The role of microRNA in cisplatin resistance or sensitivity

MicroRNA-146b-5p/FDFT1 mediates cisplatin sensitivity in bladder cancer by redirecting cholesterol biosynthesis to the non-sterol branch

Chemotherapy against muscle-invasive bladder cancer is increasingly challenged by the prevalence of chemoresistance. The cholesterol biosynthesis pathway has garnered attention in studies of chemoresistance, but conflicting clinical and molecular findings necessitate a clearer understanding of its underlying mechanisms. Recently, we identified farnesyl-diphosphate farnesyltransferase 1 (FDFT1)-the first specific gene in this pathway-as a tumor suppressor and chemoresistance modulator. Raman spectroscopy revealed higher levels of FDFT1-related metabolites in chemotherapy-sensitive bladder cancer tissue compared to resistant tissue; however, this observation lacks mechanistic insight. FDFT1 expression was reduced in our cisplatin-resistant bladder cancer cells (T24R) compared to parental cisplatin-sensitive cells (T24). Using functional knockdown and ectopic overexpression in T24/T24R cells, we mechanistically demonstrate the pathway through which FDFT1 mediates cisplatin sensitivity in bladder cancer cells. Bioinformatics analysis and rescue experiments showed that microRNA-146b-5p directly targets and downregulates FDFT1, reducing the cisplatin sensitivity of T24 cells, which can be restored by forced FDFT1 expression. Further investigation into the downstream cholesterol pathway revealed that FDFT1 suppression redirects its substrate toward the non-sterol branch of the pathway, as evidenced by the upregulation of non-sterol branch-associated genes and a reduced total cholesterol level in the sterol branch. Since the non-sterol pathway leads to the prenylation of isoprenoids and activation of Ras and Rho family proteins involved in cancer progression and chemoresistance, our findings suggest that redirection of the cholesterol biosynthesis pathway is a key mechanism underlying FDFT1-mediated cisplatin resistance in bladder cancer. The miR-146b-5p/FDFT1 axis represents a promising target for overcoming chemoresistance in bladder cancer.

MiR-21-5p Modulates Cisplatin-Resistance of CD44+ Gastric Cancer Stem Cells Through Regulating the TGF-β2/SMAD Signaling Pathway

Background

Cisplatin (DDP) resistance in gastric cancer (GC) is likely to come from gastric cancer stem cells (GCSC). It is a new idea to study the mechanism of the DDP-resistance in GCSC from miRNA.

Materials and Methods

CD44+ GCSCs and CD44- control cells were constructed based on the HGC27 gastric cancer cell line. DDP sensitivities in CD44+ and CD44- cells were detected via CCK-8 assay. The differential expression of miR-21-5p in these cell lines was detected by RT‒qPCR. The expression levels of downstream TGF-β2, SMAD2 and SMAD3 were determined through RT‒PCR and Western blotting. A luciferase assay was used to detect the relationship between miR-21-5p and TGFB2, and the TCGA database, clinical data from our centre, and vivo experiment were used for validation. Finally, we knocked down miR-21-5p to detect changes in cisplatin resistance in GCSCs and to verify changes in the levels of downstream pathways in GCSCs.

Results

CD44+ GCSCs induced cisplatin resistance compared with CD44- cells. miR-21-5p was highly expressed in GCSCs, and the TGF-β2/SMAD pathway was also highly expressed. TGFB2 was proven to be a downstream target gene of miR-21-5p and had a positive relationship with it in phenotype. After knockdown of miR-21-5p, the TGF-β2/SMAD pathway was also inhibited, and the resistance of GCSCs to cisplatin was specifically decreased.

Conclusion

MiR-21-5p promotes cisplatin resistance in gastric cancer stem cells by regulating the TGF-β2/SMAD signalling pathway.

MicroRNA‑mediated approaches in ovarian cancer therapy: A comprehensive systematic review

Ovarian cancer (OC) poses a significant health risk to women worldwide, with late diagnoses and chemotherapy resistance leading to high mortality rates. Despite several histological subtypes, the primary challenge remains the subtle nature of its symptoms, resulting in advanced-stage diagnosis and reduced treatment success rates. With platinum-based therapies showing relative efficacy but limited survival enhancements, the emergence of chemotherapy resistance during recurrence remains a critical obstacle. Precision medicine development has aimed to address these challenges in the context of the molecular diversity of OC. The present review explored the landscape of microRNA (miRNA)-mediated approaches in OC treatment. miRNAs have emerged as regulators of gene expression, serving as both oncogenes and tumor suppressors in OC. Dysregulated miRNAs are associated with disease progression and chemotherapy resistance, underscoring their significance in diagnosis and tailored treatment strategies. The present review extracted 295 publications from the PUBMED database. Out of the 73 eligible studies, 55 miRNAs were assessed. A total of three of these miRNAs were not associated with any disease or cancer, whilst eight were associated with OC, albeit also associated with other diseases. The present review encompassed three dimensions: i) The role of miRNAs in treatment efficacy; ii) the use of miRNAs to enhance therapy outcomes; and iii) adjunctive strategies for improved treatment results. Furthermore, it offered insights into potential avenues for improving OC treatment using miRNA-based approaches.

