Involvement of microRNA-93, a new regulator of PTEN/Akt signaling pathway, in regulation of chemotherapeutic drug cisplatin chemosensitivity in ovarian cancer cells

Mechanistic and therapeutic perspectives of miRNA-PTEN signaling axis in cancer therapy resistance

Cancer, being one of the most lethal illnesses, presents an escalating clinical dilemma on a global scale. Despite significant efforts and advancements in cancer treatment over recent decades, the persistent challenge of resistance to traditional chemotherapeutic agents and/or emerging targeted drugs remains a prominent issue in the field of cancer therapies. Among the frequently inactivated tumor suppressor genes in cancer, phosphatase and Tensin Homolog (PTEN) stands out, and its decreased expression may contribute to the emergence of therapeutic resistance. MicroRNAs (miRNAs), characterized by their short length of 22 nucleotides, exert regulatory control over target mRNA expression by binding to complementary sequences. Recent findings indicate that microRNAs play varied regulatory roles, encompassing promotion, suppression, and dual functions on PTEN, and their aberration is implicated in heightened resistance to anticancer therapies. Significantly, recent research has revealed that competitive endogenous RNAs (ceRNAs) play a pivotal role in influencing PTEN expression, and the regulatory network involving circRNA/lncRNA-miRNA-PTEN is intricately linked to resistance in various cancer types to anticancer therapies. Finally, our findings showcase that diverse approaches, such as herbal medicine, small molecule inhibitors, low-intensity ultrasound, and engineered exosomes, can effectively overcome drug resistance in cancer by modulating the miRNA-PTEN axis.

Correlation of PTEN signaling pathway and miRNA in breast cancer

Breast cancer (BC) is one of the most common cancers among women and can be fatal if not diagnosed and treated on time. Various genetic and environmental factors play a significant role in the development and progression of BC. Within the body, different signaling pathways have been identified that contribute to cancer progression, or conversely, cancer prevention. Phosphatase and tensin homolog (PTEN) is one of the proteins that prevent cancer by inhibiting the oncogenic PI3K/Akt/mTOR signaling pathway. MicroRNAs (miRNAs) are molecules with about 18 to 28 base pairs, which regulate about 30% of human genes after transcription. miRNAs play a key role in the progression or prevention of cancer through different signaling pathway and mechanisms, e.g., apoptosis, angiogenesis, and proliferation. miRNAs, which are upstream mediators of PTEN, can reinforce or suppress the effect of PTEN signaling on BC cells, and suppressing the PTEN signaling, linked to weakness of the cancer cells to chemotherapeutic drugs. However, the precise mechanism and function of miRNAs on PTEN in BC are not yet fully understood. Therefore, in the present study, has been focused on miRNAs regulating PTEN function in BC.

Prediction of Chemoresistance-How Preclinical Data Could Help to Modify Therapeutic Strategy in High-Grade Serous Ovarian Cancer

High-grade serous ovarian cancer (HGSOC) is one of the most lethal tumors generally and the most fatal cancer of the female genital tract. The approved standard therapy consists of surgical cytoreduction and platinum/taxane-based chemotherapy, and of targeted therapy in selected patients. The main therapeutic problem is chemoresistance of recurrent and metastatic HGSOC tumors which results in low survival in the group of FIGO III/IV. Therefore, the prediction and monitoring of chemoresistance seems to be of utmost importance for the improvement of HGSOC management. This type of cancer has genetic heterogeneity with several subtypes being characterized by diverse gene signatures and disturbed peculiar epigenetic regulation. HGSOC develops and metastasizes preferentially in the specific intraperitoneal environment composed mainly of fibroblasts, adipocytes, and immune cells. Different HGSOC subtypes could be sensitive to distinct sets of drugs. Moreover, primary, metastatic, and recurrent tumors are characterized by an individual biology, and thus diverse drug responsibility. Without a precise identification of the tumor and its microenvironment, effective treatment seems to be elusive. This paper reviews tumor-derived genomic, mutational, cellular, and epigenetic biomarkers of HGSOC drug resistance, as well as tumor microenvironment-derived biomarkers of chemoresistance, and discusses their possible use in the novel complex approach to ovarian cancer therapy and monitoring.

MicroRNAs Can Influence Ovarian Cancer Progression by Dysregulating Integrin Activity

Ovarian cancer is a deadly disease that affects thousands of women worldwide. Integrins, transmembrane receptors that mediate cell adhesion and signaling, play important roles in ovarian cancer progression, metastasis, and drug resistance. Dysregulated expression of integrins is implicated in various cellular processes, such as cell migration, invasion, and proliferation. Emerging evidence suggests that microRNAs (miRNAs) can regulate integrin expression and function, thus affecting various physiological and pathological processes, including ovarian cancer. In this article, we review the current understanding of integrin-mediated cellular processes in ovarian cancer and the roles of miRNAs in regulating integrins. We also discuss the therapeutic potential of targeting miRNAs that regulate integrins for the treatment of ovarian cancer. Targeting miRNAs that regulate integrins or downstream signaling pathways of integrins may provide novel therapeutic strategies for inhibiting integrin-mediated ovarian cancer progression.

MicroRNA targeting: A novel therapeutic intervention for ovarian cancer

Ovarian cancer, a perilous form of cancer affecting the female reproductive system, exhibits intricate communication networks that contribute to its progression. This study aims to identify crucial molecular abnormalities linked to the disease to enhance diagnostic and therapeutic strategies. In particular, we investigate the role of microRNAs (miRNAs) as diagnostic biomarkers and explore their potential in treating ovarian cancer. By targeting miRNAs, which can influence multiple pathways and genes, substantial therapeutic benefits can be attained. In this review we want to shed light on the promising application of miRNA-based interventions and provide insights into the specific miRNAs implicated in ovarian cancer pathogenesis.

Double-edged sword role of miRNA-633 and miRNA-181 in human cancers

Understanding the function and mode of operation of microRNAs (miRNAs) in cancer is of growing interest. The short non-coding RNAs known as miRNAs, which target mRNA in multicellular organisms, are described as controlling essential cellular processes. The miR-181 family and miR-633 are well-known miRNAs that play a key role in the development and metastasis of tumor cells. They may facilitate either tumor-suppressive or oncogenic function in malignant cells, according to mounting evidence. Metastatic cells that are closely linked to cancer cell migration, invasion, and angiogenesis can be identified by abnormal levels of miR-181 and miR-633. Numerous studies have demonstrated their capacity to control drug resistance, cell growth, apoptosis, and the epithelial-mesenchymal transition (EMT) and metastasis process. Interestingly, the levels of miR-181 and miR-633 and their potential target genes in the basic cellular process can vary depending on the type of cancer cells and their gene expression profile. Such miRNAs' interactions with other non-coding RNAs such as long non-coding RNAs and circular RNAs can influence tumor behaviors. Herein, we concentrated on the multifaceted roles of miR-181 and miR-633 and potential targets in human tumorigenesis, ranging from cell growth and metastasis to drug resistance.

The regulation of PTEN: Novel insights into functions as cancer biomarkers and therapeutic targets

This review summarizes the implications of the primary tumor suppressor protein phosphatase and tensin homolog (PTEN) in aggressive cancer development. PTEN interacts with other cellular proteins or factors suggesting the existence of an intricate molecular network that regulates their oncogenic function. Accumulating evidence has shown that PTEN exists and plays a role in the cytoplasmic organelles and in the nucleus. PTEN blocks phosphoinositide 3-kinases (PI3K)-protein kinase B-mammalian target of rapamycin signaling pathway by dephosphorylating phosphatidylinositol (PI)-3,4,5-triphosphate to PI-4,5-bisphosphate thus counteracting PI3K function. Studies have shown that PTEN expression is tightly regulated at transcriptional, posttranscriptional, and posttranslational levels (including protein-protein interactions and posttranslational modifications). Despite recent advances in PTEN research, the regulation and function of the PTEN gene remain largely unknown. How mutation or loss of specific exons in the PTEN gene occurs and involves in cancer development is not clear. This review illustrates the regulatory mechanisms of PTEN expression and discusses how PTEN participates in tumor development and/or suppression. Future prospects for the clinical applications are also highlighted.

