Down-regulation of miR-26b induces cisplatin resistance in nasopharyngeal carcinoma by repressing JAG1

Precision medicine in nasopharyngeal carcinoma: comprehensive review of past, present, and future prospect

Nasopharyngeal carcinoma (NPC) is an aggressive malignancy with high propensity for lymphatic spread and distant metastasis. It is prominent as an endemic malignancy in Southern China and Southeast Asia regions. Studies on NPC pathogenesis mechanism in the past decades such as through Epstein Barr Virus (EBV) infection and oncogenic molecular aberrations have explored several potential targets for therapy and diagnosis. The EBV infection introduces oncoviral proteins that consequently hyperactivate many promitotic pathways and block cell-death inducers. EBV infection is so prevalent in NPC patients such that EBV serological tests were used to diagnose and screen NPC patients. On the other hand, as the downstream effectors of oncogenic mechanisms, the promitotic pathways can potentially be exploited therapeutically. With the apparent heterogeneity and distinct molecular aberrations of NPC tumor, the focus has turned into a more personalized treatment in NPC. Herein in this comprehensive review, we depict the current status of screening, diagnosis, treatment, and prevention in NPC. Subsequently, based on the limitations on those aspects, we look at their potential improvements in moving towards the path of precision medicine. The importance of recent advances on the key molecular aberration involved in pathogenesis of NPC for precision medicine progression has also been reported in the present review. Besides, the challenge and future outlook of NPC management will also be highlighted.

MicroRNAs as the pivotal regulators of cisplatin resistance in head and neck cancers

Although, there is a high rate of good prognosis in early stage head and neck tumors, about half of these tumors are detected in advanced stages with poor prognosis. A combination of chemotherapy, radiotherapy, and surgery is the treatment option in head and neck cancer (HNC) patients. Although, cisplatin (CDDP) as the first-line drug has a significant role in the treatment of HNC patients, CDDP resistance can be observed in a large number of these patients. Therefore, identification of the molecular mechanisms involved in CDDP resistance can help to reduce the side effects and also provides a better therapeutic management. MicroRNAs (miRNAs) as the post-transcriptional regulators play an important role in drug resistance. Therefore, in the present review we investigated the role of miRNAs in CDDP response of head and neck tumors. It has been reported that the miRNAs exerted their roles in CDDP response by regulation of signaling pathways such as WNT, NOTCH, PI3K/AKT, TGF-β, and NF-kB as well as apoptosis, autophagy, and EMT process. The present review paves the way to suggest a non-invasive miRNA based panel marker for the prediction of CDDP response among HNC patients. Therefore, such diagnostic miRNA based panel marker reduces the CDDP side effects and improves the clinical outcomes of these patients following an efficient therapeutic management.

miRNAs as potential game-changers in head and neck cancer: Future clinical and medicinal uses

Head and neck cancers (HNCs) are a group of heterogeneous tumors formed most frequently from epithelial cells of the larynx, lips, oropharynx, nasopharynx, and mouth. Numerous epigenetic components, including miRNAs, have been demonstrated to have an impact on HNCs characteristics like progression, angiogenesis, initiation, and resistance to therapeutic interventions. The miRNAs may control the production of numerous genes linked to HNCs pathogenesis. The roles that miRNAs play in angiogenesis, invasion, metastasis, cell cycle, proliferation, and apoptosis are responsible for this impact. The miRNAs also have an impact on crucial HNCs-related mechanistic networks like the WNT/β-catenin signaling, PTEN/Akt/mTOR pathway, TGFβ, and KRAS mutations. miRNAs may affect how the HNCs respond to treatments like radiation and chemotherapy in addition to pathophysiology. This review aims to demonstrate the relationship between miRNAs and HNCs with a particular emphasis on how miRNAs impact HNCs signaling networks.

Quercetin acts as a novel anti-cancer drug to suppress cancer aggressiveness and cisplatin-resistance in nasopharyngeal carcinoma (NPC) through regulating the yes-associated protein/Hippo signaling pathway

BACKGROUND

Quercetin has been proven to be effective for cancer treatment, including nasopharyngeal carcinoma (NPC). Also, Quercetin sensitizes cancer cells to current chemical drugs to improve their therapeutic efficacy. However, up until now, the molecular mechanisms that quercetin exerted its therapeutic effects on NPC have not been fully delineated.

METHODS

Cell proliferation abilities were examined by CCK-8 assay and colony formation assay. Real-Time qPCR and Western Blot analysis were used to detect gene expressions at RNA and protein levels. Cell mobility was determined by wound scratch assay and transwell assay. Cell death was detected using flow cytometry (FCM). Tumorigenesis of the NPC cells was determined by in vivo tumor-bearing mice models. Hematoxylin and eosin (H&E) and TUNEL staining were used to detect the tumor metastasis to lung tissues and dead cells, respectively.