Natural products reverse cisplatin resistance in the hypoxic tumor microenvironment

Cisplatin is one of the most commonly used drugs for cancer treatment. Despite much progress in improving patient outcomes, many patients are resistant to cisplatin-based treatments, leading to limited treatment efficacy and increased treatment failure. The fact that solid tumors suffer from hypoxia and an inadequate blood supply in the tumor microenvironment has been widely accepted for decades. Numerous studies have shown that a hypoxic microenvironment significantly reduces the sensitivity of tumor cells to cisplatin. Therefore, understanding how hypoxia empowers tumor cells with cisplatin resistance is essential. In the fight against tumors, developing innovative strategies for overcoming drug resistance has attracted widespread interest. Natural products have historically made major contributions to anticancer drug research due to their obvious efficacy and abundant candidate resources. Intriguingly, natural products show the potential to reverse chemoresistance, which provides new insights into cisplatin resistance in the hypoxic tumor microenvironment. In this review, we describe the role of cisplatin in tumor therapy and the mechanisms by which tumor cells generate cisplatin resistance. Subsequently, we call attention to the linkage between the hypoxic microenvironment and cisplatin resistance. Furthermore, we summarize known and potential natural products that target the hypoxic tumor microenvironment to overcome cisplatin resistance. Finally, we discuss the current challenges that limit the clinical application of natural products. Understanding the link between hypoxia and cisplatin resistance is the key to unlocking the full potential of natural products, which will serve as new therapeutic strategies capable of overcoming resistance.

Targeting ferroptosis as a potential strategy to overcome the resistance of cisplatin in oral squamous cell carcinoma

Oral squamous cell carcinoma (OSCC) is a crucial public health problem, accounting for approximately 2% of all cancers globally and 90% of oral malignancies over the world. Unfortunately, despite the achievements in surgery, radiotherapy, and chemotherapy techniques over the past decades, OSCC patients still low 5-year survival rate. Cisplatin, a platinum-containing drug, serves as one of the first-line chemotherapeutic agents of OSCC. However, the resistance to cisplatin significantly limits the clinical practice and is a crucial factor in tumor recurrence and metastasis after conventional treatments. Ferroptosis is an iron-based form of cell death, which is initiated by the intracellular accumulation of lipid peroxidation and reactive oxygen species (ROS). Interestingly, cisplatin-resistant OSCC cells exhibit lower level of ROS and lipid peroxidation compared to sensitive cells. The reduced ferroptosis in cisplatin resistance cells indicates the potential relationship between cisplatin resistance and ferroptosis, which is proved by recent studies showing that in colorectal cancer cells. However, the modulation pathway of ferroptosis reversing cisplatin resistance in OSCC cells still remains unclear. This article aims to concisely summarize the molecular mechanisms and evaluate the relationship between ferroptosis and cisplatin resistance OSCC cells, thereby providing novel strategies for overcoming cisplatin resistance and developing new therapeutic approaches.

Decoding cell death signalling: Impact on the response of breast cancer cells to approved therapies

Breast cancer is a principal cause of cancer-related mortality in female worldwide. While many approved therapies have shown promising outcomes in treating breast cancer, understanding the intricate signalling pathways controlling cell death is crucial for optimizing the treatment outcome. A growing body of evidence has unveiled the aberrations in multiple cell death pathways across diverse cancer types, highlighting these pathways as appealing targets for therapeutic interventions. In this review, we provide a comprehensive overview of the current state of knowledge on the cell death signalling mechanisms with a particular focus on their impact on the response of breast cancer cells to approved therapies. Additionally, we discuss the potentials of combination therapies that exploit the synergy between approved drugs and therapeutic agents targeting modulators of cell death pathways.

Horizontal transfer of miR-383 sensitise cells to cisplatin by targeting VEGFA-Akt signalling loop

BACKGROUND

Cellular resistance to cisplatin has been one of the major obstacles in the success of combination therapy for many types of cancers. Emerging evidences suggest that exosomes released by drug resistant tumour cells play significant role in conferring resistance to drug sensitive cells by means of horizontal transfer of genetic materials such as miRNAs. Though exosomal miRNAs have been reported to confer drug resistance, the exact underlying mechanisms are still unclear.

METHODS AND RESULTS

In the present study, mature miRNAs secreted differentially by cisplatin resistant and cisplatin sensitive HepG2 cells were profiled and the effect of most significantly lowered miRNA in conferring cisplatin resistance when horizontally transferred, was analysed. we report miR-383 to be present at the lowest levels among the differentially abundant miRNAs expressed in exosomes secreted by cisplatin resistant cells compared to that that of cisplatin sensitive cells. We therefore, checked the effect of ectopic expression of miR-383 in altering cisplatin sensitivity of Hela cells. Drug sensitivity assay and apoptotic assays revealed that miR-383 could sensitise cells to cisplatin by targeting VEGF and its downstream Akt mediated pathway.

CONCLUSION

Results presented here provide evidence for the important role of miR-383 in regulating cisplatin sensitivity by modulating VEGF signalling loop upon horizontal transfer across different cell types.

