Carboplatin Resistance Research Articles

Electrochemical Characterization of Carboplatin at Unmodified Platinum Electrodes and Its Application to Drug Uptake Studies in Ovarian Cancer Cells

Epithelial ovarian cancer affects approximately 240,000 women worldwide with an estimated of 152,000 deaths per year. Common treatments include surgery or chemotherapy using a combination of carboplatin and taxane. Unfortunately, approximately 75% patients relapse within 18 months. Of these relapsed patient, an estimate of 85% experience carboplatin resistance. The effect is devastating. One way to combat this emerging drug resistance problem is the development of novel drugs. However, cellular mechanisms of carboplatin-resistance are poorly understood. Without a thorough understanding of resistance mechanisms, developing long-lasting effective drugs for long term treatment is a challenging problem. Therefore, there is a dire need to develop methods to detect and study resistance mechanisms.One suggested mechanism is the inhibition of drug uptake to prevent the intracellular accumulation of the drug. The presented work describes the quantification of carboplatin uptake in ovarian cancer cells. For this purpose, carboplatin is thoroughly characterized by voltammetry and its suitability for physiological bioelectrochemical studies is assessed. Diffusion and adsorption processes of carboplatin are evaluated, its dependence on pH is investigated, and a limit of detection for carboplatin at unmodified Pt electrodes is identified, without the need of expensive and time-intense electrode modification strategies. The influx and efflux of carboplatin into/from ovarian cancer cells are quantified by electrochemistry to better understand mechanisms of carboplatin chemoresistance. Results emerging from this research will be important for future medical research developing novel agents to combat chemoresistance and will present the basis for future long-term funding applications under this collaboration.Reference:Luu H.T.L., Nachtigal M.W., Kuss S.: Electrochemical Characterization of Carboplatin at Unmodified Platinum Electrodes and its Application to Drug Uptake Studies in Ovarian Cancer Cells. Journal of Electroanalytical Chemistry 2020, 872C, 114253.

Cellworks Omics Biology Model (CBM) to identify amplifications of chromosome 11p and 1p predict paclitaxel and carboplatin resistance.

e21208 Background: Paclitaxel and carboplatin (PC) is used to treat a wide variety of malignancies including gynecologic, breast, lung, and occult primary cancers. In NSCLC, PC led to a substantial improvement in 1-yr survival from 10% (P alone) to approximately 50% seen with the combination. Nevertheless, a large proportion of patients do not respond. An optimal cytotoxic strategy for managing NSCLC and the discovery of chemotherapy biomarkers to guide treatment selection remain unmet needs in the clinic. Cellworks CBM platform identified a unique chromosomal signature which permits a stratification of which patients are most likely to respond to PC treatment. Methods: 22 patients treated with PC were published in TCGA dataset and selected for analysis. The mutation and copy number aberrations from individual cases served as input into the CBM (generated from PubMed and other online resources) to create a patient-specific protein network map. Disease-biomarkers unique to each patient were identified within protein network maps. Digital drug simulations were conducted by measuring effect of PC on a cell growth score comprised of a composite of cell proliferation, apoptosis, and other cancer hallmarks. Drug simulations were systematically conducted to identify and evaluate therapeutic efficacy. The drug combination was mapped to the patient genome along with a rational mechanism of action and validated based on the genomic profile and its biological consequences. Results: Of the 22 patients treated with PC, 13 had clinical responses and 9 were non-responders. The computer simulation correctly predicted response in 16/22 with 72.73% accuracy, 55.56% specificity and 84.62% sensitivity. CBM identified novel amplified segments of Chromosome 11p and 1p were responsible for non-responsiveness to PC. Key genes on these chromosomes were identified belonging to the autophagy, reactive oxygen species (ROS) scavenging, DNA repair, and microtubule polymerization pathways. Amplification of AMBRA1, ATG13 and TRAF6 (11p) led to autophagy upregulation resulting in low ROS level, a well-documented resistance loop for chemotherapy. SIRT3 and CAT (11p), ROS scavenging genes, were also upregulated due to increase in copy number. CTH (1p) is another key enzyme involved in GSH-mediated ROS scavenging and was also upregulated. Biosimulation indicated a low ROS level was the key reason of resistance to PC. Heightened DNA damage repair due FANCF and ZNF143 (11p amp) and USP1 (1p amp), was another cause of PC resistance. These discoveries suggest that a combination of an autophagy inhibitor / BCL2 mimetic might prove useful to reverse PC resistance associated with 11p and 1p amp. Conclusions: This study highlights how CBM simulation platform can help to identify novel patient segments for therapy response prediction and use drug re-purposing to overcome chemotherapy resistance.

