miRNAs in head and neck cancer revisited

MicroRNA-124 inhibits cellular proliferation and invasion by targeting Ets-1 in breast cancer

MicroRNAs (miRNAs) are small non-coding RNAs that, by targeting certain messenger RNAs (mRNAs) for translational repression or cleavage, can regulate the expression of these genes. In addition, miRNAs may also function as oncogenes and tumor-suppressor genes, as the abnormal expression of miRNAs is associated with various human tumors. However, the effects of the expression of miR-124 in breast cancer remain unclear. The present study was conducted to study the expression of miR-124 in breast cancer, paying particular attention to miR-124's relation to the proliferation, invasion, and apoptosis in breast cancer cell MCF-7 and MDA-MB-231. Real-time quantitative RT-PCR (qRT-PCR) was performed to identify miR-124 that was down-regulated in breast cancer tissues. We also showed E26 transformation specific-1 (Ets-1) and miR-124 expression levels in breast cancer tissues that were associated with lymph node metastases. With transfected synthetic miR-124 agomir into MCF-7 and MDA-MB-231, a significant reduction (P < 0.05) in MCF-7 and MDA-MB-231 cell proliferation and colony forming potential was observed after treatment with miR-124. Apoptosis and migration rates were found to be significantly higher in two breast-derived cell lines transfected with a miR-124 agomir (P < 0.05). Luciferase reporter assay and Western blot were used to verify Ets-1 as a potential major target gene of miR-124, and the result showed that miR-124 can bind to putative binding sites within the Ets-1 mRNA 3' untranslated region (UTR) to reduce its expression. Based on these findings, we propose that miR-124 and Ets-1 may serve as a therapeutic agent in breast cancer.

Estimation of vascular endothelial growth factor gene -460 C/T polymorphism as a biomarker in oral squamous cell carcinoma patients from the Indian subcontinent

AIM

Oral squamous cell carcinoma (OSCC) is one of the most common malignancies in India. Vascular endothelial growth factor (VEGF), a major mediator of angiogenesis, is known to play a key role in the pathophysiology of tumorigenesis. Polymorphisms of the VEGF gene have been shown to influence the risk of OSCC, but it remains to be elucidated in the Indian population. Thus, the present study was designed to detect the VEGF gene -460 C/T polymorphism in OSCC patients from the Indian population, which is genetically distinct from previously-studied populations.

METHODS

Peripheral blood samples of 80 OSCC patients and 80 healthy individuals were collected for a case-control study design. The VEGF gene -460 C/T polymorphism was detected by polymerase chain reaction-based restriction analysis.

RESULTS

The analysis revealed significant differences between normal individuals and patients with OSCC (P < 0.05). The distribution of the TT homozygote and the T allele in the patient group was significantly greater than in the control group.

CONCLUSION

The present study provides novel evidence of the role of the VEGF gene -460 C/T polymorphism as a suitable genetic marker of OSCC in the Indian population.

Role of human papillomavirus in oropharyngeal squamous cell carcinoma: A review

Human papillomavirus (HPV) has been implicated in the pathogenesis of a subset of oropharyngeal squamous cell carcinoma. As a result, traditional paradigms in relation to the management of head and neck squamous cell carcinoma have been changing. Research into HPV-related oropharyngeal squamous cell carcinoma is rapidly expanding, however many molecular pathological and clinical aspects of the role of HPV remain uncertain and are the subject of ongoing investigation. A detailed search of the literature pertaining to HPV-related oropharyngeal squamous cell carcinoma was performed and information on the topic was gathered. In this article, we present an extensive review of the current literature on the role of HPV in oropharyngeal squamous cell carcinoma, particularly in relation to epidemiology, risk factors, carcinogenesis, biomarkers and clinical implications. HPV has been established as a causative agent in oropharyngeal squamous cell carcinoma and biologically active HPV can act as a prognosticator with better overall survival than HPV-negative tumours. A distinct group of younger patients with limited tobacco and alcohol exposure have emerged as characteristic of this HPV-related subset of squamous cell carcinoma of the head and neck. However, the exact molecular mechanisms of carcinogenesis are not completely understood and further studies are needed to assist development of optimal prevention and treatment modalities.

Validation of an immunoassay to measure plasminogen-activator inhibitor-1 concentrations in human saliva

Introduction:

We have previously shown that the concentrations of D-dimer are significantly elevated in saliva compared with plasma. Saliva offers several advantages compared with blood analysis. We hypothesised that human saliva contains plasminogen activator inhibitor-1 (PAI-1) and that the concentrations are not affected by the time of saliva collection. The aim was to adopt and validate an immunoassay to quantify PAI-1 concentrations in saliva and to determine whether saliva collection time has an influence in the measurement.