RESULTS

Here, we validated that quercetin exerted its anti-tumor effects and increased cisplatin-sensitivity in NPC in vitro and in vivo. Specifically, quercetin inhibited NPC cell proliferation, viability, mobility, epithelial-mesenchymal transition (EMT), and tumorigenesis, and induced cell death, resulting in the inhibition of NPC progression. In addition, the NPC cells were subjected to a continuously increasing doses of cisplatin to generate cisplatin-resistant NPC (NPC/CDDP) cells. Interestingly, quercetin significantly enhanced the cytotoxic effects of high-dose cisplatin on NPC/CDDP cells. Furthermore, the potential underlying mechanisms were uncovered, and the results evidenced that quercetin inhibited Yes-associated protein (YAP) expression and its translocation to the nucleus, leading to the recovery of the Hippo pathway, inhibition of cancer progression, and increase in cisplatin-resistance. Mechanistically, upregulation of YAP by its gene manipulating vectors abrogated the inhibiting effects of quercetin on NPC malignant phenotypes, which also made NCP/CDDP cells irresponsive to high-dose cisplatin-quercetin co-treatments.

CONCLUSION

Collectively, our data evidenced that quercetin inhibited YAP to recover the Hippo pathway, which further inhibited NPC pathogenesis and increased susceptibility of NCP/CDDP cells to cisplatin treatment.

FOXD3 confers chemo-sensitivity in ovarian cancer through a miR-335/DAAM1/myosin II axis-dependent mechanism

BACKGROUND

Chemotherapy is among the most common treatment methods for ovarian cancer (OC). However, chemoresistance limits the effectiveness of chemotherapy and leads to treatment failure. We herein investigate the biological effect of forkhead box D3 (FOXD3) in the chemoresistance of OC cells.

METHODS

Expression of FOXD3, miR-335 and disheveled-associated activator of morphogenesis 1 (DAAM1) was detected in OC cells and tissues. The regulatory network of FOXD3/miR-335/DAAM1 was validated by dual-luciferase reporter and ChIP assays in vitro. After ectopic expression and depletion experiments in carboplatin/paclitaxel (CP)-resistant (A2780CP) or sensitive (A2780S) OC cells, cell viability, colony formation and apoptosis were tested by CCK-8 assay, colony formation assay and flow cytometry respectively. Effects of FOXD3 on the chemoresistance of OC cells in vivo were evaluated in OC xenografts in nude mice.

RESULTS

Overexpression of FOXD3 impaired the proliferation and chemoresistance of OC cells, which was related to the promotion of the miR-335 expression. Functionally, DAAM1 was a putative target of miR-335. Silencing of DAAM1 was responsible for the inhibition of myosin II activation, consequently leading to suppressed OC cell proliferation and chemoresistance. In vivo results further showed that FOXD3 weakened the chemoresistance of OC cells to CP.

CONCLUSION

Taken together, we unveil a novel FOXD3/miR-335/DAAM1/myosin II axis that regulates the chemoresistance of OC both in vitro and in vivo.

HOTAIR mediates cisplatin resistance in nasopharyngeal carcinoma by regulating miR-106a-5p/SOX4 axis

This study explored the function and mechanisms of HOX transcript antisense RNA (HOTAIR) in the drug resistance of nasopharyngeal carcinoma (NPC). Quantitative PCR, Western blotting, MTT assay, flow cytometry, Transwell assay, and luciferase assay were performed. HOTAIR expression levels were upregulated in cisplatin (DDP)-resistant NPC tissues and cells. Knockdown of HOTAIR in DDP-resistant NPC cells increased cell sensitivity of DDP, as well as decreased cell viability, expression of chemoresistance-related proteins, migration and invasion, increased cell apoptosis. In addition, downregulation of microRNA 106a-5p (miR-106a-5p) expression and upregulation of SRY-box transcription factor 4 (SOX4) expression were observed in DDP-resistant NPC tissues and cells. MiR-106a-5p targets HOTAIR and SOX4; thus, silencing of HOTAIR significantly increased miR-106a-5p expression. The overexpression of miR-106a-5p significantly reversed the increase in SOX4 expression induced by HOTAIR lentivirus (Lv-HOTAIR). Knockdown of SOX4 reduced the drug resistance of DDP caused by the silencing of miR-106a-5p expression. In summary, HOTAIR enhanced DDP resistance in NPC cells by regulating the miR-106a-5p/SOX4 axis.