Endothelial plasticity across PTEN and Hippo pathways: A complex hormetic rheostat modulated by extracellular vesicles

Vascularization is a multifactorial and spatiotemporally regulated process, essential for cell and tissue survival. Vascular alterations have repercussions on the development and progression of diseases such as cancer, cardiovascular diseases, and diabetes, which are the leading causes of death worldwide. Additionally, vascularization continues to be a challenge for tissue engineering and regenerative medicine. Hence, vascularization is the center of interest for physiology, pathophysiology, and therapeutic processes. Within vascularization, phosphatase and tensin homolog deleted on chromosome 10 (PTEN) and Hippo signaling have pivotal roles in the development and homeostasis of the vascular system. Their suppression is related to several pathologies, including developmental defects and cancer. Non-coding RNAs (ncRNAs) are among the regulators of PTEN and/or Hippo pathways during development and disease. The purpose of this paper is to review and discuss the mechanisms by which exosome-derived ncRNAs modulate endothelial cell plasticity during physiological and pathological angiogenesis, through the regulation of PTEN and Hippo pathways, aiming to establish new perspectives on cellular communication during tumoral and regenerative vascularization.

MiRNA-93: a novel signature in human disorders and drug resistance

miRNA-93 is a member of the miR-106b-25 family and is encoded by a gene on chromosome 7q22.1. They play a role in the etiology of various diseases, including cancer, Parkinson's disease, hepatic injury, osteoarthritis, acute myocardial infarction, atherosclerosis, rheumatoid arthritis, and chronic kidney disease. Different studies have found that this miRNA has opposing roles in the context of cancer. Recently, miRNA-93 has been downregulated in breast cancer, gastric cancer, colorectal cancer, pancreatic cancer, bladder cancer, cervical cancer, and renal cancer. However, miRNA-93 is up-regulated in a wide variety of malignancies, such as lung, colorectal, glioma, prostate, osteosarcoma, and hepatocellular carcinoma. The aim of the current review is to provide an overview of miRNA-93's function in cancer disorder progression and non-cancer disorders, with a focus on dysregulated signaling pathways. We also give an overview of this miRNA's function as a biomarker of prognosis in cancer and emphasize how it contributes to drug resistance based on in vivo, in vitro, and human studies. Video Abstract.

Interactive role of miR-29, miR-93, miR-205, and VEGF in salivary adenoid cystic carcinoma

OBJECTIVES

Salivary adenoid cystic carcinoma (SACC) is one of the most common salivary gland tumors in which patients encounter local recurrence and lung metastases. Understanding prognostic biomarkers in SACC is essential for future development in prognosis and treatment. This study aimed to assess the expression level of vascular endothelial growth factor (VEGF) and its potential regulatory microRNAs in SACC for prognostic determination. MATERIAL AND METHODS: The expression of VEGF in SACC samples was assessed using immunohistochemistry. Potential regulatory microRNAs were evaluated using quantitative reverse transcription-polymerase chain reaction. Associations between VEGF and microRNAs expression and clinicopathological parameters were investigated.

RESULTS

VEGF expression levels positively correlated with histologic grade (p = .004) and treatment modality (p = .04). Decreased expression of miR-29a (p = .01) and increased expression of miR-93-5p and miR-205 (both p < .0001) were observed in SACC compared to normal salivary gland tissue. MiR-93-5p showed a positive association (p = .02) with VEGF overexpression.

CONCLUSIONS

Our results showed the downregulation of miR-29 and overexpression of miR-93 and miR-205 in the SACC group, and the correlation between miR-93 and VEGF suggests these biomarkers as potential prognostic markers in the future.

The “Sweet Spot” of Targeting Tumor Metabolism in Ovarian Cancers

The objective of this review is to explore the metabolomic environment of epithelial ovarian cancer that contributes to chemoresistance and to use this knowledge to identify possible targets for therapeutic intervention. The Warburg effect describes increased glucose uptake and lactate production in cancer cells. In ovarian cancer, we require a better understanding of how cancer cells reprogram their glycogen metabolism to overcome their nutrient deficient environment and become chemoresistant. Glucose metabolism in ovarian cancer cells has been proposed to be influenced by altered fatty acid metabolism, oxidative phosphorylation, and acidification of the tumor microenvironment. We investigate several markers of altered metabolism in ovarian cancer including hypoxia-induced factor 1, VEGF, leptin, insulin-like growth factors, and glucose transporters. We also discuss the signaling pathways involved with these biomarkers including PI3K/AKT/mTOR, JAK/STAT and OXPHOS. This review outlines potential metabolic targets to overcome chemoresistance in ovarian cancer. Continued research of the metabolic changes in ovarian cancer is needed to identify and target these alterations to improve treatment approaches.

A comprehensive survey into the role of microRNAs in ovarian cancer chemoresistance; an updated overview

Ovarian cancer (OC), a frequent malignant tumor that affects women, is one of the leading causes of cancer-related death in this group of individuals. For the treatment of ovarian cancer, systemic chemotherapy with platinum-based drugs or taxanes is the first-line option. However, drug resistance developed over time during chemotherapy medications worsens the situation. Since uncertainty exists for the mechanism of chemotherapy resistance in ovarian cancer, there is a need to investigate and overcome this problem. miRNAs are engaged in various signaling pathways that contribute to the chemotherapeutic resistance of ovarian cancer. In the current study, we have tried to shed light on the mechanisms by which microRNAs contribute to the drug resistance of ovarian cancer and the use of some microRNAs to combat this chemoresistance, leading to the worse outcome of ovarian cancer patients treated with systemic chemotherapeutics.

Exosomal MicroRNA as Biomarkers for Diagnosing or Monitoring the Progression of Ovarian Clear Cell Carcinoma: A Pilot Study

Ovarian cancer is the most common cause of gynecological malignancy-related mortality since early-stage disease is difficult to diagnose. Advanced clear cell carcinoma of the ovary (CCCO) has dismal prognosis, and its incidence has been increasing in Japan, emphasizing the need for highly sensitive diagnostic and prognostic CCCO biomarkers. Exosomal microRNAs (miRNAs) secreted by tumor cells are known to play a role in carcinogenesis; however, their involvement in ovarian cancer is unclear. In this study, we performed expression profiling of miRNAs from exosomes released by five cell lines representing different histological types of ovarian cancer. Exosomes isolated from culture media of cancer and normal cells were compared for miRNA composition using human miRNA microarray. We detected 143 exosomal miRNAs, whose expression was ≥1.5-fold higher in ovarian cancer cells than in the control. Among them, 28 miRNAs were upregulated in cells of all histological ovarian cancer types compared to control, and three were upregulated in CCCO cells compared to other types. Functional analyses indicated that miR-21 overexpressed in CCCO cells targeted tumor suppressor genes PTEN, TPM1, PDCD4, and MASP1. The identified miRNAs could represent novel candidate biomarkers to diagnose or monitor progression of ovarian cancer, particularly CCCO.

The Role of Micro RNAs in Regulating PI3K/AKT Signaling Pathways in Glioblastoma

Glioblastoma is a type of brain cancer with aggressive and invasive nature. Such features result from increased proliferation and migration and also poor apoptosis of glioma cells leading to resistance to current treatments such as chemotherapy and radiotherapy. In recent studies, micro RNAs have been introduced as a novel target for treating glioblastoma via regulation of apoptotic signaling pathway, remarkably PI3K/AKT, which affect cellular functions and blockage or progression of the tumor. In this review, we focus on PI3K/AKT signaling pathway and other related apoptotic processes contributing to glioblastoma and investigate the role of micro RNAs interfering in apoptosis, invasion and proliferation of glioma through such apoptotic processes pathways. Databases NCBI, PubMed, and Web of Science were searched for published English articles using keywords such as 'miRNA OR microRNA', 'Glioblastoma', 'apoptotic pathways', 'PI3K and AKT', 'Caspase signaling Pathway' and 'Notch pathway'. Most articles were published from 7 May 2015 to 16 June 2020. This study focused on PI3K/AKT signaling pathway affecting glioma cells in separated subparts. Also, other related apoptotic pathways as the Caspase cycle and Notch have been also investigated. Nearly 40 miRNAs were found as tumor suppressors or onco-miRNA, and their targets, which regulated subcomponents participating in proliferation, invasion, and apoptosis of the tumoral cells. Our review reveals that miRNAs affect key molecules in signaling apoptotic pathways, partly PI3K/AKT, making them potential therapeutic targets to overcome the tumor. However, their utility as a novel treatment for glioblastoma requires further examination and investigation.

