miR-125b regulates the drug-resistance of breast cancer cells to doxorubicin by targeting HAX-1

Non-coding RNA transcripts, incredible modulators of cisplatin chemo-resistance in bladder cancer through operating a broad spectrum of cellular processes and signaling mechanism

Bladder cancer (BC) is a highly frequent neoplasm in correlation with significant rate of morbidity, mortality, and cost. The onset of BC is predominantly triggered by environmental and/or occupational exposures to carcinogens, such as tobacco. There are two distinct pathways by which BC can be developed, including non-muscle-invasive papillary tumors (NMIBC) and non-papillary (or solid) muscle-invasive tumors (MIBC). The Cancer Genome Atlas project has further recognized key genetic drivers of MIBC along with its subtypes with particular properties and therapeutic responses; nonetheless, NMIBC is the predominant BC presentation among the suffering individuals. Radical cystoprostatectomy, radiotherapy, and chemotherapy have been verified to be the common therapeutic interventions in metastatic tumors, among which chemotherapeutics are more conventionally utilized. Although multiple chemo drugs have been broadly administered for BC treatment, cisplatin is reportedly the most effective chemo drug against the corresponding malignancy. Notwithstanding, tumor recurrence is usually occurred following the consumption of cisplatin regimens, particularly due to the progression of chemo-resistant trait. In this framework, non-coding RNAs (ncRNAs), as abundant RNA transcripts arise from the human genome, are introduced to serve as crucial contributors to tumor expansion and cisplatin chemo-resistance in bladder neoplasm. In the current review, we first investigated the best-known ncRNAs, i.e. microRNAs (miRNAs), long ncRNAs (lncRNAs), and circular RNAs (circRNAs), correlated with cisplatin chemo-resistance in BC cells and tissues. We noticed that these ncRNAs could mediate the BC-related cisplatin-resistant phenotype through diverse cellular processes and signaling mechanisms, reviewed here. Eventually, diagnostic and prognostic potential of ncRNAs, as well as their therapeutic capabilities were highlighted in regard to BC management.

miR-125b reverses cisplatin resistance by regulating autophagy via targeting RORA/BNIP3L axis in lung adenocarcinoma

The platinum-based chemotherapy is one of the most frequently used treatment protocols for lung adenocarcinoma (LUAD), and chemoresistance, however, usually results in treatment failure and limits its application in the clinic. It has been shown that microRNAs (miRNAs) play a significant role in tumor chemoresistance. In this study, miR-125b was identified as a specific cisplatin (DDP)-resistant gene in LUAD, as indicated by the bioinformatics analysis and the real-time quantitative PCR assay. The decreased serum level of miR-125b in LUAD patients was correlated with the poor treatment response rate and short survival time. MiR-125b decreased the A549/DDP proliferation, and the multiple drug resistance- and autophagy-related protein expression levels, which were all reversed by the inhibition of miR-125b. In addition, xenografts of human tumors in nude mice were suppressed by miR-125b, demonstrating that through autophagy regulation, miR-125b could reverse the DDP resistance in LUAD cells, both in vitro and in vivo. Further mechanistic studies indicated that miR-125b directly repressed the expression levels of RORA and its downstream BNIP3L, which in turn inhibited autophagy and reversed chemoresistance. Based on these findings, miR-125b in combination with DDP might be an effective treatment option to overcome DDP resistance in LUAD.

miRNAs as short non-coding RNAs in regulating doxorubicin resistance

The treatment of cancer patients has been prohibited by chemoresistance. Doxorubicin (DOX) is an anti-tumor compound disrupting proliferation and triggering cell cycle arrest via inhibiting activity of topoisomerase I and II. miRNAs are endogenous RNAs localized in cytoplasm to reduce gene level. Abnormal expression of miRNAs changes DOX cytotoxicity. Overexpression of tumor-promoting miRNAs induces DOX resistance, while tumor-suppressor miRNAs inhibit DOX resistance. The miRNA-mediated regulation of cell death and hallmarks of cancer can affect response to DOX chemotherapy in tumor cells. The transporters such as P-glycoprotein are regulated by miRNAs in DOX chemotherapy. Upstream mediators including lncRNAs and circRNAs target miRNAs in affecting capacity of DOX. The response to DOX chemotherapy can be facilitated after administration of agents that are mostly phytochemicals including curcumol, honokiol and ursolic acid. These agents can regulate miRNA expression increasing DOX's cytotoxicity. Since delivery of DOX alone or in combination with other drugs and genes can cause synergistic impact, the nanoparticles have been introduced for drug sensitivity. The non-coding RNAs determine the response of tumor cells to doxorubicin chemotherapy. microRNAs play a key role in this case and they can be sponged by lncRNAs and circRNAs, showing interaction among non-coding RNAs in the regulation of doxorubicin sensitivity.