Andrographis modulates cisplatin resistance in lung cancer via miR-155-5p/SIRT1 axis

Andrographis (Andro) has been identified as an anti-cancer herbal. This study was to explore its underlying regulatory routes regarding cisplatin (DDP) resistance in lung cancer. The impacts of Andro on cell viability in lung cancer cells and normal cells BEAS-2B were validated using CCK8 tests. Then, cell viability and apoptosis analysis was performed in the cells after DDP, Andro, or combined treatment. RT-qPCR was applied for evaluating miR-155-5p and SIRT1 mRNA expressions, while western blot was for evaluating SIRT1 protein expressions. Binding sites between SIRT1 and miR-155-5p were predicted on TargetScan and were confirmed using luciferase reporter assays. Xenograft animal models were established for in vivo validation of the regulatory function of Andro in lung cancer. Andro decreased the cell viability in lung cancer cells but not normal cells BEAS-2B. The combined treatment with DDP and Andro induced the lowest viability and highest apoptosis in both A549 and A549/DDP cells. MiR-155-5p expression was suppressed, and SIRT was promoted by the Andro treatment, while overexpression of miR-155-5p reversed effects of Andro in cells, which was further counteracted by SIRT1 activation. SIRT1 was verified to be a target of miR-155-5p in A549/DDP cells. Moreover, Andro synergized with DDP in mice with lung cancer via miR-155-5p/SIRT1. Andro modulates cisplatin resistance in lung cancer via miR-155-5p/SIRT1 axis.

MiR-590-5p promotes cisplatin resistance via targeting hMSH2 in ovarian cancer

OBJECTIVE

The mechanisms of ovarian cancer generate chemotherapy resistance are still unclear. This study aimed to explore the role of microRNA (miR)-590-5p in regulating hMSH2 expression and cisplatin resistance in ovarian cancer.

METHODS

MiR-590-5p was identified as a regulator of hMSH2 with miRDB database and Target Scan database. Then cisplatin sensitive cell line (SKOV3) and resistant cell line (SKOV3-DDP) of ovarian cancer were cultured for cell functional assay and molecular biology assay. The expression levels of MiR-590-5p and hMSH2 were compared between the two cell lines. Dual luciferase reporter assay was used to verify the targeted regulatory relationship between miR-590-5p and hMSH2. CCK-8 assay and cell apoptosis assay were utilized to assess the role of MiR-590-5p and hMSH2 in cell viability under cisplatin.

RESULTS

The expression of hMSH2 was significantly decreased, and miR-590-5p was significantly up-regulated in SKOV3-DDP. Up-regulation of hMSH2 weakened the viability of SKOV3 and SKOV3-DDP cell under cisplatin. Transfection with miR‑590-5p mimics reduced the expression of hMSH2 and enhanced the viability of ovarian cancer cells under cisplatin, whereas inhibition of miR‑590-5p increased the expression of hMSH2, and decreased ovarian cancer cells' viability under cisplatin. Furthermore, luciferase reporter assay showed that hMSH2 was a direct target of miR-590-5p.

CONCLUSION

The present study demonstrates that miR‑590-5p promotes cisplatin resistance of ovarian cancer via negatively regulating hMSH2 expression. Inhibition of miR‑590-5p decreases ovarian cancer cells' viability under cisplatin. Thus miR‑590-5p and hMSH2 may serve as therapeutic targets for cisplatin resistant ovarian cancer.

The Role of mTORC1 Pathway and Autophagy in Resistance to Platinum-Based Chemotherapeutics

Cisplatin (cis-diamminedichloroplatinum I) is a platinum-based drug, the mainstay of anticancer treatment for numerous solid tumors. Since its approval by the FDA in 1978, the drug has continued to be used for the treatment of half of epithelial cancers. However, resistance to cisplatin represents a major obstacle during anticancer therapy. Here, we review recent findings on how the mTORC1 pathway and autophagy can influence cisplatin sensitivity and resistance and how these data can be applicable for the development of new therapeutic strategies.

Chemoresistance in pancreatic ductal adenocarcinoma: Overcoming resistance to therapy

Pancreatic ductal adenocarcinoma (PDAC), a prominent cause of cancer deaths worldwide, is a highly aggressive cancer most frequently detected at an advanced stage that limits treatment options to systemic chemotherapy, which has provided only marginal positive clinical outcomes. More than 90% of patients with PDAC die within a year of being diagnosed. PDAC is increasing at a rate of 0.5-1.0% per year, and it is expected to be the second leading cause of cancer-related mortality by 2030. The resistance of tumor cells to chemotherapeutic drugs, which can be innate or acquired, is the primary factor contributing to the ineffectiveness of cancer treatments. Although many PDAC patients initially responds to standard of care (SOC) drugs they soon develop resistance caused partly by the substantial cellular heterogeneity seen in PDAC tissue and the tumor microenvironment (TME), which are considered key factors contributing to resistance to therapy. A deeper understanding of molecular mechanisms involved in PDAC progression and metastasis development, and the interplay of the TME in all these processes is essential to better comprehend the etiology and pathobiology of chemoresistance observed in PDAC. Recent research has recognized new therapeutic targets ushering in the development of innovative combinatorial therapies as well as enhancing our comprehension of several different cell death pathways. These approaches facilitate the lowering of the therapeutic threshold; however, the possibility of subsequent resistance development still remains a key issue and concern. Discoveries, that can target PDAC resistance, either alone or in combination, have the potential to serve as the foundation for future treatments that are effective without posing undue health risks. In this chapter, we discuss potential causes of PDAC chemoresistance and approaches for combating chemoresistance by targeting different pathways and different cellular functions associated with and mediating resistance.