Comparing the Secretomes of Chemorefractory and Chemoresistant Ovarian Cancer Cell Populations

High-grade serous ovarian cancer (HGSOC) constitutes the majority of all ovarian cancer cases and has staggering rates of both refractory and recurrent disease. While most patients respond to the initial treatment with paclitaxel and platinum-based drugs, up to 25% do not, and of the remaining that do, 75% experience disease recurrence within the subsequent two years. Intrinsic resistance in refractory cases is driven by environmental stressors like tumor hypoxia which alter the tumor microenvironment to promote cancer progression and resistance to anticancer drugs. Recurrent disease describes the acquisition of chemoresistance whereby cancer cells survive the initial exposure to chemotherapy and develop adaptations to enhance their chances of surviving subsequent treatments. Of the environmental stressors cancer cells endure, exposure to hypoxia has been identified as a potent trigger and priming agent for the development of chemoresistance. Both in the presence of the stress of hypoxia or the therapeutic stress of chemotherapy, cancer cells manage to cope and develop adaptations which prime populations to survive in future stress. One adaptation is the modification in the secretome. Chemoresistance is associated with translational reprogramming for increased protein synthesis, ribosome biogenesis, and vesicle trafficking. This leads to increased production of soluble proteins and extracellular vesicles (EVs) involved in autocrine and paracrine signaling processes. Numerous studies have demonstrated that these factors are largely altered between the secretomes of chemosensitive and chemoresistant patients. Such factors include cytokines, growth factors, EVs, and EV-encapsulated microRNAs (miRNAs), which serve to induce invasive molecular, biophysical, and chemoresistant phenotypes in neighboring normal and cancer cells. This review examines the modifications in the secretome of distinct chemoresistant ovarian cancer cell populations and specific secreted factors, which may serve as candidate biomarkers for aggressive and chemoresistant cancers.

Deregulated miRNA clusters in ovarian cancer: Imperative implications in personalized medicine

Ovarian cancer (OC) is one of the most common and fatal types of gynecological cancer. OC is usually detected at the advanced stages of the disease, making it highly lethal. miRNAs are single-stranded, small non-coding RNAs with an approximate size ranging around 22 nt. Interestingly, a considerable proportion of miRNAs are organized in clusters with miRNA genes placed adjacent to one another, getting transcribed together to result in miRNA clusters (MCs). MCs comprise two or more miRNAs that follow the same orientation during transcription. Abnormal expression of the miRNA cluster has been identified as one of the key drivers in OC. MC exists both as tumor-suppressive and oncogenic clusters and has a significant role in OC pathogenesis by facilitating cancer cells to acquire various hallmarks. The present review summarizes the regulation and biological function of MCs in OC. The review also highlights the utility of abnormally expressed MCs in the clinical management of OC.

PI3K Inhibition Sensitize the Cisplatin-resistant Human Ovarian Cancer Cell OVCAR3 by Induction of Oxidative Stress

BACKGROUND

This study evaluates the effect of simultaneous AKT inhibition and cisplatin therapy in changes of Reactive Oxygen Species (ROS) production, apoptosis induction, and cell survival in cisplatin-resistant OVCAR3 cell.

METHODS

OVCAR3 cancer cells were treated with cisplatin, Ly 294002 (LY), and cisplatin+Ly to investigate the cytotoxicity effect of the mentioned groups via MTT assay. Then, DCFH-DA (2', 7'-dichlorodihydro fluorescein diacetate) assay kit is used to assess the potential of treated groups in intracellular ROS generation. Protein expression levels of caspase-3, cleaved caspase 3, PI3K, Akt, p-Akt, XIAP, and Survivin are estimated through immunoblotting assay in all three experimental groups.

RESULTS

The results showed that all three treated groups, including cisplatin and Ly alone and co-administration of cisplatin+Ly, could reduce the cell vitality of OVCAR3 cancer cells, induced intracellular production of ROS and increased the expression level of activated caspase 3 and Akt protein, whereas down-regulated the phosphorylation of Akt protein. However, the effect of combination therapy was more tangible compared to single therapy and control groups. In contrast, the expression amount of XIAP, Survivin, and PI3K did not show detectable changes in comparison with the control group.

CONCLUSION

The results showed that the AKT inhibition by Ly could sensitize the OVCAR3 cancer cells to the cisplatin and lower the effective dose of cisplatin through hyperactivation of oxidative stress.

MicroRNA and Alternative mRNA Splicing Events in Cancer Drug Response/Resistance: Potent Therapeutic Targets

Cancer is a multifaceted disease that involves several molecular mechanisms including changes in gene expression. Two important processes altered in cancer that lead to changes in gene expression include altered microRNA (miRNA) expression and aberrant splicing events. MiRNAs are short non-coding RNAs that play a central role in regulating RNA silencing and gene expression. Alternative splicing increases the diversity of the proteome by producing several different spliced mRNAs from a single gene for translation. MiRNA expression and alternative splicing events are rigorously regulated processes. Dysregulation of miRNA and splicing events promote carcinogenesis and drug resistance in cancers including breast, cervical, prostate, colorectal, ovarian and leukemia. Alternative splicing may change the target mRNA 3'UTR binding site. This alteration can affect the produced protein and may ultimately affect the drug affinity of target proteins, eventually leading to drug resistance. Drug resistance can be caused by intrinsic and extrinsic factors. The interplay between miRNA and alternative splicing is largely due to splicing resulting in altered 3'UTR targeted binding of miRNAs. This can result in the altered targeting of these isoforms and altered drug targets and drug resistance. Furthermore, the increasing prevalence of cancer drug resistance poses a substantial challenge in the management of the disease. Henceforth, molecular alterations have become highly attractive drug targets to reverse the aberrant effects of miRNAs and splicing events that promote malignancy and drug resistance. While the miRNA-mRNA splicing interplay in cancer drug resistance remains largely to be elucidated, this review focuses on miRNA and alternative mRNA splicing (AS) events in breast, cervical, prostate, colorectal and ovarian cancer, as well as leukemia, and the role these events play in drug resistance. MiRNA induced cancer drug resistance; alternative mRNA splicing (AS) in cancer drug resistance; the interplay between AS and miRNA in chemoresistance will be discussed. Despite this great potential, the interplay between aberrant splicing events and miRNA is understudied but holds great potential in deciphering miRNA-mediated drug resistance.

Regulation of Neuroendocrine-like Differentiation in Prostate Cancer by Non-Coding RNAs

Neuroendocrine prostate cancer (NEPC) represents a variant of prostate cancer that occurs in response to treatment resistance or, to a much lesser extent, de novo. Unravelling the molecular mechanisms behind transdifferentiation of cancer cells to neuroendocrine-like cancer cells is essential for development of new treatment opportunities. This review focuses on summarizing the role of small molecules, predominantly microRNAs, in this phenomenon. A published literature search was performed to identify microRNAs, which are reported and experimentally validated to modulate neuroendocrine markers and/or regulators and to affect the complex neuroendocrine phenotype. Next, available patients’ expression datasets were surveyed to identify deregulated microRNAs, and their effect on NEPC and prostate cancer progression is summarized. Finally, possibilities of miRNA detection and quantification in body fluids of prostate cancer patients and their possible use as liquid biopsy in prostate cancer monitoring are discussed. All the addressed clinical and experimental contexts point to an association of NEPC with upregulation of miR-375 and downregulation of miR-34a and miR-19b-3p. Together, this review provides an overview of different roles of non-coding RNAs in the emergence of neuroendocrine prostate cancer.