Exosomal proteomic signatures correlate with drug resistance and carboplatin treatment outcome in a spontaneous model of canine osteosarcoma

BackgroundOsteosarcoma patients often experience poor outcomes despite chemotherapy treatment, likely due in part to various mechanisms of tumor cell innate and/or acquired drug resistance. Exosomes, microvesicles secreted by cells, have been shown to play a role in drug resistance, but a comprehensive protein signature relating to osteosarcoma carboplatin resistance has not been fully characterized.MethodsIn this study, cell lysates and exosomes from two derivatives (HMPOS-2.5R and HMPOS-10R) of the HMPOS osteosarcoma cell line generated by repeated carboplatin treatment and recovery, were characterized proteomically by mass spectrometry. Protein cargos of circulating serum exosomes from dogs with naturally occurring osteosarcoma, were also assessed by mass spectrometry, to identify biomarkers that discriminate between good and poor responders to carboplatin therapy.ResultsBoth cell lysates and exosomes exhibited distinct protein signatures related to drug resistance. Furthermore, exosomes from the resistant HMPOS-2.5R cell line were found to transfer drug resistance to drug-sensitive HMPOS cells. The comparison of serum exosomes from dogs with a favorable disease-free interval [DFI] of > 300 days, and dogs with < 100 days DFI revealed a proteomic signature that could discriminate between the two cohorts with high accuracy. Furthermore, when the patient’s exosomes were compared to exosomes isolated from carboplatin resistant cell lines, several putative biomarkers were found to be shared.ConclusionsThe findings of this study highlight the significance of exosomes in the potential transfer of drug resistance, and the discovery of novel biomarkers for the development of liquid biopsies to better guide personalized chemotherapy treatment.

AURKB promotes tumorigenesis and carboplatin resistance by regulating the ERK pathway in neuroblastoma cells

Background Previous research has revealed that activation or aberrant expression of kinases can lead to tumorigenesis of various cancers, including neuroblastoma (NB). Suppression of kinase expression can reduce drug resistance. We explored the potential role and mechanism of the aurora kinase B (AURKB) gene in the acquisition of carboplatin resistance in NB. Methods Immunohistochemistry (IHC) and qRT-PCR were used to explore the AURKB expression in NB patients. Subsequently, we structured Carboplatin-resistant NB cells. The potential biological functions of AURKB in carboplatin resistance were examined through knockdown of AURKB combined with CCK8, flow cytometry, immunohistochemistry, and western blot. Finally, overexpression of AURKB combined with ERK inhibitor (U0126) was carried out to explore the role of downstream signaling pathways. Results Overexpression of AURKB was closely correlated to poor prognosis in NB patients. In vitro, knockdown of AURKB could lead to a decline in IC50 value and restrain the invasion and the expression of MRP1 and Ki67, while promotes apoptosis in carboplatin-resistant cells (IMR-32-R and SK-N-AS-R). Additionally, AURKB overexpression could potentiate the invasion and the expression of MRP1 and Ki67, while suppresses apoptosis in SK-N-AS-R and IMR-32-R, whereas ERK inhibitor U0126 could reverse the phenomenon caused by AURKB overexpression. Conclusion AURKB overexpression was strongly associated with poor prognosis and carboplatin resistant acquisition. Additionally, suppression of AURKB-ERK axis might be a potential therapy for carboplatin resistance in NB patients.

Detailed Molecular Mechanism and Potential Drugs for COL1A1 in Carboplatin-Resistant Ovarian Cancer.