Materials and methods:

Two saliva samples (morning and afternoon) from the same day were collected from healthy subjects (N = 40) who have had no underlying heart conditions. A customized AlphaLISA® immunoassay (PerkinElmer®, MA, USA) was adopted and used to quantify PAI-1 concentrations. We validated the analytical performance of the customized immunoassay by calculating recovery of known amount of analyte spiked in saliva.

Results:

The recovery (95.03%), intra- (8.59%) and inter-assay (7.52%) variations were within the acceptable ranges. The median salivary PAI-1 concentrations were 394 pg/mL (interquartile ranges (IQR) 243.4–833.1 pg/mL) in the morning and 376 (129.1–615.4) pg/mL in the afternoon and the plasma concentration was 59,000 (24,000–110,000) pg/mL. Salivary PAI-1 did not correlate with plasma (P = 0.812).

Conclusions:

The adopted immunoassay produced acceptable assay sensitivity and specificity. The data demonstrated that saliva contains PAI-1 and that its concentration is not affected by the time of saliva collection. There is no correlation between salivary and plasma PAI-1 concentrations. Further studies are required to demonstrate the utility of salivary PAI-1 in CVD risk factor studies.

ROCK1, a novel target of miR-145, promotes glioma cell invasion

Malignant glioma is the most common type of cancer in the central nervous system, with highly invasive characteristics. The Rho-associated protein kinase (ROCK1) has been found to act as key regulator of actin cytoskeleton reorganization, a process closely associated with cancer cell invasion. microRNA-145 (miRNA-145) has been recently shown to act as a suppressor in several types of tumor, including glioma. However, the exact regulatory mechanism by which miR-145 inhibits glioma still remains to be uncovered. In this study, we report that the miR-145 level was significantly reduced in glioma tissues and in the human glioma cell lines U87 and U251, as compared to matched adjacent and normal brain tissues. We then identified the ROCK1 gene as a novel target of miR-145. The expression of ROCK1 was markedly upregulated in glioma tissues, as well as in U87 and U251 cells. Moreover, miR-145 significantly inhibited ROCK1 protein expression in U87 cells. We further show that miR-145 transfection considerably reduced the invasive ability of U87 cells, and was accompanied by the downregulation of matrix metalloproteinase 2 and 9, an effect which could be attenuated by overexpression of ROCK1. In conclusion, the present study suggests that miR-145 can inhibit U87 glioma cell invasion, at least partially via downregulation of the RhoA/ROCK1 pathway. In conclusion, this is the first study to report that ROCK1, as a novel target of miR-145, acts as a positive regulator of glioma cell invasion. Therefore, ROCK1 may constitute a promising target for glioma treatment.

Disturbing miR-182 and -381 inhibits BRD7 transcription and glioma growth by directly targeting LRRC4

Inactivated LRRC4 has been clinically detected in gliomas, and promoter hypermethylation has been implicated as the mechanism of inactivation in some of those tumors. Our previous researches indicated that LRRC4 is a target gene of miR-381, the interaction of miR-381 and LRRC4 is involved in glioma growth. In this study, we demonstrate that LRRC4 is a target gene of the other microRNA, miR-182. We found that the high expression of miR-182 and miR-381 in gliomas are involved in pathological malignant progression. The silencing of miR-182 and miR-381 inhibited the proliferation in vitro and growth of glioma cell with in vivo magnetic resonance imaging by intracranial transplanted tumor model in rats. We also demonstrated that BRD7, a transcriptional cofactor for p53, is highly expressed and negatively correlated with LRRC4 expression in gliomas. Disturbing miR-182 and miR-381 affected transcriptional regulation of the BRD7 gene. This finding was verified by ectopic overexpression of LRRC4 or restoration of endogenous LRRC4 expression by treatment with the DNA demethylating agent 5-Aza-dC. Taken together, miR-182 and miR-381 may be a useful therapeutic target for treatment of glioma.

siRNA-mediated knock-down of DFF45 amplifies doxorubicin therapeutic effects in breast cancer cells

PURPOSE

RNA interference (RNAi) has become a promising tool for cancer therapy. Small interfering RNAs (siRNAs) can synergistically enhance the cell killing effects of drugs used in cancer treatment. Here we examined the effects of siRNA-mediated DNA fragmentation factor 45 (DFF45) gene silencing on breast cancer cell viability, cell cycle arrest, and apoptosis in the presence and absence of doxorubicin.

METHODS

We designed three siRNAs, which target different regions of the DFF45 mRNA. Gene silencing was confirmed by real time RT-PCR and Western blot analyses. The impact of DFF45 siRNA, doxorubicin, and their combination on the viability, cell cycle and apoptosis of T-47D and MDA-MB-231 breast cancer cells were determined by MTT, PI staining, annexin V binding, caspase-3 activity, DNA laddering, and chromatin condensation assays.

