The significance of lumican expression in ovarian cancer drug-resistant cell lines

Integrated analysis of spatial transcriptomics and CT phenotypes for unveiling the novel molecular characteristics of recurrent and non-recurrent high-grade serous ovarian cancer

BACKGROUND

High-grade serous ovarian cancer (HGSOC), which is known for its heterogeneity, high recurrence rate, and metastasis, is often diagnosed after being dispersed in several sites, with about 80% of patients experiencing recurrence. Despite a better understanding of its metastatic nature, the survival rates of patients with HGSOC remain poor.

METHODS

Our study utilized spatial transcriptomics (ST) to interpret the tumor microenvironment and computed tomography (CT) to examine spatial characteristics in eight patients with HGSOC divided into recurrent (R) and challenging-to-collect non-recurrent (NR) groups.

RESULTS

By integrating ST data with public single-cell RNA sequencing data, bulk RNA sequencing data, and CT data, we identified specific cell population enrichments and differentially expressed genes that correlate with CT phenotypes. Importantly, we elucidated that tumor necrosis factor-α signaling via NF-κB, oxidative phosphorylation, G2/M checkpoint, E2F targets, and MYC targets served as an indicator of recurrence (poor prognostic markers), and these pathways were significantly enriched in both the R group and certain CT phenotypes. In addition, we identified numerous prognostic markers indicative of nonrecurrence (good prognostic markers). Downregulated expression of PTGDS was linked to a higher number of seeding sites (≥ 3) in both internal HGSOC samples and public HGSOC TCIA and TCGA samples. Additionally, lower PTGDS expression in the tumor and stromal regions was observed in the R group than in the NR group based on our ST data. Chemotaxis-related markers (CXCL14 and NTN4) and markers associated with immune modulation (DAPL1 and RNASE1) were also found to be good prognostic markers in our ST and radiogenomics analyses.

CONCLUSIONS

This study demonstrates the potential of radiogenomics, combining CT and ST, for identifying diagnostic and therapeutic targets for HGSOC, marking a step towards personalized medicine.

The post-chemotherapy changes of tumor physical microenvironment: Targeting extracellular matrix to address chemoresistance

The tumor physical microenvironment (TPME) contributes to cancer chemoresistance in both mechanical and mechanobiological approaches. Along with chemotherapy, the tumor microenvironment undergoes dramatic changes, most of which can regulate TPME through extracellular matrix (ECM) remodeling and related signaling pathways. However, there is still no discussion about the post-chemotherapy TPME changes mediated by ECM remodeling, and consequent impact on chemoresistance. Herein, we summarize the TPME alterations induced by chemotherapy and corresponding influence on chemotherapy response of cancer cells in context of ECM. The response of cancer cell to chemotherapy, imposed by post-chemotherapy ECM, are discussed in both mechanical (ECM physical features) and mechanobiological (ECM-responsive signaling pathways) manner. In the end, we present ECM remodeling and related signaling pathways as two promising clinic strategies to relieve or overcome chemoresistance induced by TPME change, and summarize the corresponding therapeutic agents currently being tested in clinical trials.

Scientific and clinical relevance of non-cellular tumor microenvironment components in ovarian cancer chemotherapy resistance

The tumor microenvironment (TME) components play a crucial role in cancer cells' resistance to chemotherapeutic agents. This phenomenon is exceptionally fundamental in patients with ovarian cancer (OvCa), whose outcome depends mainly on their response to chemotherapy. Until now, most reports have focused on the role of cellular components of the TME, while less attention has been paid to the stroma and other non-cellular elements of the TME, which may play an essential role in the therapy resistance. Inhibiting these components could help define new therapeutic targets and potentially restore chemosensitivity. The aim of the present article is both to summarize the knowledge about non-cellular components of the TME in the development of OvCa chemoresistance and to suggest targeting of non-cellular elements of the TME as a valuable strategy to overcome chemoresistance and to develop new therapeutic strategies in OvCA patients.

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.

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.

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.

