumors affecting the female reproductive system. The aim of this study was to evaluate mitochondria-associated platinum resistance genes using organoid models. Univariate Cox regression, LASSO and multivariate Cox regression analyses were performed on The Cancer Genome Atlas (TCGA) database to construct 2-gene prognostic signature (MUL1 and SSBP1), and GSE26712 dataset was used for external validation. In addition, the relationship between MUL1 and platinum resistance was examined by organoid culture, lentiviral transduction, CCK8 assay, and Western blot. The results showed that patients in the high-risk group exhibited significantly worse OS (P = 0.002, P = 0.017). Drug sensitivity analysis revealed that platinum resistance increased with the upregulation of MUL1 expression (Cor = 0.5154, P = 0.02). Our experimental findings demonstrated that knockout of the MUL1 gene significantly increased apoptosis and enhanced the sensitivity of the OC cell line A2780 to cisplatin. Through this study, we have provided strong evidence for further research on prognostic risk factors and individualized treatment in OC patients, and provided new insights into addressing platinum resistance in OC.

PARP1 expression predicts PARP inhibitor sensitivity and correlates with metastatic potential and overall survival in melanoma

Metastatic melanoma is still a difficult-to-treat cancer type owing to its frequent resistance mechanisms to targeted and immunotherapy. Therefore, we aimed to unravel novel therapeutic strategies for melanoma patients. Preclinical and clinical studies show that melanoma patients may benefit from a treatment with poly (ADP-ribose) polymerase (PARP) inhibitors (PARPi). In this study, we focus on PARP1 as a potential biomarker to predict the response of melanoma cells to PARPi therapy. We found that melanoma cells with high basal PARP1 expression exhibit significantly increased cell death after PARPi treatment owing to higher PARP1 trapping compared with melanoma cells with low PARP1 expression. In addition, we could demonstrate that PARP1 expression levels are low in nonmalignant skin cells, and metastatic melanomas show considerably higher PARP1 levels compared with primary melanomas. Most strikingly, we found that high PARP1 levels correlate with worse overall survival of late stage metastasized melanoma patients. In conclusion, we show that PARP1 might act as a biomarker to predict the response to PARPi therapy, and that in particular the late stage metastasized melanoma patients are especially sensitive to PARPi therapy owing to elevated PARP1 expression. Our data suggest that the PARPi cytotoxicity primarily will affect the high PARP1 expressing melanoma cells, rather than the low PARP1 expressing nonmalignant skin cells resulting in only low side effects.

Mechanisms of Drug Resistance in Ovarian Cancer and Associated Gene Targets

In the United States, over 100,000 women are diagnosed with a gynecologic malignancy every year, with ovarian cancer being the most lethal. One of the hallmark characteristics of ovarian cancer is the development of resistance to chemotherapeutics. While the exact mechanisms of chemoresistance are poorly understood, it is known that changes at the cellular and molecular level make chemoresistance challenging to treat. Improved therapeutic options are needed to target these changes at the molecular level. Using a precision medicine approach, such as gene therapy, genes can be specifically exploited to resensitize tumors to therapeutics. This review highlights traditional and novel gene targets that can be used to develop new and improved targeted therapies, from drug efflux proteins to ovarian cancer stem cells. The review also addresses the clinical relevance and landscape of the discussed gene targets.

High Expression of PARP1 in Tumor and Stroma Cells Predicts Different Prognosis and Platinum Resistance in Patients With Advanced Epithelial Ovarian Cancer

Objective

This study aimed to explore the roles of PARP1 mRNA and protein expression in platinum resistance and prognosis of EOC patients, and reveal the different roles of PARP1 protein in epithelial tumor and stroma cells.

Methods

The PARP1 mRNA expression of the EOC tissues was examined by RT-qPCR. The impacts of PARP1 expression on prognosis were measured by Kaplan-Meier and Cox regression. Receiver operating characteristic (ROC) curve analysis was employed for calculating the diagnostic value of PARP1 on platinum resistance. The microarray of formalin-fixed, paraffin-embedded (FFPE) tissues was processed for multiplex immunofluorescence to detect the protein levels of PARP1 and cytokeratin (CK).