A vicious circle in breast cancer: The interplay between inflammation, reactive oxygen species, and microRNAs

Breast cancer (BC) is the most common cancer in women worldwide. This highly heterogeneous disease is molecularly stratified into luminal A, luminal B, HER2, triple-negative/basal-like, and normal-like subtypes. An important aspect in BC progression is the activation of inflammatory processes. The activation of CD8+/Th1, NK, and M1 tumor associated macrophages (TAMs), leads to tumor destruction. In contrast, an anti-inflammatory response mediated by CD4+/Th2 and M2 TAMs will favor tumor progression. Inflammation also stimulates the production of inflammatory mediators like reactive oxygen species (ROS). In chronic inflammation, ROS activates oxidative stress and endothelial dysfunction. In cancer, ROS plays a dual role with anti-tumorigenic and pro-tumorigenic effects in cell signaling pathways that control proliferation, survival, apoptosis, and inflammation. MicroRNAs (miRNAs), which are known to be involved in BC progression and inflammation, can be regulated by ROS. At the same time, miRNAs regulate the expression of genes modulating oxidative stress. In this review, we will discuss the interplay between inflammation, ROS, and miRNAs as anticancer and tumor promoter molecules in BC. A clear understanding of the role of miRNAs in the regulation of ROS production and inflammation, may lead to new opportunities for therapy in BC.

Effect of Nanoparticles of DOX and miR-125b on DNA Damage Repair in Glioma U251 Cells and Underlying Mechanisms

Glioma is the most common primary craniocerebral malignant tumor, arising from the canceration of glial cells in the brain and spinal cord. The quality of life and prognosis of patients with this disease are still poor. Doxorubicin (DOX) is one of the most traditional and economical chemotherapeutic drugs for the treatment of glioma, but its toxic effect on normal cells and the resistance of tumor cells to DOX make the application of DOX in the treatment of glioma gradually less effective. To solve this problem, we co-encapsulated DOX and endogenous tumor suppressor miR-125b into nanoparticles (NPs) by nanoprecipitation methods, and passively targeted them into glioma cells. In vitro experiments show that miR-125b and DOX can be effectively encapsulated into nanoparticles with different ratios, and by targeting YES proto-oncogene 1 (YES1), they can affect the adenosine 5′-monophosphate (AMP)-activated protein kinase (AMPK)/p53 pathway and induce brain glioma cell apoptosis. They can also affect the DNA damage repair process and inhibit cell proliferation. The obtained data suggest that co-delivery of DOX and miR-125b could achieve synergistic effects on tumor suppression. Nanosystem-based co-delivery of tumor suppressive miRNAs and chemotherapeutic agents may be a promising combined therapeutic strategy for enhanced anti-tumor therapy.

Evaluating the role of propolis and bee venom on the oxidative stress induced by gamma rays in rats

Honeybee products consist of many substances, which have long been known for their medicinal and health-promoting properties. This study set out to appraise the protective potential of Egyptian propolis (EP) and bee venom (BV) separately or combined against total body irradiation (TBI) induced oxidative injury in rats. Besides, we assessed the bioactive components in EP and BV using HPLC and UPLC/ ESI-MS analysis in the positive ion mode. The animals were subjected to a source of gamma ionizing radiation at a dose of 6 Gy. Propolis and BV were administered independently and in combination before 14 days of γ-irradiation. Liver and kidney functions were estimated besides, DNA damage index (8- OHdG) by ELISA. Antioxidants, including glutathione (GSH), catalase (CAT), superoxide dismutase (SOD), and glutathione peroxidase (GPx) were detected. Gene expression technique investigated for BAX, BCL2, and in plasma also miR125b expression in serum of rats. Besides, the histopathological for the brain, liver, kidney, and heart were investigated. In addition, lipid peroxidation was investigated in plasma and in the previous organs. The present results provide opportunities to advance the use of bee products as promising medicinal sources.