Radiotherapy, Chemotherapy and Immunotherapy-Current Practice and Future Perspectives for Recurrent/Metastatic Oral Cavity Squamous Cell Carcinoma

Oral squamous cell carcinoma is the most common malignant epithelial neoplasm affecting the oral cavity. While surgical resection is the cornerstone of a multimodal curative approach, some tumors are deemed recurrent or metastatic (R/M) and often not suitable for curative surgery. This mainly occurs due to the extent of lesions or when surgery is expected to result in poor functional outcomes. Amongst the main non-surgical therapeutic options for oral squamous cell carcinoma are radiotherapy, chemotherapy, molecular targeted agents, and immunotherapy. Depending on the disease setting, these therapeutic approaches can be used isolated or in combination, with distinct efficacy and side effects. All these factors must be considered for treatment decisions within a multidisciplinary approach. The present article reviews the evidence regarding the treatment of patients with R/M oral squamous cell carcinoma. The main goal is to provide an overview of available treatment options and address future therapeutic perspectives.

Hypoxia induces docetaxel resistance in triple-negative breast cancer via the HIF-1α/miR-494/Survivin signaling pathway

Cytotoxic chemotherapy is the major strategy to prevent and reduce triple-negative breast cancer (TNBC) progression and metastasis. Hypoxia increases chemoresistance and is associated with a poor prognosis for patients with cancer. Based on accumulating evidence, microRNAs (miRNAs) play an important role in acquired drug resistance. However, the role of miRNAs in hypoxia-induced TNBC drug resistance remains to be clarified. Here, we found that hypoxia induced TNBC docetaxel resistance by decreasing the miR-494 level. Modulating miR-494 expression altered the sensitivity of TNBC cells to DTX under hypoxic conditions. Furthermore, we identified Survivin as a direct miR-494 target. Hypoxia upregulated survivin expression. In a clinical study, the HIF-1α/miR-494/Survivin signaling pathway was also active in primary human TNBC, and miR-494 expression negatively correlated with HIF-1α and survivin expression. Finally, in a xenograft model, both miR-494 overexpression and the HIF-1α inhibitor PX-478 increased the sensitivity of TNBC to DTX by suppressing the HIF-1α/miR-494/Survivin signaling pathway in vivo. In conclusion, treatments targeting the HIF-1α/miR-494/Survivin signaling pathway potentially reverse hypoxia-induced drug resistance in TNBC.

All-trans retinoic acid-mediated miR-30a up-regulation suppresses autophagy and sensitizes gastric cancer cells to cisplatin

AIMS

The potential of all-trans retinoic acid (ATRA) in regulating some microRNAs (miRNAs) involved in multiple cancer-related pathways, including resistance to chemotherapeutics, may be a valuable idea for overcoming the CDDP resistance of GC cells.

MAIN METHODS

Treatment of gastric AGS and MKN-45 cells with CDDP enriched the CDDP surviving cells (CDDP-SCs). The abilities of chemoresistance to CDDP drug, migration, either apoptosis or cell cycle distribution, spheroid body formation and changes at miRNA and protein levels were evaluated in vitro by MTT assay, colony formation assay, flow cytometry, tumor spheres culture, qRT-PCR and western blot assay in CDDP-SCs and ATRA-treated CDDP-SCs cells, respectively.

KEY FINDINGS

CDDP-based chemotherapy significantly reduced microRNA-30a (miR-30a) levels in GC cells. We also observed elevated autophagy activity in cancer cells that possess stem cell-like properties with overexpressed specific stem cell markers. Our extended study suggested that the reduction of miR-30a by CDDP treatment, is the possible underlying mechanism of enhanced autophagic activity, as demonstrated by enhancing autophagy-related protein beclin 1 and LC3-II/LC-I ratio. The addition of ATRA in the culture medium of GC cells increased the expression of miR-30a, and disturbed characteristic CSC-like properties. Additional studies revealed that the increased expression of miR-30a declined the expression level of its target gene, beclin 1, and beclin 1-mediated autophagy. This leads to promoted CDDP-induced GC cell apoptosis and G2/M cell cycle arrest.

SIGNIFICANCE

Overall, miR-30a/autophagy signaling has a critical role in regulating the chemoresistance of GC cells that ATRA could modulate.

Non‑SMC condensin I complex subunit H promotes the malignant progression and cisplatin resistance of breast cancer MCF‑7 cells

