Radosław Januchowski

Elacridar Reverses P-gp-Mediated Drug Resistance in Ovarian Cancer Cells in 2D and 3D Culture Models

Multidrug resistance (MDR) remains a major obstacle in the treatment of ovarian cancer. MDR is often mediated by the overexpression of ATP-binding cassette (ABC) transporters, such as P-glycoprotein (P-gp) and Breast Cancer Resistance Protein (BCRP). In this study, we evaluated the ability of elacridar, a dual P-gp and BCRP inhibitor, to overcome MDR in W1, an ovarian cancer cell line sensitive to Paclitaxel (PAC) and its PAC-resistant variants. Cells were cultured under both two-dimensional (2D) and three-dimensional (3D) conditions to account for differences in tumor-like microenvironments. The MDR1 gene and P-gp protein expression were determined for the analyzed model; P-gp activity was measured by flow-cytometry and fluorescent observation, with and without elacridar. The MTT tests were carried out to evaluate how elacridar, combined with chemotherapeutics, affects cell viability. Our results demonstrate that elacridar effectively inhibited transporter activity and increased cellular sensitivity to PAC and DOX. The inhibitory effect was observed in both 2D and 3D cultures, although the re-sensitization effect in 3D conditions was less pronounced, reflecting the complexity of tumor-specific resistance mechanisms. These findings highlight elacridar as a promising compound for reversing MDR in ovarian cancer and emphasize the importance of 3D models in preclinical drug evaluation. Further studies in advanced in vitro and in vivo models are required to assess the potential of elacridar better.

The Role of Elacridar, a P-gp Inhibitor, in the Re-Sensitization of PAC-Resistant Ovarian Cancer Cell Lines to Cytotoxic Drugs in 2D and 3D Cell Culture Models

Chemotherapy resistance is a significant barrier to effective cancer treatment. A key mechanism of resistance at the single-cell level is the overexpression of drug transporters in the ABC family, particularly P-glycoprotein (P-gp), which leads to multidrug resistance (MDR). Inhibitors of these transporters can help re-sensitize cancer cells to chemotherapeutics. This study evaluated elacridar (GG918 and GF120918), a potent third-generation P-gp inhibitor, for its ability to reverse MDR in paclitaxel (PAC)-resistant ovarian cancer cell lines. Sensitive and PAC-resistant cells were cultured in two-dimensional (2D) and three-dimensional (3D) models. MDR1 gene expression was analyzed using Q-PCR, and P-gp protein expression was examined via Western blot and immunofluorescence. Drug sensitivity was evaluated with MTT assays, and P-gp activity was analyzed by flow cytometry and fluorescence microscopy. Elacridar effectively inhibited P-gp activity and increased sensitivity to PAC and doxorubicin (DOX) in 2D cultures but not cisplatin (CIS). In 3D spheroids, P-gp activity inhibition was observed via Calcein-AM staining. However, no re-sensitization to PAC occurred and limited improvement was observed for DOX. These findings suggest that elacridar effectively inhibits P-gp in both 2D and 3D conditions. However, its ability to overcome drug resistance in 3D models is limited, highlighting the complexity of tissue-specific resistance mechanisms.

Elacridar Inhibits BCRP Protein Activity in 2D and 3D Cell Culture Models of Ovarian Cancer and Re-Sensitizes Cells to Cytotoxic Drugs

Chemotherapy resistance is a major obstacle in the treatment of ovarian cancer, often resulting in disease recurrence and poor prognosis for patients. A key contributor to this resistance is the overexpression of ATP-binding cassette (ABC) transporters, including breast cancer resistance protein (BCRP/ABCG2), which actively effluxes chemotherapeutic agents such as topotecan (TOP) or mitoxantrone (MIT), limiting their intracellular accumulation and efficacy. This study investigated the potential of elacridar (GG918), a potent dual P-gp and BCRP inhibitor, to overcome drug resistance in ovarian cancer cell lines. Both TOP-sensitive and TOP-resistant ovarian cancer cells were grown in two-dimensional (2D) monolayers and three-dimensional (3D) spheroid models to better mimic the tumor microenvironment. The expression of the ABCG2 gene was quantified via qPCR and BCRP protein levels were assessed by western blotting and immunofluorescence. Drug response was evaluated using MTT viability assays, while BCRP transporter activity was examined using flow cytometry and microscopic assessment of the intracellular retention of BCRP fluorescent substrates (Hoechst 33342 and MIT). In both 2D and 3D cultures, elacridar effectively inhibited BCRP function and significantly enhanced sensitivity to TOP. These findings suggest that elacridar can inhibit BCRP-mediated drug resistance in ovarian cancer cell models.

