Chemosensitivity Of Cancer Cells Research Articles

Abstract 3250: Microbial metabolite, Urolithin A acts as chemo-sensitizing adjuvant in conventional drug therapies via modulation of drug transporters and EMT markers

Abstract Colon cancer is the third leading cause in cancer related deaths in United States of America. Chemoresistance (drug resistance) of tumors is the primary reason for the failure of chemotherapy and a major cause of mortality in colon cancer. The molecular mechanisms involved in chemoresistance or methods to chemosensitization of cancer cells to chemotherapy remain elusive. Recent studies suggest that gut microbiota and microbial metabolites play a crucial role in the development and progression of colon cancer. Urolithin A (UroA) is a gut microbial metabolite derived from ellagitannin/ellagic acid rich-diets such as pomegranate and berries. Here, we identified that UroA and its novel structural analogue (UAS03) chemosensitize 5FU resistant (5FUR) colon cancer cells to 5FU treatment. Our data suggested that combination of 5FU with UroA or UAS03 significantly reduced cell viability of 5FUR colon cancer cell lines with combination index (CI) less than 1 suggesting their synergism. Moreover, UroA or UAS03 in combination with 5FU significantly inhibited 5FUR colon cancer cell proliferation, migration as well as induced apoptosis. Mechanistically, UroA or UAS03 treatment down regulated drug transporters (MDR1, BCRP and MRP2) leading to decreased efflux of drug (e.g., 5FU) and potentially responsible for chemosensitization. Furthermore, treatment with these compounds also modulated EMT makers (e.g., downregulated Snail and β-catenin; upregulated ZO-1 and E-cadherin) to reduce EMT transition. Treatment of UroA or UAS03 in combination with 5FU significantly reduced the growth of 5FUR-tumor xenografts in NRGS mice. Taken together, utilization of UroA or UAS03 in combination with 5FU treatment may provide better therapeutic options for 5FUR colon cancer alleviation. Citation Format: Sweta Ghosh, Rajbir Singh, Zachary M. Vanwinkle, Haixun Guo, Praveen K. Vemula, Ajay Goel, Bodduluri Haribabu, Venkatakrishna Rao Jala. Microbial metabolite, Urolithin A acts as chemo-sensitizing adjuvant in conventional drug therapies via modulation of drug transporters and EMT markers [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2022; 2022 Apr 8-13. Philadelphia (PA): AACR; Cancer Res 2022;82(12_Suppl):Abstract nr 3250.

Nicotine-induced miR-21-3p promotes chemoresistance in lung cancer by negatively regulating FOXO3a.

Lung cancer is the leading cause of cancer-related mortality worldwide and cigarette smoking is reported to contribute to the lung cancer-related mortality. The present study aimed to investigate the molecular mechanism underlying nicotine-induced chemoresistance in lung cancer. The expression of microRNA (miR)-21-3p and its predicted target FOXO3a in lung cancer cells was detected via reverse transcription-quantitative PCR, in the presence or absence of nicotine. The regulatory effect of miR-21-3p and FOXO3a on lung cancer cell proliferation and apoptosis induced by docetaxel or cisplatin treatment was evaluated by performing Cell Counting Kit-8 and Annexin V/PI staining assays, respectively. The interaction between miR-21-3p and FOXO3a was analyzed by performing luciferase reporter assays and western blotting. FOXO3a overexpression rescue experiments were conducted in vitro and in vivo using a xenograft mouse model to assess the function of miR-21-3p/FOXO3a in lung cancer. Nicotine induced miR-21-3p expression in lung cancer cells in a dose-dependent manner. miR-21-3p downregulated FOXO3a expression by directly binding to the 3′-untranslated region of FOXO3a. Moreover, miR-21-3p knockdown sensitized lung cancer cells to docetaxel or cisplatin treatment. Mechanistically, FOXO3a was predicted as a direct target of miR-21-3p. FOXO3a overexpression promoted the chemosensitivity of lung cancer cells to docetaxel or cisplatin treatment. Furthermore, FOXO3a overexpression antagonized the regulatory function of miR-21-3p on docetaxel- or cisplatin-treated lung cancer cells. In the docetaxel- or cisplatin-treated lung cancer xenograft mouse model, miR-21-3p promoted chemoresistance via negatively regulating FOXO3a. Therefore, the present study demonstrated that nicotine-induced miR-21-3p promoted chemoresistance to docetaxel or cisplatin treatment via negatively regulating FOXO3a, which may serve as a novel therapeutic strategy for the treatment of patients with chemoresistant lung cancer.

