New and Old Genes Associated with Primary and Established Responses to Paclitaxel Treatment in Ovarian Cancer Cell Lines

Comprehensive profiling of endocrine metabolism identifies a novel signature with robust predictive value in ovarian cancer

BACKGROUND

The cell endocrine pathway is a critical physiological process composed of the endoplasmic reticulum, Golgi apparatus and associated vesicles. Loss of enzymes or proteins can cause dysfunction of endoplasmic reticulum and Golgi apparatus and affect secretion pathways leading to a variety of human diseases, including cancer.

METHODS

The single-cell RNA sequencing and single nucleotide variant principal component analysis data of ovarian cancer were retrieved from The Cancer Genome Atlas and Gene Expression Omnibus (GEO) datasets. Eighty-four genes from SECRETORY_PATHWAYs were obtained from the gene set enrichment analysis (GSEA) website. Univariate cox regression analyses and ConsensusClusterPlus were used to identify prognostic genes and molecular subtypes, which were validated using the tumor immune dysfunction and exclusion (i.e. TIDE) analysis and gene mutation analysis. A prognosis model was established by randomForestSRC. Abundant infiltrated immune cells and pathway enrichment analyses were carried out, respectively, through ssGSEA, ESTIMATE, MCP-counter and GSEA. The drug sensitive analysis was performed using pRRophetic package. Immunotherapy datasets and pan-carcinoma analysis were used to examine the performance of prognostic model.

RESULTS

Eighteen prognostic genes from SECRETORY_PATHWAYs were found in both TCGA and GEO datasets. Next, two clusters (C1 and C2) were determined, for which C1 with a poor prognosis had higher immune infiltration. Tumor-related pathways, such as PATHWAYS_IN_CANCER and B_CELL_RECEPTOR_SIGNALING_PATHWAY, were enriched in C1. Moreover, C2 was suitable for immunotherapy. A four-gene (DNAJA1, NDRG3, LUZP1 and ZCCHC24) signature was developed and successfully validated. RiskScore of higher levels were significantly associated with worse prognoses. An enhanced immune infiltration, increased pathways score and inappropriate immunotherapy were observed in the high RiskScore group. The high- and low-RiskScore groups had different drug sensitivities. Immunotherapy datasets and pan-carcinoma analysis indicated that the low RiskScore group may benefit from immunotherapy.

CONCLUSIONS

Based on the perspective of the secretory signaling pathway, a robust prognostic signature with great performances was determined, which may provide clues for clinical precision treatment of ovarian cancer.

Anti-cancer effects of alpha lipoic acid, cisplatin and paclitaxel combination in the OVCAR-3 ovarian adenocarcinoma cell line

BACKGROUND

Ovarian cancer is the leading cause of gynecological cancer deaths. One of the major challenges in treating ovarian cancer with chemotherapy is managing the resistance developed by cancer cells to drugs, while also minimizing the side effects caused by these agents In the present study, we aimed to examine the effects of a combination of alpha lipoic acid (ALA), with cisplatin and paclitaxel in ovarian cancer(OVCAR-3).

METHODS

The cytotoxic effects of ALA, cisplatin and paclitaxel on OVCAR-3 cells were determined. Four groups were formed: Control, ALA, Cisplatin + Paclitaxel, ALA + Cisplatin + Paclitaxel. The effects of single and combined therapy on cell migration, invasion and colony formation were analyzed. Changes in the expression of genes related to apoptosis, cell adhesion and cell cycle were analyzed with Real-time polymerase chain reaction(RT-PCR). The oxidative stress index and The Annexin V test were performed.

RESULTS

The reduction in rapamycin-insensitive companion of mTOR(RICTOR) expression in the ALA + Cisplatin + Paclitaxel group was found statistically significant(p < 0.05). The decrease in MMP-9 and - 11 expressions the ALA + Cisplatin + Paclitaxel group was statistically significant(p < 0.05). The lowest values for mitogen-activated protein kinase(MAPK) proteins were found in the ALA + Cisplatin + Paclitaxel group. No colony formation was observed in the Cisplatin + Paclitaxel and ALA + Cisplatin + Paclitaxel groups. The lowest wound healing at 24 h was seen in the ALA + Cisplatin + Paclitaxel group.

