Downregulation of TGF-β1 suppressed proliferation and increased chemosensitivity of ovarian cancer cells by promoting BRCA1/Smad3 signaling

Uncovering miRNA-mRNA Regulatory Networks Related to Olaparib Resistance and Resensitization of BRCA2MUT Ovarian Cancer PEO1-OR Cells with the ATR/CHK1 Pathway Inhibitors

Resistance to olaparib is the major obstacle in targeted therapy for ovarian cancer (OC) with poly(ADP-ribose) polymerase inhibitors (PARPis), prompting studies on novel combination therapies to enhance olaparib efficacy. Despite identifying various mechanisms, understanding how OC cells acquire PARPi resistance remains incomplete. This study investigated microRNA (miRNA) expression in olaparib-sensitive (PEO1, PEO4) and previously established olaparib-resistant OC cell lines (PEO1-OR) using high-throughput RT-qPCR and bioinformatic analyses. The role of miRNAs was explored regarding acquired resistance and resensitization with the ATR/CHK1 pathway inhibitors. Differentially expressed miRNAs were used to construct miRNA-mRNA regulatory networks and perform functional enrichment analyses for target genes with miRNet 2.0. TCGA-OV dataset was analyzed to explore the prognostic value of selected miRNAs and target genes in clinical samples. We identified potential processes associated with olaparib resistance, including cell proliferation, migration, cell cycle, and growth factor signaling. Resensitized PEO1-OR cells were enriched in growth factor signaling via PDGF, EGFR, FGFR1, VEGFR2, and TGFβR, regulation of the cell cycle via the G2/M checkpoint, and caspase-mediated apoptosis. Antibody microarray analysis confirmed dysregulated growth factor expression. The addition of the ATR/CHK1 pathway inhibitors to olaparib downregulated FGF4, FGF6, NT-4, PLGF, and TGFβ1 exclusively in PEO1-OR cells. Survival and differential expression analyses for serous OC patients revealed prognostic miRNAs likely associated with olaparib resistance (miR-99b-5p, miR-424-3p, and miR-505-5p) and resensitization to olaparib (miR-324-5p and miR-424-3p). Essential miRNA-mRNA interactions were reconstructed based on prognostic miRNAs and target genes. In conclusion, our data highlight distinct miRNA profiles in olaparib-sensitive and olaparib-resistant cells, offering molecular insights into overcoming resistance with the ATR/CHK1 inhibitors in OC. Moreover, some miRNAs might serve as potential predictive signature molecules of resistance and therapeutic response.

Exploring the therapeutic potential of regulatory T cell in rheumatoid arthritis: Insights into subsets, markers, and signaling pathways

Rheumatoid arthritis (RA) is a complex autoimmune inflammatory rheumatic disease characterized by an imbalance between immunological reactivity and immune tolerance. Regulatory T cells (Tregs), which play a crucial role in controlling ongoing autoimmunity and maintaining peripheral tolerance, have shown great potential for the treatment of autoimmune inflammatory rheumatic diseases such as RA. This review aims to provide an updated summary of the latest insights into Treg-targeting techniques in RA. We focus on current therapeutic strategies for targeting Tregs based on discussing their subsets, surface markers, suppressive function, and signaling pathways in RA.

Role of PPARG in Chemosensitivity-Regulating Network for Hypopharyngeal Squamous Cell Carcinoma

PPARG has been reported to promote chemosensitivity in hypopharyngeal squamous cell carcinoma (HSCC). However, few studies tested its significance in the texture of a complex molecular network regulating chemosensitivity in HSCC. Here, we first employed RNA expression data analysis and literature data mining to uncover candidate genes related to HSCC chemosensitivity. Then, we constructed the molecular network regulating chemosensitivity in HSCC. After that, we employed degree centrality (DC) and weighted centrality (WC) to test the significance of PPARG within the regulating network. Pathway enrichment was done to study the cofunctions of PPARG and the rest of the genes within the network. The findings of our study contribute to the construction of a comprehensive network that regulates HSCC chemosensitivity, consisting of 57 genes, including PPARG. Notably, within this network, PPARG demonstrates a ranking of #5 and #13 based on DC and WC, respectively. Moreover, PPARG is connected to 29 out of the 57 genes and plays roles in multiple functional groups. These top related genes include AKT1, TP53, PTEN, MAPK1, NOTCH1, BECN1, PTGS2, SPP1, and RAC1. PPARG gets enriched in several key functional groups that have been implicated in the regulation of chemosensitivity, including those associated with the response to nutrients, vitamins, and peptides, the cellular response to chemical stress, and the regulation of hormone secretion and growth. Our results emphasize the involvement of PPARG and its interconnectedness with other genes in the regulation of HSCC chemosensitivity.