Carboplatin resistance in ovarian cancer (OV) is a major medical problem. Thus, there is an urgent need to find novel therapeutic targets to improve the prognosis of patients with carboplatin-resistant OV. Accumulating evidence indicates that the gene COL1A1 (collagen type I alpha 1 chain) has an important role in chemoresistance and could be a therapeutic target. However, there have been no reports about the role of COL1A1 in carboplatin-resistant OV. This study aimed to establish the detailed molecular mechanism of COL1A1 and predict potential drugs for its treatment. We found that COL1A1 had a pivotal role in carboplatin resistance in OV by weighted gene correlation network analysis and survival analysis. Moreover, we constructed a competing endogenous RNA network (LINC00052/SMCR5-miR-98-COL1A1) based on multi-omics data and experiments to explore the upstream regulatory mechanisms of COL1A1. Two key pathways involving COL1A1 in carboplatin resistance were identified by co-expression analysis and pathway enrichment: the “ECM-receptor interaction” and “focal adhesion” Kyoto Encyclopedia of Genes and Genomes pathways. Furthermore, combining these results with those of cell viability assays, we proposed that ZINC000085537017 and quercetin were potential drugs for COL1A1 based on virtual screening and the TCMSP database, respectively. These results might help to improve the outcome of OV in the future.

The mitotic checkpoint is a targetable vulnerability of carboplatin-resistant triple negative breast cancers

Triple-negative breast cancer (TNBC) is the most aggressive breast cancer subtype, lacking effective therapy. Many TNBCs show remarkable response to carboplatin-based chemotherapy, but often develop resistance over time. With increasing use of carboplatin in the clinic, there is a pressing need to identify vulnerabilities of carboplatin-resistant tumors. In this study, we generated carboplatin-resistant TNBC MDA-MB-468 cell line and patient derived TNBC xenograft models. Mass spectrometry-based proteome profiling demonstrated that carboplatin resistance in TNBC is linked to drastic metabolism rewiring and upregulation of anti-oxidative response that supports cell replication by maintaining low levels of DNA damage in the presence of carboplatin. Carboplatin-resistant cells also exhibited dysregulation of the mitotic checkpoint. A kinome shRNA screen revealed that carboplatin-resistant cells are vulnerable to the depletion of the mitotic checkpoint regulators, whereas the checkpoint kinases CHEK1 and WEE1 are indispensable for the survival of carboplatin-resistant cells in the presence of carboplatin. We confirmed that pharmacological inhibition of CHEK1 by prexasertib in the presence of carboplatin is well tolerated by mice and suppresses the growth of carboplatin-resistant TNBC xenografts. Thus, abrogation of the mitotic checkpoint by CHEK1 inhibition re-sensitizes carboplatin-resistant TNBCs to carboplatin and represents a potential strategy for the treatment of carboplatin-resistant TNBCs.

ABCA1 is associated with the development of acquired chemotherapy resistance and predicts poor ovarian cancer outcome.

Aim: This study investigated the ATP binding cassette (ABC) transporter (ABCA1, ABCB1, ABCB3, ABCC2 and ABCG2) expression in high grade serous ovarian cancer (HGSOC) tissues, cell lines and primary cells to determine their potential relationship with acquired chemotherapy resistance and patient outcome.Methods: ABC transporter mRNA and protein expression (ABCA1, ABCB1, ABCB3, ABCC2 and ABCG2) was assessed in publicly available datasets and in a tissue microarray (TMA) cohort of HGSOC at diagnosis, respectively. ABC transporter mRNA expression was also assessed in chemosensitive ovarian cancer cell lines (OVCAR-5 and CaOV3) versus matching cell lines with acquired carboplatin resistance and in primary HGSOC cells from patients with chemosensitive disease at diagnosis (n = 10) as well as patients with acquired chemotherapy resistance at relapse (n = 6). The effects of the ABCA1 inhibitor apabetalone in carboplatin-sensitive and -resistant cell lines were also investigated.Results: High ABCA1 mRNA and protein expression was found to be significantly associated with poor patient outcome. ABCA1 mRNA and protein levels were significantly increased in ovarian cancer cell lines (OVCAR-5 CBPR and CaOV3 CBPR) with acquired carboplatin resistance. ABCA1 mRNA was significantly increased in primary HGSOC cells obtained from patients with acquired chemotherapy resistance. Apabetalone treatment reduced ABCA1 protein expression and increased the sensitivity of both parental and carboplatin-resistant ovarian cancer cells to carboplatin.Conclusion: These results suggest that inhibiting ABCA1 transporter may be useful in overcoming acquired chemotherapy resistance and improving outcome for patients with HGSOC.

