MiR-128 reverses the gefitinib resistance of the lung cancer stem cells by inhibiting the c-met/PI3K/AKT pathway

Bio-molecular Fe(III) and Zn(II) complexes stimulate the interplay between PI3K/AKT1/EGFR inhibition and induce autophagy and apoptosis in epidermal skin cell cancer

This study investigated the effectiveness and safety of a hybrid thiosemicarbazone ligand (HL) and its metal complexes (MnII-L, FeIII-L, NiII-HL, and ZnII-HL) against epidermoid carcinoma (A-431). The results indicated that FeIII-L is the most effective, with a high selectivity index of 8.01 and an IC50 of 17.49 ± 2.12 μM for FeIII-L. The study also revealed that the synthesized complexes effectively inhibited gene expression of the Phosphoinositide 3-kinases (PI3K), alpha serine/threonine-protein kinase (AKT1), epidermal growth factor receptor (EGFR2) axis mechanism (P < 0.0001). Additionally, these complexes trigger a chain of events that include the inhibition of proliferating cell nuclear antigen (PCNA), transforming growth factor β1 (TGF β1), and topoisomerase II, and leading to a decrease in epidermoid cell proliferation. Furthermore, the inhibitory activity also resulted in the upregulation of caspases 3 and 9, indicating the acceleration of apoptotic markers, and the down regulation of miRNA221, suggesting a decrease in epidermoid proliferation. Molecular modeling of FeIII-L revealed that it had the best binding energy -8.02 kcal/mol and interacted with five hydrophobic π-interactions with Val270, Gln79, Leu210, and Trp80 against AKT1. Furthermore, the binding orientation of FeIII-L with Topoisomerase II was found to be the most stable, with a binding energy -8.25 kcal/mol. This stability was attributed to the presence of five hydrophobic π-interactions with His759, Guanin13, Cytosin8, and Ala465, and numerous ionic interactions, which were more favorable than those of doxorubicin and etoposide for new regimens of chemotherapeutic activities against skin cancer.

Clinical applications of circulating biomarkers in non-small cell lung cancer

Despite recent advances in cancer diagnostics and treatment, the mortality associated with lung cancer is still the highest in the world. Late-stage diagnosis, often accompanied by metastasis, is a major contributor to the high mortality rates, emphasizing the urgent need for reliable and readily accessible diagnostic tools that can detect biomarkers unique to lung cancer. Circulating factors, such as circulating tumor DNA and extracellular vesicles, from liquid biopsy have been recognized as diagnostic or prognostic markers in lung cancer. Numerous clinical studies are currently underway to investigate the potential of circulating tumor DNA, circulating tumor RNA, exosomes, and exosomal microRNA within the context of lung cancer. Those clinical studies aim to address the poor diagnostics and limited treatment options for lung cancer, with the ultimate goal of developing clinical markers and personalized therapies. In this review, we discuss the roles of each circulating factor, its current research status, and ongoing clinical studies of circulating factors in non-small cell lung cancer. Additionally, we discuss the circulating factors specifically found in lung cancer stem cells and examine approved diagnostic assays designed to detect circulating biomarkers in lung cancer patients.

Dual blockade of EGFR and PI3K signaling pathways offers a therapeutic strategy for glioblastoma

BACKGROUND

Glioblastoma multiforme (GBM) is a devastating disease that lacks effective drugs for targeted therapy. Previously, we found that the third-generation epidermal growth factor receptor (EGFR) inhibitor AZD-9291 persistently blocked the activation of the ERK pathway but had no inhibitory effect on the phosphoinositide 3-kinase (PI3K)/Akt pathway. Given that the PI3K inhibitor GDC-0084 is being evaluated in phase I/II clinical trials of GBM treatment, we hypothesized that combined inhibition of the EGFR/ERK and PI3K/Akt pathways may have a synergistic effect in the treatment of GBM.

METHODS

The synergistic effects of cotreatment with AZD-9291 and GDC-0084 were validated using cell viability assays in GBM and primary GBM cell lines. Moreover, the underlying inhibitory mechanisms were assessed through colony formation, EdU proliferation, and cell cycle assays, as well as RNA-seq analyses and western blot. The therapeutic effects of the drug combination on tumor growth and survival were investigated in mice bearing tumors using subcutaneously or intracranially injected LN229 xenografts.

RESULTS

Combined treatment with AZD-9291 and GDC-0084 synergistically inhibited the proliferation and clonogenic survival, as well as induced cell cycle arrest of GBM cells and primary GBM cells, compared to monotherapy. Moreover, AZD-9291 plus GDC-0084 combination therapy significantly inhibited the growth of subcutaneous tumors and orthotopic brain tumor xenografts, thus prolonging the survival of tumor-bearing mice. More importantly, the combination of AZD-9291 and GDC-0084 simultaneously blocked the activation of the EGFR/MEK/ERK and PI3K/AKT/mTOR signaling pathways, thereby exerting significant antitumor activity.

CONCLUSION

Our findings demonstrate that the combined blockade of the EGFR/MEK/ERK and PI3K/AKT/mTOR pathways is more effective against GBM than inhibition of each pathway alone, both in vitro and in vivo. Our results suggest that AZD-9291 combined with GDC-0084 may be considered as a potential treatment strategy in future clinical trials. Video Abstract.

The role of miR-128 in cancer development, prevention, drug resistance, and immunotherapy

A growing body of evidence has revealed that microRNA (miRNA) expression is dysregulated in cancer, and they can act as either oncogenes or suppressors under certain conditions. Furthermore, some studies have discovered that miRNAs play a role in cancer cell drug resistance by targeting drug-resistance-related genes or influencing genes involved in cell proliferation, cell cycle, and apoptosis. In this regard, the abnormal expression of miRNA-128 (miR-128) has been found in various human malignancies, and its verified target genes are essential in cancer-related processes, including apoptosis, cell propagation, and differentiation. This review will discuss the functions and processes of miR-128 in multiple cancer types. Furthermore, the possible involvement of miR-128 in cancer drug resistance and tumor immunotherapeutic will be addressed.

The role of miRNA-128 in the development and progression of gastrointestinal and urogenital cancer

Increasing data have shown the significance of various miRNAs in malignancy. In this regard, parallel to its biological role in normal tissues, miRNA-128 (miR-128) has been found to play an essential immunomodulatory function in the process of cancer initiation and development. The occurrence of the aberrant expression of miR-128 in tumors and the unique properties of miRNAs raise the prospect of their use as biomarkers and the next generation of molecular anticancer therapies. The function of miR-128 in malignancies such as breast, prostate, colorectal, gastric, pancreatic, esophageal, cervical, ovarian and bladder cancers and hepatocellular carcinoma is discussed in this review. Finally, the effect of exosomal miR-128 on cancer resistance to therapeutics and cancer immunotherapy in certain malignancies is highlighted.

MicroRNAs as the critical regulators of tyrosine kinase inhibitors resistance in lung tumor cells

Lung cancer is the second most common and the leading cause of cancer related deaths globally. Tyrosine Kinase Inhibitors (TKIs) are among the common therapeutic strategies in lung cancer patients, however the treatment process fails in a wide range of patients due to TKIs resistance. Given that the use of anti-cancer drugs can always have side effects on normal tissues, predicting the TKI responses can provide an efficient therapeutic strategy. Therefore, it is required to clarify the molecular mechanisms of TKIs resistance in lung cancer patients. MicroRNAs (miRNAs) are involved in regulation of various pathophysiological cellular processes. In the present review, we discussed the miRNAs that have been associated with TKIs responses in lung cancer. MiRNAs mainly exert their role on TKIs response through regulation of Tyrosine Kinase Receptors (TKRs) and down-stream signaling pathways. This review paves the way for introducing a panel of miRNAs for the prediction of TKIs responses in lung cancer patients.