TGF-β mediated drug resistance in solid cancer

Transforming growth factor β (TGF-β) is an important signaling molecule which is expressed in three different isoforms in mammals (i.e. TGF-β1, -β2, and -β3). The interaction between TGF-β and its receptor triggers several pathways, which are classified into SMAD-dependent (canonical) and SMAD-independent (non-canonical) signaling, whose activation/transduction is finely regulated by several mechanisms. TGF-β is involved in many physiological and pathological processes, assuming a dualistic role in cancer progression depending on tumor stage. Indeed, TGF-β inhibits cell proliferation in early-stage tumor cells, while it promotes cancer progression and invasion in advanced tumors, where high levels of TGF-β have been reported in both tumor and stromal cells. In particular, TGF-β signaling has been found to be strongly activated in cancers after treatment with chemotherapeutic agents and radiotherapy, resulting in the onset of drug resistance conditions. In this review we provide an up-to-date description of several mechanisms involved in TGF-β-mediated drug resistance, and we report different strategies that are currently under development in order to target TGF-β pathway and increase tumor sensitivity to therapy.

NR2F1 Regulates TGF-β1-Mediated Epithelial-Mesenchymal Transition Affecting Platinum Sensitivity and Immune Response in Ovarian Cancer

The mechanism underlying platinum resistance in ovarian cancer (OC) remains unclear. We used bioinformatic analyses to screen differentially expressed genes responsible for platinum resistance and explore NR2F1′s correlation with prognostic implication and OC staging. Moreover, Gene-set enrichment analysis (GSEA) and Gene Ontology (GO) analyses were used for pathway analysis. Epithelial-mesenchymal transition (EMT) properties, invasion, and migration capacities were analyzed by biochemical methods. The association between NR2F1 and cancer-associated fibroblast (CAF) infiltration and immunotherapeutic responses were also researched. A total of 13 co-upregulated genes and one co-downregulated gene were obtained. Among them, NR2F1 revealed the highest correlation with a poor prognosis and positively correlated with OC staging. GSEA and GO analysis suggested the induction of EMT via TGFβ-1 might be a possible mechanism that NR2F1 participates in resistance. In vitro experiments showed that NR2F1 knockdown did not affect cell proliferation, but suppressed cell invasion and migration with or without cisplatin treatment through the EMT pathway. We also found that NR2F1 could regulate TGF-β1 signaling, and treating with TGF-β1 could reverse these effects. Additionally, NR2F1 was predominantly associated with immunosuppressive CAF infiltration, which might cause a poor response to immune check blockades. In conclusion, NR2F1 regulates TGF-β1-mediated EMT affecting platinum sensitivity and immune response in OC patients.

Delivery of small interfering RNAs by nanovesicles for cancer therapy

Small interfering ribonucleic acids (siRNAs) are originally recognized as an intermediate of the RNA interference (RNAi) pathway. They can inhibit or silence various cellular pathways by knocking down specific messenger RNA molecules. In cancer cells, siRNAs can suppress the expression of several multidrug-resistant genes, leading to the increased deposition of chemotherapeutic drugs at the tumor site. siRNA therapy can be used to selectively increase apoptosis of cancer cells or activate an immune response to the cancer. However, delivering siRNAs to the targeted location is the main limitation in achieving safe and effective delivery of siRNAs. This review highlights some representative examples of nonviral delivery systems, especially nanovesicles such as exosomes, liposomes, and niosomes. Nanovesicles can improve the delivery of siRNAs by increasing their intracellular delivery, and they have demonstrated excellent potential for cancer therapy. This review focuses on recent discoveries of siRNA targets for cancer therapy and the use of siRNAs to successfully silence these targets. In addition, this review summarizes the recent progress in designing nanovesicles (liposomes or niosomes) for siRNA delivery to cancer cells and the effects of a combination of anticancer drugs and siRNA therapy in cancer therapy.

Tumor-suppressing effect of bartogenic acid in ovarian (SKOV-3) xenograft mouse model

Bartogenic acid (BA), a natural pentacyclic triterpenoid, proved to have chemomodulatory, anticancer, antidiabetic, anti-arthritic, and anti-inflammatory activity. Based on structure-activity relationship (SAR) approaches, BA has close structural resemblance to oleanolic acid and ursolic acid. These two pentacyclic triterpenoids are well accepted with respect to their therapeutic value in various ailments including anti-cancer activity. The aim of this study is to evaluate the efficacy of BA as a possible antitumor agent, along with its safety in SKOV-3 ovarian cancer. In vitro cytotoxicity of BA and paclitaxel on human ovarian cancer cells (SKOV-3) was assessed using MTT assay. Antitumor potential of BA alone, standard anticancer drug (paclitaxel) alone, and BA in combination with paclitaxel were evaluated in SKOV-3 xenografted SCID mice. Immunohistochemical analysis of NF-κB was performed and analyzed in SKOV-3 tumors. BA alone and BA in combination with paclitaxel significantly inhibited the tumor growth. IC₅₀ of BA was found to be 15.72 μM. Similarly, paclitaxel showed significant antitumor effect with IC₅₀ of 3.234 μM. Treatments of paclitaxel, BA, and combination of BA with paclitaxel were well tolerated during treatment period. Immunohistochemical analysis of NF-κB in SKOV-3 tumors treated with BA in combination with paclitaxel revealed antitumor effect in terms of inhibition of NF-κB. Our results suggested that BA exhibits promising antitumor effect in the restriction of SKOV-3 cells and tumors with considerable safety.