LncRNA-H19 regulates chemoresistance to carboplatin in epithelial ovarian cancer through microRNA-29b-3p and STAT3.

Background: Platinum-based chemotherapy is part of current standard treatment for epithelial ovarian cancer (EOC). However, chemoresistance often rapidly developed, leading to chemotherapy failure and unfavored prognosis. Increasing evidence has demonstrated the important role of oncogenic long noncoding RNA H19 in various cancers, including EOC. No current study is available in exploring the role of lncRNA-H19 in carboplatin resistance of EOC and its underlying mechanism.Methods: Levels of lncRNA-H19, miR-29b-3p, and STAT3 mRNA were measured by qRT-PCR. The 50% inhibitory concentration value was detected with Cell Counting Kit-8 (CCK8). Colony-formation and CCK8 assays were employed to measure cell viability. Cell migration and invasion ability was evaluated with transwells. Western blot assay was utilized to measure P-gp, MRP1, LRP, and STAT3 protein levels. The targeting between lncRNA-H19 and miR-29b-3p, as well as miR-29b-3p and STAT3, was verified by dual-luciferase, RNA immunoprecipitation, and RNA pull-down experiments.Results: lncRNA-H19 and STAT3 were sharply increased, while miR-29b-3p was decreased in carboplatin-resistant EOC. Carboplatin efficacy was enhanced by lncRNA-H19 silencing in chemo-resistant EOC cells. lncRNA-H19 served as a competing endogenous RNA of miR-29b-3p, causing the derepression of miR-29b-3p downstream target STAT3, leading to chemoresistance in carboplatin-tolerated EOC.Conclusions: The lncRNA-H19/miR-29b-3p axis improved carboplatin resistance of EOC by targeting STAT3, indicating a possible approach to improving chemotherapy for EOC.

Electrochemical Characterization of Carboplatin at Unmodified Platinum Electrodes and Its Application to Drug Uptake Studies in Ovarian Cancer Cells

Epithelial ovarian cancer (EOC) has the highest mortality rate among gynecological cancers and affects patients on all continents. Primary treatments involve surgery and the administration of chemotherapeutics, such as carboplatin, which is listed by the World Health Organization as an essential medication for the treatment of human cancers. Unfortunately, due to high rates of drug resistance of EOC towards carboplatin, cancer relapse rates are devastating, and the mechanisms of chemoresistance to carboplatin have not been adequately identified. Consequently, there is a dire need for innovative strategies that are able to detect carboplatin resistance in cancer and to further our understanding of the fundamental nature of chemoresistance towards carboplatin.The presented work describes the thorough electrochemical characterization of carboplatin. We quantify the uptake of carboplatin by ovarian cancer cells by electrochemistry to better understand mechanisms of carboplatin chemoresistance. Results emerging from this research will be important for future medical research developing novel agents to combat chemoresistance.

Electrochemical characterization of carboplatin at unmodified platinum electrodes and its application to drug consumption studies in ovarian cancer cells

Carboplatin is one of the most prescribed and essential medications for chemotherapy treatment of human cancers. Unfortunately, many patients relapse with carboplatin resistance, making treatment inefficient and cost-intense. The cellular mechanisms of carboplatin-resistance are poorly understood. One suggested mechanism is the inhibition of drug uptake to prevent the intracellular accumulation of the drug. Herein, we present an electroanalytical approach to monitor the consumption of carboplatin by drug-susceptible and drug-resistant ovarian cancer cells. For this purpose, carboplatin was thoroughly characterized by voltammetry and its suitability for physiological bioelectrochemical studies was assessed. Diffusion and adsorption processes of carboplatin were evaluated, its dependence on pH was investigated, and a limit of detection for carboplatin at unmodified Pt electrodes was identified, without the need of expensive and time-intense electrode modification strategies. Our results report the application of voltammetry as a rapid, inexpensive, and sensitive method to quantify drug consumption by cancer cells.

LncRNA LINC00152 Increases the Aggressiveness of Human Retinoblastoma and Enhances Carboplatin and Adriamycin Resistance by Regulating MiR-613/Yes-Associated Protein 1 (YAP1) Axis.