Upregulation of MiR-340-5p Reverses Cisplatin Sensitivity by Inhibiting the Expression of CDK6 in HepG2 Cells

Cisplatin (CDDP) has been successfully used in chemotherapy for liver cancer. However, the development of CDDP resistance in HepG2 cells usually leads to relapse and a worsening prognosis. MiR-340-5p has attracted much attention because of its ability to affect cell resistance. This project is intended to explore the role of miR-340-5p and CDK6 in CDDP-R HepG2 cells and provide new ideas for the treatment of liver cancer. A dual-luciferase reporter assay was used to confirm the targeting relationship between miR-340-5p and CDK6. We constructed a CDDP-resistant model of HepG2 cells to examine the effect of miR-340-5p on the drug sensitivity of HepG2 cells. CDDP-R HepG2 cells were transfected with miR-340-5p overexpression plasmid and CDK6 silencing plasmid. QRT-PCR was used to detect the expression of miR-340-5p and CDK6. A western blot was performed to determine the expression of CDK6, CyclinD1, and CyclinD2. CCK-8, flow cytometry, TUNEL and Clonogenic assays were also carried out to detect CDDP-R HepG2 cells. There is a targeting relationship between miR-340-5p and CDK6. The drug resistance of CDDP-R HepG2 cells was significantly higher than that of CDDP-S HepG2 cells. CDDP-R HepG2 cells transfected with both miR-340-5p overexpressing plasmid and CDK6 silencing plasmid showed a lower proliferation ability, cell cycle arrest in the G0/G1 phase, and lower drug resistance compared with single CDDP-R HepG2 cells. Overexpression of miR-340-5p aggravated CDDP-R HepG2 cells' apoptosis and inhibited cell viability. Overexpression of miR-340-5p could reverse the sensitivity of HepG2 cells to CDDP by inhibiting the expression of CDK6 in HepG2 cells.

Advances in targeted therapy mainly based on signal pathways for nasopharyngeal carcinoma

Nasopharyngeal carcinoma (NPC) is a malignant epithelial carcinoma of the head and neck region which mainly distributes in southern China and Southeast Asia and has a crucial association with the Epstein-Barr virus. Based on epidemiological data, both incidence and mortality of NPC have significantly declined in recent decades grounded on the improvement of living standard and medical level in an endemic region, in particular, with the clinical use of individualized chemotherapy and intensity-modulated radiotherapy (IMRT) which profoundly contributes to the cure rate of NPC patients. To tackle the challenges including local recurrence and distant metastasis in the current NPC treatment, we discussed the implication of using targeted therapy against critical molecules in various signal pathways, and how they synergize with chemoradiotherapy in the NPC treatment. Combination treatment including targeted therapy and IMRT or concurrent chemoradiotherapy is presumably to be future options, which may reduce radiation or chemotherapy toxicities and open new avenues for the improvement of the expected functional outcome for patients with advanced NPC.

The oncogenic role of Jagged1/Notch signaling in cancer

Aberrant activation of Notch signaling plays an oncogenic role in cancer development. Jagged1 (JAG1) is an important Notch ligand that triggers Notch signaling through cell-cell interactions. JAG1 overexpression has been reported in many different types of cancer and correlates with a poor clinical prognosis. JAG1/Notch signaling controls oncogenic processes in different cell types and cellular contexts. Furthermore, JAG1/Notch signaling cascades activate a number of oncogenic factors that regulate cellular functions such as proliferation, metastasis, drug-resistance, and angiogenesis. To suppress the severe toxicity of pan-Notch inhibitors, JAG1 is attracting increasing attention as a source of therapeutic targets for cancers. In this review, the oncogenic role of JAG1/Notch signaling in cancer is discussed, as well as implications of strategies to inhibit JAG1/Notch signaling activity.

FOXD3 inhibits cell proliferation, migration, and invasion in nasopharyngeal carcinoma through regulation of the PI3K-Akt pathway