The Role of MicroRNAs in Mitochondria-Mediated Eye Diseases

The retina is among the most metabolically active tissues with high-energy demands. The peculiar distribution of mitochondria in cells of retinal layers is necessary to assure the appropriate energy supply for the transmission of the light signal. Photoreceptor cells (PRs), retinal pigment epithelium (RPE), and retinal ganglion cells (RGCs) present a great concentration of mitochondria, which makes them particularly sensitive to mitochondrial dysfunction. To date, visual loss has been extensively correlated to defective mitochondrial functions. Many mitochondrial diseases (MDs) show indeed neuro-ophthalmic manifestations, including retinal and optic nerve phenotypes. Moreover, abnormal mitochondrial functions are frequently found in the most common retinal pathologies, i.e., glaucoma, age-related macular degeneration (AMD), and diabetic retinopathy (DR), that share clinical similarities with the hereditary primary MDs. MicroRNAs (miRNAs) are established as key regulators of several developmental, physiological, and pathological processes. Dysregulated miRNA expression profiles in retinal degeneration models and in patients underline the potentiality of miRNA modulation as a possible gene/mutation-independent strategy in retinal diseases and highlight their promising role as disease predictive or prognostic biomarkers. In this review, we will summarize the current knowledge about the participation of miRNAs in both rare and common mitochondria-mediated eye diseases. Definitely, given the involvement of miRNAs in retina pathologies and therapy as well as their use as molecular biomarkers, they represent a determining target for clinical applications.

Advances in Understanding Mitochondrial MicroRNAs (mitomiRs) on the Pathogenesis of Triple-Negative Breast Cancer (TNBC)

Triple-negative breast cancer (TNBC) is characterized by poor outcome and the most challenging breast cancer type to treat worldwide. TNBC manifests distinct profile of mitochondrial functions, which dictates reprogrammed metabolism, fosters tumor progression, and notably serves as therapeutic targets. Mitochondrial microRNAs (mitomiRs) are a group of microRNAs that critically modulate mitochondrial homeostasis. By a pathway-centric manner, mitomiRs tightly orchestrate metabolic reprogramming, redox status, cell apoptosis, mitochondrial dynamics, mitophagy, mitochondrial DNA (mtDNA) maintenance, and calcium balance, leading to an emerging field of study in various cancer types, including TNBC. We herein review the recent insights into the roles and mechanism of mitomiRs in TNBC and highlight its clinical value in diagnosis and prognosis as well as vital advances on therapeutics of preclinical and clinical studies.

Mitochondrial microRNA (MitomiRs) in cancer and complex mitochondrial diseases: current status and future perspectives

Mitochondria are not only important for cellular bioenergetics but also lie at the heart of critical metabolic pathways. They can rapidly adjust themselves in response to changing conditions and the metabolic needs of the cell. Mitochondrial involvement as well as its dysfunction has been found to be associated with variety of pathological processes and diseases. mitomiRs are class of miRNA(s) that regulate mitochondrial gene expression and function. This review sheds light on the role of mitomiRs in regulating different biological processes-mitochondrial dynamics, oxidative stress, cell metabolism, chemoresistance, apoptosis,and their relevance in metabolic diseases, neurodegenerative disorders, and cancer. Insilico analysis of predicted targets of mitomiRs targeting energy metabolism identified several significantly altered pathways (needs in vivo validations) that may provide a new therapeutic approach for the treatment of human diseases. Last part of the review discusses about the clinical aspects of miRNA(s) and mitomiRs in Medicine.