BackgroundLong noncoding RNA (lncRNA) acts as key regulator in human cancers, including retinoblastoma. However, the function of LINC00152 remains largely unknown in retinoblastoma. Thus, this study aimed to explore the role and molecular mechanisms of LINC00152 in retinoblastoma.Material/MethodsThe real-time quantitative polymerase chain reaction (RT-qPCR) was used to quantify the expression levels of LINC00152, miR-613 and yes-associated protein 1 (YAP1). The target genes of LINC00152 and miR-613 were identified by dual-luciferase reporter analysis, RNA immunoprecipitation (RIP) and RNA pulldown assays. The viability, apoptosis, and invasion of retinoblastoma cells were assessed by Cell Counting Kit-8, flow cytometry, and Transwell assays, respectively. In addition, western blot was used to test the protein expression in retinoblastoma cells or tissues. Cell sensitivity to carboplatin and adriamycin was analyzed by computing IC50 value. The effects of LINC00152 silencing in vivo were measured by a xenograft experiment.ResultsLINC00152 was obviously upregulated, while miR-613 was decreased in retinoblastoma tissues and cells. MiR-613, a target of LINC00152, was negatively regulated by LINC00152. Functional experiment further illustrated that silencing of LINC00152 evidently repressed proliferation, invasion, and autophagy while reinforced apoptosis of retinoblastoma cells, besides, retinoblastoma cells were more sensitive to carboplatin and adriamycin after knockdown of LINC00152. Importantly, knockdown of LINC00152-induced effects on retinoblastoma cells could be overturned by introducing miR-613 inhibitor. Downregulation of miR-613 abolished silencing of YAP1-effects on proliferation, apoptosis, invasion, autophagy, and chemoresistance of retinoblastoma cells. The results of the xenograft experiment indicated that LINC00152 silencing impeded tumor growth in vivo.ConclusionsMechanistically, LINC00152 enhanced the aggressiveness of retinoblastoma and boosted carboplatin and adriamycin resistance by regulating YAP1 by sponging miR-613 in human retinoblastoma.

Pegylated Liposomal Doxorubicin/Oxaliplatin Chemotherapy Can Overcome Cisplatin Resistance in Spectrin αII-Overexpressing Ovarian Carcinoma.

Spectrin αII contributes to cisplatin and carboplatin resistance in ovarian serous carcinoma cells, and its expression in surgical specimens is a valid predictor of prognosis. We sought to identify effective drugs for spectrin αII-mediated cisplatin-resistant cells. We employed SKOV3 cells with small interfering RNA-mediated spectrin αII downregulation, serous carcinoma cells (NOS2), cisplatin-resistant cells (NOS2CR2), and oxaliplatin-resistant cells (NOS2OXR). In the drug-sensitivity test, oxaliplatin was not affected by the inhibition of spectrin αII expression and was effective for cisplatin-resistant NOS2CR2 cells. NOS2OXR cells did not express higher levels of spectrin αII compared to NOS2 in western blot analysis. Six non-platinum anticancer drugs were not affected by the inhibition and was effective for resistant NOS2CR2 and NOS2OXR cells. Doxorubicin exhibited potent cytotoxicity at 2 μM against both resistant cell lines. Pegylated liposomal doxorubicin/oxaliplatin regimen may be effective for cisplatin-resistant ovarian carcinoma with spectrin αII-overexpression.

Electrochemical Characterization of Carboplatin Toward the Detection of Drug Resistance in Cancer

Epithelial ovarian cancer (EOC) has the highest mortality rate among gynecological cancers and affects patients on all continents. Primary treatments involve surgery and the administration of chemotherapeutics, such as carboplatin, which is listed by the World Health Organization as an essential medication for the treatment of human cancers. Unfortunately, due to high rates of drug resistance of EOC towards carboplatin, cancer relapse rates are devastating, and the mechanisms of chemoresistance to carboplatin have not been adequately identified. Consequently, there is a dire need for innovative strategies that are able to detect carboplatin resistance in cancer and to further our understanding of the fundamental nature of chemoresistance towards carboplatin.The presented work describes the thorough electrochemical characterization of carboplatin. We quantify the influx and efflux of carboplatin into/from ovarian cancer cells by electrochemistry to better understand mechanisms of carboplatin chemoresistance. Results emerging from this research will be important for future medical research developing novel agents to combat chemoresistance and will present the basis for future long-term funding applications under this collaboration.