Prohibitin 1 interacts with p53 in the regulation of mitochondrial dynamics and chemoresistance in gynecologic cancers

BackgroundMitochondrial dynamics (e.g. fission/fusion) play an important role in controlling chemoresistance in representative gynecologic malignancies, ovarian and cervical cancer. Processing the long form of Optic atrophy (L-Opa)1 is a distinctive character of mitochondrial fragmentation, associated with chemosensitivity. Here, we examined the role of prohibitin (Phb)1 in increasing L-Opa1 processing via the regulating mitochondrial protease, Oma1 and its direct interaction with p-p53 (ser15) and pro-apoptotic Bcl-2 antagonist/killer (Bak) 1 in the signaling axis and if this phenomenon is associated with prognosis of patients.MethodsWe compared Cisplatin (CDDP)-induced response of mitochondrial dynamics, molecular interaction among p-p53 (ser15)-Phb1-Bak, and chemoresponsiveness in paired chemosensitive and chemoresistant gynecologic cancer cells (ovarian and cervical cancer cell lines) using western blot, immunoprecipitation, sea horse, and immunofluorescence. Translational strategy with proximity ligation assessment in phb1-p-p53 (ser15) in human ovarian tumor sections further confirmed in vitro finding, associated with clinical outcome.ResultsWe report that: (1) Knock-down of Phb1 prevents Cisplatin (cis-diamine-dichloroplatinum; CDDP) -induced changes in mitochondrial fragmentation and Oma1 mediated cleavage, and Opa1 processing; (2) In response to CDDP, Phb1 facilitates the p-p53 (ser15)-Phb1-Bak interaction in mitochondria in chemosensitive gynecologic cancer cells but not in chemoresistant cells; (3) Akt overexpression results in suppressed p-p53(Ser15)-Phb1 interaction and dysregulated mitochondrial dynamics, and (4) Consistent with in vitro findings, proximity ligation assessment (PLA) in human ovarian tumor sections demonstrated that p-p53(ser15)-Phb1-Bak interaction in mitochondria is associated with better chemoresponsiveness and clinical outcome of patients. Determining the molecular mechanisms by which Phb1 facilitates mitochondrial fragmentation and interacts with p53 may advance the current understanding of chemoresistance and pathogenesis of gynecologic cancer.ConclusionDetermining the key molecular mechanisms by which Phb1 facilitates the formation of p-p53 (ser15)-Bak-Phb1 and its involvement in the regulation of mitochondrial dynamics and apoptosis may ultimately contribute to the current understanding of molecular and cellular basis of chemoresistance in this gynecologic cancer.

MiR-126-5p affects the chemosensitivity of colorectal cancer cells by regulating SPRED1, ERK1/2 pathway and apoptosis

miR-126-5p affects the chemosensitivity of colorectal cancer cells by regulating SPRED1, ERK1/2 pathway and apoptosis

ARIH2 regulates the proliferation, DNA damage and chemosensitivity of gastric cancer cells by reducing the stability of p21 via ubiquitination

Ariadne homolog 2 (ARIH2) is a key member of the RING-between-RING (RBR) E3 ligase family, which is characterized by an RBR domain involved in the polyubiquitination process. However, the molecular mechanism and biological function of ARIH2 in the pathogenesis of gastric cancer remain unclear. In this paper, we found that high ARIH2 expression is correlated with poor prognosis in gastric cancer patients and that ARIH2 can significantly promote the proliferation of gastric cancer cells. The effect of ARIH2 knockdown on colony formation and tumorigenesis of gastric cancer cells was also shown both in vivo and in vitro. Further mechanistic investigations revealed that ARIH2 interacts with p21 and induces p21 ubiquitination, and that the K48 residue of ubiquitin and the K161 residue of p21 play key roles in ARIH2-mediated p21 ubiquitination. We identified ARIH2 as an E3 ligase of p21 by an in vitro ubiquitination assay. In addition, ARIH2 knockdown induced DNA damage, and then induced cell apoptosis and regulated the chemosensitivity of gastric cancer cells after combined treatment with 5-fluorouracil. Generally, our results indicated that ARIH2 promotes the proliferation of gastric cancer cells and regulates p21 expression. These data demonstrate the need to further evaluate the potential therapeutic implications of ARIH2 in gastric cancer.