Breast cancer is one of the most frequently diagnosed types of cancer worldwide. The present study aimed to investigate the role and underlying regulatory mechanism of non-structural maintenance of chromosome condensin I complex subunit H (NCAPH) in the malignant progression and cisplatin (DDP) resistance of breast cancer cells. Therefore, the mRNA and protein expression levels of NCAPH were first determined in breast cancer cells via reverse transcription-quantitative PCR and western blotting. Furthermore, following transfection of NCAPH interference plasmids, the effect of NCAPH knockdown on cell proliferation, migration, invasion were also assessed using CCK-8, wound healing and Transwell assays. Apoptosis was evaluated using TUNEL assay, and western blotting was performed in breast cancer cells and DDP-resistant breast cancer cells. The association between NCAPH and its downstream target, aurora kinase B (AURKB), was verified using bioinformatic analysis and the co-immunoprecipitation assay. Furthermore, the effect of AURKB overexpression on the aforementioned processes and the Akt/mTOR signaling pathway were also assessed. The results demonstrated that NCAPH mRNA and protein expression levels were significantly upregulated in breast cancer cells, whereas NCAPH knockdown significantly attenuated the proliferation, migration and invasion of breast cancer cells. NCAPH silencing also exacerbated the apoptosis of DDP-resistant breast cancer cells. AURKB mRNA and protein expression levels were also significantly upregulated in MCF-7 cells, whereas its overexpression significantly reversed the effects of NCAPH knockdown on breast cancer cells and the Akt/mTOR signaling pathway. Overall, NCAPH knockdown significantly downregulated AURKB mRNA and protein expression levels to block the Akt/mTOR signaling pathway and inhibited breast cancer cell proliferation, migration, invasion, and aggravate DDP-resistant breast cancer cell apoptosis, indicating that NCAPH may serve as a promising therapeutic target for breast cancer.

MicroRNAs and Long Non-Coding RNAs in Adrenocortical Carcinoma

Non-coding RNAs (ncRNAs) are a type of genetic material that do not encode proteins but regulate the gene expression at an epigenetic level, such as microRNAs (miRNAs) and long non-coding RNAs (lncRNAs). The role played by ncRNAs in many physiological and pathological processes has gained attention during the last few decades, as they might be useful in the diagnosis, treatment and management of several human disorders, including endocrine and oncological diseases. Adrenocortical carcinoma (ACC) is a rare and aggressive endocrine cancer, still characterized by high mortality and morbidity due to both endocrine and oncological complications. Despite the rarity of this disease, recently, the role of ncRNA has been quite extensively evaluated in ACC. In order to better explore the role of the ncRNA in human ACC, this review summarizes the current knowledge on ncRNA dysregulation in ACC and its potential role in the diagnosis, treatment, and management of this tumor.

Is Autophagy Always a Barrier to Cisplatin Therapy?

Cisplatin has long been a first-line chemotherapeutic agent in the treatment of cancer, largely for solid tumors. During the course of the past two decades, autophagy has been identified in response to cancer treatments and almost uniformly detected in studies involving cisplatin. There has been increasing recognition of autophagy as a critical factor affecting tumor cell death and tumor chemoresistance. In this review and commentary, we introduce four mechanisms of resistance to cisplatin followed by a discussion of the factors that affect the role of autophagy in cisplatin-sensitive and resistant cells and explore the two-sided outcomes that occur when autophagy inhibitors are combined with cisplatin. Our goal is to analyze the potential for the combinatorial use of cisplatin and autophagy inhibitors in the clinic.

Vulnerability of Triple-Negative Breast Cancer to Saponin Formosanin C-Induced Ferroptosis

Targeting ferritin via autophagy (ferritinophagy) to induce ferroptosis, an iron- and reactive oxygen species (ROS)-dependent cell death, provides novel strategies for cancer therapy. Using a ferroptosis-specific inhibitor and iron chelator, the vulnerability of triple-negative breast cancer (TNBC) MDA-MB-231 cells to ferroptosis was identified and compared to that of luminal A MCF-7 cells. Saponin formosanin C (FC) was revealed as a potent ferroptosis inducer characterized by superior induction in cytosolic and lipid ROS formation as well as GPX4 depletion in MDA-MB-231 cells. The FC-induced ferroptosis was paralleled by downregulation of ferroportin and xCT expressions. Immunoprecipitation and electron microscopy demonstrated the involvement of ferritinophagy in FC-treated MDA-MB-231 cells. The association of FC with ferroptosis was strengthened by the results that observed an enriched pathway with differentially expressed genes from FC-treated cells. FC sensitized cisplatin-induced ferroptosis in MDA-MB-231 cells. Through integrated analysis of differentially expressed genes and pathways using the METABRIC patients’ database, we confirmed that autophagy and ferroptosis were discrepant between TNBC and luminal A and that TNBC was hypersensitive to ferroptosis. Our data suggest a therapeutic strategy by ferroptosis against TNBC, an aggressive subtype with a poor prognosis.

MicroRNA-20a-5p Inhibits the Autophagy and Cisplatin Resistance in Ovarian Cancer via Regulating DNMT3B-mediated DNA Methylation of RBP1

Ovarian cancer (OvCa) is the third most common female malignancy worldwide and poses great threats on women health. Chemotherapy is the most recommended post-surgery treatment for OvCa patients; but, cisplatin resistance is a main cause of chemotherapy failure. In addition, autophagy modulates the sensitivity of tumor cells to chemotherapeutic agents. Hence, it is significant to explore the molecular mechanism concerning the autophagy and cisplatin resistance in OvCa. In this study, quantitative real-time PCR (qRT-PCR) was used to detect miR-20a-5p expression and western blot to measure RBP1 expression. A series of assays were conducted to explore the gain-of-function effects of miR-20a-5p. Luciferase reporter assay was applied to determine the downstream target of miR-20a-5p. The results proved that miR-20a-5p represses malignant phenotypes and autophagy in cisplatin-resistant OvCa cells. In addition, DNMT3B mediates DNA methylation of RBP1 to impair the promoting effects of RBP1 on carcinogenesis and autophagy in OvCa. Through rescue experiments, we certified that miR-20a-5p inhibits the autophagy and cisplatin resistance in OvCa via DNMT3B-mediated DNA methylation of RBP1. Collectively, we demonstrated that miR-20a-5p plays a crucial role in the modulation of autophagy and cisplatin resistance in OvCa, which might offer novel insights into developing effective treatment strategies for OvCa.