CONCLUSIONS

This study is the first one to investigate the combined treatment of ALA, Cisplatin, Paclitaxel on OVCAR-3. While ALA alone was not effective, combined therapy with ALA, has been found to reduce cell invasion, especially wound healing in the first 24 h, along with tumor cell adhesion.

Fam198b as a novel biomarker for gastric cancer and a potential therapeutic target to prevent tumor cell proliferation dysregulation

BACKGROUND

It has been reported that the human family with sequence similarity 198, member B (Fam198b) play an important role in the occurrence and development of various cancers. Nevertheless, its function in gastric cancer is not completely clear. Hereby, we investigated the function and prognostic value of Fam198b in gastric cancer and further validated the results in gastric cancer through a series of in vitro experiments.

METHODS

We used R software and online bioinformatics analysis tools-GEPIA2, TIMER2, Kaplan-Meier plotter, cBioPortal, TISIDB COSMIC, and STRING to study the characteristics and functions of Fam198b in GC, such as aberrant expression, prognostic value, genomic alterations, immune microenvironment, anticancer drug sensitivity, and related signaling pathways. In addition, in vitro experiments such as immunohistochemistry (IHC), cell function experiments, and signaling pathway experiments were performed to validate the key conclusions.

RESULT

Fam198b is obviously highly expressed in gastric cancer, and its expression is intensively correlated with tumor prognosis. The etiology of abnormal Fam198b expression was superficially investigated and validated by associating genomic alterations and the immune microenvironment. Furthermore, Fam198b is intensively correlated with the sensitivity of multiple antitumor drugs. It was demonstrated by functional enrichment analysis that Fam198b was linked to myogenesis, angiogenesis, epithelial mesenchymal transition and cytokine binding. It was observed in vitro experiments that knockdown Fam198b could significantly inhibit tumor cell proliferation and migration. These results were reversed when Fam198b was overexpressed. It was validated by signaling pathway experiments that Fam198b promoted gastric cancer progression by up-regulating the PI3K/AKT/BCL-2 signaling pathway.

CONCLUSION

As a novel biomarker to predict GC prognosis and tumor progression, Fam198b is a promising therapeutic target to reverse tumor progression.

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

PURPOSE

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.

MATERIALS AND METHODS

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.

RESULTS

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.

CONCLUSION

The expression of TGFBI in ovarian cancer cell lines suggests its role in the development of drug resistance.

The response and resistance to drugs in ovarian cancer cell lines in 2D monolayers and 3D spheroids

Ovarian cancer is the most common type of gynecologic cancer. One of the leading causes of high mortality is chemoresistance, developed primarily or during treatment. Different mechanisms of drug resistance appear at the cellular and cancer tissue organization levels. We examined the differences in response to the cytotoxic drugs CIS, MTX, DOX, VIN, PAC, and TOP using 2D (two-dimensional) and 3D (three-dimensional) culture methods. We tested the drug-sensitive ovarian cancer cell line W1 and established resistant cell lines to appropriate cytotoxic drugs. The following qualitative and quantitative methods were used to assess: 1) morphology - inverted microscope and hematoxylin & eosin staining; 2) viability - MTT assay; 3) gene expression - a quantitative polymerase chain reaction; 4) identification of proteins - immunohistochemistry, and immunofluorescence. Our results indicate that the drug-sensitive and drug-resistant cells cultured in 3D conditions exhibit stronger resistance than the cells cultured in 2D conditions. A traditional 2D model shows that drug resistance of cancer cells is caused mainly by changes in the expression of genes encoding ATP-binding cassette transporter proteins, components of the extracellular matrix, "new" established genes related to drug resistance in ovarian cancer cell lines, and universal marker of cancer stem cells. Whereas in a 3D model, the drug resistance in spheroids can be related to other mechanisms such as the structure of the spheroid (dense or loose), the cell type (necrotic, quiescent, proliferating cells), drug concentrations or drug diffusion into the dense cellular/ECM structure.