Assessment of Ovarian Tumor Growth in Wild-Type and Lumican-Deficient Mice: Insights Using Infrared Spectral Imaging, Histopathology, and Immunohistochemistry

Simple Summary

Lumican, a small leucine-rich proteoglycan (SLRP), maintains extracellular matrix (ECM) integrity while inhibiting melanoma primary tumor development, as well as metastatic spread. The aim of this study was to analyze the effect of lumican on tumor growth of murine ovarian carcinoma. C57BL/6 wild type mice (n = 12) and lumican-deficient mice (n = 10) were subcutaneously injected with murine ovarian epithelial carcinoma ID8 cells, and sacrificed after 18 days. Label-free infrared spectral imaging (IRSI) generated high contrast IR images allowing identification of different ECM regions of the skin and the ovarian tumor. IRSI showed a good correlation with collagen distribution as well as organization, as analyzed using second harmonic generation imaging within the tumor area. The results demonstrated that lumican inhibited the growth of ovarian cancer mainly by altering collagen fibrilogenesis.

Abstract

Ovarian cancer remains one of the most fatal cancers due to a lack of robust screening methods of detection at early stages. Extracellular matrix (ECM) mediates interactions between cancer cells and their microenvironment via specific molecules. Lumican, a small leucine-rich proteoglycan (SLRP), maintains ECM integrity and inhibits both melanoma primary tumor development, as well as metastatic spread. The aim of this study was to analyze the effect of lumican on tumor growth of murine ovarian epithelial cancer. C57BL/6 wild type mice (n = 12) and lumican-deficient mice (n = 10) were subcutaneously injected with murine ovarian epithelial carcinoma ID8 cells, and then sacrificed after 18 days. Analysis of tumor volumes demonstrated an inhibitory effect of endogenous lumican on ovarian tumor growth. The ovarian primary tumors were subjected to histological and immunohistochemical staining using anti-lumican, anti-αv integrin, anti-CD31 and anti-cyclin D1 antibodies, and then further examined by label-free infrared spectral imaging (IRSI), second harmonic generation (SHG) and Picrosirius red staining. The IR tissue images allowed for the identification of different ECM tissue regions of the skin and the ovarian tumor. Moreover, IRSI showed a good correlation with αv integrin immunostaining and collagen organization within the tumor. Our results demonstrate that lumican inhibits ovarian cancer growth mainly by altering collagen fibrilogenesis.

The Downregulation of Placental Lumican Promotes the Progression of Preeclampsia

Multiple pieces of evidence illustrate that impaired trophoblast function results in preeclampsia (PE), and migration/invasion of human trophoblast cells is stringently regulated by extracellular matrix (ECM) components. Many studies have indicated abnormal expressions of placental ECM components are associated with preeclampsia. However, the change and influence of lumican, a vital member of extracellular matrix (ECM) molecules, on trophoblast cells during preeclampsia remain unclear. This study examines the possibility that the roles of lumican in trophoblast cells contribute to PE. To address this issue, the expression of lumican in human placental tissues was observed using immunohistochemistry, fluorescence quantitative PCR, and Western blot technology. After the HTR-8/SVneo cell line was transfected with pcDNA3.1-human lumican, pGPU6-human lumican shRNA, and their negative controls, the impact of lumican on the HTR-8/SVneo cell line was investigated. Lumican was expressed in human placental tissues. Compared with the control group, its expression was significantly lower in PE placentas. Lumican downregulation inhibited cell proliferation significantly and reduced Bcl-2 expression, but increased P53 expression. These results indicate that the downregulation of placental lumican may drive PE development via promoting the downregulation of Bcl-2 expression and upregulation of P53.

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.

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.