Glycometabolic rearrangements-aerobic glycolysis in pancreatic ductal adenocarcinoma (PDAC): roles, regulatory networks, and therapeutic potential

INTRODUCTION

Glycometabolic rearrangements (aerobic glycolysis) is a hallmark of pancreatic ductal adenocarcinoma (PDAC) and contributes to tumorigenesis and progression through numerous mechanisms. The targeting of aerobic glycolysis is recognized as a potential therapeutic strategy which offers the possibility of improving treatment outcomes for PDAC patients.

AREAS COVERED

In this review, the role of aerobic glycolysis and its regulatory networks in PDAC are discussed. The targeting of aerobic glycolysis in PDAC is examined, and its therapeutic potential is evaluated. The relevant literature published from 2001 to 2021 was searched in databases including PubMed, Scopus, and Embase.

EXPERT OPINION

Regulatory networks of aerobic glycolysis in PDAC are based on key factors such as c-Myc, hypoxia-inducible factor 1α, the mammalian target of rapamycin pathway, and non-coding RNAs. Experimental evidence suggests that modulators or inhibitors of aerobic glycolysis promote therapeutic effects in preclinical tumor models. Nevertheless, successful clinical translation of drugs that target aerobic glycolysis in PDAC is an obstacle. Moreover, it is necessary to identify the potential targets for future interventions from regulatory networks to design efficacious and safer agents.

LncRNA OTUD6B-AS1 Induces Cisplatin Resistance in Cervical Cancer Cells Through Up-Regulating Cyclin D2 via miR-206

Cervical cancer is one of the most common gynecological cancers. Cisplatin resistance remains a major hurdle in the successful treatment of cervical cancer. Aberrant expression of long non-coding RNAs (lncRNAs) and microRNAs (miRNAs) are implicated in cisplatin resistance. However, the regulatory functions of lncRNAs and miRNAs in cervical cancer cisplatin resistance and the underlying mechanisms are still elusive. Our qRT-PCR assays verified that miR-206 levels were down-regulated in cisplatin-resistant cervical cancer cells. The introduction of miR-206 sensitized cisplatin-resistant cervical cancer cells to cisplatin. Our qRT-PCR and luciferase reporter assays showed that Cyclin D2 (CCND2) was the direct target for miR-206 in cervical cancer cells. The cisplatin-resistant cervical cancer cells expressed higher CCND2 expression than the parental cells, whereas inhibition of CCND2 could sensitize the resistant cells to cisplatin treatment. Furthermore, we demonstrated that lncRNA OTUD6B-AS1 was up-regulated in cisplatin-resistant cervical cancer cells, and knocking down OTUD6B-AS1 expression induced re-acquirement of chemosensitivity to cisplatin in cervical cancer cells. We also showed that OTUD6B-AS1 up-regulated the expression of CCND2 by sponging miR-206. Low miR-206 and high OTUD6B-AS1 expression were associated with significantly poorer overall survival. Taken together, these results suggest that OTUD6B-AS1-mediated down-regulation of miR-206 increases CCND2 expression, leading to cisplatin resistance. Modulation of these molecules may be a therapeutic approach for cisplatin-resistant cervical cancer.

miR-874-3p mitigates cisplatin resistance through modulating NF-κB/inhibitor of apoptosis protein signaling pathway in epithelial ovarian cancer cells

The resistance to cisplatin, the most common platinum chemotherapy drug, may confine the efficacy of treatment in epithelial ovarian cancer patients. Aberrant expression of inhibitor of apoptosis proteins set the stage for resistance to cisplatin in EOC; besides, chemosensitivity in EOC can be chalked up to dysregulation of specific miRNAs. Herein, we investigated whether there is a potential correlation between miR-874-3p and the X-chromosome-linked inhibitor of apoptosis, a member of the IAP protein family in cisplatin-resistant EOC cells. The lower expression of miR-874-3p was found in SKOV3-DDP cells; it was also in association with cisplatin-resistance in EOC cells. XIAP was found to contribute to developing platinum resistance and is an authentic target for miR-874-3p in SKOV3-DDP cells. Consistently, restoration of miR-874-3p expression reversed cisplatin resistance in such cells by modulating XIAP and NF-κB/Survivin signaling pathway. Besides, siRNA knock down of XIAP in SKOV3-DDP cells had an anti-migratory effect like those with miR-874 overexpression. Importantly, the enforced expression of XIAP rescued SKOV3-DDP cells from the cytotoxic effects of miR-874-3p. Finally, miR-874-3p sensitized EOC cells to cisplatin-induced apoptosis, at least in part, through targeting XIAP. The cytotoxic effects of miR-874-3p can be attributed to the targeting XIAP in cisplatin-resistant EOC cells. We believe that the combination of cisplatin with miR-874-3p may make a potential strategy to reverse cisplatin resistance.