Regulation of secretory pathway kinase or kinase-like proteins in human cancers

Secretory pathway kinase or kinase-like proteins (SPKKPs) are effective in the lumen of the endoplasmic reticulum (ER), Golgi apparatus (GA), and extracellular space. These proteins are involved in secretory signaling pathways and are distinctive from typical protein kinases. Various reports have shown that SPKKPs regulate the tumorigenesis and progression of human cancer via the phosphorylation of various substrates, which is essential in physiological and pathological processes. Emerging evidence has revealed that the expression of SPKKPs in human cancers is regulated by multiple factors. This review summarizes the current understanding of the contribution of SPKKPs in tumorigenesis and the progression of immunity. With the epidemic trend of immunotherapy, targeting SPKKPs may be a novel approach to anticancer therapy. This study briefly discusses the recent advances regarding SPKKPs.

The significance of interferon gamma inducible protein 16 (IFI16) expression in drug resistant ovarian cancer cell lines

BACKGROUND

Inherent or developed during treatment drug resistance is the main reason for the low effectiveness of chemotherapy in ovarian cancer. IFI16 is a cytoplasmic/nuclear protein involved in response to virus's infection and cell cycle arrest associated with the cellular senescence.

METHODS

Here we performed a detailed IFI16 expression analysis in ovarian cancer cell lines sensitive (A2780) and resistant to doxorubicin (DOX) (A2780DR1 and A2780DR2) and paclitaxel (PAC) (A2780PR1). IFI16 mRNA level, protein level in the nuclear and cytoplasmic fraction (Western blot analysis), the protein expression in cancer cells and nuclei (immunofluorescence analysis) and cancer patient lesions (immunohistochemistry) were performed in this study.

RESULTS

We observed upregulation of IFI16 expression in drug resistant cell lines with dominant cytoplasmic localization in DOX-resistant cell lines and nuclear one in the PAC-resistant cell line. The most abundantly overexpressed isoforms of IFI16 were IFI16A and IFI16C. Finally, an analysis of a histological type of ovarian cancer (immunohistochemistry) showed expression in serous ovarian cancer.

CONCLUSIONS

Expression of IFI16 in drug-resistant cell lines suggests its role in drug resistance development in ovarian cancer. Expression in serous ovarian cancer suggests its role in the pathogenesis of this histological type.

FAM198B promotes colorectal cancer progression by regulating the polarization of tumor-associated macrophages via the SMAD2 signaling pathway

Colorectal cancer (CRC) is one of the most common malignant tumors. Tumor-associated macrophages (TAMs) promote the progression of CRC, but the mechanism is not completely clear. The present study aimed to reveal the expression and function of FAM198B in TAMs, and the role of FAM198B in mediating macrophage polarization in CRC. The role of FAM198B in macrophage activity, cell cycle, and angiogenesis was evaluated by CCK-8 assay, flow cytometry, and vasculogenic mimicry assay. The effects of FAM198B on macrophage polarization were determined by flow cytometry. The function of FAM198B-mediated macrophage polarization on CRC progression was evaluated by transwell assays. Bioinformatic analyses and rescue assays were performed to identify biological functions and signaling pathways involved in FAM198B regulation of macrophage polarization. Increased FAM198B expression in TAMs is negatively associated with poor CRC prognosis. Functional assays showed that FAM198B promotes M2 macrophage polarization, which leads to CRC cell proliferation, migration, and invasion. Mechanistically, FAM198B regulates the M2 polarization of macrophages by targeting SMAD2, identifying the SMAD2 pathway as a mechanism by which FAM198B promotes CRC progression through regulating macrophage polarization. These findings provide a possible molecular mechanism for FAM198B in TAMs in CRC and suggest that FAM198B may be a novel therapeutic target in CRC.

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.

Clinical Efficacy of Fuzheng Guben Anticancer Decoction Combined with Taxol in Treating Ovarian Carcinoma and Its Effect on Complication Incidence

Objective

To investigate the clinical value of Fuzheng Guben anticancer decoction combined with taxol in treating ovarian carcinoma (OC).