Protective effects of the notoginsenoside R1 on acute lung injury by regulating the miR-128-2-5p/Tollip signaling pathway in rats with severe acute pancreatitis

Notoginsenoside R1 (NG-R1), the extract and the main ingredient of Panax notoginseng, has anti-inflammatory effects and can be used in treating acute lung injury (ALI). In this study, we explored the pulmonary protective effect and the underlying mechanism of the NG-R1 on rats with ALI induced by severe acute pancreatitis (SAP). MiR-128-2-5p, ERK1, Tollip, HMGB1, TLR4, IκB, and NF-κB mRNA expression levels were measured using real-time qPCR, and TLR4, Tollip, HMGB1, IRAK1, MyD88, ERK1, NF-κB65, and P-IκB-α protein expression levels using Western blot. The NF-κB and the TLR4 activities were determined using immunohistochemistry, and TNF-α, IL-6, IL-1β, and ICAM-1 levels in the bronchoalveolar lavage fluid (BALF) using ELISA. Lung histopathological changes were observed in each group. NG-R1 treatment reduced miR-128-2-5p expression in the lung tissue, increased Tollip expression, inhibited HMGB1, TLR4, TRAF6, IRAK1, MyD88, NF-κB65, and p-IκB-α expression levels, suppressed NF-κB65 and the TLR4 expression levels, reduced MPO activity, reduced TNF-α, IL-1β, IL-6, and ICAM-1 levels in BALF, and alleviated SAP-induced ALI. NG-R1 can attenuate SAP-induced ALI. The mechanism of action may be due to a decreased expression of miR-128-2-5p, increased activity of the Tollip signaling pathway, decreased activity of HMGB1/TLR4 and ERK1 signaling pathways, and decreased inflammatory response to SAP-induced ALI. Tollip was the regulatory target of miR-128-2-5p.

The efficacy of PI3Kγ and EGFR inhibitors on the suppression of the characteristics of cancer stem cells

Cancer stem cells (CSCs) are capable of continuous proliferation, self-renewal and are proposed to play significant roles in oncogenesis, tumor growth, metastasis and cancer recurrence. We have established a model of CSCs that was originally developed from mouse induced pluripotent stem cells (miPSCs) by proposing miPSCs to the conditioned medium (CM) of cancer derived cells, which is a mimic of carcinoma microenvironment. Further research found that not only PI3K-Akt but also EGFR signaling pathway was activated during converting miPSCs into CSCs. In this study, we tried to observe both of PI3Kγ inhibitor Eganelisib and EGFR inhibitor Gefitinib antitumor effects on the models of CSCs derived from miPSCs (miPS-CSC) in vitro and in vivo. As the results, targeting these two pathways exhibited significant inhibition of cell proliferation, self-renewal, migration and invasion abilities in vitro. Both Eganelisib and Gefitinib showed antitumor effects in vivo while Eganelisib displayed more significant therapeutic efficacy and less side effects than Gefitinib on all miPS-CSC models. Thus, these data suggest that the inhibitiors of PI3K and EGFR, especially PI3Kγ, might be a promising therapeutic strategy against CSCs defeating cancer in the near future.

Cancer Stem Cells: An Ever-Hiding Foe

Cancer stem cells are a population of cells enable to reproduce the original phenotype of the tumor and capable to self-renewal, which is crucial for tumor proliferation, differentiation, recurrence, and metastasis, as well as chemoresistance. Therefore, the cancer stem cells (CSCs) have become one of the main targets for anticancer therapy and many ongoing clinical trials test anti-CSCs efficacy of plenty of drugs. This chapter describes CSCs starting from general description of this cell population, through CSCs markers, signaling pathways, genetic and epigenetic regulation, role of epithelial-mesenchymal transition (EMT) transition and autophagy, cooperation with microenvironment (CSCs niche), and finally role of CSCs in escaping host immunosurveillance against cancer.

Cell Behavior of Non-Small Cell Lung Cancer Is at EGFR and MicroRNAs Hands

Lung cancer is a complex disease associated with gene mutations, particularly mutations of Kirsten Rat Sarcoma Viral Oncogene Homolog (KRAS) and epidermal growth factor receptor (EGFR). Non-small cell lung cancer (NSCLC) and small cell lung cancer (SCLC) are the two major types of lung cancer. The former includes most lung cancers (85%) and are commonly associated with EGFR mutations. Several EGFR-tyrosine kinase inhibitors (EGFR-TKIs), including erlotinib, gefitinib, and osimertinib, are effective therapeutic agents in EGFR-mutated NSCLC. However, their effectiveness is limited by the development (acquired) or presence of intrinsic drug resistance. MicroRNAs (miRNAs) are key gene regulators that play a profound role in the development and outcomes for NSCLC via their role as oncogenes or oncosuppressors. The regulatory role of miRNA-dependent EGFR crosstalk depends on EGFR signaling pathway, including Rat Sarcoma/Rapidly Accelerated Fibrosarcoma/Mitogen-Activated Protein Kinase/Extracellular Signal-Regulated Kinase 1/2 (Ras/Raf/MEK/ERK1/2), Signal Transducer and Activator of Transcription (STAT), Nuclear Factor Kappa-Light-Chain-Enhancer of Activated B Cells (NF-kB), phosphoinositide 3-kinase/protein kinase B (PI3K/AKT), Janus kinase 1 (JAK1), and growth factor receptor-bound protein 2 (GRB2). Dysregulated expression of miRNAs affects sensitivity to treatment with EGFR-TKIs. Thus, abnormalities in miRNA-dependent EGFR crosstalk can be used as diagnostic and prognostic markers, as well as therapeutic targets in NSCLC. In this review, we present an overview of miRNA-dependent EGFR expression regulation, which modulates the behavior and progression of NSCLC.

Micro-RNA Regulation on Oct4 Gene Expression and Functional Differentiation in Skin Cancer Cells

Micro-RNA has a very important role in gene regulation. The stem gene Oct4 is related with the growth, mobility, and infiltration of skin cancer cells. Studying the regulatory mechanism of micro-RNAs of Oct4 in skin cancer cells is of important clinical significance. Oct4 gene was analyzed using bioinformatics methods to find mir-RNA with regulatory functions. mir-RNA high-expression vector and suppression vector with pcDNA3.1-EGFP was transfected to skin cancer cell line HS-4 followed analysis of Oct4 expression 24 h and 48 h after transfection and transwell in-vitro cell invasion assay. Bioinformatics showed that mir-335 has relationship with the Oct4 gene. pcDNA3.1-EGFP-335-up and pcDNA3.1-EGFP-335-down were successfully constructed. 24 and 48 hours after transfection, the Oct4 expression in the high-expression group was gradually and significantly decreased (P < 0.05). Meanwhile, the cell migration and infiltration capacity was decreased significantly and showed time dependence with significant differences between groups (P < 0.05). mir-335 expression in suppression group was reduced without change of Oct4 (P > 0.05). Increased mir-335 can decrease the performance of Oct4 in skin cancer cells and inhibit the infiltration ability of cells without affecting cell infiltration capability.