FOXD3 has been found previously to positively regulate miR-26b, a tumor inhibitor of nasopharyngeal carcinoma (NPC). However, FOXD3's precise function and associated mechanism of action in NPC have not yet been investigated. In this study, the expression of FOXD3 mRNA and protein was evaluated using RT-qPCR, western blotting, and immunohistochemistry. Protein levels involved in the phosphoinositide 3-kinase - protein kinase B (PI3K-Akt) pathway were assessed by western blot, and cell proliferation was determined by MTT and colony forming assays. Additionally, cell apoptosis was assessed by flow cytometric assay. Finally, the migration and invasion capabilities of the NPC cells were determined using wound healing and Transwell assays. We found that FOXD3 levels were relatively low in NPC tissue and cells, while an increase caused the inhibition of the PI3K-Akt pathway. Functional experiments found that overexpression of FOXD3 suppressed cell proliferation, migration, and invasion and enhanced cell apoptosis in NPC C6661 cells. IGF-1, an activator of the PI3K-Akt pathway, reversed the inhibitory effect of FOXD3. Furthermore, we found upregulation of the PI3K-Akt pathway and upregulation of the inhibitory effects of FOXD3 on C6661 cellular activities. In conclusion, FOXD3 negatively affected the PI3K-Akt pathway to restrain the processes involved in C6661 cell pathology. These findings further exposed the function and downstream axis of FOXD3 in NPC and displayed a promising new target for NPC therapy.

Non-coding RNAs in drug resistance of head and neck cancers: A review

Head and neck cancer (HNC), which includes epithelial malignancies of the upper aerodigestive tract (oral cavity, oropharynx, pharynx, hypopharynx, larynx, and thyroid), are slowly but consistently increasing, while the overall survival rate remains unsatisfactory. Because of the multifunctional anatomical intricacies of the head and neck, disease progression and therapy-related side effects often severely affect the patient's appearance and self-image, as well as their ability to breathe, speak, and swallow. Patients with HNC require a multidisciplinary approach involving surgery, radiation therapy, and chemotherapeutics. Chemotherapy is an important part of the comprehensive treatment of tumors, especially advanced HNC, but drug resistance is the main cause of poor clinical efficacy. The most important determinant of this phenomenon is still largely unknown. Recent studies have shown that non-coding RNAs have a crucial role in HNC drug resistance. In addition, they can serve as biomarkers in the diagnosis, treatment, and prognosis of HNCs. In this review, we summarize the relationship between non-coding RNAs and drug resistance of HNC, and discuss their potential clinical application in overcoming HNC chemoresistance.

Effect of miR-26b-5p on cis-diamine dichloroplatinum-induced ovarian granulosa cell injury by targeting MAP3K9

The proliferation and differentiation of granulosa cells are very important for follicular development. The dysfunction of granulosa cells leading to follicular development is an important cause of ovarian endocrine abnormalities. More and more evidence shows that microRNAs are involved in the regulation of ovarian granulosa cell function. It has been found that MiR-26b may be involved in CDDP resistance. Studies have shown that miR-26b can promote apoptosis of ovarian granulosa cells, but there are few studies on its mechanism, and no studies have been found on the damage of miR-26b-5p to rat ovarian granulosa cells induced by CDDP. Identification of ovarian granulosa cells was conducted by immunochemical staining. Cell counting kit 8 (CCK-8) was used to detect cell viability, flow cytometry was used to detect cell apoptosis, quantitative reverse transcription polymerase chain reaction (qRT-PCR) and Western blot (WB) were used to analyze the expression of miR-26b-5p, MAP3K9, cleaved Caspase-3, Bax, and Bcl-2; dual-luciferase reporter assay results further verify the targeting relation between miR-26b-5p and MAP3K9. CDDP remarkably inhibited ovarian granulosa cell viability and induced ovarian granulosa cell apoptosis; miR-26b-5p inhibitor enhanced viability and inhibited apoptosis of ovarian granulosa cells, which treated with CDDP, but had little effect on normal cells. MAP3K9 partially reversed the effect of miR-26b-5p on ovarian granulosa cells induced by CDDP. miR-26b-5p has a protective effect on CDDP-induced ovarian granulosa cells via targeting MAP3K9.

Restoration of miR-26b expression partially reverses the cisplatin resistance of NSCLC by targeting tafazzin

Background

Dysregulation of microRNAs has been reported to be responsible for drug resistance of cancers. However, the association between aberrant expression of miR-26b and cisplatin resistance in non-small cell lung cancer (NSCLC) remains unclear.

Methods

PC9 and A549 were used to establish the cisplatin resistance models on NSCLC. Expression of miR-26b in cisplatin-resistant PC9 and A549 cells (PC9/R and A549/R) was detected by quantitative real-time PCR assays. Drug sensitivity and mitochondrial apoptosis were detected by Cell Counting Kit-8 assay and flow cytometry assay, respectively. The target relationship between miR-26b and tafazzin (TAZ) was validated by dual-luciferase reporter assay.

Results

Obvious downregulation of miR-26b was observed in PC9/R and A549/R cells. Restoration of miR-26b partially reversed the cisplatin resistance of PC9/R and A549/R cells. Expression of TAZ was increased in PC9/R and A549/R cells compared to the parental PC9 and A549 cells. Results of dual-luciferase reporter assays verified that TAZ was targeted by miR-26b. We showed that restoration of miR-26b expression inhibited the TAZ expression and thus expanded the mitochondrial pathway of apoptosis induced by cisplatin in PC9/R and A549/R cells.