Methods

The medical records of 80 OC patients treated in the First People's Hospital of Fuyang Hangzhou (January 2018-January 2021) were retrospectively analyzed, and the patients were split into the control group and the experimental group according to the treatment regimen, with 40 cases each. Those in the control group accepted the taxol chemotherapy, and on this basis, those in the experimental group took the Fuzheng Guben anticancer decoction, so as to compare its clinical efficacy and complication incidence.

Results

No statistical between-group differences in patients' general information were observed (P > 0.05); compared with the control group, the disease objective remission rate of the experimental group was greatly higher (P < 0.05); before and after treatment, the changes in CD8+ were not significant, indicating no statistically significant between-group differences (P > 0.05), and after treatment, CD3+, CD4+, and CD4+/CD8+ were obviously higher than before and were obviously higher in the experimental group than in the control group (P < 0.05); after treatment, the CA125, CA199, and CEA levels were obviously lower than before and were significantly lower in the experimental group than in the control group (P < 0.05); the mean survival of the experimental group was significantly higher than that of the control group (19.80 ± 5.84 vs. 14.075 ± 5.12 months, P < 0.05); and between the two groups, the incidence rate of adverse reactions of the experimental group was remarkably lower (P < 0.05).

Conclusion

On the basis of taxol chemotherapy, jointly applying Fuzheng Guben anticancer decoction can significantly improve the clinical efficacy of OC, help to improve patients' immune function, lower the complication incidence rate, and prolong the mean survival.

The Pellagra Problem

Objective

To investigate the clinical value of Fuzheng Guben anticancer decoction combined with taxol in treating ovarian carcinoma (OC).

Methods

The medical records of 80 OC patients treated in the First People's Hospital of Fuyang Hangzhou (January 2018–January 2021) were retrospectively analyzed, and the patients were split into the control group and the experimental group according to the treatment regimen, with 40 cases each. Those in the control group accepted the taxol chemotherapy, and on this basis, those in the experimental group took the Fuzheng Guben anticancer decoction, so as to compare its clinical efficacy and complication incidence.

Results

No statistical between-group differences in patients' general information were observed (P > 0.05); compared with the control group, the disease objective remission rate of the experimental group was greatly higher (P < 0.05); before and after treatment, the changes in CD8+ were not significant, indicating no statistically significant between-group differences (P > 0.05), and after treatment, CD3+, CD4+, and CD4+/CD8+ were obviously higher than before and were obviously higher in the experimental group than in the control group (P < 0.05); after treatment, the CA125, CA199, and CEA levels were obviously lower than before and were significantly lower in the experimental group than in the control group (P < 0.05); the mean survival of the experimental group was significantly higher than that of the control group (19.80 ± 5.84 vs. 14.075 ± 5.12 months, P < 0.05); and between the two groups, the incidence rate of adverse reactions of the experimental group was remarkably lower (P < 0.05).

Conclusion

On the basis of taxol chemotherapy, jointly applying Fuzheng Guben anticancer decoction can significantly improve the clinical efficacy of OC, help to improve patients' immune function, lower the complication incidence rate, and prolong the mean survival.

Drug resistance evaluation in novel 3D in vitro model

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 changes in the expression of many drug resistance genes as well as expression of extracellular matrix proteins and cell density in the tumor. We developed a simple two-dimensional and three-dimensional model of drug sensitive A2780 and resistant to cisplatin and paclitaxel variants of ovarian cancer cell line. Using MTT assay, we compared drug resistance in two-dimensional and three-dimensional cell culture conditions. Real-time polymerase chain reaction analysis was used to compare the expression of drug resistance genes. The expression of proteins in spheroids was determined by immunohistochemistry. We observed a moderate increase in cisplatin resistance and a significant increase in paclitaxel resistance between two-dimensional and three-dimensional cell culture conditions. Our findings show that changes in the expression of drug resistance genes may play a crucial role in the drug resistance of cancer cells in traditional cell culture. On the other hand, the drug resistance in spheroids may result from different mechanisms such as cell density in the spheroid, extracellular matrix proteins expression and drug capacity to diffuse into the spheroid.

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.