Epigenetic Mechanisms and Therapeutic Targets in Chemoresistant High-Grade Serous Ovarian Cancer

High-grade serous ovarian cancer (HGSOC) is the most common ovarian cancer subtype, and the overall survival rate has not improved in the last three decades. Currently, most patients develop recurrent disease within 3 years and succumb to the disease within 5 years. This is an important area of research, as the major obstacle to the treatment of HGSOC is the development of resistance to platinum chemotherapy. The cause of chemoresistance is still largely unknown and may be due to epigenetics modifications that are driving HGSOC metastasis and treatment resistance. The identification of epigenetic changes in chemoresistant HGSOC enables the development of epigenetic modulating drugs that may be used to improve outcomes. Several epigenetic modulating drugs have displayed promise as drug targets for HGSOC, such as demethylating agents azacitidine and decitabine. Others, such as histone deacetylase inhibitors and miRNA-targeting therapies, demonstrated promising preclinical results but resulted in off-target side effects in clinical trials. This article reviews the epigenetic modifications identified in chemoresistant HGSOC and clinical trials utilizing epigenetic therapies in HGSOC.

MicroRNAs as the critical regulators of Cisplatin resistance in ovarian cancer cells

BACKGROUND

Ovarian cancer (OC) is one of the leading causes of cancer related deaths among women. Due to the asymptomatic tumor progression and lack of efficient screening methods, majority of OC patients are diagnosed in advanced tumor stages. A combination of surgical resection and platinum based-therapy is the common treatment option for advanced OC patients. However, tumor relapse is observed in about 70% of cases due to the treatment failure. Cisplatin is widely used as an efficient first-line treatment option for OC; however cisplatin resistance is observed in a noticeable ratio of cases. Regarding, the severe cisplatin side effects, it is required to clarify the molecular biology of cisplatin resistance to improve the clinical outcomes of OC patients. Cisplatin resistance in OC is associated with abnormal drug transportation, increased detoxification, abnormal apoptosis, and abnormal DNA repair ability. MicroRNAs (miRNAs) are critical factors involved in cell proliferation, apoptosis, and chemo resistance. MiRNAs as non-invasive and more stable factors compared with mRNAs, can be introduced as efficient markers of cisplatin response in OC patients.

MAIN BODY

In present review, we have summarized all of the miRNAs that have been associated with cisplatin resistance in OC. We also categorized the miRNAs based on their targets to clarify their probable molecular mechanisms during cisplatin resistance in ovarian tumor cells.

CONCLUSIONS

It was observed that miRNAs mainly exert their role in cisplatin response through regulation of apoptosis, signaling pathways, and transcription factors in OC cells. This review highlighted the miRNAs as important regulators of cisplatin response in ovarian tumor cells. Moreover, present review paves the way of suggesting a non-invasive panel of prediction markers for cisplatin response among OC patients.

The Non-Coding RNAs Inducing Drug Resistance in Ovarian Cancer: A New Perspective for Understanding Drug Resistance

Ovarian cancer, a common malignant tumor, is one of the primary causes of cancer-related deaths in women. Systemic chemotherapy with platinum-based compounds or taxanes is the first-line treatment for ovarian cancer. However, resistance to these chemotherapeutic drugs worsens the prognosis. The underlying mechanism of chemotherapeutic resistance in ovarian cancer remains unclear. Non-coding RNAs, including long non-coding RNAs, microRNAs, and circular RNAs, have been implicated in the development of drug resistance. Abnormally expressed non-coding RNAs can promote ovarian cancer resistance by inducing apoptosis inhibition, protective autophagy, abnormal tumor cell proliferation, epithelial-mesenchymal transition, abnormal glycolysis, drug efflux, and cancer cell stemness. This review summarizes the role of non-coding RNAs in the development of chemotherapeutic resistance in ovarian cancer, including their mechanisms, targets, and potential signaling pathways. This will facilitate the development of novel chemotherapeutic agents that can target these non-coding RNAs and improve ovarian cancer treatment.

Long non‑coding RNA HAND2‑AS1/miR‑106a/PTEN axis re‑sensitizes cisplatin‑resistant ovarian cells to cisplatin treatment

Cisplatin (DDP) resistance in patients suffering from ovarian cancer is a considerable hurdle to successful treatment. The present study aimed to identify a possible long non‑coding RNA (lncRNA)‑microRNA (miRNA)‑mRNA axis participating in ovarian cancer DDP‑resistance based on the critical roles of non‑coding RNAs, including lncRNAs and miRNAs, in carcinogenesis. According to online data and experimental results, lncRNA HAND2‑AS1 expression was significantly downregulated within ovarian carcinoma, especially within recurrent and DDP‑resistant ovarian carcinoma. The expression of HAND2‑AS1 was also shown to be markedly inhibited in SKOV3/DDP (DDP) cells with resistance to DDP. In SKOV3/DDP cells, HAND2‑AS1 overexpression inhibited cell viability and promoted cell apoptosis upon DDP treatment through the Bcl‑2/caspase‑3 apoptotic signaling. It was hypothesized that PTEN mRNA expression was also markedly inhibited in SKOV3/DDP ovarian cancer cells, while HAND2‑AS1 overexpression rescued PTEN proteins and blocked PI3K/AKT signaling activation. Moreover, miR‑106a was found to bind directly to PTEN 3' UTR and HAND2‑AS1. Upon DDP treatment, miR‑106a overexpression in SKOV3/DDP cells promoted cell viability. It inhibited cell apoptosis through the Bcl‑2/caspase‑3 apoptotic signaling pathway and downregulated the protein levels of PTEN and upregulated PI3K/AKT signaling activity. Furthermore, miR‑106a overexpression partially reversed the effect of HAND2‑AS1 overexpression upon PTEN proteins and SKOV3/DDP cell proliferation upon DDP treatment. In conclusion, a lncRNA HAND2‑AS1/miR‑106a/PTEN axis that re‑sensitizes DDP‑resistant SKOV3/DDP cells to DDP treatment has been established.

Chemotherapy resistance in epithelial ovarian cancer: Mechanisms and emerging treatments

Ovarian cancer (OC) remains a fatal malignancy because most patients experience recurrent disease, which is resistant to chemotherapy. The outcomes for patients with platinum-resistant OC are poor, response rates to further chemotherapy are low and median survival is lower than 12 months. The complexity of platinum-resistant OC, which comprises a heterogeneous spectrum of diseases, is indeed far from being completely understood. Therefore, comprehending tumors' biological behaviour to identify reliable biomarkers, which may predict responses to therapies, is a demanding challenge to improve OC management. In the age of precision medicine, efforts to overcome platinum resistance in OC represent a dynamic and vast field in which innovative drugs and clinical trials rapidly develop. This review will present the exceptional biochemical environment implicated in OC and highlights mechanisms of chemoresistance. Furthermore, innovative molecules and new therapeutic opportunities are presented, along with currently available therapies and ongoing clinical trials.

Screening of MicroRNA Related to Irradiation Response and the Regulation Mechanism of miRNA-96-5p in Rectal Cancer Cells

Neoadjuvant chemoradiotherapy has been widely used in the treatment of locally advanced rectal cancer due to the excellent advantages of irradiation in cancer therapy. Unfortunately, not every patient can benefit from this treatment, therefore, it is of great significance to explore biomarkers that can predict irradiation sensitivity. In this study, we screened microRNAs (miRNAs) which were positively correlated with irradiation resistance and found that miRNA-552 and miRNA-183 families were positively correlated with the irradiation resistance of rectal cancer, and found that high expression of miRNA-96-5p enhanced the irradiation resistance of rectal cancer cells through direct regulation of the GPC3 gene and abnormal activation of the canonical Wnt signal transduction pathway. Based on the radioreactivity results of patient-derived xenograft models, this is the first screening report for radio-resistant biomarkers in rectal cancer. Our results suggest that miRNA-96-5p expression is an important factor affecting the radiation response of colorectal cancer cells.