Results

The PARP1mRNA expression of EOC patients was higher in the platinum-resistant group compared with the sensitive group (P<0.01). Kaplan-Meier analysis demonstrated that high PARP1 mRNA expression was associated with poor survival of EOC patients. In Cox regression analyses, high PARP1 mRNA expression independently predicted poor prognosis (P=0.001, HR=2.076, 95%CI=1.373-3.140). The area under the ROC curve of PARP1 mRNA for predicting the platinum resistance in EOC patients was 0.649, with a sensitivity of 0.607 and specificity of 0.668. Furthermore, the protein expression of PARP1 was higher in the platinum-resistant group than in the sensitive group (P<0.01) and associated with a worse prognosis. Additionally, according to CK labeling, we observed that enhanced expression of PARP1 in the CK+ region was associated with platinum resistance and lower survival, but in CK- region, it predicted a good prognosis and platinum sensitivity.

Conclusion

PARP1 may be a potential biomarker to predict platinum resistance and prognosis for EOC patients, exerting different roles on epithelial tumor and stromal cells.

YTHDF3 Facilitates eIF2AK2 and eIF3A Recruitment on mRNAs to Regulate Translational Processes in Oxaliplatin-Resistant Colorectal Cancer

Oxaliplatin, as a first-line drug, frequently causes chemo-resistance in colorectal cancer (CRC). The role of N6-methyladenosine (m6A) modification in multiple biological functions has been well studied. However, the molecular mechanisms underlying m6A methylation in modulating anti-cancer drug resistance in CRC remain obscure. In the present study, we found that YTH m6A RNA-binding protein 3 (YTHDF3) was highly expressed in oxaliplatin-resistant (OXAR) CRC tissues and cells. Moreover, we observed that YTHDF3 could recognize the 5' untranslated region of significantly m6A-methylated RNAs, which were associated with tumor resistance and recruit eukaryotic translation initiation factor 3 subunit A (eIF3A) to facilitate the translation of these target genes. Furthermore, we determined that eukaryotic translation initiation factor 2 alpha kinase 2 (eIF2AK2) bridged YTHDF3 and eIF3A, enhancing the stability of the YTHDF3/eIF3A complex in OXAR CRC cells. Taken together, our data identified YTHDF3 as a novel hallmark and revealed the molecular mechanism of YTHDF3 on gene translation via coordination with eIF2AK2 in OXAR CRC cells.

PARP-1 modulates the expression of miR-223 through histone acetylation to involve in the hydroquinone-induced carcinogenesis of TK6 cells

The upstream regulators of microRNAs were rarely reported. Hydroquinone (HQ) is the main metabolite of benzene, one of the important environmental factors contributing to leukemia and lymphoma. In HQ-induced malignant transformed TK6 (TK6-HT) cells, the expression of PARP-1 and miR-223 were upregulated. When in PARP-1 silencing TK6-HT cells, miR-223 was downregulated and the apoptotic cell number correspondingly increased. In TK6 cells treated with HQ for different terms, the expression of miR-223 and PARP-1 were dynamically observed and found to be decreased and increased, respectively. Trichostatin A could increase the expression of miR-223, then the expression of HDAC1-2 and nuclear factor kappa B were found to be increased, but that of mH2A was decreased. PARP-1 silencing inhibited the protein expression of H3Ac, mH2A, and H3K27ac. By co-immunoprecipitation experiment, PARP-1 and HDAC2 were found to form a regulatory complex. In conclusion, we demonstrated that the upregulation of PARP-1 mediated activation of acetylation to promote the transcription of miR-223 possibly via coregulating with HDAC2, an epigenetic regulation mechanism involved in cell malignant transformation resulting from long-term exposure to HQ, in which course, H3K27ac might be a specific marker for the activation of histone H3, which also gives hints for benzene exposure research.

Small non-coding RNA profiling in breast cancer: plasma U6 snRNA, miR-451a and miR-548b-5p as novel diagnostic and prognostic biomarkers

BACKGROUND

Breast cancer is a leading cause of cancer-related death in women. Most cases are invasive ductal carcinomas of no special type (NST breast carcinomas).

METHODS AND RESULTS

In this prospective, multicentric biomarker discovery study, we analyzed the expression of small non-coding RNAs (mainly microRNAs) in plasma by qPCR and evaluated their association with NST breast cancer. Large-scale expression profiling and subsequent validations have been performed in patient and control groups and compared with clinicopathological data. Small nuclear U6 snRNA, miR-548b-5p and miR-451a have been identified as candidate biomarkers. U6 snRNA was remarkably overexpressed in all the validations, miR-548b-5p levels were generally elevated and miR-451a expression was mostly downregulated in breast cancer groups. Combined U6 snRNA/miR-548b-5p signature demonstrated the best diagnostic performance based on the ROC curve analysis with AUC of 0.813, sensitivity 73.1% and specificity 82.6%. There was a trend towards increased expression of both miR-548b-5p and U6 snRNA in more advanced stages. Further, increased miR-548b-5p levels have been partially associated with higher grades, multifocality, Ki-67 positivity, and luminal B rather than luminal A samples. On the other hand, an association has been observed between high miR-451a expression and progesterone receptor positivity, lower grade, unifocal samples, Ki-67-negativity, luminal A rather than luminal B samples as well as improved progression-free survival and overall survival.

