Project description:Ovarian cancer is the deadliest gynaecologic malignancies worldwide. Platinum based chemotherapy is the mainstay treatment for ovarian cancer; however, frequent recurrence and chemoresistance onset in patients with advanced diseases remain a therapeutic challenge. Although mechanisms underlying the development of chemoresistance are still ambiguous, the B-cell lymphoma-2 (Bcl-2) family is closely associated with chemoresistance in ovarian cancer. We previously disclosed that Zeta-Crystallin (CryZ) is a post-transcriptional regulator of Bcl-2 gene expression, by binding to Bcl-2 mRNA and increasing its half-life. Here, we investigated the role of CryZ as a novel therapeutic target in A2780 ovarian carcinoma cells by modulating the protein activity with acetylsalicylic acid (ASA) to restore chemosensitivity. Molecular docking and fragment-mapping based approach revealed potential interaction of ASA within CryZ protein. Inhibition of CryZ binding activity to Bcl-2 and Bcl-xl mRNA targets by ASA was demonstrated in A375 cells. Cytotoxicity assays were conducted in A2780S and A2780R ovarian cancer cells to evaluate if CryZ binding activity inhibition and CryZ silencing were able to reverse cisplatin resistance. ASA-treatment determined a downregulation of Bcl-2 and Bcl-xl mRNA levels in A2780S and A2780R cells. ASA-treatment or CryZ silencing were able to increase and restore the chemosensitivity in both sensitive and resistant A2780 ovarian cancer cells, respectively. In this research article we demonstrated that the pharmacological or genetic inhibition of CryZ restores the sensitivity to cisplatin in a model of sensitive or resistant ovarian cancer cells. These findings suggest a new gene-targeted chemotherapeutic approach to restore the cytotoxicity in drug-resistant ovarian cancers and increase the sensitivity in non-resistant cells.
Project description:ObjectiveOur study was designed to explore the association miR-335-5p and BCL2L2 and to investigate the influence of miR-335-5p/BCL2L2 axis on cisplatin-resistant ovarian cancer cells.MethodsMicroarray analysis was used to determine differentially expressed microRNAs in primary and cisplatin-resistant A2780 cells. Cell function experiments were conducted to investigate the effect of miR-335-5p on the cisplatin sensitivity of A2780 cells. The targeted relationship between BCL2L2 mRNA and miR-335-5p was validated through luciferase assay. Tumor xenograft was performed to confirm the function of miR-335-5p in restoring the cisplatin sensitivity of the ovarian cancer cells.ResultsMiR-335-5p was lowly expressed in cisplatin-resistant A2780 cells. Overexpression of miR-335-5p reduced cell survival and enhanced cisplatin-induced cell apoptosis. BCL2L2 mRNA was a target of miR-335-5p, and silencing of BCL2L2 showed the similar results on the cell viability as miR-335-5p overexpression.ConclusionUpregulation of miR-335-5p expression enhanced the cisplatin sensitivity of ovarian cancer cells through suppressing BCL2L2, suggesting the potential of miR-335-5p/BCL2L2 axis as a therapeutic target for the cisplatin resistance of patients with ovarian cancer.
Project description:Chemoresistance is the inevitable outcome of chemotherapy for epithelial ovarian carcinoma (EOC), and its mechanism is still not fully understood. This study explored the role of ribosomal protein L23 (RPL23) in cisplatin resistance of EOC. WGCNA based on TCGA and GEO was used to screen and analyze target genes related to EOC chemotherapy sensitivity. Clinical samples of cisplatin resistance were collected to detect the expression of target genes. Cisplatin resistance was induced in EOC cell lines A2780 and SKOV3. The cell abilities of invasion, migration and adhesion were observed. Western blotting was used to detect protein expressions. Bioinformatics analysis showed that RPL23 may be related to EOC chemotherapy sensitivity, and was highly expressed in clinical samples and cell lines of cisplatin-resistant. After A2780 and SKOV3 were resistant to cisplatin, the inhibitory abilities of therapeutic dose of cisplatin on their invasion, migration and adhesion were significantly attenuated, and N-cadherin and vimentin were significantly up-regulated while E-cadherin was significantly down-regulated. However, above phenomena were significantly reversed after RPL23 knockdown. Taken together, the overexpressed RPL23 may lead to platinum resistance by inducing epithelial-mesenchymal transition (EMT) in EOC. Targeting knockdown RPL23 would restore the sensitivity of EOC cells to cisplatin by inhibiting EMT, suggesting that RPL23 is a potential therapeutic target for EOC after platinum resistance.