The TGFBI gene and protein expression in topotecan resistant ovarian cancer cell lines

The primary limiting factor in achieving cures for patients with cancer, particularly ovarian cancer, is drug resistance. The mechanisms of drug resistance of cancer cells during chemotherapy may include compounds of the extracellular matrix, such as the transforming growth factor-beta-induced protein (TGFBI). In this study, we aimed to analyze the TGFBI gene and protein expression in different sensitive and drug-resistant ovarian cancer cell lines, as well as test if TGFBI can be involved in the response to topotecan (TOP) at the very early stages of treatment. In this study, we conducted a detailed analysis of TGFBI expression in different ovarian cancer cell lines (A2780, A2780TR1, A2780TR2, W1, W1TR, SKOV-3, PEA1, PEA2 and PEO23). The level of TGFBI mRNA (QPCR), intracellular and extracellular protein (Western blot analysis) were assessed in this study. We observed upregulation of TGFBI mRNA in drug-resistant cell lines and estrogen-receptor positive cell lines, which was supported by overexpression of both intracellular and extracellular TGFBI protein. We also showed the TGFBI expression after a short period of treatment of sensitive ovarian cancer cell lines with TOP. The expression of TGFBI in ovarian cancer cell lines suggests its role in the development of drug resistance.

Insight into Cisplatin-Resistance Signaling of W1 Ovarian Cancer Cells Emerges mTOR and HSP27 as Targets for Sensitization Strategies

The microenvironment possesses a strong impact on the tumor chemoresistance when cells bind to components of the extracellular matrix. Here we elucidate the signaling pathways of cisplatin resistance in W1 ovarian cancer cells binding to collagen type 1 (COL1) and signaling interference with constitutive cisplatin resistance in W1CR cells to discover the targets for sensitization. Proteome kinase arrays and Western blots were used to identify the signaling components, their impact on cisplatin resistance was evaluated by inhibitory or knockdown approaches. W1 cell binding to COL1 upregulates integrin-associated signals via FAK/PRAS40/mTOR, confirmed by β1-integrin (ITGB1) knockdown. mTOR appears as key for resistance, its blockade reversed COL1 effects on W1 cell resistance completely. W1CR cells compensate ITGB1-knockdown by upregulation of discoidin domain receptor 1 (DDR1) as alternative COL1 sensor. COL1 binding via DDR1 activates the MAPK pathway, of which JNK1/2 appears critical for COL1-mediated resistance. JNK1/2 inhibition inverts COL1 effects in W1CR cells, whereas intrinsic cisplatin resistance remained unaffected. Remarkably, knockdown of HSP27, another downstream MAPK pathway component overcomes intrinsic resistance completely sensitizing W1CR cells to the level of W1 cells for cisplatin cytotoxicity. Our data confirm the independent regulation of matrix-induced and intrinsic chemoresistance in W1 ovarian cancer cells and offer novel targets for sensitization.

The Significance of MicroRNAs Expression in Regulation of Extracellular Matrix and Other Drug Resistant Genes in Drug Resistant Ovarian Cancer Cell Lines

Ovarian cancer rates the highest mortality among all gynecological malignancies. The main reason for high mortality is the development of drug resistance. It can be related to increased expression of drug transporters and increased expression of extracellular matrix (ECM) proteins. Our foremost aim was to exhibit alterations in the miRNA expression levels in cisplatin (CIS), paclitaxel (PAC), doxorubicin (DOX), and topotecan (TOP)—resistant variants of the W1 sensitive ovarian cancer cell line—using miRNA microarray. The second goal was to identify miRNAs responsible for the regulation of drug-resistant genes. According to our observation, alterations in the expression of 40 miRNAs were present. We could observe that, in at least one drug-resistant cell line, the expression of 21 miRNAs was upregulated and that of 19 miRNAs was downregulated. We identified target genes for 22 miRNAs. Target analysis showed that miRNA regulates key genes responsible for drug resistance. Among others, we observed regulation of the ATP-binding cassette subfamily B member 1 gene (ABCB1) in the paclitaxel-resistant cell line by miR-363 and regulation of the collagen type III alpha 1 chain gene (COL3A1) in the topotekan-resistant cell line by miR-29a.