A Peptide-Based Small RNA Delivery System to Suppress Tumor Growth by Remodeling the Tumor Microenvironment

MicroRNAs can regulate a variety of physiological and pathological processes and are increasingly recognized as being involved in regulating the malignant progression of cancer, which is an important direction for the study and treatment of cancer. In addition, the tumor microenvironment has gradually become an important direction of study for combating cancer. Researchers can inhibit tumor growth by remodeling and suppressing an immunosuppressive phenotype in the tumor microenvironment. Therefore, the combination of microRNA delivery and tumor microenvironment remodeling may be a potential research direction. In a previous study, we developed a novel cationic and hydrophilic antimicrobial peptide, DP7, by computer simulation. It was found that cholesterol-modified DP7 (DP7-C) has dual functions as a carrier and an immune adjuvant. In this experiment, we used DP7-C to deliver microRNAs or inhibitors intratumorally, where it played a dual role as a carrier and an immune adjuvant. As a delivery vector, DP7-C has more advantages in terms of transfection efficiency and cytotoxicity than Lipo2000 and PEI25K. Components of the DP7-C/RNA complex can effectively escape endosomes after uptake via caveolin- and clathrin-dependent pathways. As an immune adjuvant, DP7-C can activate dendritic cells and promote macrophage polarization. Moreover, it can transform the immunosuppressive tumor microenvironment into an immune-activated tumor microenvironment, indicating its potential as an anticancer therapy. In conclusion, this study identifies a novel microRNA and inhibitor delivery system that can remodel the tumor microenvironment and introduces an alternative scheme for antitumor treatment.

Flavonoid display ability to target microRNAs in cancer pathogenesis

MicroRNAs (miRNAs) are non-coding, conserved, single-stranded nucleotide sequences involved in physiological and developmental processes. Recent evidence suggests an association between miRNAs' deregulation with initiation, promotion, progression, and drug resistance in cancer cells. Besides, miRNAs are known to regulate the epithelial-mesenchymal transition, angiogenesis, autophagy, and senescence in different cancer types. Previous reports proposed that apart from the antioxidant potential, flavonoids play an essential role in miRNAs modulation associated with changes in cancer-related proteins, tumor suppressor genes, and oncogenes. Thus, flavonoids can suppress proliferation, help in the development of drug sensitivity, suppress metastasis and angiogenesis by modulating miRNAs expression. In the present review, we summarize the role of miRNAs in cancer, drug resistance, and the chemopreventive potential of flavonoids mediated by miRNAs. The potential of flavonoids to modulate miRNAs expression in different cancer types demonstrate their selectivity and importance as regulators of carcinogenesis. Flavonoids as chemopreventive agents targeting miRNAs are extensively studied in vitro, in vivo, and pre-clinical studies, but their efficiency in targeting miRNAs in clinical studies is less investigated. The evidence presented in this review highlights the potential of flavonoids in cancer prevention/treatment by regulating miRNAs, although further investigations are required to validate and establish their clinical usefulness.

Covid-19 pathogenesis in prostatic cancer and TMPRSS2-ERG regulatory genetic pathway

Members of Coronaviridae family have been the source of respiratory illnesses. The outbreak of SARS-CoV-2 that produced a severe lung disease in afflicted patients in China and other countries was the reason for the incredible attention paid toward this viral infection. It is known that SARS-CoV-2 is dependent on TMPRSS2 activity for entrance and subsequent infection of the host cells and TMPRSS2 is a host cell molecule that is important for the spread of viruses such as coronaviruses.

Different factors can increase the risk of prostate cancer, including older age, a family history of the disease. Androgen receptor (AR) initiates a transcriptional cascade which plays a serious role in both normal and malignant prostate tissues. TMPRSS2 protein is highly expressed in prostate secretory epithelial cells, and its expression is dependent on androgen signals. One of the molecular signs of prostate cancer is TMPRSS2-ERG gene fusion. In TMPRSS2-ERG-positive prostate cancers different patterns of changed gene expression can be detected. The possible molecular relation between fusion positive prostate cancer patients and the increased risk of lethal respiratory viral infections especially SARS-CoV-2 can candidate TMPRSS2 as an attractive drug target. The studies show that some molecules such as nicotinamide, PARP1, ETS and IL-1R can be studied deeper in order to control SARS-CoV-2 infection especially in prostate cancer patients.

This review attempts to investigate the possible relation between the gene expression pattern that is produced through TMPRSS2-ERG fusion positive prostate cancer and the possible influence of these fluctuations on the pathogenesis and development of viral infections such as SARS-CoV-2.

MicroRNAs as Biomarkers in Canine Osteosarcoma: A New Future?

Sarcomas are frequent in dogs and canine species are excellent animal models for studying the human counterpart. However, osteosarcomas are a rare form of sarcoma with high death rates in humans and dogs. miRNAs are small endogenous RNAs that regulate gene expression post-transcriptionally. The discovery of miRNAs could give a contribute in the diagnosis and prognosis of different types of tumors in animal species, as already in humans. The differentiated expression of miRNAs is a frequent finding in cancers and is related to their pathogenesis in many cases. Most canine and human sarcomas show similar miRNA aberrations. Lower levels of miR-1 and miR-133b in canine osteosarcoma tissues were found to increase tumorigenesis through a higher expression of their target genes MET and MCL1. The overexpression of miR-9 promotes a metastatic phenotype in canine osteosarcomas and its capacity as a prognostic biomarker for the disease is currently being evaluated. MicroRNAs at the 14q32 locus could be used as prognostic biomarkers, since their decreased expression has been associated with poor prognosis in canine and human osteosarcomas. Furthermore, a decreased expression of miR-34a in osteosarcoma tumour cells has been associated with shorter disease-free survival times and its reintroduction as a synthetic prodrug shows good potential as a novel therapeutic target to fight the disease. Circulating miR-214 and miR-126 are significantly increased in a broad-spectrum cancer and have the ability to successfully predict the prognosis of dogs. However, further studies are needed to make the use of miRNAs as biomarkers a common practice.

Inflammatory state of lymphatic vessels and miRNA profiles associated with relapse in ovarian cancer patients

Lymphogenic spread is associated with poor prognosis in epithelial ovarian cancer (EOC), yet little is known regarding roles of non-peri-tumoural lymphatic vessels (LVs) outside the tumour microenvironment that may impact relapse. The aim of this feasibility study was to assess whether inflammatory status of the LVs and/or changes in the miRNA profile of the LVs have potential prognostic and predictive value for overall outcome and risk of relapse. Samples of macroscopically normal human lymph LVs (n = 10) were isolated from the external iliac vessels draining the pelvic region of patients undergoing debulking surgery. This was followed by quantification of the inflammatory state (low, medium and high) and presence of cancer-infiltration of each LV using immunohistochemistry. LV miRNA expression profiling was also performed, and analysed in the context of high versus low inflammation, and cancer-infiltrated versus non-cancer-infiltrated. Results were correlated with clinical outcome data including relapse with an average follow-up time of 13.3 months. The presence of a high degree of inflammation correlated significantly with patient relapse (p = 0.033). Cancer-infiltrated LVs showed a moderate but non-significant association with relapse (p = 0.07). Differential miRNA profiles were identified in cancer-infiltrated LVs and those with high versus low inflammation. In particular, several members of the let-7 family were consistently down-regulated in highly inflamed LVs (>1.8-fold, p<0.05) compared to the less inflamed ones. Down-regulation of the let-7 family appears to be associated with inflammation, but whether inflammation contributes to or is an effect of cancer-infiltration requires further investigation.

Flaming the fight against cancer cells: the role of microRNA-93

There have been attempts to develop novel anti-tumor drugs in cancer therapy. Although satisfying results have been observed at a consequence of application of chemotherapeutic agents, the cancer cells are capable of making resistance into these agents. This has forced scientists into genetic manipulation as genetic alterations are responsible for generation of a high number of cancer cells. MicroRNAs (miRs) are endogenous, short non-coding RNAs that affect target genes at the post-transcriptional level. Increasing evidence reveals the potential role of miRs in regulation of biological processes including angiogenesis, metabolism, cell proliferation, cell division, and cell differentiation. Abnormal expression of miRs is associated with development of a number of pathologic events, particularly cancer. MiR-93 plays a significant role in both physiological and pathological mechanisms. At the present review, we show how this miR dually affects the proliferation and invasion of cancer cells. Besides, we elucidate the oncogenesis or oncosuppressor function of miR-93.