Project description:BackgroundDrug resistance hampers the efficient treatment of malignancies, including advanced stage ovarian cancer, which has a 5-year survival rate of only 30 %. The molecular processes underlying resistance have been extensively studied, however, not much is known about the involvement of microRNAs.MethodsDifferentially expressed microRNAs between cisplatin sensitive and resistant cancer cell line pairs were determined using microarrays. Mimics were used to study the role of microRNAs in drug sensitivity of ovarian cancer cell lines and patient derived tumor cells. Luciferase reporter constructs were used to establish regulation of target genes by microRNAs.ResultsMiR-634 downregulation was associated with cisplatin resistance. Overexpression of miR-634 affected cell cycle progression and enhanced apoptosis in ovarian cancer cells. miR-634 resensitized resistant ovarian cancer cell lines and patient derived drug resistant tumor cells to cisplatin. Similarly, miR-634 enhanced the response to carboplatin and doxorubicin, but not to paclitaxel. The cell cycle regulator CCND1, and Ras-MAPK pathway components GRB2, ERK2 and RSK2 were directly repressed by miR-634 overexpression. Repression of the Ras-MAPK pathway using a MEK inhibitor phenocopied the miR-634 effects on viability and chemosensitivity.ConclusionmiR-634 levels determine chemosensitivity in ovarian cancer cells. We identify miR-634 as a therapeutic candidate to resensitize chemotherapy resistant ovarian tumors.
Project description:BackgroundOvarian cancer is one of the most lethal gynecological malignancies, in which platinum resistance is a common cause of its relapse and death. Glycosylation has been reported to be involved in drug resistance, and glycomic analyses of ovarian cancer may improve our understanding of the mechanisms underlying cancer cell drug resistance and provide potential biomarkers and therapeutic targets.MethodsThe serous ovarian cancer cell line A2780 and its platinum-resistant counterpart A2780-cp were used in this study. We performed a lectin array analysis to compare the glycosylation patterns of the two cell lines, a gene expression array was employed to probe the differences in glycogenes. Furthermore, the results were verified by lectin blots.ResultsA2780-cp cell exhibited stronger intensities of Lens culinaris (LCA) Canavalia ensiformis (ConA), and Lycopersicon esculentum (LEL) and weaker intensities of Sambucus nigra (SNA) lectins. The gene expression array analysis revealed increased expression of Fut8, B3gnt4, B3gnt5, B4galt2 and decreased expression of Fut1 and ST6GalNAc 6 expression were evident in the A2780-cp cells. The lectin blot confirmed the differences in LCA, ConA, SNA and LEL between the A2780 and A2780-cp cells.ConclusionsThe combination of the lectin and gene expression analyses showed that the levels of core fucosylation and poly-LacNAc were increased in the A2780-cp cells and the levels of Fuc α1-2(gal β1-4) GlcNAc and α2-6-linked sialic structures were decreased in the A2780-cp cells. These glycans represent potential biomarkers and might be involved in the mechanism of drug resistance in ovarian cancer.
Project description:The development of drug resistance is still a major impediment for the successful treatment of cancer, such as advanced stage ovarian cancer, which has a 5-year survival rate of only 30%. The molecular processes that contribute to resistance have been extensively studied, however, not much is known about the role of microRNAs. We compared microRNA expression profiles of three isogenic cisplatin sensitive and resistant cell line pairs. The only microRNA that was consistently downregulated (FDR = 0.000) in all resistant cell lines was miR-634. We investigated the effects of miR-634 modulation in ovarian cancer cell lines and patient derived tumor cells. Overexpression of miR-634 gave rise to a modest G1 phase block and enhanced apoptosis. Furthermore, miR-634 resensitized resistant ovarian cancer cell lines and patient derived tumor cells to cisplatin chemotherapy. Similarly, miR-634 enhanced the response of tumor cells to carboplatin and doxorubicin, but not to paclitaxel. We showed that miR-634 regulates cyclin D1 (CCND1), which is required for the G1-S phase transition, explaining the effects on the cell cycle. In addition, miR-634 repressed expression of GRB2, ERK2, RSK1 and RSK2, components of the Ras-MAPK pathway. Altogether, our findings suggest that miR-634 modulates several cancer relevant targets and therefore miR-634 is an attractive therapeutic candidate to resensitize chemotherapy resistant ovarian tumors. The miRNA expression profile was determined of three cisplatin sensitive/resistant cell line pairs (ovarian cancer cell line pair A2780/A2780 DDP; colon cancer cell line pair HCT8/HCT8 DDP; bladder cancer cell line pairT24/T24 DDP10).