MiRNa signature in small extracellular vesicles and their association with platinum resistance and cancer recurrence in ovarian cancer

Carboplatin, administered as a single drug or in combination with paclitaxel, is the standard chemotherapy treatment for patients with ovarian cancer (OVCA). Recent evidence suggests that miRNAs associated with small extracellular vesicles (sEVs) participate in the development of chemoresistance. We studied the effect of carboplatin in a heterogeneity population of OVCA cells and their derived sEVs to identify mechanisms associated with chemoresistance. sEVs were quantified using an engineered superparamagnetic material, gold-loaded ferric oxide nanotubes and a screen-printed electrode. miR-21-3p, miR-21-5p, and miR-891-5p are enriched in sEVs, and they contribute to carboplatin resistance in OVCA. Using a quantitative MS/MS, miR-21-5p activates glycolysis and increases the expression of ATP-binding cassette family and a detoxification enzyme. miR-21-3p and miR-891-5p increase the expression of proteins involved in DNA repair mechanisms. Interestingly, the levels of miR-891-5p within sEVs are significantly higher in patients at risk of ovarian cancer relapse. Identification of miRNAs in sEVs also provides the opportunity to track them in biological fluids to potentially determine patient response to chemotherapy.

Adipocyte-Induced FABP4 Expression in Ovarian Cancer Cells Promotes Metastasis and Mediates Carboplatin Resistance.

Adipocytes are critical for ovarian cancer cells to home to the omentum, but the metabolic changes initiated by this interaction are unknown. To this end, we carried out unbiased mass spectrometry-based metabolomic and proteomic profiling of cancer cells cocultured with primary human omental adipocytes. Cancer cells underwent significant proteo-metabolomic alteration(s), typified by changes in the lipidome with corresponding upregulation of lipid metabolism proteins. FABP4, a lipid chaperone protein, was identified as the critical regulator of lipid responses in ovarian cancer cells cocultured with adipocytes. Subsequently, knockdown of FABP4 resulted in increased 5-hydroxymethylcytosine levels in the DNA, downregulation of gene signatures associated with ovarian cancer metastasis, and reduced clonogenic cancer cell survival. In addition, clustered regularly interspaced short palindromic repeats (CRISPR)-mediated knockout of FABP4 in high-grade serous ovarian cancer cells reduced metastatic tumor burden in mice. Consequently, a small-molecule inhibitor of FABP4 (BMS309403) not only significantly reduced tumor burden in a syngeneic orthotopic mouse model but also increased the sensitivity of cancer cells toward carboplatin both in vitro and in vivo. Taken together, these results show that targeting FABP4 in ovarian cancer cells can inhibit their ability to adapt and colonize lipid-rich tumor microenvironments, providing an opportunity for specific metabolic targeting of ovarian cancer metastasis. SIGNIFICANCE: Ovarian cancer metastatic progression can be restricted by targeting a critical regulator of lipid responses, FABP4.

Polyclonal BRCA2 mutations following carboplatin treatment confer resistance to the PARP inhibitor rucaparib in a patient with mCRPC: a case report

BackgroundPoly (ADP-ribose) polymerase (PARP) inhibitors are approved for the treatment of breast cancer susceptibility genes 1 and 2 (BRCA1/2) mutant ovarian and breast cancers, and are now being evaluated in metastatic castration-resistant prostate cancer (mCRPC). Reversion mutations that restore BRCA1/2 function have been shown to be responsible for resistance to platinum-based chemotherapy and PARP inhibitors, however there is no information on the sequential use of these agents in prostate cancer.Case presentationA patient with mCRPC associated with a germline BRCA2 mutation was sequentially treated with carboplatin and the PARP inhibitor rucaparib. Genomic profiling of the available baseline tumor and progression blood samples using next-generation sequencing panel tests identified polyclonal BRCA2 reversion mutations post carboplatin treatment but prior to rucaparib treatment. A total of 12 somatic reversion mutations were detected and ranged from small indels to larger deletions of up to 387 amino acids. These alterations are all predicted to restore the BRCA2 open reading frame and potentially protein function. The patient received limited benefit while on rucaparib, likely due to these reversion mutations observed prior to treatment.ConclusionsHere we report a case of a patient with prostate cancer who received a platinum agent and PARP inhibitor sequentially and in whom polyclonal BRCA2 reversion mutations were identified as the likely mechanism of acquired resistance to carboplatin and primary resistance to PARP inhibition. These findings suggest caution is warranted in sequencing these agents.