P-282 Impact of death-associated protein-3 (DAP3) and DAP3 binding cell death enhancer 1 (DELE1) on drug sensitivity in colorectal cancer cells

Death association protein-3 (DAP3) is an important growth/death regulator of cells, has been found to have important clinical value in various cancer. DELE1 (DAP3 Binding Cell Death Enhancer 1) has been reported to be a partner of DAP3 and plays a key part in mitochondrial metabolism and mitochondria stress signalling (1). DELE1 also appears to regulate the apoptotic signalling in cells including cancer cells. However, the role played by the two molecules markedly vary depending on cell and tumour types with only a very limited tumour types have been investigated. High expressions of DAP3 and DELE1 have been found to strongly correlated with poor overall survival, disease free survival and distant metastasis free survival in colorectal cancer (2). The present study was to assess the impact of DAP3 and DELE1 on the drug sensitivity of colorectal cancers in vitro. Human colorectal cancer cell lines, RKO and HT115 were used. RKO and HT115 cells were transfected with the lentivirus particles that contained an anti-DAP3 shRNA to create the DAP3 knockdown cell model, designated as RKODAP3kd and HT115DAP3kd, respectively. A DELE1 siRNA was also applied to these cells in order to silence the expression of DELE1 (the new submodels designated as RKODELE1kd and HT115DELE1kd). The DAP3/DELE1 Dual knockdown cell models were established by using the anti-DAP3 shRNA and DELE1 siRNA combination transfection and are referred here as RKODAP3kd/DELE1kd and HT115DAP3kd/DELE1kd. The knockdown of the respective gene transcripts was confirmed by quantitative PCR analysis and respective proteins by Western blot method. Cytotoxicity tests were performed on these sub-models using 5-fluorouracil (5-FU), Docetaxel (DTX) and Methotrexate (MTX) with different concentrations. Additionally, the mitochondrial response following genetic knockdowns were also evaluated. Knockdown DAP3 and knockdown of DELE1 sensitised the RKO cells to 5-FU, MTX and DTX with a IC50 at for control cells at respectively at 14.2mM, 1.6mM, 57.1nM and for RKODAP3kd at 10.4mM, 1.2mM and 51.0nM. Although knocking down DELE1 had less impact than the DAP3 knockdown, DAP3/DELE1 double knockdown however had more profound effects compared with single knockdowns and with wild type controls (IC50 for 5-FU, MTX and DTX in RKODAP3kd/DELE1kd cells being respectively at 7.0mM, 0.6mM and 1.5nM). In the metabolic analyses including metabolism of glucose, lactate, NAD(P)H and nitrogen dioxide (NO2), we did not detect a significant change following DAP3 knockdown, DELE1 knockdown or the double knockdown, arguing an mitochondria pathway independent regulation of the drug sensitivity by the two molecules. DAP3 and DELE1, important growth/death regulators and prognostic factors of in colorectal cancer, have a role in the chemosensitivity in colorectal cancer cells. The findings suggest that molecules are potential targets in therapeutic intervention in colorectal cancer.

Silencing of LINC01963 enhances the chemosensitivity of prostate cancer cells to docetaxel by targeting the miR-216b-5p/TrkB axis