Expression of ALDH1A1 and CD133 is associated with the prognosis and effect of different chemotherapeutic regimens in gastric cancer

Gastric cancer (GC) is one of the most common malignant tumors worldwide. Previous studies have reported that aldehyde dehydrogenase-1A1 (ALDH1A1) and cluster of differentiation (CD)-133 are considered to be cancer stem cell markers in GCs. The present study immunohistochemically examined the distribution and expression of two tumor stem cell markers, CD133 and ALDH1A1, in both primary tumors and para-tumor tissues. In 91 cases with stage III, 57 (62%) were positive for ALDH1A1 and 60 (66%) were positive for CD133. ALDH1A1 was detected in para-tumors and cancerous tissues of the stomach, and the immunoreactivity of the tumors was stronger than that in para-tumor tissues. CD133 was only detected in tumors. The expression of ALDH1A1 was significantly associated with advanced T/N stage (T stage, P=0.012; N stage, P=0.023) and poor differentiation (P=0.020), while CD133 was associated with advanced T stage (P=0.007). Univariate and multivariate Cox proportional hazards analysis revealed that tumor stage, CD133 expression, vascular invasion and sex were independent predictors of disease-free survival (DFS) time, and tumor size, vascular invasion and sex were independent predictors of overall survival (OS) time in patients with GC. Patients with CD133⁺ GC had poorer DFS (P=0.042), while ALDH1A1⁺ GC was not associated with poorer DFS. In regard to chemotherapy, improvements in survival were not observed after the addition of taxane compared with two-drug therapy. However, the subgroup analysis indicated that in the ALDH1A1⁻ subgroup, and CD133⁺ and ALDH1A1⁻ subgroups, an increased OS was observed in two-drug therapy (P=0.043). The results of the present study indicate that ALDH1A1 and CD133 may play an important role in tumor invasion, metastasis and prognosis, and ALDH1A1⁻ expression does not benefit the taxane-based triple chemotherapeutic regimen in patients with GC.

Expression of Osteoblast-Specific Factor 2 (OSF-2, Periostin) Is Associated with Drug Resistance in Ovarian Cancer Cell Lines

One of the main obstacles to the effective treatment of ovarian cancer patients continues to be the drug resistance of cancer cells. Osteoblast-Specific Factor 2 (OSF-2, Periostin) is a secreted extracellular matrix protein (ECM) expressed in fibroblasts during bone and teeth development. Expression of OSF-2 has been also related to the progression and drug resistance of different tumors. The present study investigated the role of OSF-2 by evaluating its expression in the primary serous ovarian cancer cell line, sensitive (W1) and resistant to doxorubicin (DOX) (W1DR) and methotrexate (MTX) (W1MR). The OSF-2 transcript (real-time PCR analysis), protein expression in cell lysates and cell culture medium (western blot), and expression of the OSF-2 protein in cell lines (immunofluorescence) were investigated in this study. Increased expression of OSF-2 mRNA was observed in drug-resistant cells and followed by increased protein expression in cell culture media of drug-resistant cell lines. A subpopulation of ALDH1A1-positive cells was noted for W1DR and W1MR cell lines; however, no direct co-expression with OSF-2 was demonstrated. Both drugs induced OSF-2 expression after a short period of exposure of the drug-sensitive cell line to DOX and MTX. The obtained results indicate that OSF-2 expression might be associated with the development of DOX and MTX resistance in the primary serous W1 ovarian cancer cell line.

PTPRK Expression Is Downregulated in Drug Resistant Ovarian Cancer Cell Lines, and Especially in ALDH1A1 Positive CSCs-Like Populations