Quantitative analysis of proteins related to chemoresistance to paclitaxel and carboplatin in human SiHa cervical cancer cells via iTRAQ.

ObjectiveThis study aimed to identify proteins related to paclitaxel and carboplatin chemoresistance in cervical cancer.MethodsQuantitative proteomic analysis was performed on normal SiHa cells and those treated with paclitaxel and carboplatin for 14 days, with isobaric tags for relative and absolute quantitation (iTRAQ) analysis. Gene Ontology (GO) and Kyoto Encyclopedia of Genes and Genomes (KEGG) enrichment analyses were used to identify related processes and differentially expressed proteins.ResultsA total of 67 and 96 differentially expressed proteins were identified in the paclitaxel- and carboplatin- treated groups, respectively. GO and KEGG enrichment analyses identified 53 (43 upregulated and 10 downregulated) and 85 differentially expressed proteins (70 upregulated and 15 downregulated) in the paclitaxel- and carboplatin-treated groups, respectively. The cell counting kit-8 results revealed that APOA1 was overexpressed in both the paclitaxel- and carboplatin- resistant SiHa cells compared with the control cells. Immunohistochemistry showed that APOA1 was highly expressed in the paclitaxel- and carboplatin- resistant squamous cell carcinoma of the cervix.ConclusionThis study is the first to use iTRAQ to identify paclitaxel- and carboplatin- resistance proteins in cervical cells. We identified several proteins previously unassociated with paclitaxel and carboplatin resistance in cervical cancer, thereby expanding our understanding of paclitaxel and carboplatin resistance mechanisms. Moreover, these findings indicate that the APOA1 protein could serve as a potential marker for monitoring and predicting paclitaxel and carboplatin resistance levels.

Cordyceps militaris Exerts Antitumor Effect on Carboplatin-Resistant Ovarian Cancer via Activation of ATF3/TP53 Signaling In Vitro and In Vivo

This study aimed to investigate the effect of Cordyceps militaris extract on the proliferation and apoptosis of carboplatin- resistant SKOV-3 and determine the underlying mechanisms for overcoming carboplatin resistance in human ovarian cancer. We cultured the carboplatin-resistant SKOV-3 cells in vitro until the exponential growth phase and then treated with different concentrations of C. militaris for 24, 48, and 72 hours. We performed cell proliferation assay, cell morphological change assessment using transmission electron microscopy, apoptosis assay, and immunoblotting to measure the protein expression of caspase-3 and -8, poly (ADP-ribose) polymerase (PARP)-1, B-cell lymphoma (Bcl)-2, and activating transcription factor 3 (ATF3)/TP53 signaling-related proteins. As a result, C. militaris reduced the viability of carboplatin-resistant SKOV-3 and induced morphological disruptions in a dose- and time-dependent manner. The gene expression profiles indicated a reprogramming pattern of the previously known and unknown genes and transcription factors associated with the action of TCTN3 on carboplatin-resistant SKOV-3 cells. We also confirmed the C. militaris-induced activation of the ATF3/TP53 pathway. Immunoblotting indicated that cotreatment of C. militaris and carboplatin-mediated ATF3/TP53 upregulation induced apoptosis in the carboplatin-resistant SKOV-3 cells, which are involved in the serial activation of pro-apoptotic proteins, including Bcl-2, Bax, caspases, and PARP-1. Further, when the ATF3 and TP53 expression increased, the CHOP and PUMA expressions were upregulated. Consequently, the upregulated CHOP/PUMA expression activated the positive regulation of the apoptotic signaling pathway. In addition, it decreased the Bcl-2 expression, leading to marked ovarian cancer cells sensitive to carboplatin by enhancing apoptosis. We then corroborated these results using in vivo experiments. Taken together, C. militaris inhibits carboplatin-resistant SKOV-3 cell proliferation and induces apoptosis possibly through ATF3/TP53 signaling upregulation and CHOP/PUMA activation. Therefore, our findings provide new insights into the treatment of carboplatin-resistant ovarian cancer using C. militaris.