AbstractDocetaxel (DTX) treatment effectively prolongs the overall survival of patients with prostate cancer. However, most patients eventually develop resistance to chemotherapy and experience tumor progression or even death. Long noncoding RNAs (lncRNAs) affect docetaxel chemosensitivity. However, the biological role and regulatory mechanisms of lncRNAs in docetaxel-resistant prostate cancer remain unclear. Differences in lncRNAs were evaluated by lncRNA sequencing and evaluated using quantitative real-time polymerase chain reaction, and TrkB expression was measured through western blot analysis. Proliferation was measured using the MTS, while apoptosis and cell cycle were measured using flow cytometry. In addition, migration and invasion were measured using transwell assays. Forty-eight female BALB/c nude mice were used for subcutaneous tumorigenicity and lung metastasis assays. We found that LINC01963 was overexpressed in the PC3-DR cells. LINC01963 silencing enhanced the chemosensitivity of PC3-DR to docetaxel and inhibited tumorigenicity and lung metastasis, while LINC01963 overexpression enhanced the chemoresistance of PC3 cells to docetaxel. It was found that LINC01963 bind to miR-216b-5p. The miR-216b-5p inhibitor reversed the suppressive effect of sh-LINC01963 on PC3-DR cell proliferation, migration, and invasion. Furthermore, miR-216b-5p can bind to the 3′-UTR of NTRK2 and inhibit TrkB protein levels. TrkB enhances docetaxel resistance in prostate cancer and reverses the effects of LINC01963 silencing and miR-216b-5p overexpression. In conclusion, silencing LINC01963 inhibited TrkB protein level to enhance the chemosensitivity of PC3-DR to docetaxel by means of competitively binding to miR-216b-5p. This study illustrates that LINC01963 is a novel therapeutic target for treating prostate cancer patients with DTX resistance.

Metabolic reprogramming by dual-targeting biomimetic nanoparticles for enhanced tumor chemo-immunotherapy

Cancer-associated fibroblasts (CAFs)-mediated metabolic support plays a vital role in tumorigenesis. The metabolic network between cancer cells and CAFs may serve as promising targets for cancer therapy. Here, aiming at targeted blockade of the metabolic support of CAFs to cancer cells, a biomimetic nanocarrier is designed by coating solid lipid nanoparticles containing chemotherapeutic paclitaxel (PTX) and glycolysis inhibitor PFK15 with hybrid membranes of cancer cells and activated fibroblasts. The nanoparticles possess outstanding dual-targeting ability which can simultaneously target cancer cells and CAFs. The encapsulated glycolysis inhibitor PFK15 can prevent the glycolysis of cancer cells and CAFs at the same time, thus increasing the chemosensitivity of cancer cells and blocking the metabolic support of CAFs to cancer cells. The results showed that the combination of PTX and PFK15 exhibited synergistic effects and inhibited tumor growth effectively. Moreover, the biomimetic nanoparticles obviously reduced the lactate production in the tumor microenvironment, leading to activated immune responses and enhanced tumor suppression. This work presents a facile strategy to destroy the metabolic network between cancer cells and CAFs, and proves the potential to elevate chemo-immunotherapy by glycolysis inhibition. Statement of significanceIn many solid tumors, most cancer cells produce energy and carry out biosynthesis through glycolysis, even in aerobic conditions. As the main tumor stromal cells, cancer-associated fibroblasts (CAFs) usually turn oxidative phosphorylation into aerobic glycolysis with metabolic reprogramming and provide high-energy glycolytic metabolites for cancer cells. The metabolic network between cancer cells and CAFs is regarded as the vulnerability among cancer cells. Moreover, lactate produced by cancer cells and CAFs through glycolysis often leads to the immunosuppressive tumor microenvironment. The present study provides an effective approach to destroy the metabolic network between cancer cells and CAFs and greatly improves the antitumor immune response by reducing lactate production, which serves as a promising strategy for combined chemo-immunotherapy mediated by glycolysis.

Bioactivity inspired C19-diterpenoid alkaloids for overcoming multidrug-resistant cancer.

The pharmacological activities of C19-diterpenoid alkaloids are related to their basic skeletons (e.g., aconitine-type or lycoctonine-type). Also, few studies have been reported on the chemosensitizing effects of diterpenoid alkaloids. Consequently, this study was aimed at determining the chemosensitizing effects of synthetic derivatives of lycoctonine-type C19-diterpenoid alkaloids on a P-glycoprotein (P-gp)-overexpressing multidrug-resistant (MDR) cancer cell line KB-VIN. The acyl-derivatives of delpheline and delcosine showed moderate cytotoxicity against chemosensitive cancer cell lines. Among non-cytotoxic synthetic analogs (1-14), several derivatives effectively and significantly sensitized MDR cells by interfering with the drug transport function of P-gp to three anticancer drugs, vincristine, paclitaxel, and doxorubicin. The chemosensitizing effect of derivatives 2, 4, and 6 on KB-VIN cells against vincristine were more potent than 5μM verapamil, and derivatives 4 and 13 were more effective than 5μM verapamil for paclitaxel. Among them, 2 in particular increased the sensitivity of KB-VIN cells to vincristine by 253-fold.