Lumican inhibits immune escape and carcinogenic pathways in colorectal adenocarcinoma

Lumican (LUM), a small leucine-rich proteoglycan, is a component of the extracellular matrix. Abnormal LUM expression is potentially associated with cancer progression. In the present study, we confirmed high LUM mRNA expression in colorectal adenocarcinoma (COAD) through the UALCAN database. The Kaplan-Meier method, univariate, and multivariate COX analysis showed that high LUM expression is an independent determinant of poor prognosis in COAD. A COX regression model was constructed based on clinical information and LUM expression. The receiver operating characteristic (ROC) curve indicated that this model was highly accurate in monitoring COAD prognosis. The co-expression network of LUM was determined by LinkedOmics, which showed that LUM expression was closely related to immune escape and the miR200 family. Furthermore, we studied the co-expression network of LUM and found that LUM could promote tumor metastasis and invasion. The Tumor Immune Estimation Resource website showed that LUM was closely related to immune infiltration and correlated with regulatory T cells, tumour-associated macrophages, and dendritic cells. We found that LUM cultivated cancer progression by targeting the miR200 family to promote epithelial-to-mesenchymal transition. These findings suggest that LUM is a potential target for inhibiting immune escape and carcinogenic pathways.

Lumican, pro-tumorigenic or anti-tumorigenic: A conundrum

The extracellular matrix (ECM) consists of a myriad of structural and signaling molecules which potentially regulate cell function and homeostasis. Lumican, a class II SLRP (small leucine rich proteoglycan) is a ubiquitous ECM component which not only organizes the collagen based structural matrix, but also modulates cell proliferation signals as observed in cancer. In the perspective of cancer biology, lumican expression in the tumor microenvironment is associated with signaling, which can result in either pro-tumorigenic or anti-tumorigenic effects. Its pro-tumorigenic effects are mainly observed in gastric, bladder and liver cancers, which is associated with deterioration of clinical prognosis. Lumican mediated pro-tumorigenic effects involve activation of focal adhesion kinases (FAK), mitogen activated protein kinases (MAPK) and metalloproteinase-9 (MMP-9). On the contrary, in breast cancer, pancreatic cancer and melanoma, lumican demonstrates anti-tumorigenic effects, which are associated with favorable clinical outcomes. Anti-tumorigenic potential of lumican is clubbed with epithelial-mesenchymal transition reprogramming as well as downregulation of extracellular signal-regulated kinases (ERK), FAK and MMP-14 mediated pathways thereby preventing tumorigenesis. This review highlights that the expressional significance of lumican in cancer biogenesis is tumor specific and demands rigorous cancer-specific evaluation to understand its role as a potential anti-cancer target or a therapeutic molecule.

Targeting Notch signaling pathway as an effective strategy in overcoming drug resistance in ovarian cancer

Ovarian cancer, as one of the most common types of gynecological malignancies, has an increasing rate of incidence worldwide. Despite huge amounts of recent efforts in designing novel therapeutic strategies for complete removal of tumors and increasing overall survival of patients, chemotherapy is still the preferred therapy for ovarian cancer. However, chemotherapy is also challenged by development of drug resistance. Therefore, elucidating the underlying mechanisms of drug reissuance is an urgent need in ovarian cancer. Numerous studies have shown the implication of the Notch signaling pathway in the development of various human malignancies. Therefore, this study will provide a brief overview of the published evidence in support of Notch targeting in reverting multidrug resistance as a safer and novel approach for the improvement of ovarian cancer treatment.

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.

An omentum-inspired 3D PEG hydrogel for identifying ECM-drivers of drug resistant ovarian cancer

Ovarian cancer (OvCa) is a challenging disease to treat due to poor screening techniques and late diagnosis. There is an urgent need for additional therapy options, as patients recur in 70% of cases. The limited availability of clinical treatment options could be a result of poor predictions in early stage drug screens on standard tissue culture polystyrene (TCPS). TCPS does not capture the mechanical and biochemical cues that cells experience in vivo, which can impact how cells will respond to a drug. Therefore, an in vitro model that captures some of the microenvironment features that the cells experience in vivo could provide better insights into drug responses. In this study, we formed 3D multicellular tumor spheroids (MCTS) in microwells and encapsulated them in 3D omentum-inspired hydrogels. SKOV-3 MCTS were resistant to Paclitaxel in our 3D hydrogels compared to a monolayer on TCPS. Toward clinical application, we tested cells from patients [ovarian carcinoma ascites spheroids (OCAS)] who had been treated with Paclitaxel, and drug responses predicted by using the 3D omentum-inspired hydrogels demonstrated the lack of the Paclitaxel response of these samples. Additionally, we observed the presence of collagen production around the encapsulated SKOV-3 MCTS, but not significantly on TCPS. Our results demonstrated that our 3D omentum-inspired hydrogel is an improved in vitro drug testing platform to study the OvCa drug response for patient-derived cells and helped us identify collagen 3 as a potential driver of Paclitaxel resistance in 3D.