Piperine Targets Different Drug Resistance Mechanisms in Human Ovarian Cancer Cell Lines Leading to Increased Sensitivity to Cytotoxic Drugs

Our goal was to examine the anticancer effects of piperine against the resistant human ovarian cancer cells and to explore the molecular mechanisms responsible for its anticancer effects. Our study used drug-sensitive ovarian cancer cell line W1 and its sublines resistant to paclitaxel (PAC) and topotecan (TOP). We analyzed the cytotoxic effect of piperine and cytostatic drugs using an MTT assay. The impact of piperine on protein expression was determined by immunofluorescence and Western blot. We also examined its effect on cell proliferation and migration. We noticed a different level of piperine resistance between cell lines. Piperine increases the cytotoxic effect of PAC and TOP in drug-resistant cells. We observed an increase in PTPRK expression correlated with decreased pTYR level after piperine treatment and downregulation of P-gp and BCRP expression. We also noted a decrease in COL3A1 and TGFBI expression in investigated cell lines and increased COL3A1 expression in media from W1PR2 cells. The expression of Ki67 protein and cell proliferation rate decreased after piperine treatment. Piperine markedly inhibited W1TR cell migration. Piperine can be considered a potential anticancer agent that can increase chemotherapy effectiveness in cancer patients.

The Profile of MicroRNA Expression and Potential Role in the Regulation of Drug-Resistant Genes in Doxorubicin and Topotecan Resistant Ovarian Cancer Cell Lines

Epithelial ovarian cancer has the highest mortality among all gynecological malignancies. The main reasons for high mortality are late diagnosis and development of resistance to chemotherapy. Resistance to chemotherapeutic drugs can result from altered expression of drug-resistance genes regulated by miRNA. The main goal of our study was to detect differences in miRNA expression levels in two doxorubicin (DOX)- and two topotecan (TOP)-resistant variants of the A2780 drug-sensitive ovarian cancer cell line by miRNA microarray. The next aim was to recognize miRNAs as factors responsible for the regulation of drug-resistance genes. We observed altered expression of 28 miRNA that may be related to drug resistance. The upregulation of miR-125b-5p and miR-935 and downregulation of miR-218-5p was observed in both DOX-resistant cell lines. In both TOP-resistant cell lines, we noted the overexpression of miR-99a-5p, miR-100-5p, miR-125b-5p, and miR-125b-2-3p and decreased expression of miR-551b-3p, miR-551b-5p, and miR-383-5p. Analysis of the targets suggested that expression of important drug-resistant genes such as the collagen type I alpha 2 chain (COL1A2), protein Tyrosine Phosphatase Receptor Type K (PTPRK), receptor tyrosine kinase—EPHA7, Roundabout Guidance Receptor 2 (ROBO2), myristoylated alanine-rich C-kinase substrate (MARCK), and the ATP-binding cassette subfamily G member 2 (ABCG2) can be regulated by miRNA.

Effect of ALDH1A1 Gene Knockout on Drug Resistance in Paclitaxel and Topotecan Resistant Human Ovarian Cancer Cell Lines in 2D and 3D Model