CONCLUSIONS

Our results indicated that U6 snRNA and miR-548b-5p may have pro-oncogenic functions, while miR-451a may act as tumor suppressor in breast cancer.

Low Expression of SLC7A11 Confers Drug Resistance and Worse Survival in Ovarian Cancer via Inhibition of Cell Autophagy as a Competing Endogenous RNA

Drug resistance is the main cause of chemotherapy failure in ovarian cancer (OC), and identifying potential druggable targets of autophagy is a novel and promising approach to overcoming drug resistance. In this study, 131 genes associated with autophagy were identified from three autophagy-related databases, and of these, 14 were differentially expressed in 90 drug-resistant OC tissues versus 197 sensitive tissues according to the Cancer Genome Atlas ovarian cancer cohort. Among these 14 genes, SLC7A11 was significantly decreased in two paclitaxel-resistant OC cells (HeyA8-R and SKOV3-R) and in 90 drug-resistant tissues compared with their controls. In vitro overexpression of SLC7A11 significantly increased the sensitivity of HeyA8-R cells to paclitaxel, inhibited colony formation, induced apoptosis, and arrested cell cycle. Further, low SLC7A11 expression was correlated with poor overall survival (OS), progression-free survival (PFS), and post-progression survival (PPS) in 1815 OC patients. Mechanistically, SLC7A11 strongly regulated cell autophagy as a competing endogenous RNA (ceRNA) based on pan-cancer analyses of 32 tumor types. Specifically, as a ceRNA for autophagy genes STX17, RAB33B, and UVRAG, SLC7A11 was strongly and positively co-expressed with these three genes in 20, 12, and 12 different tumors, respectively, in 379 OC tissues and in 90 drug-resistant OC tissues, and the former two were significantly upregulated in SLC7A11-overexpressed HeyA8-R cells. Further, SLC7A11 induced the protein expression of other autophagy genes, such as LC3, Atg16L1, and Atg7, and the expression of the respective proteins was further increased when the cells were treated with paclitaxel. The results strongly suggest that SLC7A11 regulates autophagy via ceRNA interactions with the three abovementioned genes in pan-cancer and in drug-resistant OC. Moreover, low expression of STX17 and UVRAG also significantly predicted low OS, PFS, and PPS. The combination of SLC7A11 with STX17 was more predictive of OS and PFS than either individually, and the combination of SLC7A11 with UVRAG was highly predictive of OS and PPS. The above results indicated that decreased SLC7A11 resulted in drug resistance and effected low rates of survival in OC patients, probably via ceRNA interactions with autophagy genes, and thus the gene could serve as a therapeutic target and potential biomarker in OC.

PARP1 as a prognostic biomarker for human cancers: a meta-analysis

Aim: A comprehensive meta-analysis was carried out to evaluate the association between high PARP1 expression and clinical outcomes in diverse types of cancers. Materials & methods: The electronic databases for all articles about PARP1 expression and cancers were searched. Additionally, bioinformatics analysis was utilized to validate the results of the meta-analysis. Results: Fifty-two studies with a total of 7140 patients were included in the current meta-analysis. High PARP1 expression was found to be significantly associated with poor overall survival and recurrence in various cancers, which were further strengthened and complemented by the results of bioinformatic analysis. Furthermore, increased PAPR1 expression was also related to clinicopathological features. Conclusion: Our findings confirmed that PARP1 might be a promising biomarker for prognosis in human cancers.