Project description:Cisplatin is a widely used anti-cancer agent. However, the effectiveness of cisplatin has been limited by the commonly developed drug resistance. This study aimed to investigate the potential effects of endoplasmic reticulum (ER) stress to overcome drug resistance using the cisplatin-resistant A2780/CisR ovarian cancer cell model. The synthetic chalcone derivative (E)-3-(3,5-dimethoxyphenyl)-1-(2-methoxyphenyl)prop-2-en-1-one (named DPP23) is an ER stress inducer. We found that DPP23 triggered apoptosis in both parental cisplatinsensitive A2780 and cisplatin-resistant A2780/CisR ovarian cancer cells due to activation of reactive oxygen species (ROS)-mediated unfolded protein response (UPR) pathway in the endoplasmic reticulum. This result suggests that ROSmediated UPR activation is potential in overcoming drug resistance. DPP23 can be used as a target pharmacophore for the development of novel chemotherapeutic agents capable of overcoming drug resistance in cancer cells, particularly ovarian cancer cells. [BMB Reports 2020; 53(2): 88-93].
Project description:Conventional chemotherapeutic regimens are unable to prevent metastasis of non-small cell lung carcinoma (NSCLC) thereby leaving cancer incurable. Cancer stem cells (CSCs) are considered to be the origin of this therapeutic limitation. In the present study we report that the migration potential of NSCLCs is linked to its CSC content. While cisplatin alone fails to inhibit the migration of CSC-enriched NSCLC spheroids, in a combination with non-steroidal anti inflammatory drug (NSAID) aspirin retards the same. A search for the underlying mechanism revealed that aspirin pre-treatment abrogates p300 binding both at TATA-box and initiator (INR) regions of mTOR promoter of CSCs, thereby impeding RNA polymerase II binding at those sites and repressing mTOR gene transcription. As a consequence of mTOR down-regulation, Akt is deactivated via dephosphorylation at Ser473 residue thereby activating Gsk3β that in turn causes destabilization of Snail and β-catenin, thus reverting epithelial to mesenchymal transition (EMT). However, alone aspirin fails to hinder migration since it does not inhibit the Integrin/Fak pathway, which is highly activated in NSCLC stem cells. On the other hand, in aspirin pre-treated CSCs, cisplatin stalls migration by hindering the integrin pathway. These results signify the efficacy of aspirin in sensitizing NSCLC stem cells towards the anti-migration effect of cisplatin. Cumulatively, our findings raise the possibility that aspirin might emerge as a promising drug in combinatorial therapy with the existing chemotherapeutic agents that fail to impede migration of NSCLC stem cells otherwise. This may consequently lead to the advancement of remedial outcome for the metastatic NSCLCs.
Project description:BackgroundOvarian cancer is the most common gynecological malignancy and is difficult to manage due to the emergence of resistance to various chemotherapeutic drugs. New efforts are urgently awaited. Aspirin, which is traditionally considered a nonsteroidal anti-inflammatory drug (NSAID), has been reported to exert potential chemopreventive effects. Therefore, we aimed to investigate the anticancer effect and explore the underlying molecular mechanisms of aspirin on epithelial ovarian cancer (EOC) cells.MethodsWe conducted wound healing, transwell migration, EdU cell proliferation, colony formation and apoptosis detection assays to observe the effects of aspirin on the migration, proliferation and apoptosis of EOC cells (A2870, Caov-3, and SK-OV-3). EOC cells were treated with a combination of aspirin and cisplatin (CDDP) to observe the effect of aspirin on enhancing CDDP sensitivity. Orthotopic xenograft models of ovarian cancer established with A2780-Luciferase-GFP cells were applied to compare tumor growth inhibition in the control, CDDP and CDDP plus aspirin groups through in vivo imaging, which can be used to continuously monitor tumor growth. The expression and acetylation levels of p53 in EOC cells treated with aspirin were determined using western blotting, and p53 acetylation levels were examined in tumors harvested from the transplanted mice. Quantitative real-time PCR was used to assess the mRNA expression of p53 target genes.ResultsAspirin inhibited migration and proliferation and induced apoptosis in EOC cell lines in a concentration-dependent manner. In vitro, aspirin enhanced the sensitivity of EOC cells to CDDP by increasing its inhibitory effect on proliferation and its effect on inducing apoptosis. In vivo, the differences in the tumor growth inhibition rates among the different CDDP experimental groups were statistically significant (p < 0.05). Aspirin did not affect p53 protein expression but increased the p53 acetylation level in a concentration-dependent manner. In addition, the mRNA levels of CDKN1A, BAX, FOXF1, PUMA, and RRAD in EOC cells were significantly increased by the aspirin treatment.ConclusionsAspirin inhibits tumor progression and enhances the CDDP sensitivity of EOC cells. These antitumor effects of aspirin might be mediated by p53 acetylation and subsequent activation of p53 target genes.