Emerging strategies for sensitization of therapy resistant tumors toward cancer therapeutics by targeting the Bcl-2 family, TGF-β, Wnt/β-Catenin, RASSF and miRNA regulated signaling pathways

Conventional chemotherapy relies on the cytotoxicity of chemo-drugs to inflict destructive effects on tumor cells. However, as most tumor cells develop resistance to chemo-drugs, small doses of chemo-drugs are unlikely to provide significant clinical benefits in cancer treatment while high doses of chemo-drugs have been shown to impact normal human cells negatively due to the non-specific nature and cytotoxicity associated with chemo-drugs. To overcome this challenge, sensitizations of tumor cells with bioactive molecules that specifically target the pro-survival and pro-apoptosis signaling pathways of the tumor cells are likely to increase the therapeutic impacts and improve the clinical outcomes by reducing the dependency and adverse effects associated with using high doses of chemo-drugs in cancer treatment. This review focuses on emerging strategies to enhance the sensitization of tumor cells toward cancer therapies based on our understanding of tumor cell biology and underlying signaling pathways.

MicroRNA-4429 restrains colorectal cancer cell invasion and migration via regulating SMAD3-induced epithelial-mesenchymal transition

Colorectal cancer (CRC) is one of the commonest human cancers and the fourth primary cause of cancer-related death. Previous studies have reported that miR-4429 develops anticancer function in follicular thyroid carcinoma and non-small cell lung cancer. However, whether miR-4429 is implicated in the CRC progression remains to be clarified. The aim of our current study was to explore the potential role of miR-4429 in CRC. According to the result of quantitative real-time polymerase chain reaction analysis, miR-4429 was expressed at a low level in CRC cells. Gain-of-function assays showed that the upregulation of miR-4429 inhibited cell proliferation, migration, invasion, and epithelial-mesenchymal transition (EMT) process in CRC, whereas miR-4429 inhibition led to the opposite results. It was uncovered from mechanism experiments that miR-4429 targeted forkhead box M1 (FOXM1) and therefore regulating SMAD family member 3 (SMAD3) expression. Rescue experiments elucidated that miR-4429 influenced cell proliferation, migration, invasion, and EMT process in CRC by targeting FOXM1 to inactivate SMAD3. In conclusion, our study revealed that miR-4429 targeted FOXM1 to decrease SMAD3 expression and thus impeding cell proliferation, migration, invasion, and EMT process of CRC cells.

Small interfering RNA for cancer treatment: overcoming hurdles in delivery

In many ways, cancer cells are different from healthy cells. A lot of tactical nano-based drug delivery systems are based on the difference between cancer and healthy cells. Currently, nanotechnology-based delivery systems are the most promising tool to deliver DNA-based products to cancer cells. This review aims to highlight the latest development in the lipids and polymeric nanocarrier for siRNA delivery to the cancer cells. It also provides the necessary information about siRNA development and its mechanism of action. Overall, this review gives us a clear picture of lipid and polymer-based drug delivery systems, which in the future could form the base to translate the basic siRNA biology into siRNA-based cancer therapies.

Inhibition mechanism of lung cancer cell metastasis through targeted regulation of Smad3 by miR-15a

Effect of targeted regulation of mothers against decapentaplegic homolog 3 (Smad3) by microRNA-15a (miR-15a) on the proliferation, invasion and metastasis of non-small cell lung cancer (NSCLC) cells and its related mechanisms were investigated. Fifty pairs of NSCLC and para-cancerous tissues were collected to identify the expression level of miR-15a in NSCLC, para-cancerous tissue, and cell lines A549, H1299, H1975 and BEAS-2B by real-time fluorescence quantitative PCR (RT-PCR); A549 cells were transfected with miR-15a mimic; the MTT assay was performed to detect the role of miR-15a transfection in proliferation of A549 cells, the wound healing assay was carried out to identify the role of miR-15a in migration of A549 cells; Transwell invasion assay was conducted to analyze the role of miR-15a in invasion of A549 cells; western blotting was carried out to find the effect of miR-15a on Smad3 expression, and Spearman's rank correlation was used to analyze the correlation between miR-15a and Smad3 expression. NSCLC tissues and cells showed significantly lower miR-15a expression, compared with para-cancerous tissues and normal cell lines (P=0.023). miR-15a was significantly more expressed in A549 cells transfected with miR-15a mimic (P=0.043). Overexpression of miR-15a can significantly inhibit A549 cell proliferation (P=0.038), migration (P=0.033) and invasion (P=0.025), and significantly reduced the expression level of Smad3 (P=0.031) in A549 cells. Spearman's rank correlation showed negative correlation of miR-15a expression with Smad3, which may indicate negative regulation (r=−0.34, P<0.0001). Inhibition of proliferation, migration and invasion of NSCLC cells can be achieved with targeted regulation of Smad3 by miR-15a.