Blockade of p38 MAPK overcomes AML stem cell line KG1a resistance to 5-Fluorouridine and the impact on miRNA profiling.

Most of the AML patients in remission develop multidrug resistance after the first-line therapy and relapse. AML stem cells have gained attention for their chemoresistance potentials. Chemoresistance is a multifactorial process resulting from altered survival signaling pathways and apoptosis regulators such as MAPK, NF-κB activation and ROS production. We targeted the survival pathway p38 MAPK, NF-κB and ROS generation in human chemoresistant AML stem cell line KG1a, susceptible to enhance cell sensitivity to the chemotherapy drug 5-Fluorouridine, compared to the chemosensitive AML cell line HL60. After confirming the phenotypic characterization of KG1a and HL60 cells using flow cytometry and transcriptomic array analyses, cell treatment with the NF-κB inhibitor IKKVII resulted in a complete induction of apoptosis, and a few p38 MAPK inhibitor SB202190-treated cells underwent apoptosis. No change in the apoptosis status was observed in the ROS scavenger N-acetylcysteine-treated cells. The p38 MAPK pathway blockade enhanced the KG1a cell sensitivity to 5-Fluorouridine, which was associated with the upregulation of microribonucleic acid-(miR-)328-3p, as determined by the microarray-based miRNA transcriptomic analysis. The downregulation of the miR-210-5p in SB202190-treated KG1a cells exposed to FUrd was monitored using RT-qPCR. The miR-328-3p is known for the enhancement of cancer cell chemosensitivity and apoptosis induction, and the downregulation of miR-210-5p is found in AML patients in complete remission. In conclusion, we highlighted the key role of the p38 MAPK survival pathway in the chemoresistance capacity of the AML stem cells and potentially involved miRNAs, which may pave the way for the development of a new therapeutic strategy targeting survival signaling proteins and reduce the rate of AML relapse.

Retraction notice to Downregulation of MicroRNA-147 Inhibits Cell Proliferation and Increases the Chemosensitivity of Gastric Cancer Cells to 5-Fluorouracil by Directly Targeting PTEN [Oncology Research 26(6) (2018) 901-911

Retraction notice to Downregulation of MicroRNA-147 Inhibits Cell Proliferation and Increases the Chemosensitivity of Gastric Cancer Cells to 5-Fluorouracil by Directly Targeting PTEN [Oncology Research 26(6) (2018) 901-911

Polyphyllin I Inhibits Cisplatin Resistance of Cervical Cancer Cells by Inducing Mitochondrial Dysfunction and Endoplasmic Reticulum Stress

Resistance of cervical cancer to cisplatin chemotherapy compromises the therapeutic efficacy of the treatment. Polyphyllin I, a bioactive compound extracted from rhizoma of Paris polyphyllin, displays a selective inhibitory effect on a variety of tumor cells. Furthermore, it potentiates the chemosensitivity of cisplatin against cisplatin resistant gastric cancer cells and lung adenocarcinoma. However, its role in modulating chemosensitivity of cisplatin resistant cervical cancer cells remains unexplored. To this end, the repressive effect of polyphyllin I on proliferation, invasion and migration of cisplatin resistant cervical cancer cells compared to the parental cervical cancer cells as well as downregulation of mitochondrial membrane potential of cisplatin resistant cervical cancer cells, as well as upregulation of protein kinase R-like ER kinase/translation initiation factor 2-alpha kinase 3, protein-kinase and site-specific endoribonuclease/inositol-requiring enzyme 1, binding immunoglobulin protein, and C/EBP homologous transcription factor proteins. In conclusion, polyphyllin I stimulate mitochondrial dysfunction and endoplasmic reticulum stress to attenuate cisplatin resistance of cervical cancer.