Conclusion

Restoration of miR-26b expression partially reverses the cisplatin resistance of NSCLC by targeting TAZ. miR-26b/TAZ axis may represent a potential strategy to reverse the cisplatin in NSCLC.

Inhibition of the Numb/Notch signaling pathway increases radiation sensitivity in human nasopharyngeal carcinoma cells

Radiation therapy is the primary treatment for primary nasopharyngeal carcinoma (NPC). The aim of this study is to identify the effect of the Numb/Notch signaling pathway on radiation sensitivity in human NPC cells. NPC tissues and normal nasopharyngeal tissues were collected. To evaluate the regulatory effects of the Numb/Notch signaling pathway, NPC cells were subjected to radiotherapy and various doses of the Numb/Notch signaling pathway inhibitor gamma secretase inhibitor (GSI). Next, the expression of Notch and Numb proteins was determined in NPC tissues and normal nasopharyngeal tissues, and the correlation of Notch and Numb protein expression with the clinicopathological features of NPC tissues was analyzed. Then, the effect of radiotherapy on NPC cell survival rate, survival fraction, apoptosis rate, proliferation, migration, and invasion as well as Numb/Notch signaling pathway-related molecules was detected. The results demonstrated that the Numb/Notch signaling pathway was activated in NPC tissues. Following treatment with radiotherapy and GSI, the Numb/Notch signaling pathway was inhibited. In addition, the NPC cell survival rate, survival fraction, cell proliferation, migration, and invasion were decreased, whereas the colony number and apoptosis rate were increased. Following radiotherapy and GSI treatment, Numb expression was increased, whereas Notch1, Hes1, Jagged1, and c-Myc expression was decreased. However, the greatest difference was noted upon treatment with radiotherapy +15 μM GSI. The results reported in this study suggest that a high dose of the inhibitor of the Numb/Notch signaling pathway GSI increased the radiation sensitivity in human NPC cells.

Long noncoding RNA DANCR contributes to docetaxel resistance in prostate cancer through targeting the miR-34a-5p/JAG1 pathway

Background: Chemotherapy is one of the available options for prostate cancer (PC). However, the acquisition of chemoresistance has become a major cause of chemotherapy failure. The long noncoding RNA DANCR is demonstrated to serve as an oncogene in various human cancers, including PC. However, the potential role of DANCR in docetaxel (DTX) resistance of PC and its underlying mechanism remains unclear.

Methods: The abundance of DANCR, miR-34a-5p, and JAG1 mRNA was examined by quantitative reverse transcription PCR. The Cell Counting Kit-8 (CCK8) was used to determine the 50% inhibitory concentration value. Cell viability was evaluated by CCK8 and colony-formation assays. Transwells were utilized to analyze cell migration and invasion ability. The protein levels of LRP, P-gp, MRP1, and JAG1 were measured by Western blot assay. The target relationship between DANCR and miR-34a-5p, as well as miR-34a-5p and JAG1, was demonstrated by dual-luciferase, RNA immunoprecipitation, and RNA pull-down analysis. Tumor xenograft was undertaken to confirm the effect of DANCR on DTX resistance in PC.

Results: DANCR and JAG1 were significantly upregulated, but miR-34a-5p was downregulated in DTX-resistant PC. Silencing of DANCR improved the DTX efficacy in DTX-resistant PC cells. DANCR served as a competing endogenous RNA of miR-34a-5p, leading to the derepression of miR-34a-5p target JAG1, which eventually triggered the resistance to DTX in DTX-tolerated PC.

Conclusion: The DANCR/miR-34a-5p axis enhanced DTX resistance of PC via targeting JAG1, providing a novel insight to improve chemotherapy for PC.