Combined BRM270 and endostatin inhibit relapse of NSCLC while suppressing lung cancer stem cell proliferation induced by endostatin

Endostatin (ES, ENDO) has been reported to suppress the growth of tumors while inducing the proliferation of lung cancer stem cells (LCSCs), causing a poor prognosis for lung cancer. In this study, we aimed to clarify whether BRM270 can inhibit the proliferation of cancer stem cells (CSCs). Endostatin + BRM270 showed anti-tumor effects by reducing tumor volume and increasing survival. Administration of BRM270 reduced the number of aldehyde dehydrogenase-positive (ALDH+) cells and the level of ALDH1A1 expression in tumors by increasing the level of miR-128 while decreasing the levels of BMI-1, ABCC-5, E2F3, and c-MET. The luciferase activity of miR-128 promoter was increased by an increasing concentration of BRM270. In addition, BMI-1, ABCC-5, E2F3, and c-MET were identified as candidate targets of miR-128, and the overexpression of miR-128 significantly reduced mRNA/protein levels of BMI-1, ABCC-5, E2F3, and c-MET in A549 and H460 cells. Administration of BRM270 inhibited the expression of BMI-1, ABCC-5, E2F3, and c-MET in a dose-dependent manner. In this study, we showed for the first time that the combined administration of endostatin and BRM270 achieved anti-tumor effects while suppressing the proliferation of stem cells.

The expression of miRNA-152-3p and miRNA-185 in tumor tissues versus margin tissues of patients with chemo-treated breast cancer

OBJECTIVE

Breast cancer (BC) is the most significant and lethal type of cancer in women. Although there are many newly develop chemotherapy drugs for patients with BC treating at various stages, drug resistance is the most important obstacle in their effectiveness for BC treatment. On the other hand, microRNAs are considered key regulators of genes involved in carcinogenesis and chemoresistance in cancers. The purpose of this study was to evaluate the role of miR-152-3p and miR-185 in intrinsic chemoresistance and proliferation of BC. In addition, the potential role of these miRNAs during chemoresistance was evaluated through possible signaling pathways.

RESULTS

Here, miR-152-3p was significantly downregulated in tumor tissues compared to the corresponding margin tissues in patients with BC (p-value ≥ 0.04407 and fold change = - 2.0552). In contrast, no statistically significant difference was observed in the miR-185 expression between the two groups. Furthermore, no significant correlation was found between the expression of these two miRNAs and subfactors, including cancer family history, abortion, and age. Downregulation of miR-152-3p could be considered a promising regulator of BC chemoresistance.

Long non-coding RNA TP73-AS1 promotes pancreatic cancer growth and metastasis through miRNA-128-3p/GOLM1 axis

BACKGROUND

Previous studies have suggested that long non-coding RNAs (lncRNA) TP73-AS1 is significantly upregulated in several cancers. However, the biological role and clinical significance of TP73-AS1 in pancreatic cancer (PC) remain unclear.

AIM

To investigate the role of TP73-AS1 in the growth and metastasis of PC.

METHODS

The expression of lncRNA TP73-AS1, miR-128-3p, and GOLM1 in PC tissues and cells was detected by quantitative real-time polymerase chain reaction. The bioinformatics prediction software ENCORI was used to predict the putative binding sites of miR-128-3p. The regulatory roles of TP73-AS1 and miR-128-3p in cell proliferation, migration, and invasion abilities were verified by Cell Counting Kit-8, wound-healing, and transwell assays, as well as flow cytometry and Western blot analysis. The interactions among TP73-AS1, miR-128-3p, and GOLM1 were explored by bioinformatics prediction, luciferase assay, and Western blot.

RESULTS

The expression of TP73-AS1 and miRNA-128-3p was dysregulated in PC tissues and cells. High TP73-AS1 expression was correlated with a poor prognosis. TP73-AS1 silencing inhibited PC cell proliferation, migration, and invasion in vitro as well as suppressed tumor growth in vivo. Mechanistically, TP73-AS1 was validated to promote PC progression through GOLM1 upregulation by competitively binding to miR-128-3p.

CONCLUSION

Our results demonstrated that TP73-AS1 promotes PC progression by regulating the miR-128-3p/GOLM1 axis, which might provide a potential treatment strategy for patients with PC.

Roles of microRNAs in Gastrointestinal Cancer Stem Cell Resistance and Therapeutic Development

Resistance to cancer treatment is one of the major challenges currently faced when treating gastrointestinal (GI) cancers. A major contributing factor to this resistance is the presence of cancer stem cells (CSCs) in GI cancers (e.g., colorectal, pancreatic, gastric, liver cancer). Non-coding RNAs, such as microRNAs (miRNAs), have been found to regulate several key targets that are responsible for cancer stemness, and function as oncogenic miRNAs (oncomiRs) or tumor suppressor miRNAs. As a result, several miRNAs have been found to alter, or be altered by, the expression of CSC-defining markers and their related pathways. These miRNAs can be utilized to affect stemness in multiple ways, including directly targeting CSCs and enhancing the efficacy of cancer therapeutics. This review highlights current studies regarding the roles of miRNAs in GI CSCs, and efforts towards the development of cancer therapeutics.

miR-128 regulated the proliferation and autophagy in porcine adipose-derived stem cells through targeting the JNK signaling pathway

PURPOSE

microRNA-128 (miR-128), a brain-enriched microRNA, has been reported to play a crucial role in the treatment of diseases. The c-Jun N-terminal kinase (JNK) signaling pathway exerts various biological functions such as regulation of cell proliferation, differentiation and apoptosis. In this study, we investigated the role of the miRNA-128-JNK signaling pathway in proliferation, apoptosis and autophagy of porcine adipose-derived stem cells (ASCs).

METHODS

After over-expressing miR-128 in porcine ASCs, cell proliferation was determined by 2,3-Bis-(2-Methoxy-4-Nitro-5-Sulfophenyl)-2H-Tetrazolium-5-Carboxanilide (XTT) method, cell apoptosis was observed by Flow cytometry (FCM), the expression of miR-128, B-cell lymphoma 2 (Bcl-2), and Bcl-2-associated X protein (Bax) was measured by RNA preparation and reverse transcription polymerase chain reaction (RT-PCR), and protein expression of JNK, phosphorylated JNK (p-JNK) and LC3B was analyzed by Western Blot analysis.

RESULTS

The over-expression of miR-128 potently promoted cell proliferation and autophagy while suppressed the apoptosis of porcine ASCs. In addition, the down-regulated expression level of p-JNK was detected in miR-128-over-expressed porcine ASCs. However, followed by the block of the JNK signaling pathway using SP600125 inhibitor, the effects of miR-128 on the proliferation, apoptosis and autophagy of porcine ASCs were significantly suppressed.

CONCLUSION

It is demonstrated that the miR-128-JNK signaling pathway is a potential therapeutic target for the treatment of obesity.