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.

Small Leucine Rich Proteoglycans (decorin, biglycan and lumican) in cancer

The extracellular matrix (ECM) prevents invasion of tumour cells and possesses an intrinsic mechanism to down-regulate signalling processes that promote cancer proliferation. Small Leucine Rich Proteoglycans (SLRPs) are ubiquitous ECM components involved in matrix structural organization and as such can potentially regulate cancer cell multiplication, angiogenesis and migration. Decorin, a class I SLRP that modulates collagen fibrillogenesis, also functions as a natural pan-tyrosine kinase inhibitor to reduce tumour growth. In fact, decreased decorin expression has been associated with tumour aggressiveness and lower survival. In contrast, biglycan, another class I SLRP, was highly expressed in cancer and was associated with metastatic activity and lower survival. Tissue expression of lumican, a class II SLRP, was associated with clinical outcome and appears tumour specific. Recently, decorin, biglycan and lumican were found to be potential biomarkers in bladder cancer. This review updates our current understanding on the molecular interplay and significance of decorin, biglycan and lumican expression in cancer.

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.

A Proteomic Approach for Understanding the Mechanisms of Delayed Corneal Wound Healing in Diabetic Keratopathy Using Diabetic Model Rat

Diabetes mellitus is a widespread metabolic disorder, and long-term hyperglycemia in diabetics leads to diabetic keratopathy. In the present study, we used a shotgun liquid chromatography/mass spectrometry-based global proteomic approach using the cornea of streptozotocin-induced diabetic (STZ) rats to examine the mechanisms of delayed corneal wound healing in diabetic keratopathy. Applying a label-free quantitation method based on spectral counting, we identified 188 proteins that showed expression changes of >2.0-fold in the cornea of STZ rats. In particular, the level of lumican expression in the cornea of STZ rats was higher than that of the normal rats. In the cornea of the normal rat, the expression level of lumican was elevated during the wound healing process, and it returned to the same expression level as before cornea injury after the wound was healed completely. On the other hand, a high expression level of lumican in the cornea of STZ rats was still maintained even after the wound was healed completely. In addition, adhesion deficiency in corneal basal cells and Bowman’s membrane was observed in the STZ rat. Thus, abnormally overexpressed lumican may lead to adhesion deficiency in the cornea of STZ rats.

Myotilin, a New Topotecan Resistant Protein in Ovarian Cancer Cell Lines

Background: Low effectiveness of chemotherapy in ovarian cancer results from development of drug resistance during treatment. Topotecan (TOP) is a chemotherapeutic drug used in second-line chemotherapy of this cancer. Unfortunately, during treatment cancer can develop diverse cellular and tissue specific mechanisms of resistance to cytotoxic drugs.

Methods: We analyzed development of TOP resistance in ovarian cancer cell lines (A2780 and W1). On the base of our previous results where a set of “new genes” with different functions that can be related to TOP-resistance was described hereby we performed detailed analysis of MYOT expression. MYOT mRNA level (real time PCR analysis), protein expression in cell lysates and cell culture medium (western blot analysis) and protein expression in cancer cells (immunofluorescence analysis) were determined in this study.

Results: We observed increased expression of MYOT in TOP resistant cell lines at both mRNA and protein level. MYOT, together with extracellular matrix molecules like COL1A2 and COL15A1 were also secreted to corresponding cell culture media.

Conclusion: Our results suggest that upregulation of MYOT can be related to TOP resistance in ovarian cancer cell lines.

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.