Expression of miR-26b in ovarian carcinoma tissues and its correlation with clinicopathology

The expression of microRNA (miR)-26b in ovarian carcinoma tissues, its correlation with clinicopathology, and its effect on diagnostic value and prognosis of ovarian cancer was investigated. A total of 74 patients with ovarian cancer (the study group) and 30 patients with benign ovarian tumors (the control group) in the Affiliated Hospital of Inner Mongolia Medical University from July 2011 to June 2013 were retrospectively analyzed. The expression of miR-26b in ovarian carcinoma tissues was detected by fluorescence reverse transcription-quantitative polymerase chain reaction (RT-qPCR), and the correlation between the expression of miR-26b and the pathological features of ovarian carcinoma tissues and prognosis of patients was analyzed. The expression level of miR-26b in the study group (0.28±0.07) was significantly lower than that in the control group (0.54±0.11; P<0.050). There was no significant correlation between miR-26b expression and age, tumor type, exercise habit, smoking habit of patients with ovarian cancer (P>0.050), but there was close correlation between the miR-26b expression and lymph node metastasis, differentiation degree and pathological stage of patients with ovarian cancer (P<0.001). ROC curve showed that the area under curve (AUC) was 0.839, and when the maximum cut-off value was 0.815, the sensitivity and specificity of miR-26b in diagnosing the ovary was 84.932% and 77.936%, respectively. The 5-year overall survival rate in the low-expression group (61.54%) was significantly lower than that in the high-expression group (84.85; P=0.028). miR-26b is under-expressed in the ovary and has a close relationship with pathological stage, differentiation degree, and lymph node metastasis of ovarian cancer, which indicates that miR-26b is involved in the occurrence and development of ovarian cancer and is expected to be an effective indicator for treatment and diagnosis of ovarian cancer and the prognosis of patients.

Roles of β-catenin, TCF-4, and survivin in nasopharyngeal carcinoma: correlation with clinicopathological features and prognostic significance

Background

Nasopharyngeal carcinoma (NPC) is a common malignant tumor of the head and neck region with poorly understood progression and prognosis. The present study aims at exploring whether the expression of β-catenin, TCF-4, and survivin affects clinicopathological features and prognostic significance in NPC.

Methods

We enrolled 164 patients with NPC and 70 patients with chronic nasopharyngitis (CNP) in this study. Reverse transcription quantitative polymerase chain reaction (RT-qPCR) and immunohistochemistry (IHC) were conducted to evaluate the expression of β-catenin, TCF-4, and survivin. Spearman’s rank correlation analysis and Pearson correlation analysis were used to measure the correlation of β-catenin, TCF-4, and survivin. Risk factors for prognosis and survival conditions of NPC patients were analyzed by Cox proportional hazards model and Kaplan–Meier curves.

Results

The results obtained revealed that mRNA and protein expression of β-catenin, TCF-4, and survivin was higher in NPC tissues than in CNP tissues. Positive correlations amongst β-catenin, TCF-4, and survivin were identified by Spearman’s rank correlation analysis and Pearson correlation analysis. There was a significant correlation in expression of β-catenin, TCF-4, and survivin with EBV DNA, EBV-VCA-IgA, EBV-EA-IgA, T stage, N stage, and clinicopathological stages. Lower overall survival (OS), distant metastasis-free survival (DMFS), local recurrence-free survival (LRFS), and disease-free survival (DFS) rates were detected in NPC patients with positive expression of β-catenin, TCF-4, and survivin, in contrast to those with negative expression. Cox proportional hazards model demonstrated that β-catenin, TCF-4, and survivin protein positive expression were independent risk factors for OS and DFS of NPC prognosis; there was an evident correlation between clinicopathological stages, TCF-4, and EBV-EA-IgA and OS, DMFS, LRFS, and DFS of NPC.

Conclusions

The aforementioned results indicate that β-catenin, TCF-4, and survivin proteins are highly expressed in NPC, which can be used as factors to predict the malignancy of NPC. In addition, positive expression of β-catenin, TCF-4, and survivin are potential risk factors that lead to an unfavorable prognosis of OS and DFS in NPC patients.

Expression of vimentin in nasopharyngeal carcinoma and its possible molecular mechanism: A study based on immunohistochemistry and bioinformatics analysis

BACKGROUND

Although previous researchers have analyzed the expression level of vimentin in nasopharyngeal carcinoma (NPC), the sample size of each study was too small, and there was no further in-depth study utilizing microarray and RNA-sequencing data. More importantly, the role and molecular mechanism of vimentin in NPC have not yet been addressed comprehensively. Accordingly, the aim of the present research was to conduct a full exploration of the clinical significance of vimentin in NPC in a large sample size.

MATERIALS AND METHODS

Immunohistochemistry was used to test the expression of vimentin in clinical samples. Data from relevant microarray and RNA-sequencing datasets were screened and extracted to explore the clinical role of vimentin in NPC. Subsequently, vimentin-related signaling pathways were investigated via in-silico approaches.