DLX6-AS1 activated by H3K4me1 enhanced secondary cisplatin resistance of lung squamous cell carcinoma through modulating miR-181a-5p/miR-382-5p/CELF1 axis

Cisplatin (CDDP) based chemotherapy is widely used as the first-line strategy in treating non-small cell lung cancer (NSCLC), especially lung squamous cell carcinoma (LUSC). However, secondary cisplatin resistance majorly undermines the cisplatin efficacy leading to a worse prognosis. In this respect, we have identified the role of the DLX6-AS1/miR-181a-5p/miR-382-5p/CELF1 axis in regulating cisplatin resistance of LUSC. qRT-PCR and Western blot analysis were applied to detect gene expression. Transwell assay was used to evaluate the migration and invasion ability of LUSC cells. CCK-8 assay was used to investigate the IC50 of LUSC cells. Flow cytometry was used to test cell apoptosis rate. RNA pull-down and Dual luciferase reporter gene assay were performed to evaluate the crosstalk. DLX6-AS1 was aberrantly high expressed in LUSC tissues and cell lines, and negatively correlated with miR-181a-5p and miR-382-5p expression. DLX6-AS1 expression was enhanced by H3K4me1 in cisplatin resistant LUSC cells. Besides, DLX6-AS1 knockdown led to impaired IC50 of cisplatin resistant LUSC cells. Furthermore, DLX6-AS1 interacted with miR-181a-5p and miR-382-5p to regulate CELF1 expression and thereby mediated the cisplatin sensitivity of cisplatin resistant LUSC cells. DLX6-AS1 induced by H3K4me1 played an important role in promoting secondary cisplatin resistance of LUSC through regulating the miR-181a-5p/miR-382-5p/CELF1 axis. Therefore, targeting DLX6-AS1 might be a novel way of reversing secondary cisplatin resistance in LUSC.

Identification and Experimental Validation of Immune-Associate lncRNAs for Predicting Prognosis in Cervical Cancer

Purpose

Cervical cancer (CC) is a major risk for health of modern women. Immune-related long non-coding RNAs (lncRNAs) can also serve as prognostic markers of overall survival (OS) in patients with CC. This study aimed to identify an immune-related lncRNA signature for the prospective assessment of prognosis in CC patients.

Methods

We first calculated immune scores of CC patients in the Cancer Genome Atlas (TCGA) database. Univariate Cox, Lasso Cox and multivariate Cox regression analyses were perfumed to establish an immune-relative lncRNA signature. In addition, we processed pathway enrichment analysis and immune infiltration analysis between patients with higher or lower risk. Finally, T-cell Chemotaxis assays were processed to verify the function of 2 key lncRNAs.

Results

Our results suggested that patients with higher immune scores had longer survival time and some lncRNAs expressed differentially between two groups. Eight lncRNAs (LINC02802, LINC01877, RBAKDN, LINC02480, WWC2-AS2, LINC01281, ZBTB20-AS1, IFNG-AS1) were identified as prognostic signatures for CC. The immune-related lncRNA signature was correlated with disease progression and worse prognosis. Immune infiltration analysis indicated that the expression of 8-lncRNA signatures were corrected with infiltration level of immune cell subtypes. In addition, T-cell Chemotaxis assay validated that 2 key lncRNAs (ZBTB20-AS1 and LINC01281) could significantly promote the migration ability of T cells to CC cells.

Conclusion

Our finding demonstrated the value of lncRNAs in evaluating the immune infiltrate of the tumor. The 8-lncRNA signature could predict the prognosis of CC and contribute to decisions regarding the immunotherapeutic strategy.

The miRNAs involved in prostate cancer chemotherapy response as chemoresistance and chemosensitivity predictors

BACKGROUND

Reliable molecular markers that allow the rational prescription of an effective chemotherapy type for each prostate cancer patient are still needed. Since microRNAs expression is associated with the response to different types of prostate cancer therapy, microRNAs represent a pool of perspective markers of therapy effectiveness comprising chemotherapy.

OBJECTIVES

The available data on microRNAs associated with chemotherapy response (resistance and sensitivity) are summarized and analyzed in the article.

MATERIALS AND METHODS

A review of the published data, as well as their analysis by current bioinformatics resources, was conducted. The molecular targets of microRNAs, as well as the reciprocal relationships between the microRNAs and their targets, were studied using the DIANA, STRING, and TransmiR databases. Special attention was dedicated to the mechanisms of prostate cancer chemoresistance development.

RESULTS AND DISCUSSION

The combined analysis of bioinformatics resources and the available literature indicated that the expression of eight microRNAs that are associated with different responses to chemotherapy have a high potential for the prediction of the prostate cancer chemotherapy response, as found in the experiments and confirmed by the functions of regulated genes.

CONCLUSION

An overview on the published data and bioinformatics resources, with respect to predictive microRNA markers of chemotherapy response, is presented in this review. The selected microRNA and gene panel has a high potential for predicting the chemosensitivity or chemoresistance of prostate cancer and could represent a set of markers for subsequent study using samples of cell-free microRNAs from different patient groups.

Role of epithelial-mesenchymal transition in chemoresistance in pancreatic ductal adenocarcinoma

Pancreatic cancer (PC) is the seventh leading cause of cancer death worldwide. The vast majority of patients who have PC develop metastases, resulting in poor treatment effects. Although great progress in therapeutic approaches has been achieved in recent decades, extensive drug resistance still persists, representing a major hurdle to effective anticancer therapy for pancreatic ductal adenocarcinoma (PDAC). Therefore, there is an urgent need to better understand the drug resistance mechanisms and develop novel treatment strategies to improve patient outcomes. Numerous studies suggest that chemoresistance is closely related to epithelial-mesenchymal transition (EMT) of PDAC cells. Thus, this article summarizes the impact of EMT on PDAC from the perspective of chemotherapy resistance and discusses the possible novel applications of EMT inhibition to develop more effective drugs against PDAC.