The novel mechanism of Med12-mediated drug resistance in a TGFBR2-independent manner

Inevitable emergence of drug resistance is the biggest hurdle to both chemotherapies and targeted therapies. Understanding the resistance mechanisms will contribute to identification of biomarkers for predicting response to therapy and design new therapeutic strategies to overcome drug resistance in human cancers. The type II transforming growth factor (TGF)-β receptor gene (TGFBR2) is frequently frameshift mutated in several cancer types, especially in colorectal, endometrium and gastric cancers cells. Here, we found that Med12, a component of the transcriptional mediator complex, plays a role in modulating chemosensitivity in TGFBR2 deficient cancer cells. Loss of Med12 leads to chemoresistance in multiple TGFBR2 deficient cancer cells. Interestingly, RNA sequencing data revealed that interferon IFN-related DNA damage resistance signature (IRDS) is upregulated in Med12 knockdown cancer cells. And the expression of IRDS pattern is negatively correlated with chemosensitivity. Therefore, our study identifies a novel mechanism of Med12-mediated drug resistance, which is a TGFBR-independent manner.

New synthetic phenylquinazoline derivatives induce apoptosis by targeting the pro-survival members of the BCL-2 family

Chemo-resistant cancer cells acquire robust growth potential through cell signaling mechanisms such as the down-regulation of tumor suppressors and the up-regulation of pro-survival proteins, respectively. To overcome chemo-resistance of cancer, small molecule drugs that interact with the cell signaling proteins to enhance sensitization of cancer cells toward cancer therapies are likely to be effective for the treatment of chemo-drug resistant cancer. To identify high potency small molecules, a series of ten novel phenylquinazoline derivatives were synthesized to determine their cellular effects in MCF-7 and MCF-7- cisplatin-resistant (CR) human breast cancer cells which led to the identification of two bioactive compounds, SMS-IV-20 and SMS-IV-40, that exhibited an elevated level of cytotoxicity against the human breast cancer cells and spheroid cells. In addition, both compounds enhanced chemo-sensitization of the human breast cancer cells that were genetically engineered to express the tumor suppressor and pro-apoptotic proteins, MOAP-1, Bax, and RASSF1a (MBR), suggesting that the compounds interact with the MBR signaling pathway. Furthermore, when MCF-7-CR cells were treated with SMS-IV-20 and SMS-IV-40 in the presence of ABT-737, a BCL-XL and BCL-2 inhibitor, enhanced chemo-sensitization was observed, suggesting SMS-IV-20 and SMS-IV-40 exert antagonistic activity to regulate the functional activity of BCL-2 and BCL-XL. Western blot analysis showed that both SMS-IV-20 and SMS-IV-40 induced down-regulation of BCL-2 or both BCl-2 and BCL-XL expression, respectively while promoting the release of mitochondrial Cytochrome C. Taken together, the data showed that SMS-IV-20 and SMS-IV-40 are potent activators of apoptosis that enhance chemo-sensitization through their antagonistic actions on the pro-survival activity of the BCl-2 family in human cancer cells.

The multi-targeted tyrosine kinase inhibitor SKLB610 resensitizes ABCG2-overexpressing multidrug-resistant cancer cells to chemotherapeutic drugs

The overexpression of ATP-binding cassette (ABC) transporter ABCB1 (P-glycoprotein) or ABCG2 (BCRP/MXR/ABCP) in cancer cells is frequently associated with the development of multidrug resistance (MDR) in cancer patients, which remains a major obstacle to effective cancer treatment. By utilizing energy derived from ATP hydrolysis, both transporters have been shown to reduce the chemosensitivity of cancer cells by actively effluxing cytotoxic anticancer drugs out of cancer cells. Knowing that there are presently no approved drugs or other therapeutics for the treatment of multidrug-resistant cancers, in recent years, studies have investigated the repurposing of tyrosine kinase inhibitors (TKIs) to act as agents against MDR mediated by ABCB1 and/or ABCG2. SKLB610 is a multi-targeted TKI with potent activity against vascular endothelial growth factor receptor 2 (VEGFR2), platelet-derived growth factor receptor (PDGFR), and fibroblast growth factor receptor 2 (FGFR2). In this study, we investigate the interaction of SKLB610 with ABCB1 and ABCG2. We discovered that neither ABCB1 nor ABCG2 confers resistance to SKLB610, but SKLB610 selectively sensitizes ABCG2-overexpressing multidrug-resistant cancer cells to cytotoxic anticancer agents in a concentration-dependent manner. Our data indicate that SKLB610 reverses ABCG2-mediated MDR by attenuating the drug-efflux function of ABCG2 without affecting its total cell expression. These findings are further supported by results of SKLB610-stimulated ABCG2 ATPase activity and in silico docking of SKLB610 in the drug-binding pocket of ABCG2. In summary, we reveal the potential of SKLB610 to overcome resistance to cytotoxic anticancer drugs, which offers an additional treatment option for patients with multidrug-resistant cancers and warrants further investigation.