Background: Ovarian cancer is the 7th most common cancer and 8th most mortal cancer among woman. The standard treatment includes cytoreduction surgery followed by chemotherapy. Unfortunately, in most cases, after treatment, cancer develops drug resistance. Decreased expression and/or activity of protein phosphatases leads to increased signal transduction and development of drug resistance in cancer cells. Methods: Using sensitive (W1, A2780) and resistant ovarian cancer cell lines, the expression of Protein Tyrosine Phosphatase Receptor Type K (PTPRK) was performed at the mRNA (real-time PCR analysis) and protein level (Western blot, immunofluorescence analysis). The protein expression in ovarian cancer tissues was determined by immunohistochemistry. Results: The results showed a decreased level of PTPRK expression in ovarian cancer cell lines resistant to cisplatin (CIS), paclitaxel (PAC), doxorubicin (DOX), topotecan (TOP), vincristine (VIN) and methotrexate (MTX). Additionally, the lower PTPRK expression was observed in Aldehyde Dehydrogenase 1 Family Member A1 (ALDH1A1) positive cancer stem cells (CSCs) population, suggesting the role of PTPRK downregulation in primary as well as acquired resistance to cytotoxic drugs. Conclusions: These results provide important insights into the role of PTPRK in mechanism leading to drug resistance in ovarian cancer and has raised important questions about the role of imbalance in processes of phosphorylation and dephosphorylation.

Mutual Expression of ALDH1A1, LOX, and Collagens in Ovarian Cancer Cell Lines as Combined CSCs- and ECM-Related Models of Drug Resistance Development

A major contributor leading to treatment failure of ovarian cancer patients is the drug resistance of cancer cell. CSCs- (cancer stem cells) and ECM (extracellular matrix)-related models of drug resistance are described as independently occurring in cancer cells. Lysyl oxidase (LOX) is another extracellular protein involved in collagen cross-linking and remodeling of extracellular matrix and has been correlated with tumor progression. The expression of LOX, COL1A2, COL3A1, and ALDH1A1 was performed in sensitive (A2780, W1) and resistant to paclitaxel (PAC) (A2780PR1 and W1PR2) and topotecan (TOP) (W1TR) cell lines at the mRNA (real-time PCR analysis) and protein level (Western blot and immunofluorescence analysis). The ALDH1A1 activity was measured with the ALDEFLUOR test and flow cytometry analysis. The protein expression in ovarian cancer tissues was determined by immunohistochemistry. We observed an increased expression of LOX and collagens in PAC and TOP resistant cell lines. Subpopulations of ALDH1A1 positive and negative cells were also noted for examined cell lines. Additionally, the coexpression of LOX with ALDH1A1 and COL1A2 with ALDH1A1 was observed. The expression of LOX, collagens, and ALDH1A1 was also detected in ovarian cancer lesions. In our study LOX, ALDH1A1 and collagens were found to be coordinately expressed by cells resistant to PAC (LOX, ALDH1A1, and COL1A2) or to TOP (LOX and ALDH1A1). This represents the study where molecules related with CSCs (ALDH1A1) and ECM (LOX, collagens) models of drug resistance are described as occurring simultaneously in ovarian cancer cells treated with PAC and TOP.

The Role of Matrix Gla Protein (MGP) Expression in Paclitaxel and Topotecan Resistant Ovarian Cancer Cell Lines

The major cause of ovarian cancer treatment failure in cancer patients is inherent or acquired during treatment drug resistance of cancer. Matrix Gla protein (MGP) is a secreted, non-collagenous extracellular matrix protein involved in inhibition of tissue calcification. Recently, MGP expression was related to cellular differentiation and tumor progression. A detailed MGP expression analysis in sensitive (A2780) and resistant to paclitaxel (PAC) (A2780PR) and topotecan (TOP) (A2780TR) ovarian cancer cell lines and their corresponding media was performed. MGP mRNA level (real time PCR analysis) and protein expression in cell lysates and cell culture medium (Western blot analysis) and protein expression in cancer cells (immunofluorescence analysis) and cancer patient lesions (immunohistochemistry) were determined in this study. We observed increased expression of MGP in PAC and TOP resistant cell lines at both mRNA and protein level. MGP protein was also detected in the corresponding culture media. Finally, we detected expression of MGP protein in ovarian cancer lesions from different histological type of cancer. MGP is an important factor that might contribute to cancer resistance mechanism by augmenting the interaction of cells with ECM components leading to increased resistance of ovarian cancer cells to paclitaxel and topotecan. Expression found in ovarian cancer tissue suggests its possible role in ovarian cancer pathogenesis.