Ovarian cancer is the most common cause of gynecological cancer death. Cancer Stem Cells (CSCs) characterized by drug transporters and extracellular matrix (ECM) molecules expression are responsible for drug resistance development. The goal of our study was to examine the role of aldehyde dehydrogenase 1A1 (ALDH1A1) expression in paclitaxel (PAC) and topotecan (TOP) resistant ovarian cancer cell lines. In both cell lines, we knocked out the ALDH1A1 gene using the CRISPR/Cas9 technique. Additionally, we derived an ALDH1A1 positive TOP-resistant cell line with ALDH1A1 expression in all cells via clonal selection. The effect of ALDH1A1 gene knockout or clonal selection on the expression of ALDH1A1, drug transporters (P-gp and BCRP), and ECM (COL3A1) was determined by Q-PCR, Western blot and immunofluorescence. Using MTT assay, we compared drug resistance in two-dimensional (2D) and three-dimensional (3D) cell culture conditions. We did not observe any effect of ALDH1A1 gene knockout on MDR1/P-gp expression and drug resistance in the PAC-resistant cell line. The knockout of ALDH1A1 in the TOP-resistant cell line resulted in a moderate decrease of BCRP and COL3A1 expression and weakened TOP resistance. The clonal selection of ALDH1A1 cells resulted in very strong downregulation of BCPR and COL3A1 expression and overexpression of MDR1/P-gp. This finally resulted in decreased resistance to TOP but increased resistance to PAC. All spheroids were more resistant than cells growing as monolayers, but the resistance mechanism differs. The spheroids’ resistance may result from the presence of cell zones with different proliferation paces, the density of the spheroid, ECM expression, and drug capacity to diffuse into the spheroid.

The Profile of MicroRNA Expression and Potential Role in the Regulation of Drug-Resistant Genes in Cisplatin- and Paclitaxel-Resistant Ovarian Cancer Cell Lines

Ovarian cancer is the most lethal gynecological malignancy. The high mortality results from late diagnosis and the development of drug resistance. Drug resistance results from changes in the expression of different drug-resistance genes that may be regulated miRNA. The main aim of our study was to detect changes in miRNA expression levels in two cisplatin (CIS) and two paclitaxel (PAC)—resistant variants of the A2780 drug-sensitive ovarian cancer cell line—by miRNA microarray. The next goal was to identify miRNAs responsible for the regulation of drug-resistance genes. We observed changes in the expression of 46 miRNA that may be related to drug resistance. The overexpression of miR-125b-5p, miR-99a-5p, miR-296-3p, and miR-887-3p and downregulation of miR-218-5p, miR-221-3p, and miR-222-3p was observed in both CIS-resistant cell lines. In both PAC-resistant cell lines, we observed the upregulation of miR-221-3p, miR-222-3p, and miR-4485, and decreased expression of miR-551b-3p, miR-551b-5p, and miR-218-5p. Analysis of targets suggest that expression of important drug-resistant genes like protein Tyrosine Phosphatase Receptor Type K (PTPRK), receptor tyrosine kinase—EPHA7, Semaphorin 3A (SEMA3A), or the ATP-binding cassette subfamily B member 1 gene (ABCB1) can be regulated by miRNA.

Doxorubicin and topotecan resistance in ovarian cancer: Gene expression and microenvironment analysis in 2D and 3D models

This study explores the mechanisms underlying chemotherapy resistance in ovarian cancer (OC) using doxorubicin (DOX) and topotecan (TOP)-resistant cell lines derived from the drug-sensitive A2780 ovarian cancer cell line. Both two-dimensional (2D) monolayer cell cultures and three-dimensional (3D) spheroid models were employed to examine the differential drug responses in these environments. The results revealed that 3D spheroids demonstrated significantly higher resistance to DOX and TOP than 2D cultures, suggesting a closer mimicry of in vivo tumour conditions. Molecular analyses identified overexpression of essential drug resistance-related genes, including MDR1 and BCRP, and extracellular matrix (ECM) components, such as MYOT and SPP1, which were more pronounced in resistant cell lines. MDR1 and BCRP overexpression contribute to chemotherapy resistance in OC by expelling drugs like DOX and TOP. Targeting these transporters with inhibitors or gene silencing could improve drug efficacy, making them key therapeutic targets to enhance treatment outcomes for drug-resistant OC. The study further showed that EMT-associated markers, including VIM, SNAIL1, and SNAIL2, were upregulated in the 3D spheroids, reflecting a more mesenchymal phenotype. These findings suggest that factors beyond gene expression, such as spheroid architecture, cell-cell interactions, and drug penetration, contribute to the enhanced resistance observed in 3D cultures. These results highlight the importance of 3D cell culture models for a more accurate representation of tumour drug resistance mechanisms in ovarian cancer, providing valuable insights for therapeutic development.