Essential functions of miR-125b in cancer

MicroRNAs (miRNAs) are small and highly conserved non-coding RNAs that silence target mRNAs, and compelling evidence suggests that they play an essential role in the pathogenesis of human diseases, especially cancer. miR-125b, which is the mammalian orthologue of the first discovered miRNA lin-4 in Caenorhabditis elegans, is one of the most important miRNAs that regulate various physiological and pathological processes. The role of miR-125b in many types of cancer has been well established, and so here we review the current knowledge of how miR-125b is deregulated in different types of cancer; its oncogenic and/or tumour-suppressive roles in tumourigenesis and cancer progression; and its regulation with regard to treatment response, all of which are underlined in multiple studies. The emerging information that elucidates the essential functions of miR-125b might help support its potentiality as a diagnostic and prognostic biomarker as well as an effective therapeutic tool against cancer.

Connecting the Missing Dots: ncRNAs as Critical Regulators of Therapeutic Susceptibility in Breast Cancer

Whether acquired or de novo, drug resistance remains a significant hurdle in achieving therapeutic success in breast cancer (BC). Thus, there is an urge to find reliable biomarkers that will help in predicting the therapeutic response. Stable and easily accessible molecules such as microRNAs (miRNAs) and long non-coding RNAs (lncRNAs) are regarded as valuable prognostic biomarkers and therapeutic targets since they act as crucial regulators of the various mechanisms involved in BC drug resistance. Here, we reviewed the current literature on ncRNAs as mediators of resistance to systemic therapies in BC. Interestingly, upon integrating data results from individual studies, we concluded that miR-221, miR-222, miR-451, Urothelial Carcinoma Associated 1 (UCA1), and Growth arrest-specific 5 (GAS5) are strong candidates as prognostic biomarkers and therapeutic targets since they are regulating multiple drug resistance phenotypes in BC. However, further research around their clinical implications is needed to validate and integrate them into therapeutic applications. Therefore, we believe that our review may provide relevant evidence for the selection of novel therapeutic targets and prognostic biomarkers for BC and will serve as a foundation for future translational research in the field.

The Role of Non-Coding RNAs as Prognostic Factor, Predictor of Drug Response or Resistance and Pharmacological Targets, in the Cutaneous Squamous Cell Carcinoma

Cutaneous squamous cell carcinoma (CSCC) is the most common keratinocyte-derived skin cancer in the Caucasian population. Exposure to UV radiations (UVRs) represents the main risk carcinogenesis, causing a considerable accumulation of DNA damage in epidermal keratinocytes with an uncontrolled hyperproliferation and tumor development. The limited and rarely durable response of CSCC to the current therapeutic options has led researchers to look for new therapeutic strategies. Recently, the multi-omics approaches have contributed to the identification and prediction of the key role of non-coding RNAs (ncRNAs), such as microRNAs (miRNAs), circularRNAs (circRNAs) and long non-coding RNAs (lncRNAs) in the regulation of several cellular processes in different tumor types, including CSCC. ncRNAs can modulate transcriptional and post-transcriptional events by interacting either with each other or with DNA and proteins, such as transcription factors and RNA-binding proteins. In this review, the implication of ncRNAs in tumorigenesis and their potential role as diagnostic biomarkers and therapeutic targets in human CSCC are reported.

The Regulatory Role of Mitochondrial MicroRNAs (MitomiRs) in Breast Cancer: Translational Implications Present and Future

Simple Summary

Mitochondrial microRNAs (mitomiRs) are an emerging field of study in a wide range of tumours including breast cancer. By targeting mitochondrial, or non-mitochondrial products, mitomiRs are able to regulate the functions of this organelle, thus controlling multiple carcinogenic processes. The knowledge of this system may provide a novel approach for targeted therapies, as potential biomarkers or helping in the diagnosis of such a complex malignancy.

Abstract

Breast cancer is the most prevalent and incident female neoplasm worldwide. Although survival rates have considerably improved, it is still the leading cause of cancer-related mortality in women. MicroRNAs are small non-coding RNA molecules that regulate the posttranscriptional expression of a wide variety of genes. Although it is usually located in the cytoplasm, several studies have detected a regulatory role of microRNAs in other cell compartments such as the nucleus or mitochondrion, known as “mitomiRs”. MitomiRs are essential modulators of mitochondrion tasks and their abnormal expression has been linked to the aetiology of several human diseases related to mitochondrial dysfunction, including breast cancer. This review aims to examine basic knowledge of the role of mitomiRs in breast cancer and discusses their prospects as biomarkers or therapeutic targets.