MiR-497-5p Enhances the Chemosensitivity of Non-Small Cell Lung Cancer Cells to Cisplatin via Targeting of the CDCA4 Gene

Non-Small Cell Lung Cancer (N-SCLC) accounts for almost 85% of all diagnosed lung cancer and the prognosis remains poor usually because of assimilated drug resistance including cisplatin. The miR-497-5p family has been discovered to play a significant role in regulating biological functions in N-SCLC. The purpose of this study was to investigate the molecular mechanism of miR-497-5p and its target gene on modulating cisplatin chemosensitivity in N-SCLC cells. The enhanced chemosensitivity effect of miR-497-5p to cisplatin in A549 and H1299 cells was detected by MTT method. Dual luciferase reporter assay, quantitative Real-Time PCR (qRT-PCR) and Western blotting were performed to demonstrate that miR-497-5p directly targets CDCA4 to reduce the expression. Transwell, colony formation and flow cytometry assays showed that combination of miR-497-5p and cisplatin exerted stronger effects on inhibiting N-SCLC cells proliferation, migration and invasion as well as promoting apoptosis and G1 phase arrest than miR-497-5p and cisplatin alone. The same tendency was observed in the upregulation of apoptosis-related protein Bax and Cytochrome-C and downregulation of cycle-related proteins CyclinB1 and CDK1. Our results indicate that upregulation of miR-497-5p targets CDCA4 directly and may function as an important modifier to sensitize N-SCLC cells to cisplatin.

Nanog suppression enhanced the chemosensitivity of human non-small-cell lung cancer cells to Cisplatin and inhibited cell migration

Lung cancer is the leading cause of cancer-associated death in the world. As one of the leading transcription factors in controlling stemness features, Nanog was shown to promote cancer progression, metastasis, and drug resistance. Considering that, this research was conducted to evaluate the effect of Nanog suppression using specific siRNA on the chemosensitivity of lung cancer cells to Cisplatin through inhibition of cell proliferation, migration, and stemness as well as apoptosis induction. Then, A549 lung cancer cells were transfected with Nanog siRNA and treated with Cisplatin individually or combined. Subsequently, to investigate cell proliferation and apoptosis induction, MTT assay and Annexin V/PI staining were performed, respectively. Also, colony formation assay was carried out to evaluate cell stemness features, and migration ability of A549 cells was followed using a wound-healing assay. Gene expression was quantified via qRT-PCR. The obtained results illustrated that siRNA-mediated Nanog suppression remarkably increased the chemosensitivity of A549 cells to Cisplatin through apoptosis induction. Consistently, Nanog suppression combined with Cisplatin led to upregulation of Caspase-3 apoptotic gene and Bax/Bcl-2 ratio. Besides, Nanog knockdown, individually or combined with Cisplatin, prevented colony formation ability of A549 cells by downregulating Sox2 and CD44 genes. It was also indicated that the combination therapy remarkably downregulated MMP9 expression and subsequently suppressed A549 cell migration. A significant reduction was also observed in c-Myc and PD-L1 gene expression levels. In conclusion, the findings of the current study demonstrated that silencing Nanog combined with Cisplatin could be a potent treatment approach for lung cancer patients.

Long non-coding RNA placenta‑specific protein 2 regulates the chemosensitivity of cancer cells to cisplatin in hepatocellular carcinoma (HCC) by sponging microRNA-96 to upregulate X-linked inhibitor of apoptosis protein