Bioactive Hexapeptide Reduced the Resistance of Ovarian Cancer Cells to DDP by Affecting HSF1/HSP70 Signaling Pathway

Ovarian cancer is the leading cause of death in gynecologic malignancies. Ovarian cancer as a metastatic malignant tumor is highly recurrent and prone to drug resistance. Bioactive peptides are an emerging area of biomedical research in reducing resistance of tumor cell to drugs. In this paper, we investigated the effects and mechanisms of bioactive hexapeptide (PGPIPN) derived in milk protein on the sensitivity of ovarian cancer cells to cis-dichlorodiammine platinum (DDP). Human ovarian cancer cell lines (SKOV3 and COC1), their DDP-resistant sublines (SKOV3/DDP and COC1/DDP) and human primary ovarian cancer cells were cultured in vitro under the combined treatment of DDP (close to IC50) and different concentrations of PGPIPN. The viabilities, apoptosis and cell cycle changes were respectively measured by WST-8 and flow cytometry. The mRNA and protein expression levels of HSF1, HSP70, MDR1, ERCC1 and β-actin gene were respectively assayed by RT-qPCR and western blotting. The results showed that PGPIPN significantly increased the sensitivity of human ovarian cancer cells to DDP in inhibiting viability and inducing apoptosis in vitro. But the effects in sensitive cells were lower than DDP-resistant cells. PGPIPN significantly changed the cell cycles in all human ovarian cancer cells, which leaded to a significant increase in the percentage of cells blocked at G2/M phase and decrease the percentage of cells at G1 phases in a dose-dependent manner. PGPIPN affected the expression levels of HSF1, HSP70, MDR1 and ERCC1 genes. Compared with cells in DDP treatment alone, the expression levels of HSF1 and HSP70 in human ovarian cancer cells treated with DDP and PGPIPN together significantly decreased in dose-dependent manner. PGPIPN significantly decreased MDR1 and ERCC1 of drug-resistant ovarian cancer cell lines and human primary ovarian cancer cell in a dose-dependent manner. Pifithrin-μ (PFTμ, HSP70 inhibitor) decreased or removed the effects of peptide in increasing the sensitivity of ovarian cancer cells to DDP. This suggests that PGPIPN enhanced the sensitivity of ovarian cancer cells to DDP partially via reducing the activity of HSF1/HSP70 signaling pathway, thus inducing cell apoptosis and decreasing repairment of DNA damage.

ERCC1 rs11615 polymorphism and chemosensitivity to platinum drugs in patients with ovarian cancer: a systematic review and meta-analysis

OBJECTIVE

To explore the relationship between ERCC1 rs11615 polymorphism and chemosensitivity to platinum drugs in ovarian cancer by the method of meta-analysis.

METHODS

Pubmed, Web of Science, EMBASE, Cochrane Library, China National Knowledge Infrastructure (CNKI), and China Wanfang databases were comprehensively searched up to September 2020, to identify the relationship between ERCC1 rs11615 polymorphism and chemosensitivity of ovarian cancer. The data was analyzed by Stata 15.0 statistic software.

RESULTS

A total of 10 published papers were included, including 1866 patients with ovarian cancer. The results showed that compared allele C at ERCC1 rs11615 locus with allele T, the pooled OR was 0.92 (95%CI:0.68 ~ 1.24, P > 0.05). There were no significant differences in recessive, dominant, homozygous, and heterozygous models. In accordance with a subgroup analysis of Ethnicity, all genotypes were statistically significant in the Asian population. In the allelic, dominant, recessive, homozygous and heterozygous models, the OR was 0.70 (95%CI:0.51 ~ 0.95), 0.20 (95%CI:0.07 ~ 0.56), 0.79 (95%CI:0.63 ~ 1.00), 0.21 (95%CI:0.07 ~ 0.59), 0.19 (95%CI:0.07 ~ 0.54), respectively, while in the Caucasian population, no statistically significant genotype was found.

CONCLUSION

The ERCC1 rs11615 polymorphism is associated with chemosensitivity in patients with ovarian cancer, especially in the Asian population, but not in the Caucasian population.

DNA damage response and repair in osteosarcoma: Defects, regulation and therapeutic implications

Osteosarcoma (OS) is the most common primary bone malignancy in children and adolescents which has the survival rate of 20% in its advanced stages. Osteosarcomas are mostly resistance to our common treatments. DNA damage response (DDR) is a specialized multistep process containing abundant proteins which are necessary for the survival of any cell and organism. DDR machinery detects a diversity of DNA lesions and inhibits the cell cycle progression if these lesions are not repairable. DDR is involved in aging, age-related diseases, and cancer. In recent years, DDR inhibitors have gained the attention of researches due to their potentials in offering novel therapeutic targets and improving the response of many cancers to either chemo- or radio-therapy. In this regard, we tried to gather a great body of evidence about the role of DDR ingredients in osteosarcoma's initiation/progression, prognosis, and treatment.