BRM270 targets cancer stem cells and augments chemo-sensitivity in cancer

Over the past decade, a number of studies have demonstrated the resistance of cancer cells to conventional drugs and have recognized this as a major challenge in cancer therapy. While attempting to understand the underlying mechanisms of chemoresistance, several studies have suggested that the presence of cancer stem cells (CSCs) in tumors is one of the major pathways contributing toward resistance. Chemoresistance leads to cancer treatment failure and worsens the prognosis of patients. Natural herbal compounds are gaining attention as an alternative treatment strategy for cancer. These compounds may be effective against chemoresistant cells either alone or synergistically alongside conventional drugs, sensitizing cancer cells and enhancing the therapeutic efficacy. BRM270 is a natural compound made from seven herbal plant (Saururus chinensis, Citrus unshiu Markovich, Aloe vera, Arnebia euchroma, Portulaca oleracea, Prunella vulgaris var. lilacina and Scutellaria bacicalensis) extracts used in Asian traditional medicine and has the potential to target CSCs. Several studies have demonstrated the positive effects of BRM270 against chemoresistant cancer and its synergy alongside existing cancer drugs, including paclitaxel and gefitinib. These effects have been observed against various cancer types, including resistant non-small cell lung cancer (NSCLC), glioblastoma, multi-drug resistant osteosarcoma, cervical cancer, pancreatic cancer and hepatocarcinoma. The present review discusses the effects of BRM270 treatment against CSC-associated chemoresistance in common types of cancer.

miR-365a-5p suppresses gefitinib resistance in non-small-cell lung cancer through targeting PELI3

Aim: Demonstrate the function of dysregulated miR-365a-5p-PELI3 signaling axis in the generation of gefitinib resistance during treatment for non-small-cell lung cancer (NSCLC). Patients & methods: All the NSCLC patients who participated in this research were recruited from the Second Hospital of Hebei Medical University. PC9 cells and PC9GR cells were cultured for in vitro experiments. Results: Patients who were primary resistant to EGFR-tyrosine kinase inhibitor had lower miR-365a-5p levels. MiR-365a-5p directly targeted PELI3 mRNA. MiR-365a-5p overexpression enhanced the function of gefitinib in inhibiting cell viability. Tumor growth was suppressed through miR-365a-5p in nude mice. Conclusion: Dysregulated miR-365a-5p-PELI3 signaling axis triggered the generation of gefitinib resistance in NSCLC.

PAICS, a De Novo Purine Biosynthetic Enzyme, Is Overexpressed in Pancreatic Cancer and Is Involved in Its Progression

Pancreatic ductal adenocarcinoma (PDAC) is an aggressive cancer with an extremely poor prognosis. There is an urgent need to identify new therapeutic targets and also understand the mechanism of PDAC progression that leads to aggressiveness of the disease. To find therapeutic targets, we analyzed data related to PDAC transcriptome sequencing and found overexpression of the de novo purine metabolic enzyme phosphoribosylaminoimidazole succinocarboxamide synthetase (PAICS). Immunohistochemical analysis of PDAC tissues showed high expression of the PAICS protein. To assess the biological roles of PAICS, we used RNA interference and knock down of its expression in PDAC cell lines that caused a reduction in PDAC cell proliferation and invasion. Furthermore, results of chorioallantoic membrane assays and pancreatic cancer xenografts demonstrated that PAICS regulated pancreatic tumor growth. Our data also showed that, in PDAC cells, microRNA-128 regulates and targets PAICS. PAICS depletion in PDAC cells caused upregulation in E-cadherin, a marker of the epithelial-mesenchymal transition. In PDAC cells, a BET inhibitor, JQ1, reduced PAICS expression. Thus, our investigations show that PAICS is a therapeutic target for PDAC and, as an enzyme, is amenable to targeting by small molecules.

Recent updates on the resistance mechanisms to epidermal growth factor receptor tyrosine kinase inhibitors and resistance reversion strategies in lung cancer

Epidermal growth factor receptor tyrosine kinase inhibitors (EGFR-TKIs) have led to a substantial improvement in the prognosis of lung cancer patients by explicitly targeting the activating mutations within the EGFR. Initially, patients harboring tumors with EGFR mutations show progression-free survival and improvement in the response rates toward all-generation EGFR-TKIs; however, these agents fail to deliver the intended results in the long-term due to drug resistance. Therefore, it is necessary to recognize specific cardinal mechanisms that regulate the resistance phenomenon. Understanding the intricate mechanisms underlying EGFR-TKIs resistance in lung cancer could provide cognizance for more advanced targeted therapeutics. The present review features insights into current updates on the discrete mechanisms, including secondary or tertiary mutations, parallel and downstream signaling pathways, acquiring an epithelial-to-mesenchymal transition (EMT) signature, microRNAs (miRNAs), and epigenetic alterations, which lead to intrinsic and acquired resistance against EGFR-TKIs in lung cancer. In addition, this paper also reviews current possible strategies to overcome this issue using combination treatment of recently developed MET inhibitors, allosteric inhibitors or immunotherapies, transformation of EMT, targeting miRNAs, and epigenetic alterations in intrinsic and acquired EGFR-TKIs resistant lung cancer. In conclusion, multiple factors are responsible for intrinsic and acquired resistance to EGFR-TKIs and understanding of the detailed molecular mechanisms, and recent advancements in pharmacological studies are needed to develop new strategies to overcome intrinsic and acquired EGFR-TKIs resistance in lung cancer.

Long Non-coding RNA MIAT Mediates Non-small Cell Lung Cancer Development Through Regulating the miR-128-3p/PELI3 Axis

In this study, we set out to characterize the expression status of long non-coding RNA (lncRNA) Myocardial Infarction Associated Transcript (MIAT) in non-small cell lung cancer (NSCLC) and elucidate its mechanistic contribution to this disease. Relative expression levels of MIAT, Pellino E3 Ubiquitin Protein Ligase Family Member 3 (PELI3), and microRNA (miR)-128-3p were analyzed by real-time polymerase chain reaction. PELI3 protein level was determined by immunoblotting. Cell viability and proliferation were evaluated by the MTT assay and colony formation assay, respectively. Cell invasion and migration were assessed by wound-healing closure and transwell assays, respectively. The regulatory actions of miR-128-3p on both MIAT and PELI3 were interrogated by luciferase reporter assay. We demonstrated the aberrant upregulation of MIAT in NSCLC and its association with tumor progression. We further uncovered the negative correlation among MIAT, PELI3, and miR-128-3p. MIAT deficiency significantly compromised cell viability, proliferation, invasion, and migration, while increased miR-128-3p and decreased PELI3 expressions. Application of miR-128-3p inhibitor significantly stimulated luciferase activities driven by both MIAT and PELI3 promoter and phenotypically promoted cell viability, proliferation, migration, and invasion. Our study highlighted the mechanistic contribution of the MIAT/miR-128-3p/PELI3 signaling cascade in NSCLC.

MiR-124 sensitizes cisplatin-induced cytotoxicity against CD133+ hepatocellular carcinoma cells by targeting SIRT1/ROS/JNK pathway

Drug resistance is still a major obstacle for efficient treatment of hepatocellular carcinoma (HCC) during the cisplatin-based chemotherapy. Recent studies have demonstrated that CD133 positive population of cancer cells are responsible for multiple drug resistance. We are supposed to take strategies to sensitize CD133⁺ HCC cells to cisplatin treatment. In the present study, CD133⁺ HCC cells showed significant cisplatin-resistance compared to the CD133^- HCC cells. Downregulation of miR-124 was observed in CD133⁺ HCC cells. However, enforced expression of miR-124 can increase the sensitivity of CD133⁺ HCC cells to cisplatin treatment in vitro and in vivo. Mechanically, overexpression of miR-124 was found to inhibit the expression of SIRT1 and thus promoted the generation of ROS and phosphorylation of JNK. As the results, overexpression of miR-124 expanded the apoptosis in cisplatin-treated CD133⁺ HCC cells. We then demonstrated that overexpression of miR-124 sensitized cisplatin-induced cytotoxicity against CD133⁺ hepatocellular carcinoma cells by targeting SIRT1/ROS/JNK pathway.