MK2206 Enhances Cisplatin-Induced Cytotoxicity and Apoptosis in Testicular Cancer Through Akt Signaling Pathway Inhibition

OBJECTIVE

To improve conventional chemotherapeutic efficacy, it is significant to identify novel molecular markers for chemosensitivity as well as possible molecules accelerating cell-killing mechanisms. In this study, we attempted to elucidate how MK2206, an allosteric Akt inhibitor, enhances the cisplatin (CDDP)-induced cytotoxicity and apoptosis in testicular cancer.

MATERIALS AND METHODS

We checked three testicular cancer cell lines for the expression of phospho(p)-Akt and its downstream molecules targets by Western blot. The potential antitumor effects were analyzed by MTT assay in vitro and by subcutaneous xenograft models in vivo. The cell invasion was analyzed by transwell invasion assay, and the activities of Akt signaling pathway and expression of apoptosis-related proteins were measured by Western blot.

RESULTS

Our results indicated that there was overactivation of p-Akt and its downstream molecules in testicular cancer cell lines compared with normal testis epithelium cells. MK2206 (600 nM) inhibited cell invasion in TCAM-2 and P19 cell lines and significantly increased the susceptibility of testicular cancer to CDDP. Combined with CDDP, MK2206 potentiated CDDP-induced cytotoxicity and apoptosis, with repressed expression of p-Akt and its downstream targets. The subcutaneous xenograft models also showed that a combined CDDP/MK2206 therapy completely suppressed tumor growth without any side effects.

CONCLUSION

These results suggested that the concomitant use of MK2206 could enhance the CDDP-induced cytotoxicity and apoptosis in testicular cancer with the suppressed expression of Akt pathway.

MiR-186 bidirectionally regulates cisplatin sensitivity of ovarian cancer cells via suppressing targets PIK3R3 and PTEN and upregulating APAF1 expression

Ovarian cancer is a highly lethal malignancy in the female reproductive system. Platinum drugs, represented by cisplatin, are the first-line chemotherapeutic agents for treatment of various malignancies including ovarian cancer, but drug resistance leads to chemotherapy failure. MicroRNAs emerged as promising molecules in reversal of cisplatin resistance. MiR-186 was reported to be downregulated in the cisplatin-resistant ovarian cell lines and miR-186 expression increased cisplatin sensitivity. However, we found the bidirectional regulatory effects of miR-186 on cisplatin sensitivity for the first time that overexpression of miR-186 at low concentration increased the cisplatin sensitivity of ovarian cancer cells A2780/DDP, while high concentration of miR-186 decreased the cisplatin sensitivity. The survival assay in other types of cancer cell lines verified the bidirectional regulatory function of miR-186 on cisplatin sensitivity in dose and cell type dependent manners. MiR-186 suppressed the protein levels of PTEN and PIK3R3 dose-dependently, which are opposite regulatory molecules of the oncogenic AKT pathway. MiR-186 also enhanced the protein levels of apoptotic gene APAF1 dose-dependently. We proposed the final effects of PTEN and APAF1 outweighed PIK3R3 when miR-186 at low concentration so as to increase the cisplatin sensitivity of ovarian cancer cells, while the final effects of PIK3R3 outweighed PTEN and APAF1 when miR-186 at high concentration so as to decrease the cisplatin sensitivity. We concluded the outcome of regulation of these opposite functional molecules contributed to the bidirectional regulatory effects of miR-186 in ovarian cancer cisplatin sensitivity. It deserves more attentions when developing therapeutic strategies based on the bidirectional functional miRNAs.

miR-106B-25 Cluster expression: a comparative human and canine osteosarcoma study

Background

Osteosarcoma (OS) is the most common primary malignant bone tumour in dogs and human beings, characterised by similar genetic and clinical features. With the aim to define similarities and differences in the biological aspects involved in OS progression, a comparative study was performed to create a model to improve patient outcome.

Methods

First, the expression of microRNAs (miRNAs) belonging to the cluster miR-106b-25 (miR-106b, miR-25 and miR-93-5p) in human and canine OS tissue was compared.

Results

miR-25 and miR-106b presented a variable expression not significantly different from the corresponding normal bone, while miR-93-5p expression was increased in all OS specimens, with higher levels in the canine subset compared with human. Accordingly, its target p21 presented a weaker and less homogeneous immunostaining distribution in the canine group. Given the high expression of miR-93-5p in all OS specimens, the functional response of human 143B and canine DAN OS cells to miRNA inhibition was evaluated. Although p21 expression increased after miR-93-5p inhibition both at mRNA and protein level, a more significant cell response in terms of proliferation and apoptosis was seen in canine OS cells.

Conclusions

In conclusion, canine OS tissue and cell line presented higher expression levels of miR-93-5p than human OS. In addition, the introduction of miR-93-5p inhibitor caused a cell response in 143B and DAN that differed for the more intense functional impact in the canine OS cell line.

miR-139 Controls Viability Of Ovarian Cancer Cells Through Apoptosis Induction And Exosome Shedding Inhibition By Targeting ATP7A

Background

Emerging proof suggests that microRNA (miRNA) malfunction is correlated to the generation and development of multiple malignancies. It has been proven that miRNA (miR)-139 represses a variety of malignancies. However, the understanding of its impact on ovarian cancer (OC) is insufficient. We aimed to investigate the expression and function of miR-139 in OC.

Methods

The expression of mir-139 was detected and recorded, and the relationship of mir-139 remaining OC cells was explored. At the same time, we studied the correlation between ATP7A and mir-139 by the luciferase reporter test, Western blot, and quantitative real-time reverse transcription PCR.

Results

The expression of miR-139 was remarkably downregulated in OC specimens. Furthermore, excessive miR-139 expression noticeably inhibited the migration, colony generation, proliferation, and invasion of OC cells. In addition, excessive miR-139 expression remarkably repressed the death and the expression of proteins related to cell death in OC cells, as well as inhibited the shedding of exosomes. According to the luciferase reporter test, Western blot, and quantitative real-time reverse transcription PCR, miR-139 directly targeted ATP7A. Furthermore, the expression of ATP7A was found to be negatively related to miR-139 levels in OC specimens. It was revealed via a rescue experiment that excessive ATP7A expression counteracted the repressive effect of miR-139 in OC cells.

Conclusion

It was revealed via an in vivo study that miR-139 remarkably inhibited the growth of malignancies by downregulating ATP7A in nude mice. miR-139 represses the development of malignancies in OC by directly targeting ATP7A, offering an innovative approach for molecular therapy of OC.

Cisplatin-resistant triple-negative breast cancer subtypes: multiple mechanisms of resistance

BACKGROUND

Understanding mechanisms underlying specific chemotherapeutic responses in subtypes of cancer may improve identification of treatment strategies most likely to benefit particular patients. For example, triple-negative breast cancer (TNBC) patients have variable response to the chemotherapeutic agent cisplatin. Understanding the basis of treatment response in cancer subtypes will lead to more informed decisions about selection of treatment strategies.

METHODS

In this study we used an integrative functional genomics approach to investigate the molecular mechanisms underlying known cisplatin-response differences among subtypes of TNBC. To identify changes in gene expression that could explain mechanisms of resistance, we examined 102 evolutionarily conserved cisplatin-associated genes, evaluating their differential expression in the cisplatin-sensitive, basal-like 1 (BL1) and basal-like 2 (BL2) subtypes, and the two cisplatin-resistant, luminal androgen receptor (LAR) and mesenchymal (M) subtypes of TNBC.

RESULTS

We found 20 genes that were differentially expressed in at least one subtype. Fifteen of the 20 genes are associated with cell death and are distributed among all TNBC subtypes. The less cisplatin-responsive LAR and M TNBC subtypes show different regulation of 13 genes compared to the more sensitive BL1 and BL2 subtypes. These 13 genes identify a variety of cisplatin-resistance mechanisms including increased transport and detoxification of cisplatin, and mis-regulation of the epithelial to mesenchymal transition.