Parthanatos and its associated components: Promising therapeutic targets for cancer

Parthanatos is a PARP1-dependent, caspase-independent, cell-death pathway that is distinct from apoptosis, necrosis, or other known forms of cell death. Parthanatos is a multistep pathway that plays a pivotal role in tumorigenesis. There are many molecules in the parthanatos cascade that can be exploited to create therapeutic interventions for cancer management, including PARP1, PARG, ARH3, AIF, and MIF. These critical molecules are involved in tumor cell proliferation, progression, invasion, and metastasis. Therefore, these molecular signals in the parthanatos cascade represent promising therapeutic targets for cancer therapy. In addition, intimate interactions occur between parthanatos and other forms of cancer cell death, such as apoptosis and autophagy. Thus, co-targeting a combination of parthanatos and other death pathways may further provide a new avenue for cancer precision treatment. In this review, we elaborate on the signaling pathways of canonical parthanatos and briefly introduce the non-canonical parthanatos. We also shed light on the role parthanatos and its associated components play in tumorigenesis, particularly with respect to the aforementioned five molecules, and discuss the promise targeted therapy of parthanatos and its associated components holds for cancer therapy.

Network Pharmacology-Based and Clinically Relevant Prediction of the Potential Targets of Chinese Herbs in Ovarian Cancer Patients

Reports increasingly suggest that Chinese herbal medicine (CHM) has been used to treat ovarian cancer (OvCa) with a good curative effect; however, the molecular mechanisms underlying CHM are still unclear. In this retrospective study, we explored CHM's molecular targets for the treatment of OvCa based on clinical data and network pharmacology. We used the Kaplan-Meier method and Cox regression analysis to verify the survival rate of 202 patients with CHM-treated OvCa. The association between CHM and survival time was analyzed by bivariate correlation. A target network of CHM active ingredients against OvCa was established via network pharmacology. Cox regression analysis showed that CHM is an independent favorable prognostic factor. The median survival time was 91 months in the CHM group and 65 months in the non-CHM group. The survival time of FIGO stage III patients in the two groups was 91 months and 52 months, and the median survival period of FIOG stage IV patients was 60 months and 22 months, respectively (p < 0.001). Correlation analysis demonstrated that 12 herbs were closely associated with prognosis, especially in regard to the long-term benefits. Bioinformatics analysis indicated that the anti-OvCa activity of these 12 herbs occurs mainly through the regulation of apoptosis-related protein expression, which promotes OvCa cell apoptosis and inhibits OvCa development. They also regulate the progress of OvCa treatment by promoting or inhibiting protein expression on the p53 signaling pathway and by inhibiting the NF-κB signaling pathway by directly inhibiting NF-κB.

Impact of ERCC1, XPF and DNA Polymerase β Expression on Platinum Response in Patient-Derived Ovarian Cancer Xenografts

Platinum resistance is an unmet medical need in ovarian carcinoma. Molecular biomarkers to predict the response to platinum-based therapy could allow patient stratification and alternative therapeutic strategies early in clinical management. Sensitivity and resistance to platinum therapy are partially determined by the tumor’s intrinsic DNA repair activities, including nucleotide excision repair (NER) and base excision repair (BER). We investigated the role of the NER proteins—ERCC1, XPF, ERCC1/XPF complex—and of the BER protein DNA polymerase β, as possible biomarkers of cisplatin (DDP) response in a platform of recently established patient-derived ovarian carcinoma xenografts (OC-PDXs). ERCC1 and DNA polymerase β protein expressions were measured by immunohistochemistry, the ERCC1/XPF foci number was detected by proximity ligation assay (PLA) and their mRNA levels by real-time PCR. We then correlated the proteins, gene expression and ERCC1/XPF complexes with OC-PDXs’ response to platinum. To the best of our knowledge, this is the first investigation of the role of the ERCC1/XPF complex, detected by PLA, in relation to the response to DDP in ovarian carcinoma. None of the proteins in the BER and NER pathways studied predicted platinum activity in this panel of OC-PDXs, nor did the ERCC1/XPF foci number. These results were partially explained by the experimental evidence that the ERCC1/XPF complex increases after DDP treatment and this possibly better associates with the cancer cells’ abilities to activate the NER pathway to repair platinum-induced damage than its basal level. Our findings highlight the need for DNA functional assays to predict the response to platinum-based therapy.