RESULTS

Based on flow cytometric analyses, we found that silencing of DFF45 alone had little effect on apoptosis, especially in T-47D cells. However, when used in combination with doxorubicin (0.33 μM) a significant increase (P < 0.05) in apoptosis was observed in T-47D and MDA-MB-231 cells, i.e., ~2.5- and 3-fold, respectively. Caspase-3 activity, chromatin condensation, as well as DNA laddering supported increased apoptosis in the combinatorial treatment. Cell cycle arrest in both cell lines occurred at lower levels after siRNA + doxorubicin treatment compared to doxorubicin only.

CONCLUSIONS

Our data indicate that DFF45 gene silencing, when applied in combination with doxorubicin, may offer a novel therapeutic strategy for the treatment of breast cancer.

Differential expression profiling of microRNAs and their potential involvement in esophageal squamous cell carcinoma

MicroRNAs are small, noncoding RNAs approximately 18-24 nucleotides in length that negatively regulate gene expression at the posttranscriptional and/or translational level by binding to complimentary sequences in the 3'-untranslated regions of target mRNAs. Growing evidence has indicated the important roles for different miRNA species in the development of different cancers. Therefore, miRNAs have the potential to become new biological markers for esophageal squamous cell carcinoma (ESCC) and to be applied in the diagnosis, prognosis, and targeted treatment of ESCC. In this study, we performed a miRNA microarray to analyze the miRNA expression profile in ESCC compared to normal tissues. Then, we made a preliminary analysis of the biological function for the most differentially expressed miRNAs and their potentially target genes regulated. Some microarray results were validated by performing quantitative RT-PCR. The study provided evidence that linked the biological role of miRNAs to ESCC and showed that miRNAs could undertake a variety of mechanisms. Additionally, we also found that altered miR-429 and miR-451 expression levels were associated with the occurrence of lymph node metastases and the differentiation status and TNM stage in ESCC. The study of miRNAs may lead to finding novel methods to diagnose, treat, and prevent ESCC.

MicroRNAs in Head and Neck Cancer

microRNAs (miRs) are small noncoding single-stranded RNAs, about 19–25 nucleotides long. They have been shown to be capable of altering mRNA expression; thus some are oncogenic or tumour suppressive in nature and are regulated by cellular and epigenetic factors. The molecular pathogenic pathway of many cancers has been modified since the discovery of miRs. Head and neck squamous cell carcinoma (HNSCC), the sixth most common cancer in the world, has recently been associated with infection by the human papillomavirus (HPV). miR expression profiles are altered in the transition from dysplasia to carcinoma, with some changes being specific to the underlying risk factor. This difference is particularly significant in HPV-positive HNSCC where host miRs are modulated by the virus, creating a different profile to HPV-negative HNSCC. Saliva, as an easily collected proximal biofluid containing numerous miRs, presents an attractive noninvasive diagnostic tool in detecting HNSCC and determining prognosis. Furthermore, miRs may play a role in the analysis of surgical margins for residual tumour extension and in the development of novel miR-based therapeutic targets and agents.

Curcumin-loaded nanoparticles induce apoptotic cell death through regulation of the function of MDR1 and reactive oxygen species in cisplatin-resistant CAR human oral cancer cells

Curcumin is a polyphenolic compound which possesses anticancer potential. It has been shown to induce cell death in a variety of cancer cells, however, its effect on CAL27‑cisplatin-resistant human oral cancer cells (CAR cells) has not been elucidated to date. The low water solubility of curcumin which leads to poor bioavailability, however, has been highlighted as a major limiting factor. In this study, we utilized water-soluble PLGA curcumin nanoparticles (Cur-NPs), and investigated the effects of Cur-NPs on CAR cells. The results showed Cur-NPs induced apoptosis in CAR cells but exhibited low cytotoxicity to normal human gingival fibroblasts (HGFs) and normal human oral keratinocytes (OKs). Cur-NPs triggered DNA concentration, fragmentation and subsequent apoptosis. Compared to untreated CAR cells, a more detectable amount of Calcein-AM accumulation was found inside the treated CAR cells. Cur-NPs suppressed the protein and mRNA expression levels of MDR1. Both the activity and the expression levels of caspase-3 and caspase-9 were elevated in the treated CAR cells. The Cur-NP-triggered apoptosis was blocked by specific inhibitors of pan-caspase (z-VAD-fmk), caspase-3 (z-DEVD-fmk), caspase-9 (z-LEHD-fmk) and antioxidant agent (N-acetylcysteine; NAC). Cur-NPs increased reactive oxygen species (ROS) production, upregulated the protein expression levels of cleaved caspase-3/caspase-9, cytochrome c, Apaf-1, AIF, Bax and downregulated the protein levels of Bcl-2. Our results suggest that Cur-NPs triggered the intrinsic apoptotic pathway through regulating the function of multiple drug resistance protein 1 (MDR1) and the production of reactive oxygen species (ROS) in CAR cells. Cur-NPs could be potentially efficacious in the treatment of cisplatin-resistant human oral cancer.