Downregulation of miR-125b promotes resistance of glioma cells to TRAIL through overexpression of Tafazzin which is a mitochondrial protein

Overexpression of Tafazzin (TAZ), a mitochondrial protein, is often observed in many cancers. However, the association between aberrant expression of TAZ and drug resistance remains unclear. The aim of this study is to explore the role of TAZ in regulating the TRAIL resistance in glioma. We thus established the TRAIL resistance models on glioma by using the U87 and U251 cell lines (U87/R and U251/R). As the results, obvious overexpression of TAZ was observed in U87/R and U251/R cells. However, knockdown of TAZ increased the sensitivity of U87/R and U251/R cells to TRAIL-induced apoptosis. By contrast, expression of miR-125b was downregulated in U87/R and U251/R cells compared to the parental U87 and U251 cells. Furthermore, decrease of miR-125b was responsible for overexpression of TAZ, because the results of dual-luciferase reporter assays verified that TAZ was targeted by miR-125b. We then showed that enforced expression of miR-125b resensitized the U87/R and U251/R cells to TRAIL-dependent damage of mitochondria and activation of caspase-9 and -3. We demonstrated that overexpression of TAZ caused by downregulation of miR-125b promoted resistance of glioma cells to TRAIL. MiR-125b/TAZ axis may represent a potential strategy to reverse the TRAIL in glioma.

miRNA Regulation of Glutathione Homeostasis in Cancer Initiation, Progression and Therapy Resistance

Glutathione (GSH) is the most abundant antioxidant that contributes to regulating the cellular production of Reactive Oxygen Species (ROS) which, maintained at physiological levels, can exert a function of second messengers in living organisms. In fact, it has been demonstrated that moderate amounts of ROS can activate the signaling pathways involved in cell growth and proliferation, while high levels of ROS induce DNA damage leading to cancer development. Therefore, GSH is a crucial player in the maintenance of redox homeostasis and its metabolism has a role in tumor initiation, progression, and therapy resistance. Our recent studies demonstrated that neuroblastoma cells resistant to etoposide, a common chemotherapeutic drug, show a partial monoallelic deletion of the locus coding for miRNA 15a and 16-1 leading to a loss of these miRNAs and the activation of GSH-dependent responses. Therefore, the aim of this review is to highlight the role of specific miRNAs in the modulation of intracellular GSH levels in order to take into consideration the use of modulators of miRNA expression as a useful strategy to better sensitize tumors to current therapies.

HAX1 impact on collective cell migration, cell adhesion, and cell shape is linked to the regulation of actomyosin contractility

HAX1 protein is involved in the regulation of apoptosis, cell motility and calcium homeostasis. Its overexpression was reported in several tumors, including breast cancer. This study demonstrates that HAX1 has an impact on collective, but not single-cell migration, thus indicating the importance of cell–cell contacts for the HAX1-mediated effect. Accordingly, it was shown that HAX1 knockdown affects cell–cell junctions, substrate adhesion, and epithelial cell layer integrity. As demonstrated here, these effects can be attributed to the modulation of actomyosin contractility through changes in RhoA and septin signaling. Additionally, it was shown that HAX1 does not influence invasive potential in the breast cancer cell line, suggesting that its role in breast cancer progression may be linked instead to collective invasion of the epithelial cells but not single-cell dissemination.