MicroRNAs and Long Non-coding RNAs in c-Met-Regulated Cancers

MicroRNAs (miRNAs) and long non-coding RNAs (lncRNAs) are components of many signaling pathways associated with tumor aggressiveness and cancer metastasis. Some lncRNAs are classified as competitive endogenous RNAs (ceRNAs) that bind to specific miRNAs to prevent interaction with target mRNAs. Studies have shown that the hepatocyte growth factor/mesenchymal-epithelial transition factor (HGF/c-Met) pathway is involved in physiological and pathological processes such as cell growth, angiogenesis, and embryogenesis. Overexpression of c-Met can lead to sustained activation of downstream signals, resulting in carcinogenesis, metastasis, and resistance to targeted therapies. In this review, we evaluated the effects of anti-oncogenic and oncogenic non-coding RNAs (ncRNAs) on c-Met, and the interactions among lncRNAs, miRNAs, and c-Met in cancer using clinical and tissue chromatin immunoprecipition (ChIP) analysis data. We summarized current knowledge of the mechanisms and effects of the lncRNAs/miR-34a/c-Met axis in various tumor types, and evaluated the potential therapeutic value of lncRNAs and/or miRNAs targeted to c-Met on drug-resistance. Furthermore, we discussed the functions of lncRNAs and miRNAs in c-Met-related carcinogenesis and potential therapeutic strategies.

Identification of potential microRNAs and their targets in promoting gefitinib resistance by integrative network analysis

Background

Non-small cell lung cancer (NSCLC) accounts for about 80-85% of lung cancers. Epidermal growth factor receptor tyrosine kinase inhibitors (EGFR-TKIs) such as gefitinib are considered the best choice for first-line treatment for the patients with NSCLC harboring EGFR-activating alterations. Nonetheless, 10-30% of patients may not obtain an objective response and may also experience rapid progression. The aim of our research, based on the integrative bioinformatics review, was to identify the possible miRNAs involved in gefitinib resistance.

Method

A gefitinib-resistant network composed of 15 miRNAs and 34 targets were constructed by using the bioinformatics analyses of three microarray datasets. Of these miRNAs, effects of miR-342-3p on gefitinib resistance were investigated on a gefitinib-resistant cell model (A549/GR and PC/GR cells).

Results

We reported that over-expression of miR-342-3p could significantly increase the resistance to gefitinib of A549/GR and PC9/GR cells and vice versa. Then, we recognized CPA4 as a target of hsa-miR-342-3p by a luciferase reporter assay. The increase in hsa-miR-342-3p levels led to a significant reduction in CPA4 protein expression. However, the opposite results were observed upon miR-342-3p knockdown. Finally, we found that enforced CPA4 expression partially reversed miR-342-3p effects in A549/GR cells.

Conclusions

Collectively, these findings suggest that the upregulation of miR-342-3p contributes to gefitinib resistance by targeting CPA4, which may serve as a potential treatment option to overcome gefitinib resistance in patients with NSCLC.

Role of miRNA-Regulated Cancer Stem Cells in the Pathogenesis of Human Malignancies

Recent biomedical discoveries have revolutionized the concept and understanding of carcinogenesis, a complex and multistep phenomenon which involves accretion of genetic, epigenetic, biochemical, and histological changes, with special reference to MicroRNAs (miRNAs) and cancer stem cells (CSCs). miRNAs are small noncoding molecules known to regulate expression of more than 60% of the human genes, and their aberrant expression has been associated with the pathogenesis of human cancers and the regulation of stemness features of CSCs. CSCs are the small population of cells present in human malignancies well-known for cancer resistance, relapse, tumorigenesis, and poor clinical outcome which compels the development of novel and effective therapeutic protocols for better clinical outcome. Interestingly, the role of miRNAs in maintaining and regulating the functioning of CSCs through targeting various oncogenic signaling pathways, such as Notch, wingless (WNT)/β-Catenin, janus kinases/ signal transducer and activator of transcription (JAK/STAT), phosphatidylinositol 3-kinase/ protein kinase B (PI3/AKT), and nuclear factor kappa-light-chain-enhancer of activated B (NF-kB), is critical and poses a huge challenge to cancer treatment. Based on recent findings, here, we have documented the regulatory action or the underlying mechanisms of how miRNAs affect the signaling pathways attributed to stemness features of CSCs, such as self-renewal, differentiation, epithelial to mesenchymal transition (EMT), metastasis, resistance and recurrence etc., associated with the pathogenesis of various types of human malignancies including colorectal cancer, lung cancer, breast cancer, head and neck cancer, prostate cancer, liver cancer, etc. We also shed light on the fact that the targeted attenuation of deregulated functioning of miRNA related to stemness in human carcinogenesis could be a viable approach for cancer treatment.

MicroRNA-128/homeobox B8 axis regulates ovarian cancer cell progression

MicroRNA-128 (miR-128) has been found to be dysregulated and might function as a tumour suppressor in various cancers, including ovarian cancer. However, the underlying mechanism of miR-128 in ovarian cancer has not been fully understood. The miR-128 and homeobox B8 (HOXB8) levels in clinical samples and cultured cell lines were measured using qRT-PCR and/or Western blot analysis. Cell proliferation was assessed using Cell Counting Kit-8 assay. Cell apoptosis was determined using flow cytometry. The association between miR-128 and HOXB8 was confirmed using dual-luciferase reporter assay. Results showed that decreased miR-128 expression and increased HOXB8 expression were observed in ovarian cancer tissues and cell lines. Transfection with miR-128 mimics suppressed the cell proliferation and enhanced paclitaxel sensitivity in ovarian cancer cell lines. miR-128 directly targeted HOXB8 in ovarian cancer cell lines. Knockdown of HOXB8 abolished the effects of miR-128 inhibitor on ovarian cancer cell proliferation and paclitaxel sensitivity. Summarily, miR-128 displayed a tumour suppressor role in ovarian cancer via targeting HOXB8. It is supposed that miR-128 might be effective for targeting therapy for ovarian cancer.

NUP58 facilitates metastasis and epithelial-mesenchymal transition of lung adenocarcinoma via the GSK-3β/Snail signaling pathway

The NUP58 gene encodes a nucleus-pore protein that is a component of nuclear pore complex (NPC). NPC facilitates the transportation of macromolecules (ions and other substances) into the nuclei of eukaryotic cells. However, there are no relevant reports about the NUP58 gene in human lung cancer. In this study, we demonstrated that NUP58 was highly expressed in the primary and metastatic foci of lung adenocarcinoma, with low expression in adjacent tissues and normal lung tissue. In patients with lung adenocarcinoma, the NUP58 gene was highly expressed in patients with stage IV disease (P < 0.05); NUP58 knockdown using a lentiviral vector-mediated shRNA inhibited metastasis and invasion of lung adenocarcinoma cell lines A549 and H1299 in vivo and in vitro. Furthermore, silencing of NUP58 resulted in altered expression of EMT markers, associated GSK-3β/Snail pathways, tumor metastasis and invasion factors. In conclusion, these findings demonstrated that NUP58 can promote the metastasis and invasion of lung adenocarcinoma, which can be partially attributed to the GSK-3β/Snail signaling pathway.