Androgen Receptor-Dependent Mechanisms Mediating Drug Resistance in Prostate Cancer

Androgen receptor (AR) is a main driver of prostate cancer (PCa) growth and progression as well as the key drug target. Appropriate PCa treatments differ depending on the stage of cancer at diagnosis. Although androgen deprivation therapy (ADT) of PCa is initially effective, eventually tumors develop resistance to the drug within 2-3 years of treatment onset leading to castration resistant PCa (CRPC). Castration resistance is usually mediated by reactivation of AR signaling. Eventually, PCa develops additional resistance towards treatment with AR antagonists that occur regularly, also mostly due to bypass mechanisms that activate AR signaling. This tumor evolution with selection upon therapy is presumably based on a high degree of tumor heterogenicity and plasticity that allows PCa cells to proliferate and develop adaptive signaling to the treatment and evolve pathways in therapy resistance, including resistance to chemotherapy. The therapy-resistant PCa phenotype is associated with more aggressiveness and increased metastatic ability. By far, drug resistance remains a major cause of PCa treatment failure and lethality. In this review, various acquired and intrinsic mechanisms that are AR‑dependent and contribute to PCa drug resistance will be discussed.

Downregulation of Circ_0071589 Suppresses Cisplatin Resistance in Colorectal Cancer by Regulating the MiR-526b-3p/KLF12 Axis

BACKGROUND

Chemoresistance is one key factor for the failure of cisplatin (CDDP)-based therapy in colorectal cancer (CRC). Although circular RNAs (circRNAs) are associated with chemoresistance development, the role and mechanism of hsa_circ_0071589 (circ_0071589) in the development of CDDP resistance in CRC remain unclear.

METHODS

CDDP-resistant and sensitive CRC samples were collected. CDDP-resistant HCT116/CDDP and LOVO/CDDP cells were established. The levels of circ_0071589, microRNA (miR)-526b-3p and Krüppel-like factor 12 (KLF12) were detected via quantitative reverse transcription polymerase chain reaction, Western blot or immunohistochemistry. Cell viability, proliferation, cycle process, apoptosis, migration and invasion were examined via Cell Counting Kit-8, flow cytometry, transwell assay and Western blot. The association between miR-526b-3p and circ_0071589 or KLF12 was predicted by starBase, and explored via dual-luciferase reporter assay and RNA immunoprecipitation. The effect of circ_0071589 on CDDP resistance in CRC in vivo was investigated using a xenograft model.

RESULTS

Circ_0071589 level was upregulated in CDDP-resistant CRC tissue samples and cell lines. Circ_0071589 knockdown inhibited CDDP resistance, proliferation, migration and invasion, and promoted apoptosis in CDDP-resistant CRC cells. Circ_0071589 was a sponge for miR-526b-3p. MiR-526b-3p knockdown reversed the role of circ_0071589 inhibition in CDDP resistance. MiR-526b-3p suppressed CDDP resistance by directly targeting KLF12. Circ_0071589 regulated KLF12 expression through modulating miR-526b-3p. Circ_0071589 knockdown aggravated CDDP-induced reduction of xenograft tumor growth by upregulating miR-526b-3p and decreasing KLF12.

CONCLUSION

Knockdown of circ_0071589 repressed CDDP resistance in CDDP-resistant CRC cells by regulating the miR-526b-3p/KLF12 axis.

Identification of chemoresistance-associated microRNAs and hub genes in breast cancer using bioinformatics analysis

Breast cancer threatens women's health. Although there are a lot of methods to treat breast cancer, chemotherapy resistance still hinders the effectiveness of treatment. This study attempts to explore the mechanism of chemotherapy resistance from the perspective of miRNA and look for several new targets for developing new drugs. Three datasets (GSE73736, GSE71142 and GSE6434) from Gene Expression Omnibus (GEO) were used for the bioinformatics analysis. Differentially expressed miRNAs (DE-miRNAs) and differentially expressed genes (DE-genes) were obtained by using R package "limma". DAVID tool was used to perform gene ontology annotation analysis (GO) and Kyoto Encyclopedia of Genes and Genomes (KEGG) pathway enrichment analysis for the overlapping genes. Protein-protein interaction (PPI) network was established by STRING database and visualized by software Cytoscape. Hub genes were identified by software Cytoscape. The prognostic value of hub genes was assessed through Kaplan-Meier plotter website. In total, 22 DE-miRNAs, 1932 DE-genes and top 10 hub genes were obtained. The genes were mainly enriched in cell signaling pathways like ErbB signaling pathway and PI3K / AKT/mTOR pathway. These pathways have a significant impact on the proliferation, invasion and drug resistance in cancer. MiRNA-Gene interaction may provide new insight for exploring the mechanism of chemotherapy resistance in breast cancer. Our study ultimately identified effective biomarkers and potential drug targets, which may enhance the effect of chemotherapy in patients with breast cancer.