RESULTS

The clinical immunohistochemistry detection showed the positive expression ratio of vimentin was 24.6% (14/57) of the NPC specimens, whereas vimentin expression was negative in nasopharyngitis (NPG) tissues (0/20, P = 0.016). The mRNA and protein levels of vimentin were both remarkably up-regulated in NPC based on 196 and 1566 cases, respectively. The protein level of vimentin was also a risky factor for the prognosis prediction of NPC with the hazard ratios (HR) being 3.831. Gene ontology (GO) and kyoto encyclopedia of genes and genomes (KEGG) analyses, the localization of vimentin was in both the cytoplasm and the cytoskeleton, and vimentin was involved in the regulation of molecular function, the execution phase of apoptosis, and the regulation of cellular component organization.

CONCLUSION

The high expression of vimentin plays a pivotal role in the development and poor progression of NPC, which indicates that vimentin may be an effective predictive indicator for NPC.

MicroRNA-26b suppresses tumorigenicity and promotes apoptosis in small cell lung cancer cells by targeting myeloid cell leukemia 1 protein

The aim of this study was to investigate the role of microRNA-26b (miR-26b) in regulating the proliferation, migration, and apoptosis of small cell lung cancer (SCLC) cells. First, we examined the expression level of miR-26b in human normal fetal lung fibroblasts (NFLFs) and three SCLC cell lines NCI-H466, NCI-H1688, and NCI-H196. In the following experiments, the three SCLC cell lines were transfected with miR-26b mimic and inhibitor. Cell growth and survival, as well as migration and invasion capacities were determined by MTT, colony formation, Transwell migration and invasion, and wound healing assays. Cell apoptosis, production of reactive oxygen species, and mitochondrial membrane potential were also measured in the three cell lines following various treatments. As a result, we found that the level of miR-26b was significantly lower in SCLC cells than in NFLFs. Additionally, transfection with miR-26b mimic could inhibit proliferation, colony formation, and migration, as well as induce apoptosis in these SCLC cell lines; while miR-26b inhibitor showed the opposite effects. Further mechanistic experiment revealed that miR-26b could suppress the expression of myeloid cell leukemia 1 protein (Mcl-1) and the 3'-untranslated region (3'-UTR) of Mcl-1 may be the direct binding site of miR-26b, suggesting that the effect of miR-26b may be mediated by targeting Mcl-1. Collectively, our findings offer a new insight into the role of miR-26b in the pathogenesis of SCLC, and provide primary evidence supporting the potential of miR-26b-based therapy for the treatment of SCLC.

Decreased expression of microRNA-26b in locally advanced and inflammatory breast cancer

Advanced-stage breast cancer patients comprise a smaller proportion of breast cancer patients than do early stage patients and are more likely to experience a poor outcome. Understanding the underlying molecular mechanisms and identifying new biomarkers for treatment in this subgroup of patients is paramount. With the aim of identifying microRNAs that are regulated in advanced-stage breast cancer, we found lower expression of miR-26b, a member of the miR-26 family, in inflammatory breast cancer and noninflammatory locally advanced breast cancer tissue than in normal breast tissue, by quantitative real-time polymerase chain reaction and in situ hybridization. Quantitative real-time polymerase chain reaction (but not in situ hybridization) also revealed lower miR-26b expression in inflammatory breast cancer than in noninflammatory locally advanced breast cancer. Furthermore, lower expression of miR-26b was correlated with shorter distant metastasis-free survival and overall survival in univariate analysis, and with shorter overall survival in multivariate analysis. The expression of miRNA-26b was inversely associated with EZH2 protein expression in several breast cancer cell lines, and overexpression and knockdown of miR-26b caused corresponding changes in EZH2 expression. Our study shows that miR-26b may regulate EZH2 expression in breast cancer and may be useful as a therapeutic target for inflammatory breast cancer and noninflammatory locally advanced breast cancer.

MiR-30a-5p confers cisplatin resistance by regulating IGF1R expression in melanoma cells

BACKGROUND

Melanoma is notoriously resistant to all current modalities of cancer therapies including chemotherapy. In recent years, microRNAs (miRNAs) have emerged as molecular regulators in the development and progression of melanoma. However, the relationship between microRNA and chemo-resistance of melanoma is little known. In present study, we aimed to investigate the miRNAs related to cisplatin-resistance in melanoma cells.

METHODS

After cisplatin (DDP) resistant melanoma cells (M8/DDP and SK-Mel-19/DDP) were established in-vitro, high-throughput screening of differentially expressed miRNAs between resistant cells and parental cells were performed.

RESULTS

It was found that a cancer-related miRNA, miR-30a-5p, was highly over-expressed in resistant cells. Transfection of miR-30a-5p mimic or inhibitor could alter the sensitivity of melanoma cells to cisplatin. Next, we showed that Insulin Like Growth Factor 1 Receptor (IGF1R) gene turned out to be a direct target of miR-30a-5p. Knockdown of IGF1R in melanoma cells could not only reduce the sensitivity to cisplatin but also lead to cell cycle arrest by regulating phosphorylation of Serine-Threonine Protein Kinase (P-AKT (Ser473)) and Tumor Protein P53 (P53).