MicroRNA‑206 exerts anti‑oncogenic functions in esophageal squamous cell carcinoma by suppressing the c‑Met/AKT/mTOR pathway

Increasing evidence suggests that the dysregulation of microRNAs (miRNAs) has an important role in the progression of human cancer, including ESCC. However, the exact functions and mechanisms of miRNAs in ESCC remain largely unclear. The aim of the present study was to investigate the expression and biological functions of miRNAs in ESCC and reveal the underlying molecular mechanisms. miRNA microarray and reverse transcription-quantitative polymerase chain reaction analyses were performed, which identified and confirmed that miR-206 was significantly downregulated in ESCC tissues and cell lines. Its low expression was associated with lymph node metastasis, advanced TNM stage and N classification, as well as poorer overall survival in patients with ESCC. CCK-8 and flow cytometry assays demonstrated that ectopic miR-206 expression inhibited ESCC cell proliferation and induced cell apoptosis. In addition, MET proto-oncogene, receptor tyrosine kinase (c-Met), a well-known oncogene, was a direct target of miR-206. An inverse correlation between the levels of miR-206 and c-Met mRNA in ESCC tissue samples was confirmed. Notably, c-Met overexpression inhibited the effects of miR-206 on the proliferation and apoptosis of ESCC cells. Additionally, it was confirmed that the tumor-suppressive functions of miR-206 may have contributed to the inactivation of the c-Met/protein kinase B (AKT)/mechanistic target of rapamycin (mTOR) signaling pathway. In conclusion, the findings of the present study suggested that miR-206 exerts its anti-cancer functions via the c-Met/AKT/mTOR signaling pathway, providing a novel candidate prognostic factor and a potential therapeutic target in ESCC.

MicroRNAs as a drug resistance mechanism to targeted therapies in EGFR-mutated NSCLC: Current implications and future directions

The introduction of EGFR-tyrosine kinase inhibitors (TKIs) has revolutionized the treatment and prognosis of non-small cell lung cancer (NSCLC) patients harboring epidermal growth factor receptor (EGFR) mutations. However, these patients display disease progression driven by the onset of acquired mechanisms of drug resistance that limit the efficacy of EGFR-TKI to no longer than one year. Moreover, a small fraction of EGFR-mutated NSCLC patients does not benefit from this targeted treatment due to primary (i.e. intrinsic) mechanisms of resistance that preexist prior to TKI drug treatment. Research efforts are focusing on deciphering the distinct molecular mechanisms underlying drug resistance, which should prompt the development of novel antitumor agents that surmount such chemoresistance modalities. The capability of microRNAs (miRNAs) to regulate the expression of many oncogenic pathways and their central role in lung cancer progression, provided new directions for research on prognostic biomarkers, as well as innovative tools for predicting patients' response to systemic therapies. Recent evidence suggests that modulation of key miRNAs may also reverse oncogenic signaling pathways, and potentiate the cytotoxic effect of anti-cancer therapies. In this review, we focus on the putative emerging role of miRNAs in modulating drug resistance to EGFR-TKI treatment in EGFR-mutated NSCLC. Moreover, we discuss the current implications of miRNAs analyses in the clinical setting, using both tissue and liquid biopsies, as well as the future potential use of miRNA-based therapies in overcoming resistance to targeted agents like TKIs.

MiR-128/SOX7 alleviates myocardial ischemia injury by regulating IL-33/sST2 in acute myocardial infarction

Acute myocardial infarction (AMI) induced by ischemia hypoxia severely threatens human life. Cell apoptosis of neurocytes was identified to mediate the pathogenesis, while the potential mechanism was still unclear. Sprague Dawley (SD) rats were used to establish the AMI rat model. Real-time polymerase chain reaction (PCR) and Western blot were performed to detect gene expression in mRNA and protein levels, respectively. A TUNEL assay was carried out to determine cell apoptosis. The relationship between SRY-related HMG-box (SOX7) and miR-128 was verified using luciferase reporter assay. The expression of SOX7 was decreased, while miR-128 was increased in AMI rats and ischemia hypoxia (IH) induced H9c2 cells. Hypoxia induction significantly promoted the expression of interleukin (IL)-33 and soluble ST2 (sST2), and also promoted cell apoptosis. MiR-128 targets SOX7 to regulate its expression. Down-regulated miR-128 reversed the effects of IH on expression of SOX7, sST2 and cell apoptosis, while down-regulated sST2 abolished the effects of miR-128 inhibitor. In addition, overexpressed IL-33 abolished the effects of miR-128 inhibitor that induced by IH on the expression of SOX7 and cell apoptosis. In vivo experiments validated the expression of miR-128 on cell apoptosis. The present study indicated that miR-128 modulated cell apoptosis by targeting SOX7, which was mediated by IL-33/sST2 signaling pathway.

TGFβ1 regulates HGF-induced cell migration and hepatocyte growth factor receptor MET expression via C-ets-1 and miR-128-3p in basal-like breast cancer

Breast cancer is the most common cancer in women worldwide. The tumor microenvironment contributes to tumor progression by inducing cell dissemination from the primary tumor and metastasis. TGFβ signaling is involved in breast cancer progression and is specifically elevated during metastatic transformation in aggressive breast cancer. In this study, we performed genomewide correlation analysis of TGFBR2 expression in a panel of 51 breast cancer cell lines and identified that MET is coregulated with TGFBR2. This correlation was confirmed at the protein level in breast cancer cell lines and human tumor tissues. Flow cytometric analysis of luminal and basal‐like breast cancer cell lines and examination of 801 tumor specimens from a prospective cohort of breast cancer patients using reverse phase protein arrays revealed that expression of TGFBR2 and MET is increased in basal‐like breast cancer cell lines, as well as in triple‐negative breast cancer tumor tissues, compared to other subtypes. Using real‐time cell analysis technology, we demonstrated that TGFβ1 triggered hepatocyte growth factor (HGF)‐induced and MET‐dependent migration in vitro. Bioinformatic analysis predicted that TGFβ1 induces expression of C‐ets‐1 as a candidate transcription factor regulating MET expression. Indeed, TGFβ1‐induced expression of ETS1 and breast cancer cell migration was blocked by knockdown of ETS1. Further, we identified that MET is a direct target of miR‐128‐3p and that this miRNA is negatively regulated by TGFβ1. Overexpression of miR‐128‐3p reduced MET expression and abrogated HGF‐induced cell migration of invasive breast cancer cells. In conclusion, we have identified that TGFβ1 regulates HGF‐induced and MET‐mediated cell migration, through positive regulation of C‐ets‐1 and negative regulation of miR‐128‐3p expression in basal‐like breast cancer cell lines and in triple‐negative breast cancer tissue.

Knockdown of miR-27a sensitizes colorectal cancer stem cells to TRAIL by promoting the formation of Apaf-1-caspase-9 complex

MicroRNAs have been proved to participate in multiple biological processes in cancers. For developing resistance to cytotoxic drug, cancer cells, especially the cancer stem cells, usually change their microRNA expression profile to survive in hostile environments. In the present study, we found that expression of microRNA-27a was increased in colorectal cancer stem cells. High level of microRNA-27a was indicated to induce the resistance to TNF-related apoptosis-inducing ligand (TRAIL). Knockdown of microRNA-27a resensitized colorectal cancer stem cells to TRAIL-induced cell death. Mechanically, the gene of Apaf-1, which is associated with the mitochondrial apoptosis, was demonstrated to be the target of microRNA-27a in colorectal cancer stem cells. Knockdown of microRNA-27a increased the expression level of Apaf-1, thus enhancing the formation of Apaf-1-caspase-9 complex and subsequently promoting the TRAIL-induced apoptosis in colorectal cancer stem cells. These findings suggested that knockdown of microRNA-27a in colorectal cancer stem cells by the specific antioligonucleotides was potential to reverse the chemoresistance to TRAIL. It may represent a novel therapeutic strategy for treating the colorectal cancer more effectively.

miR-1-3p and miR-206 sensitizes HGF-induced gefitinib-resistant human lung cancer cells through inhibition of c-Met signalling and EMT