MicroRNA and Oxidative Stress Interplay in the Context of Breast Cancer Pathogenesis

Oxidative stress is a pathological condition determined by a disturbance in reactive oxygen species (ROS) homeostasis. Depending on the entity of the perturbation, normal cells can either restore equilibrium or activate pathways of cell death. On the contrary, cancer cells exploit this phenomenon to sustain a proliferative and aggressive phenotype. In fact, ROS overproduction or their reduced disposal influence all hallmarks of cancer, from genome instability to cell metabolism, angiogenesis, invasion and metastasis. A persistent state of oxidative stress can even initiate tumorigenesis. MicroRNAs (miRNAs) are small non coding RNAs with regulatory functions, which expression has been extensively proven to be dysregulated in cancer. Intuitively, miRNA transcription and biogenesis are affected by the oxidative status of the cell and, in some instances, they participate in defining it. Indeed, it is widely reported the role of miRNAs in regulating numerous factors involved in the ROS signaling pathways. Given that miRNA function and modulation relies on cell type or tumor, in order to delineate a clearer and more exhaustive picture, in this review we present a comprehensive overview of the literature concerning how miRNAs and ROS signaling interplay affects breast cancer progression.

Clinical Theragnostic Relationship between Drug-Resistance Specific miRNA Expressions, Chemotherapeutic Resistance, and Sensitivity in Breast Cancer: A Systematic Review and Meta-Analysis

Awareness of breast cancer has been increasing due to early detection, but the advanced disease has limited treatment options. There has been growing evidence on the role of miRNAs involved in regulating the resistance in several cancers. We performed a comprehensive systematic review and meta-analysis on the role of miRNAs in influencing the chemoresistance and sensitivity of breast cancer. A bibliographic search was performed in PubMed and Science Direct based on the search strategy, and studies published until December 2018 were retrieved. The eligible studies were included based on the selection criteria, and a detailed systematic review and meta-analysis were performed based on PRISMA guidelines. A random-effects model was utilised to evaluate the combined effect size of the obtained hazard ratio and 95% confidence intervals from the eligible studies. Publication bias was assessed with Cochran’s Q test, I² statistic, Orwin and Classic fail-safe N test, Begg and Mazumdar rank correlation test, Duval and Tweedie trim and fill calculation and the Egger’s bias indicator. A total of 4584 potential studies were screened. Of these, 85 articles were eligible for our systematic review and meta-analysis. In the 85 studies, 188 different miRNAs were studied, of which 96 were upregulated, 87 were downregulated and 5 were not involved in regulation. Overall, 24 drugs were used for treatment, with doxorubicin being prominently reported in 15 studies followed by Paclitaxel in 11 studies, and 5 drugs were used in combinations. We found only two significant HR values from the studies (miR-125b and miR-4443) and our meta-analysis results yielded a combined HR value of 0.748 with a 95% confidence interval of 0.508–1.100; p-value of 0.140. In conclusion, our results suggest there are different miRNAs involved in the regulation of chemoresistance through diverse drug genetic targets. These biomarkers play a crucial role in guiding the effective diagnostic and prognostic efficiency of breast cancer. The screening of miRNAs as a theragnostic biomarker must be brought into regular practice for all diseases. We anticipate that our study serves as a reference in framing future studies and clinical trials for utilising miRNAs and their respective drug targets.

MiR-125b-5p suppresses the bladder cancer progression via targeting HK2 and suppressing PI3K/AKT pathway

Bladder cancer (BCa) is identified as the most common malignant solid cancer in the urogenital tract. Recently, dysregulation of miRNAs has received more attention because of its extensive role in the carcinogenesis of BCa. This research was designed to verify how miR-125b-5p be involved in BCa development. The expression of miR-125b-5p was detected in 52 pairs of BCa specimens and adjacent normal bladder specimens. The effects of miR-125b-5p on BCa viability, migration, and apoptosis in vitro were examined. We then examined directly target gene(s) of miR-125b-5p in BCa cells. Our data demonstrated that miR-125b-5p was decreased in BCa tissues and cell lines. Patients with low miR-125b-5p expression had obviously shorter 5-year survival time. Lower miR-125b-5p expression was significant correlated with distant metastasis, tumor size and lymph node metastasis. Ectopic expression of miR-125b-5p inhibited the BCa cell viability and migration and induced cell apoptosis. Furthermore, HK2 was confirmed regulated by miR-125b-5p. HK2 recovered miR-125b-5p-mediated suppression of BCa cell viability and migration. In addition, miR-125b-5p also exhibited suppressive effect on PI3K/AKT pathway. Overall, these data indicate that miR-125b-5p played a role in the suppressive effect on BCa by targeting HK2 through suppressing PI3K/AKT pathway and offer a potential therapeutic target for BCa.