CONCLUSION

Taken together, our study demonstrated that miR-30a-5p could influence chemo-resistance by targeting IGF1R gene in melanoma cells, which might provide a potential target for the therapy of chemo-resistant melanoma cells.

Cisplatin suppresses proliferation, migration and invasion of nasopharyngeal carcinoma cells in vitro by repressing the Wnt/β-catenin/Endothelin-1 axis via activating B cell translocation gene 1

PURPOSE

Nasopharyngeal carcinoma (NPC) is one of the most commonly diagnosed cancers worldwide with significantly high prevalence in Southern China. Chemoprevention of cancer with alkylating agent compounds could potentially reverse, suppress, or prevent cancer progression. Cisplatin (CIS) is an antineoplastic or cytotoxic platinum-based drug used for chemotherapy of different types of human cancers such as NPC. Nevertheless, the effects of CIS on the migration and invasion of human NPC cells and the underlying molecular mechanisms have not yet been fully scrutinized.

METHODS

In this work, we tested the effect of CIS on the proliferation, migration and invasion of NPC cells. The results exhibited that this drug exerts remarkable inhibitory effects on the proliferation, migration and invasion of NPC cells in a dose-dependent manner. Western blotting and real time RT-PCR were used for expression analyses.

RESULTS

We found that CIS treatment led to a dose-dependent inhibition of Endothelin-1 (ET1) expression, at protein as well as mRNA levels in NPC cells. CIS was also found to activate the expression of BTG1 in NPC cells. Moreover, mechanistic analyses revealed that CIS increased the expression of B cell translocation gene 1 (BTG1) to suppress the expression of ET1. Furthermore, we show that ET1 could not be induced in CIS-resistant cells with suppressed BTG1 expression, and subsequently demote the proliferation, migration and invasion of NPC cells.

CONCLUSIONS

These findings provided compelling evidence of the role of CIS in suppressing NPC metastasis and its underlying molecular mechanisms.

MicroRNA-26b suppresses autophagy in breast cancer cells by targeting DRAM1 mRNA, and is downregulated by irradiation

MicroRNAs (miRs) are small RNAs that do not code for proteins, but instead decrease the stability and suppress the translation of target mRNAs by binding with complementary sequences in their 3'-untranslated regions (3'-UTRs). In the present study, it is reported that breast cancer tumor tissue, as well as irradiated MCF7 breast cancer cells, exhibit decreased levels of miR-26b expression compared with normal breast tissue and MCF7 cells without exposure to radiation. Additionally, a luciferase reporter assay was used to demonstrate that miR-26b directly targetsDNA damage-regulated autophagy modulator 1 (DRAM1). MCF7 cells that were transfected with an miR-26b mimicexhibited the downregulated expression of DRAM1 protein and a reduced level of irradiation-induced autophagy. Inhibiting miR-26b resulted in the upregulation of DRAM1 and increased levels of irradiation-induced autophagy in MCF7 cells. These results suggest that therapeutic strategies to target miR-26b may increase the efficacy of certain types of cancer therapy.

Overexpression of miR-26b decreases the cisplatin-resistance in laryngeal cancer by targeting ATF2

Cisplatin is a common used chemotherapeutic drug for the treatment of laryngeal cancer. However, drug-resistance is a major obstacle in platinum-based chemotherapy for laryngeal cancer. Recent studies have demonstrated that dysregulation of microRNAs (miRNAs) is responsible for chemoresistance in multiple cancers including laryngeal cancer, but the potential mechanisms are required to be explored. In the present study, we constantly exposed the laryngeal cancer cell line Hep-2 with cisplatin to establish a cisplatin-resistant laryngeal cancer cell model (Hep-2/R). We found that Hep-2/R cells exhibited obvious resistance to cisplatin compared to the Hep-2 cells. However, overexpression of miR-26b significantly decreased the half maximal inhibitory concentration (IC50) of cisplatin to Hep-2/R. Mechanically, miR-26b in Hep-2/R decreased the expression of ATF2, and thus inhibiting the phosphorylation of ATF2 and formation of cellular ATF2-c-Jun complex induced by cisplatin. As the results, Hep-2/R cells failed to overexpress the Bcl-xl which is a key anti-apoptotic protein under the cisplatin treatment. Therefore, overexpression of miR-26b was found to be able to promote mitochondrial apoptosis induced by cisplatin.