Hepatocyte growth factor (HGF) overexpression is an important mechanism in acquired epidermal growth factor receptor (EGFR) kinase inhibitor gefitinib resistance in lung cancers with EGFR activating mutations. MiR-1-3p and miR-206 act as suppressors in lung cancer proliferation and metastasis. However, whether miR-1-3p and miR-206 can overcome HGF-induced gefitinib resistance in EGFR mutant lung cancer is not clear. In this study, we showed that miR-1-3p and miR-206 restored the sensitivities of lung cancer cells PC-9 and HCC-827 to gefitinib in present of HGF. For the mechanisms, we demonstrated that both miR-1-3p and miR-206 directly target HGF receptor c-Met in lung cancer. Knockdown of c-Met mimicked the effects of miR-1-3p and miR-206 transfections Meanwhile, c-Met overexpression attenuated the effects of miR-1-3p and miR-206 in HGF-induced gefitinib resistance of lung cancers. Furthermore, we showed that miR-1-3p and miR-206 inhibited c-Met downstream Akt and Erk pathway and blocked HGF-induced epithelial-mesenchymal transition (EMT). Finally, we demonstrated that miR-1-3p and miR-206 can increase gefitinib sensitivity in xenograft mouse models in vivo. Our study for the first time indicated the new function of miR-1-3p and miR-206 in overcoming HGF-induced gefitinib resistance in EGFR mutant lung cancer cell.

BRM270 inhibits cancer stem cell maintenance via microRNA regulation in chemoresistant A549 lung adenocarcinoma cells

Chemotherapy is a standard treatment for non-small-cell lung cancer (NSCLC). However, the dose-limiting toxicity of drugs and the development of chemoresistance are major clinical challenges to successful management of NSCLC. Asian traditional medicine is gaining global attention as a non-toxic alternative to chemotherapy. BRM270 is an extract formulated from seven Asian medicinal plants that has been shown to inhibit tumor cell proliferation in diverse cancer types. We previously demonstrated that BRM270 suppresses tumorigenesis by negatively regulating nuclear factor-κB signaling in multidrug-resistant cancer stem cells (CSCs). In this study we report that the growth, migration, and invasion of normal human lung adenocarcinoma cells and their chemoresistant derivatives was inhibited by BRM270 treatment. Notably, BRM270 was found to modulate CSC self-renewal and tumor-initiating capacity via positive regulation of the miRNA-128. Thus, combination therapy with miRNA-128 and BRM270 may be an effective treatment strategy for chemoresistant NSCLC.

Tumor suppressor miR-128-3p inhibits metastasis and epithelial-mesenchymal transition by targeting ZEB1 in esophageal squamous-cell cancer

MicroRNAs (miRNAs) are some short RNAs that regulate multiple biological functions at post-transcriptional levels, such as tumorigenic processes, inflammatory lesions and cell apoptosis. Zinc finger E-box binding homeobox factor 1 (ZEB1) is a crucial mediator of epithelial-mesenchymal transition (EMT). It induces malignant progression of various cancers including human esophageal squamous-cell carcinoma (ESCC). In this study, we found that miR-128-3p was downregulated in ESCC tissues and cells by using PCR. Moreover, down-regulated expression of miR-128-3p was testified to be associated with poor prognosis of ESCC patients and might be regarded as an independent prognostic factor. Then, we examined the role of miR-128-3p in ESCC cells, and found that miR-128-3p could suppress the cell migration and invasion in vitro. Furthermore, ZEB1 was confirmed to be a direct target of miR-128-3p by luciferase reporter assay. Rescue experiments proved that EMT was regulated by miR-128-3p via suppression of ZEB1. Taken all together, we conclude that miR-128-3p suppresses EMT and metastasis via ZEB1, and miR-128-3p may be a critical mediator in ESCC.

Effects of berberine, curcumin, resveratrol alone and in combination with chemotherapeutic drugs and signal transduction inhibitors on cancer cells-Power of nutraceuticals

Over the past fifty years, society has become aware of the importance of a healthy diet in terms of human fitness and longevity. More recently, the concept of the beneficial effects of certain components of our diet and other compounds, that are consumed often by different cultures in various parts of the world, has become apparent. These "healthy" components of our diet are often referred to as nutraceuticals and they can prevent/suppress: aging, bacterial, fungal and viral infections, diabetes, inflammation, metabolic disorders and cardiovascular diseases and have other health-enhancing effects. Moreover, they are now often being investigated because of their anti-cancer properties/potentials. Understanding the effects of various natural products on cancer cells may enhance their usage as anti-proliferative agents which may be beneficial for many health problems. In this manuscript, we discuss and demonstrate how certain nutraceuticals may enhance other anti-cancer drugs to suppress proliferation of cancer cells.

FGF21 inhibitor suppresses the proliferation and migration of human umbilical vein endothelial cells through the eNOS/PI3K/AKT pathway

In this study, we investigated molecular mechanism underlying the regulation of endothelial nitric oxide synthase (eNOS) expression by fibroblast growth factor 21 (FGF21). We analyzed FGF21 and eNOS expression in hypertensive and healthy (control) subjects (n=30/group). To evaluate the effects of FGF21 on endothelial cells, we transfected FGF21 mimics or FGF21 inhibitor into human umbilical vein endothelial cells (HUVECs). Cell proliferation was analyzed using the methyl thiazolyl tetrazolium assay, and cell migration and invasion were assessed using Transwell assays. In addition, eNOS, PI3K, and AKT mRNA in the HUVECs were evaluated by quantitative reverse transcription PCR, and p-eNOS, PI3K, and p-AKT were evaluated by Western blotting. Our results showed increased levels of FGF21 mRNA and eNOS mRNA/protein in the blood of hypertensive patients compared with healthy controls. The FGF21 inhibitor inhibited HUVEC growth, migration, and invasion and significantly decreased eNOS, PI3K, and AKT mRNA levels and p-eNOS, PI3K, and p-AKT protein levels in HUVECs. Treatment with VEGF and/or overexpression of eNOS partially restored cell proliferation and p-AKT levels. Taken together, our results indicate that FGF21 regulates eNOS through the PI3K/AKT pathway.

MicroRNA-128 suppresses paclitaxel-resistant lung cancer by inhibiting MUC1-C and BMI-1 in cancer stem cells

The existence of cancer stem cells (CSCs) is the main reason for failure of cancer treatment caused by drug resistance. Therefore, eradicating cancers by targeting CSCs remains a significant challenge. In the present study, because of the important role of BMI-1 proto-oncogene, polycomb ring finger (BMI-1) and C-terminal Mucin1 (MUC1-C) in tumor growth and maintenance of CSCs, we aimed to confirm that microRNA miR-128, as an inhibitor of BMI-1 and MUC1-C, could effectively suppress paclitaxel (PTX)-resistant lung cancer stem cells. We showed that CSCs have significantly higher expression levels of BMI-1, MUC1-C, stemness proteins, signaling factors, and higher malignancy compared with normal tumor cells. After transfection with miR-128, the BMI-1 and MUC1-C levels in CSCs were suppressed. When miR-128 was stably expressed in PTX-resistant lung cancer stem cells, the cells showed decreased proliferation, metastasis, self-renewal, migration, invasive ability, clonogenicity, and tumorigenicity in vitro and in vivo and increased apoptosis compared with miR-NC (negative control) CSCs. Furthermore, miR-128 effectively decreased the levels of β-catenin and intracellular signaling pathway-related factors in CSCs. MiR-128 also decreased the luciferase activity of MUC1 reporter constructs and reduced the levels of transmembrane MUC1-C and BMI-1. These results suggested miR-128 as an attractive therapeutic strategy for PTX-resistant lung cancer via inhibition of BMI-1 and MUC1-C.