ABSTRACT This study was conducted to investigate the roles of lncRNA PLAC2 and XiaP in hepatocellular carcinoma (HCC). HCC and paired non-tumor tissues were collected from 62 HCC patients who received cisplatin-based treatment. At 0, 2, and 4 months of post-cisplatin-based therapy, blood samples (5 ml) were collected from all patients and prepared plasma samples. LncRNA PLAC2 expression in tissue and plasma samples was determined by RT-qPCR. The interactions between lncRNA PLAC2 and XiaP in HCC cell lines were assessed by overexpression experiments. Cell viability and apoptosis under cisplatin treatment were analyzed by MTT assay and cell apoptosis assay, respectively. The direct interaction between lncRNA PLAC2 and miR-96, which can target XiaP, was analyzed by performing RNA–RNA pulldown assay. It was observed that lncRNA PLAC2 was upregulated in HCC tissues than in non-tumor tissues. LncRNA PLAC2 expression in HCC tissues was not affected by HBV and HCV but upregulated after cisplatin-based treatment. Similarly, cisplatin treatment of HCC cells increased PLAC2 expression. LncRNA PLAC2 and XiaP overexpression increased viability and decreased apoptosis of cisplatin-treated HCC cells, while lncRNA PLAC2 knockdown decreased viability and increased apoptosis of cisplatin-treated HCC cells. Western blot analysis showed that lncRNA PLAC2 increased XiaP protein accumulation, while lncRNA PLAC2 siRNA silencing decreased XiaP expression in HCC cells. LncRNA PLAC2 and miR-96 directly interacted with each other, while they failed to regulate the expression of each other. In conclusion, lncRNA PLAC2 negatively regulates the chemosensitivity of HCC cells to cisplatin, possibly by sponging miR-96 to upregulate miR-96.

ARID3A promotes the chemosensitivity of colon cancer by inhibiting AKR1C3.

ARID3A is upregulated in colorectal cancer and can promote the proliferation and metastasis of cancer cells. However, patients with higher level of ARID3A have a better prognosis. This study aimed to uncover the mechanism by which ARID3A benefits the prognosis of colon cancer. Our results indicated that ARID3A upregulation enhanced the chemosensitivity of colon cancer cells to 5-fluorouracil (5-FU), whereas ARID3A downregulation inhibited the chemosensitivity of colon cancer cells to 5-FU. Through database analysis, we found that AKR1C3, a drug resistance-related gene, was the target of ARID3A. Moreover, AKR1C3 was downregulated in colon cancer tissues compared to normal tissues. Next, we assessed the interaction between AKR1C3 and ARID3A, and found that ARID3A inhibited the transcription of AKR1C3, leading to the downregulation of AKR1C3 in colon cancer cells. We also verified that AKR1C3 inhibited the chemosensitivity of colon cancer cells to 5-FU. Moreover, patients with higher ratio of ARID3A to AKR1C3 had a better prognosis. This study suggested that ARID3A promoted chemosensitivity of colon cancer cells by inhibiting AKR1C3 in colon cancer. The ratio of ARID3A to AKR1C3 is a good marker to predict the prognosis of colon cancer patients.

Analysis of Multiple Drug Resistance Mechanism in Different Types of Soft Tissue Sarcomas: Assessment of the Expression of ABC-Transporters, MVP, YB-1, and Analysis of Their Correlation with Chemosensitivity of Cancer Cells

Chemotherapy of soft tissue sarcomas (STS) is restricted by low chemosensitivity and multiple drug resistance (MDR). The purpose of our study was the analysis of MDR mechanism in different types of STS. We assessed the expression of ABC-transporters, MVP, YB-1, and analyzed their correlation with chemosensitivity of cancer cells. STS specimens were obtained from 70 patients without metastatic disease (2018–2020). Expression level of MDR-associated genes was estimated by qRT-PCR and cytofluorimetry. Mutations in ABC-transporter genes were captured by exome sequencing. Chemosensitivity (SI) of STS to doxorubicin (Dox), ifosfamide (Ifo), gemcitabine (Gem), and docetaxel (Doc) was analyzed in vitro. We found strong correlation in ABCB1, ABCC1, and ABCG2 expression. We demonstrated strong negative correlations in ABCB1 and ABCG2 expression with SI (Doc) and SI (Doc + Gem), and positive correlation of MVP expression with SI (Doc) and SI (Doc + Gem) in undifferentiated pleomorphic sarcoma. Pgp expression was shown in 5 out of 44 STS samples with prevalence of synovial sarcoma relapses and it is strongly correlated with SI (Gem). Mutations in MDR-associated genes were rarely found. Overall, STS demonstrated high heterogeneity in chemosensitivity that makes reasonable in vitro chemosensitivity testing to improve personalized STS therapy, and classic ABC-transporters are not obviously involved in MDR appearance.