CONCLUSIONS

We identified gene signatures in resistant TNBC subtypes indicative of mechanisms of cisplatin. Our results indicate that response to cisplatin in TNBC has a complex foundation based on impact of treatment on distinct cellular pathways. We find that examination of expression data in the context of heterogeneous data such as drug-gene interactions leads to a better understanding of mechanisms at work in cancer therapy response.

MicroRNA-152 suppresses cisplatin resistance in A549 cells

The present study aimed to investigate the association between microRNA-152 and cisplatin resistance in non-small cell lung cancer. A549 and cisplatin-resistant A549 cells (A549/cis) were maintained in vitro. Reverse transcription-quantitative PCR (RT-qPCR) was performed to analyze differences in microRNA-152 levels between A549 and A549/cis cells, and changes in Bcl-2 and NF-κB expression levels were analyzed via RT-qPCR and western blot analyses. MicroRNA-152 was overexpressed in A549/cis cells via transfection of a microRNA-152 mimic. Upon treating transfected or untransfected A549/cis cells with 2 µg/l cisplatin for 24 h, a Cell Counting Kit-8 assay, morphological analysis and flow cytometry analysis were performed to evaluate the effect of microRNA-152 on the inhibition of cell proliferation and induction of apoptosis. Furthermore, changes in Bcl-2 and NF-κB expression levels in microRNA-152-overexpressing A549/cis cells were also analyzed. MicroRNA-152 was significantly downregulated and Bcl-2 and NF-κB were significantly upregulated in A549/cis cells (P<0.05). MicroRNA-152 upregulation enhanced the inhibitory effect of cisplatin on A549/cis cells. These results suggest that microRNA-152 downregulates Bcl-2 and NF-κB. MicroRNA-152 downregulation may induce cisplatin resistance in non-small cell lung cancer cells, whereas microRNA-152 upregulation may improve cisplatin sensitivity among A549/cis cells via downregulation of Bcl-2 and NF-κB.

Network vulnerability-based and knowledge-guided identification of microRNA biomarkers indicating platinum resistance in high-grade serous ovarian cancer

Background

High-grade serous ovarian cancer (HGSC), the most common ovarian carcinoma type, is associated with the highest mortality rate among all gynecological malignancies. As chemoresistance has been demonstrated as the major challenge in improving the prognosis of HGSC patients, we here aimed to identify microRNA (miRNA) biomarkers for predicting platinum resistance and further explore their functions in HGSC.

Results

We developed and applied our network vulnerability-based and knowledge-guided bioinformatics model first time for the study of drug-resistance in cancer. Four miRNA biomarkers (miR-454-3p, miR-98-5p, miR-183-5p and miR-22-3p) were identified with potential in stratifying platinum-sensitive and platinum-resistant HGSC patients and predicting prognostic outcome. Among them, miR-454-3p and miR-183-5p were newly discovered to be closely implicated in platinum resistance in HGSC. Functional analyses highlighted crucial roles of the four miRNA biomarkers in platinum resistance through mediating transcriptional regulation, cell proliferation and apoptosis. Moreover, expression patterns of the miRNA biomarkers were validated in both platinum-sensitive and platinum-resistant ovarian cancer cells.

Conclusions

With bioinformatics modeling and analysis, we identified and confirmed four novel putative miRNA biomarkers, miR-454-3p, miR-98-5p, miR-183-5p and miR-22-3p that could serve as indicators of resistance to platinum-based chemotherapy, thereby contributing to the improvement of chemotherapeutic efficiency and optimization of personalized treatments in HGSC.

Correlation of plasma miR-21 and miR-93 with radiotherapy and chemotherapy efficacy and prognosis in patients with esophageal squamous cell carcinoma

BACKGROUND

Esophageal squamous cell carcinoma (ESCC) is one of the main causes of human death. It is usually already in middle or advanced stage when diagnosed due to its hidden symptoms in early stage. Therefore, patients have already lost the best surgical timing when diagnosed. Radiotherapy and chemotherapy are standard treatment methods for ESCC clinically, but the efficacy and prognosis of patients from them are still unsatisfactory. Therefore, it is of great clinical significance to seek for biomarkers that can predict the radiotherapy and chemotherapy response and prognosis of ESCC patients.

AIM

To explore the clinical value of plasma miR-21 and miR-93 in ESCC.

METHODS

A total of 128 ESCC patients admitted to the First Affiliated Hospital of Zhenzhou University were enrolled as a study group and treated with concurrent radiotherapy and chemotherapy, and other 45 healthy people during the same period were enrolled as a control group. The expression of plasma miR-21 and miR-93 was determined using quantitative real-time polymerase chain reaction, and the correlation of expression of plasma miR-21 and miR-93 with clinical pathological parameters about the patients was analyzed. The receiver operating characteristic (ROC) curve was adopted to assess the diagnostic value of plasma miR-21 and miR-93 for clinical pathological features of ESCC patients, the Logistic regression analysis adopted to analyze the risk factors for radiotherapy and chemotherapy efficacy in ESCC patients, and the Cox regression analysis to identify the prognostic factors for ESCC patients.

RESULTS

The study group showed significantly higher relative expression of plasma miR-21 and miR-93 than the control group (P < 0.01). The area under the ROC curve (AUC) of plasma miR-21 for diagnosing T stage, N stage, M stage, and pathological differentiation of ESCC was 0.819, 0.758, 0.824, and 0.725, respectively, and that of plasma miR-93 for diagnosing T stage, N stage, and M stage of ESCC was 0.827, 0.815, and 0.814, respectively. The AUC of combined plasma miR-21 and miR-93 for predicting radiotherapy and chemotherapy efficacy before radiotherapy and chemotherapy was 0.894, and the AUCs of them for predicting the 3-year overall survival (OS) were 0.861 and 0.807, respectively. T stage (P < 0.05), M stage (P < 0.05), miR-21(P < 0.01), and miR-93 (P < 0.05) were independent risk factors for radiotherapy and chemotherapy efficacy, and T stage (P < 0.01), N stage (P < 0.05), M stage (P < 0.01), miR-21 (P < 0.01), and miR-93 (P < 0.01) were independent prognostic factors for ESCC patients.

CONCLUSION

MiR-21 and miR-93 can be adopted as effective biomarkers for predicting radiotherapy and chemotherapy efficacy in ESCC and the 3-year OS of ESCC patients.

Role of the PI3K/AKT/mTOR signaling pathway in ovarian cancer: Biological and therapeutic significance

Ovarian cancer (OC) is a lethal gynecological cancer. The phosphatidylinositol 3-kinase (PI3K)/AKT/mammalian target of rapamycin (mTOR) signaling pathway plays an important role in the regulation of cell survival, growth, and proliferation. Irregularities in the major components of the PI3K/AKT/mTOR signaling pathway are common in human cancers. Despite the availability of strong pre-clinical and clinical data of PI3K/AKT/mTOR pathway inhibitors in OC, there is no FDA approved inhibitor available for the treatment of OC. Here, we outline the importance of PI3K/AKT/mTOR signaling pathway in OC tumorigenesis, proliferation and progression, and pre-clinical and clinical experience with several PI3K/AKT/mTOR pathway inhibitors in OC.

Deregulation of lncRNA-AC078883.3 and microRNA-19a is involved in the development of chemoresistance to cisplatin via modulating signaling pathway of PTEN/AKT

Non-small cell lung cancer (NSCLC) remains the leading cause of cancer death worldwide. As a platinum-based chemotherapeutic drug, cisplatin has been used in the NSCLC treatment for over 30 years, and its effects are impaired by drug resistance. This study aimed to investigate the potential role of lncRNA-AC078883.3 in the development of chemoresistance against cisplatin. Real-time PCR, Western blot analysis, Immunohistochemistry (IHC) assay, bioinformatic analysis, and luciferase assay were collaboratively used to establish the lncRNA-AC078883.3/miR-19a/PTEN/AKT pathway. Also, the effect of cisplatin on cell proliferation was observed via an MTT assay. Furthermore, Cox regression and Kaplan-Meier analyses were used to study whether lncRNA-AC078883.3 is involved in the survival of NSCLC. Compared with the Cisplatin-Sensitive group, the Cisplatin-Resistance group exhibited lower levels of lncRNA-AC078883.3 and PTEN and higher levels of miR-19a and p-Akt. The growth rate of A549 and H460 cells and the IC ₅₀ of DPP in the Cisplatin-Resistance group were higher than those in the Cisplatin-S group. miR-19a contains a putative binding site of lncRNA-AC078883.3, which enabled the luciferase activity of wild-type lncRNA-AC078883.3 to be reduced by miR-19a. In addition, by directly targeting PTEN 3'-untranslated region (UTR), miR-19a repressed the luciferase activity of wild-type PTEN 3'-UTR. The median OS of patients with reduced lncRNA-AC078883.3 expression was longer than that of patients with higher lncRNA-AC078883.3 expression. Finally, compared with low lncRNA-AC078883.3-expression patients, the high lncRNA-AC078883.3-expression patients were associated with lower miR-19a expression and higher PTEN expression. Therefore, we suggested for the first time that the low expression of lncRNA-AC078883.3 contributed to the development of chemoresistance against cisplatin.