Inhibiting PAD2 enhances the anti-tumor effect of docetaxel in tamoxifen-resistant breast cancer cells

BACKGROUND

Tamoxifen resistance presents a huge clinical challenge for breast cancer patients. An understanding of the mechanisms of tamoxifen resistance can guide development of efficient therapies to prevent drug resistance.

METHODS

We first tested whether peptidylarginine deiminase 2 (PAD2) may be involved in tamoxifen-resistance in breast cancer cells. The effect of depleting or inhibiting PAD2 in tamoxifen-resistant MCF-7 (MCF7/TamR) cells was evaluated both in vitro and in vivo. We then investigated the potential of Cl-amidine, a PAD inhibitor, to be used in combination with tamoxifen or docetaxel, and further explored the mechanism of the synergistic and effective drug regimen of PADs inhibitor and docetaxel on tamoxifen-resistant breast cancer cells.

RESULTS

We report that PAD2 is dramatically upregulated in tamoxifen-resistant breast cancer. Depletion of PAD2 in MCF7/TamR cells facilitated the sensitivity of MCF7/TamR cells to tamoxifen. Moreover, miRNA-125b-5p negatively regulated PAD2 expression in MCF7/TamR cells, therefore overexpression of miR-125b-5p also increased the cell sensitivity to tamoxifen. Furthermore, inhibiting PAD2 with Cl-amidine not only partially restored the sensitivity of MCF7/TamR cells to tamoxifen, but also more efficiently enhanced the efficacy of docetaxel on MCF7/TamR cells with lower doses of Cl-amidine and docetaxel both in vivo and in vivo. We then showed that combination treatment with Cl-amidine and docetaxel enhanced p53 nuclear accumulation, which synergistically induced cell cycle arrest and apoptosis. Meanwhile, p53 activation in the combination treatment also accelerated autophagy processes by synergistically decreasing the activation of Akt/mTOR signaling, thus enhancing the inhibition of proliferation.

CONCLUSION

Our results suggest that PAD2 functions as an important new biomarker for tamoxifen-resistant breast cancers and that inhibiting PAD2 combined with docetaxel may offer a new approach to treatment of tamoxifen-resistant breast cancers.

miRNA expression changes during the course of neoadjuvant bevacizumab and chemotherapy treatment in breast cancer

One of the hallmarks of cancer is sustained angiogenesis. Favorable results have been reported in some breast cancer (BC) patients receiving antiangiogenic therapy with bevacizumab (Bev) in combination with chemotherapy, and further knowledge on how Bev can be optimally combined with conventional treatment to increase efficacy is strongly needed. In this randomized, neoadjuvant phase II clinical trial, 132 patients with HER2-negative, nonmetastatic BC were treated with Bev in combination with sequential chemotherapy. Biopsies were sampled before treatment, after 12 weeks with anthracycline and after taxane therapy at week 25. MicroRNA (miRNA) expression profiling was performed on biopsies from each time point. Altogether, 241 biopsies were analyzed with the aim of identifying miRNA-based biomarkers of response to therapy. Results from the miRNA analyses were reported for the ER-positive cohort, which were previously demonstrated to benefit from antiangiogenic therapy in this study. For both treatment arms of this cohort, significantly different expression was observed for 217 miRNAs between objective responding and nonresponding patients before treatment initiation. These miRNAs have been linked to regulation of epithelial-mesenchymal transition, metastasis, and tumor growth, among other processes. Bev in combination with chemotherapy resulted in similar miRNA changes to chemotherapy alone. However, the deregulation of miRNA expression occurred earlier in the Bev arm. In both arms, tumor suppressor miRNAs were found upregulated after treatment, while oncogenic miRNAs were downregulated in the Bev arm. Patients responding to Bev showed a strong correlation between deregulated miRNAs and decreased proliferation score during the course of treatment, with downregulation of miR-4465 as the strongest indicator of reduced proliferation. Integrative analyses at miRNA-, gene-, and protein expression further indicated a longitudinal decrease in proliferation. Altogether, the results indicate that proliferation might represent a predictive factor for increased Bev sensitivity, which may aid in the identification of patients who could potentially benefit from Bev.