S100A10 silencing suppresses proliferation, migration and invasion of ovarian cancer cells and enhances sensitivity to carboplatin

BackgroundOvarian cancer is the leading cause of gynecological cancer-related mortality. The novel oncogene S100A10 has been reported to be involved in cancer cell proliferation, invasion and metastasis. The role of S100A10 in ovarian cancer has not been well studied and the effect of S100A10 on chemotherapy remains unclear. The aims of the present study were to investigate the functional role of S100A10 in the progression and carboplatin sensitivity of ovarian cancer.MethodsWe examined the expression levels in tissues of S100A10 in 138 cases of ovarian cancer by IHC. To determine the functional roles of downregulated S100A10 in ovarian cancer, cell proliferation, colony formation, cell migration and invasion assays were performed. Chemoresistance was analyzed by apoptosis assay. A xenograft tumor model was established to confirm the role of S100A10 in carboplatin resistance in vivo. Using Western blot assays, we also explored the possible mechanisms of S100A10 in ovarian cancer.ResultsThe results showed that increased expression of S100A10 was positively associated with carboplatin resistance (P < 0.001), tumor grade (P = 0.048) and a poorer prognosis (P = 0.0053). Functional analyses demonstrated that S100A10 suppression significantly suppressed ovarian cancer cell proliferation, colony formation, cell migration and invasion, remarkably increased carboplatin-induced apoptosis in SKOV3 and A2780 cells and inhibited tumor growth in vivo. Downregulation of S100A10 expression could inhibit cell proliferation and enhance ovarian cancer cell sensitivity to carboplatin, possibly involving the regulation of cleaved-Caspase3 and cleaved-PARP.ConclusionsTogether, the results of the present study reveal that S100A10 expression can be used as a predictive marker for the prognosis of ovarian cancer and chemosensitivity to carboplatin.

Preclinical Studies Comparing Efficacy and Toxicity of DNA Repair Inhibitors, Olaparib, and AsiDNA, in the Treatment of Carboplatin-Resistant Tumors.

Purpose: Carboplatin is used to treat many cancers, but occurrence of drug resistance and its high toxicity remain a clinical hurdle limiting its efficacy. We compared the efficacy and toxicity of DNA repair inhibitors olaparib or AsiDNA administered alone or in combination with carboplatin. Olaparib acts by inhibiting PARP-dependent repair pathways whereas AsiDNA inhibits double-strand break repair by preventing recruitment of enzymes involved in homologous recombination and non-homologous end joining.Experimental Design: Mice with MDA-MB-231 tumors were treated with carboplatin or/and olaparib or AsiDNA for three treatment cycles. Survival and tumor growth were monitored. Toxicities of treatments were assayed in C57BL/6 immunocompetent mice. Circulating blood hematocrits, bone marrow cells, and organs were analyzed 10 and 21 days after end of treatment using flow cytometry and microscopy analysis. Resistance occurrence was monitored after cycles of treatments with combination of AsiDNA and carboplatin in independent BC227 cell cultures.Results: Olaparib or AsiDNA monotherapies decreased tumor growth and increased mean survival of grafted animals. The combination with carboplatin further increased survival. Carboplatin toxicity resulted in a decrease of most blood cells, platelets, thymus, and spleen lymphocytes. Olaparib or AsiDNA monotherapies had no toxicity, and their combination with carboplatin did not increase toxicity in the bone marrow or thrombocytopenia. All animals receiving carboplatin combined with olaparib developed high liver toxicity with acute hepatitis at 21 days. In vitro, carboplatin resistance occurs after three cycles of treatment in all six tested cultures, whereas only one became resistant (1/5) after five cycles when carboplatin was associated to low doses of AsiDNA. All selected carboplatin-resistant clones retain sensitivity to AsiDNA.Conclusion: DNA repair inhibitor treatments are efficient in the platinum resistant model, MDA-MB-231. The combination with carboplatin improves survival. The association of carboplatin with olaparib is associated with high liver toxicity, which is not observed with AsiDNA. AsiDNA could delay resistance to carboplatin without increasing its toxicity.