Micromanaging aerobic respiration and glycolysis in cancer cells

BACKGROUND

Cancer cells possess a common metabolic phenotype, rewiring their metabolic pathways from mitochondrial oxidative phosphorylation to aerobic glycolysis and anabolic circuits, to support the energetic and biosynthetic requirements of continuous proliferation and migration. While, over the past decade, molecular and cellular studies have clearly highlighted the association of oncogenes and tumor suppressors with cancer-associated glycolysis, more recent attention has focused on the role of microRNAs (miRNAs) in mediating this metabolic shift. Accumulating studies have connected aberrant expression of miRNAs with direct and indirect regulation of aerobic glycolysis and associated pathways.

SCOPE OF REVIEW

This review discusses the underlying mechanisms of metabolic reprogramming in cancer cells and provides arguments that the earlier paradigm of cancer glycolysis needs to be updated to a broader concept, which involves interconnecting biological pathways that include miRNA-mediated regulation of metabolism. For these reasons and in light of recent knowledge, we illustrate the relationships between metabolic pathways in cancer cells. We further summarize our current understanding of the interplay between miRNAs and these metabolic pathways. This review aims to highlight important metabolism-associated molecular components in the hunt for selective preventive and therapeutic treatments.

MAJOR CONCLUSIONS

Metabolism in cancer cells is influenced by driver mutations but is also regulated by posttranscriptional gene silencing. Understanding the nuanced regulation of gene expression in these cells and distinguishing rapid cellular responses from chronic adaptive mechanisms provides a basis for rational drug design and novel therapeutic strategies.

Preventive Effect of the Herbal Preparation, HemoHIM, on Cisplatin-Induced Immune Suppression

We determined the functional effect of the herbal preparation, HemoHIM, on the immune system, by examining the immunomodulatory activities of HemoHIM using immunocompromised mice. In this study, to examine the effect on the restoration of immune cells and balance in the immune system, we utilized a cisplatin-induced immunosuppression mouse model. Mice were injected intraperitoneally with cisplatin, an immunosuppressive anticancer, and then received oral doses of 100, 250, and 500 mg/kg of HemoHIM for 14 days. The HemoHIM prevented the cisplatin-induced loss of body and organ weight. In terms of innate immunity, natural killer (NK) cell activity and phagocytosis increased in the HemoHIM group compared to the cisplatin control group. The HemoHIM group also showed a significantly higher expression of Th1-mediated cytokines (interferon gamma (IFN-γ), interleukin-2 (IL-2), and tumor necrosis factor alpha (TNF-α)) and inhibited the production of Th2-mediated cytokine interleukin-4 (IL-4) compared to cisplatin control group. These findings indicate that HemoHIM enhances immune activity by modulating immune cell activity and cytokine secretion in immune-suppressed mice.

Downregulation of microRNA-23b protects against ischemia-reperfusion injury via p53 signaling pathway by upregulating MDM4 in rats

Total knee arthroplasty is a commonly performed safe procedure and typically executed in severe knee arthritis, but it also triggers ischemia-reperfusion injury (IRI). More recently, microRNAs (miRs) have been reported to play a contributory role in IRI through the key signaling pathway. Hence, the current study aimed to investigate the effect and specific mechanism of microRNA-23b (miR-23b), murine double minute 4 (MDM4), and the p53 signaling pathway in IRI rat models. First, the IRI model was established, and the expression pattern of miR-23b, MDM4, and the p53 signaling pathway-related genes was characterized in cartilaginous tissues. Then, miR-23b mimics or inhibitors were applied for the elevation or the depletion of the miR-23b expression and siRNA-MDM4 for the depletion of the MDM4 expression in the articular chondrocytes. By means of immunohistochemistry, quantitative real-time polymerase chain reaction, and Western blot analysis, IRI rats exhibited increased miR-23b expression, activated p53 signaling pathway, and decreased MDM4 expression. MDM4 was verified as a target gene of miR-23b through. Downregulated miR-23b increased the expression of MDM4, AKT, and Bcl-2, but decreased the expression of p53, p21, and Bax. In addition, a series of cell experiments demonstrated that downregulated miR-23b promoted articular chondrocyte proliferation and cell cycle entry, but inhibited articular chondrocyte apoptosis. The absence of the effects of miR-23b was observed after MDM4 knocked down. Our results indicate that silencing miR-23b could act to attenuate IRI and reduce the apoptosis of articular chondrocytes through inactivation of the p53 signaling pathway by upregulating MDM4, which provide basic therapeutic considerations for a novel target against IRI.

Cycling Quiescence in Temozolomide Resistant Glioblastoma Cells Is Partly Explained by microRNA-93 and -193-Mediated Decrease of Cyclin D

Glioblastoma multiforme (GBM) is a fatal malignancy of the central nervous system, commonly associated with chemoresistance. The alkylating agent Temozolomide (TMZ) is the front-line chemotherapeutic agent and has undergone intense studies on resistance. These studies reported on mismatch repair gene upregulation, ABC-targeted drug efflux, and cell cycle alterations. The mechanism by which TMZ induces cell cycle arrest has not been well-established. TMZ-resistant GBM cells have been linked to microRNA (miRNA) and exosomes. A cell cycle miRNA array identified distinct miRNAs only in exosomes from TMZ-resistant GBM cell lines and primary spheres. We narrowed the miRs to miR-93 and -193 and showed in computational analyses that they could target Cyclin D1. Since Cyclin D1 is a major regulator of cell cycle progression, we performed cause-effect studies and showed a blunting effects of miR-93 and -193 in Cyclin D1 expression. These two miRs also decreased cell cycling quiescence and induced resistance to TMZ. Taken together, our data provide a mechanism by which GBM cells can exhibit TMZ-induced resistance through miRNA targeting of Cyclin D1. The data provide a number of therapeutic approaches to reverse chemoresistance at the miRNA, exosomal and cell cycle points.

The role and mechanisms of action of microRNAs in cancer drug resistance

MicroRNAs (miRNAs) are small non-coding RNAs with a length of about 19–25 nt, which can regulate various target genes and are thus involved in the regulation of a variety of biological and pathological processes, including the formation and development of cancer. Drug resistance in cancer chemotherapy is one of the main obstacles to curing this malignant disease. Statistical data indicate that over 90% of the mortality of patients with cancer is related to drug resistance. Drug resistance of cancer chemotherapy can be caused by many mechanisms, such as decreased antitumor drug uptake, modified drug targets, altered cell cycle checkpoints, or increased DNA damage repair, among others. In recent years, many studies have shown that miRNAs are involved in the drug resistance of tumor cells by targeting drug-resistance-related genes or influencing genes related to cell proliferation, cell cycle, and apoptosis. A single miRNA often targets a number of genes, and its regulatory effect is tissue-specific. In this review, we emphasize the miRNAs that are involved in the regulation of drug resistance among different cancers and probe the mechanisms of the deregulated expression of miRNAs. The molecular targets of miRNAs and their underlying signaling pathways are also explored comprehensively. A holistic understanding of the functions of miRNAs in drug resistance will help us develop better strategies to regulate them efficiently and will finally pave the way toward better translation of miRNAs into clinics, developing them into a promising approach in cancer therapy.