Overexpression of miR-216b sensitizes NSCLC cells to cisplatin-induced apoptosis by targeting c-Jun

Platinum-based chemotherapy is still be the standard treatment for non-small cell lung cancer (NSCLC). Recently, studies demonstrate that some kinds of microRNAs (miRNAs) are associated with chemosensitivity of NSCLC cells to platinum-based treatment. Unfortunately, cancer cells usually change their expression profile of miRNAs to form drug resistance against chemotherapy. In the present study, we focused on miR-216b to investigate whether miR-216b determined sensitivity of NSCLC cells to cisplatin. We observed that expression level of miR-216b was significantly decreased in NSCLC cell lines when they were under the cisplatin treatment. However, restore of miR-216b by transfecting with its mimics was found to increase the cytotoxicity of cisplatin to NSCLC cells. Studies on mechanisms elucidated that miR-216b targeted c-Jun in NSCLC. Overexpression of miR-216b can suppress the cisplatin-induced upregulation of c-Jun. As the downstream, overexpression of Bcl-xl induced by c-Jun/ATF2 heterodimers was inhibited in miR-216b transfected NSCLC cells. Since Bcl-xl is a key anti-apoptotic protein, we found that sensitivity of NSCLC cells to cisplatin-induced apoptosis was significantly increased because of the overexpression of miR-216b.

Overexpression of miR-101 promotes TRAIL-induced mitochondrial apoptosis in papillary thyroid carcinoma by targeting c-met and MCL-1

Tumor necrosis factor-related apoptosis inducing ligand (TRAIL) induces apoptosis in malignant cells, but not in normal cells. As papillary thyroid carcinoma cells broadly expressed TRAIL receptors (death receptor 4 and death receptor 5) on their surface, TRAIL is considered as a promising drug for treatment of papillary thyroid carcinoma. However, resistance to TRAIL still be a big obstacle to achieve a satisfactory effect for cancer therapy. Here, we found that overexpression of miR-101 was able to sensitize papillary thyroid carcinoma cells to TRAIL treatment in vitro and in vivo. Mechanically, we found that genes of c-met and MCL-1 were the targets of miR-101. Overexpression of miR-101 in TPC-1 significantly decreased the cellular protein levels of c-met and MCL-1, and thus inhibiting the PI3K/AKT pathway and reducing the resistance to TRAIL-induced mitochondrial apoptosis. Enforced expression of either c-met or MCL-1 could partially inhibit the miR-101 promoted apoptosis in TRAIL-treated TPC-1 cells. These results indicated that miR-101-c-met/MCL-1 axis determined the sensitivity of TRAIL to thyroid cancer in some extent. Combination with TRAIL and miR-101 may represent a novel approach to kill papillary thyroid carcinoma cells efficiently.

Inhibition of miR-23a increases the sensitivity of lung cancer stem cells to erlotinib through PTEN/PI3K/Akt pathway

Epidermal growth factor receptor-targeted tyrosine kinase inhibitors (EGFR-TKIs) have become first-line drugs used for non-small cell lung cancer (NSCLC) treatment. However, drug resistance to EGFR-TKIs will be developed inevitably due to the repeated use of these drugs. In the present study, we isolated cancer stem cells (CSCs) from the PC9 NSCLC cell line. We then observed that the PC9 CSCs showed significant resistance to erlotinib compared with the PC9 non-CSCs. Erlotinib failed to suppress the phosphorylation of PI3K and AKT in PC9 CSCs, although the EGFR was inhibited sufficiently. Mechanically, we observed aberrant upregulation of microRNA-23a (miR-23a) and downregulation of PTEN in PC9 CSCs compared to PC9 non-CSCs. Luciferase reporter assays proved that PTEN was the target of miR-23a in PC9 CSCs. Furthermore, knockdown of miR-23a enhanced the antitumor effect of erlotinib by increasing the expression of PTEN. In addition, transfection with miR-23a inhibitors promoted the erlotinib-dependent inhibition of PI3K/AKT pathway, thus, suppressing the proliferation and inducing apoptosis in PC9 CSCs. These results propose that upregulation of miR-23a is a potential mechanism associated with resistance to EGFR-TKIs in lung cancer stem cells. Inhibition of miR-23a serves as a novel therapeutic strategy to eliminate the EGFR-TKIs resistance of lung cancer stem cells.

Microcystin-Leucine Arginine Causes Cytotoxic Effects in Sertoli Cells Resulting in Reproductive Dysfunction in Male Mice

Microcystin-leucine arginine (MC-LR) is a potent toxin for Sertoli cells. However, the specific molecular mechanisms of MC-induced cytotoxicity still remain unclear. In this study, we performed a comprehensive analyses of changes of miRNAs and mRNAs in Sertoli cells treated with MC-LR. Through computational approaches, we showed the pivotal roles of differentially expressed miRNAs that were associated with cell metabolism, cellular growth and proliferation, cell-to-cell signaling and interaction and cellular movement. Ingenuity Pathway Analyses (IPA) revealed some differentially expressed miRNAs and mRNAs that may cause reproductive system diseases. Target gene analyses suggested that destruction in tight junctions (TJ) and adherens junctions (AJ) in testes may be mediated by miRNAs. Consistent with a significant enrichment of chemokine signaling pathways, we observed numerous macrophages in the testes of mice following treatment with MC-LR, which may cause testicular inflammation. Moreover, miR-98-5p and miR-758 were predicted to bind the 3′-UTR region of the mitogen-activated protein kinase 11 (MAPK11, p38 β isoform) gene which stimulates tumor necrosis factor-α (TNF-α) expression in Sertoli cells. TNF-α could interact with the tumor necrosis factor receptor 1 (TNFR1) on germ cells leading to induction of germ cell apoptosis. Collectively, our integrated miRNA/mRNA analyses provided a molecular paradigm, which was experimentally validated, for understanding MC-LR-induced cytotoxicity.

MicroRNA-613 suppresses proliferation, migration and invasion of osteosarcoma by targeting c-MET

MicroRNA-613 (miR-613) has been reported to play an important role in the pathogenesis of multiple cancers by negatively regulating gene expression at posttranscriptional level. However, the biological role of miR-613 in osteosarcoma (OS) remained unclear. In this study, we aimed to determine the expression and biological roles of miR-613 in OS. We found that miR-613 was significantly downregulated in OS tissues and cell lines, and that decreased miR-613 expression was correlated negatively with advanced TNM stage and lymph node metastasis. Overexpression of miR-613 in OS cells significantly suppressed the proliferation and colony formation by regulating cell arrest at G0/G1 phase, and impaired the migration and invasive abilities of OS cells, followed by suppression of the epithelial mesenchymal transition (EMT). Bioinformatic and luciferase reporter analysis identified cellular-mesenchymal to epithelial transition factor (c-MET, also named as MET) as a direct target of miR-613. Overexpression of miR-613 significantly inhibited the c-MET expression and its downstream PI3k/Akt/mTOR signaling pathway in OS cells. In OS clinical samples, there was a significant inverse correlation between miR-613 and c-MET mRNA expression. Rescue experiments showed that overexpression of c-MET partially prevented miR-613-induced suppression of OS cell proliferation, colony formation, migration and invasion. In conclusion, we provide first evidence for the suppressive activity of miR-613 by repressing c-MET, suggesting that miR-613 might be a potential therapeutic strategy for OS.