Low‑intensity ultrasound enhances the chemosensitivity of hepatocellular carcinoma cells to cisplatin via altering the miR‑34a/c‑Met axis

Recently, the use of low-intensity ultrasound (LIUS) combined with chemotherapeutic agents is widely used in clinical practice, mainly for the treatment of cancer; however, the mechanisms as to how LIUS enhances the antitumor effects of these agents are not fully understood. The aim of the present study was to explore the synergistic antitumor effects and mechanisms of cisplatin (DDP) combined with LIUS (LIUS-DDP) in hepatocellular carcinoma (HCC). We reported that LIUS effectively enhanced Huh7 and HCCLM3 cell sensitivity to a low concentration of DDP. Reverse transcription-quantitative polymerase chain reaction analysis revealed that LIUS could increase the expression of microRNA-34a (miR-34a) in HCC cells following DDP treatment. In addition, LIUS-DDP significantly increased intracellular reactive oxygen species (ROS) levels in vitro, and the upregulation of miR-34a induced by LIUS-DDP was reversed by the ROS scavenger N-acetylcysteine, suggesting that LIUS upregulates the expression of miR-34a via production of ROS. In addition, knockdown of miR-34a in HCC cells significantly suppressed the synergistic effects of LIUS-DDP treatment. Conversely, overexpression of miR-34a enhanced these synergistic effects. The results of a dual-luciferase assay indicated that c-Met, a well-known oncogene, was a target of miR-34a. We also determined that LIUS-DDP treatment inhibited the expression of c-Met, possibly due to increased ROS production, which upregulated miR-34a expression. Furthermore, overexpression of c-Met reversed the synergistic effects of LIUS-DDP treatment. Our findings suggest that LIUS could enhance the chemosensitivity of HCC cells to DDP by altering the miR-34a/c-Met axis. Therefore, DDP combined with LIUS may be a potential therapeutic application for the clinical treatment of patients with HCC.

Epigallocatechin gallate inhibits cell growth and regulates miRNA expression in cervical carcinoma cell lines infected with different high-risk human papillomavirus subtypes

The aim of the present study was to investigate the inhibitory effects of the polyphenol epigallocatechin-3-gallate (EGCG) on the growth of cervical carcinoma cell lines infected with different high-risk human papillomavirus (HPV) subtypes, as well as the associated regulation of microRNA (miR) expression. Cell proliferation was measured using an MTT assay. The effects of 7 different concentrations of EGCG (100, 80, 60, 40, 20, 10 and 0 µg/ml) on HeLa cell proliferation were assessed. HeLa cell growth was significantly inhibited by EGCG in a dose- and time-dependent manner (P<0.05), and the IC₅₀ was 90.74 and 72.74 µg/ml at 24 and 48 h, respectively. The expression of miR-210, miR-29a, miR-203 and miR-125b in HeLa (HPV16/18+), SiHa (HPV16+), CaSki (HPV16+) and C33A (HPV-) cell lines was measured using quantitative polymerase chain reaction analysis. In CA33 cells, miR-203 (all P<0.001) and miR-125b (P<0.01 and <0.0001) were significantly downregulated by EGCG, and miR-210 was significantly upregulated with 40 and 60 µg/ml EGCG (P<0.0001). miR-125b was significantly downregulated (P<0.001 and <0.0001), and miR-210 and miR-29 were significantly upregulated by ≤80 µg/ml EGCG in HeLa cells (all P<0.0001). In CaSki cells, miR-210, miR-29a (all P<0.001) and miR-125b (P<0.01–0.0001) were significantly upregulated by EGCG. In SiHa cells, miR-125b (both P<0.001) and miR-203 (P<0.01 and <0.0001) were significantly upregulated by EGCG. In conclusion, the results of the present study suggest that EGCG suppresses cervical carcinoma cell growth, possibly via regulating the expression of miRs, suggesting their potential as therapeutic targets for the control and prevention of cervical cancer. Additionally, EGCG may be considered a novel anti-cervical cancer drug in the future.