AIMS: To determine the usefulness of immunohistochemical techniques and FISH of the tumour suppressor TP 53 gene to identify microinvasion in marginal tissue sections and to relate the possible correlation between protein expression and genetic aberrations in OSCC cases in Malaysia.
METHODS: Immunohistochemistry and FISH of TP 53 genes were applied on 26 OSCC formalin fixed paraffin embed (FFEP) blocks selected from two oral cancer referral centers in Malaysia.
RESULTS: For p53 protein immunohistochemistry, 96% of the 26 OSCC studied showed positive immunostaining at the excision margins. In FISH assay, 48.9±9.7% of the cancerous cells were monoploid for p53 probe signals, 41.0±9.5 % were diploid, and 10.2±7.8 % were polyploid. A correlation between p53 immunostaining and TP53 gene aberrations was noted (p< 0.05).
CONCLUSIONS: Immunohistochemical analysis of p53 protein expression and FISH of TP53 gene could be applied as screening tool for microinvasion of OSCC.
PURPOSE: Here, we investigated whether OSCC cells were sensitive towards zerumbone treatment and further determined the molecular pathways involved in the mechanism of action.
METHODS: Cytotoxicity, anti-proliferative, anti-migratory and anti-invasive effects of zerumbone were tested on a panel of OSCC cell lines. The mechanism of action of zerumbone was investigated by analysing the effects on the CXCR4-RhoA and PI3K-mTOR pathways by western blotting.
RESULTS: Our panel of OSCC cells was broadly sensitive towards zerumbone with IC50 values of less than 5 µM whereas normal keratinocyte cells were less responsive with IC50 values of more than 25 µM. Representative OSCC cells revealed that zerumbone inhibited OSCC proliferation and induced cell cycle arrest and apoptosis. In addition, zerumbone treatment inhibited migration and invasion of OSCC cells, with concurrent suppression of endogenous CXCR4 protein expression in a time and dose-dependent manner. RhoA-pull down assay showed reduction in the expression of RhoA-GTP, suggesting the inactivation of RhoA by zerumbone. In association with this, zerumbone also inhibited the PI3K-mTOR pathway through the inactivation of Akt and S6 proteins.
CONCLUSION: We provide evidence that zerumbone could inhibit the activation of CXCR4-RhoA and PI3K-mTOR signaling pathways leading to the reduced cell viability of OSCC cells. Our results suggest that zerumbone is a promising phytoagent for development of new therapeutics for OSCC treatment.
OBJECTIVES: This study was performed to identify mechanisms of afatinib resistance and to explore potential afatinib-based combination treatments with other targeted inhibitors in oral squamous cell carcinoma.
METHODS: We determined the anti-proliferative effects of afatinib on a panel of oral squamous cell carcinoma cell lines using a crystal violet-growth inhibition assay, click-iT 5-ethynyl-2'-deoxyuridine staining, and cell-cycle analysis. Biochemical assays were performed to study the underlying mechanism of drug treatment as a single agent or in combination with the MEK inhibitor trametinib. We further evaluated and compared the anti-tumor effects of single agent and combined treatment by using oral squamous cell carcinoma xenograft models.
RESULTS: In this study, we showed that afatinib inhibited oral squamous cell carcinoma cell proliferation via cell-cycle arrest at the G0/G1 phase, and inhibited tumor growth in xenograft mouse models. Interestingly, we demonstrated reactivation of the mitogen-activated protein kinase (ERK1/2) pathway in vitro, which possibly reduced the effects of ErbB inhibition. Concomitant treatment of oral squamous cell carcinoma cells with afatinib and trametinib synergized the anti-tumor effects in oral squamous cell carcinoma-bearing mouse models.
CONCLUSIONS: Our findings provide insight into the molecular mechanism of resistance to afatinib and support further clinical evaluation into the combination of afatinib and MEK inhibition in the treatment of oral squamous cell carcinoma.
Aim: This study was carried out in order to propose a model to predict regional lymph node metastasis of OSCC using histological parameters such as tumour stage, tumour size, pattern of invasion (POI), differentiation of tumour, and host immune response, together with the expression levels of six biomarkers (periostin, HIF-1α, MMP-9, β-catenin, VEGF-C, and EGFR), and, furthermore, to compare the impact of all these parameters on recurrence and 3 yr and 5 yr survival rates. Materials and Method. Histological materials collected from the archives were used to evaluate histological parameters and immunohistochemical profiles. Standard methods were used for immunohistochemistry and for evaluation of results. Data related to recurrence and survival (3 and 5 years) was also recorded. Clinical data was collected from patients' records.
Results: Male to female ratio was 3 : 1. The commonest site of OSCC was the buccal mucosa, and majority of them were T3 or T4 tumours presented at stage 4. 62.5% of the tumours were well differentiated. Three-year and 5-year survival rates were significantly associated with lymph node metastasis and recurrence. POI was significantly correlated with tumour size, stage, 3-year survival, EGFR, HIF-1α, periostin, and MMP-9 (p < 0.05). Expression of EGFR showed a direct association with metastasis (p < 0.05).
Conclusion: POI, level of differentiation, and expression of EGFR are independent prognostic markers for lymph node metastasis. Therefore, these parameters may help in treatment planning of a clinically negative neck.
METHODS: The expression of IFITM3 in OSCC and normal oral mucosal tissues was assessed by qRT-PCR and immunohistochemistry. The role of IFITM3 in driving OSCC cell proliferation and survival was examined using siRNA-mediated gene knockdown, and the role of IFITM3 in driving cell cycle regulators was examined using Western blotting.
RESULTS: We found that IFITM3 is overexpressed in more than 79% of primary OSCCs. We also found that IFITM3 knockdown led to impaired OSCC cell growth through inhibition of cell proliferation, induction of cell cycle arrest, senescence and apoptosis. In addition, we found that IFITM3 knockdown led to reduced expressions of CCND1 and CDK4 and reduced RB phosphorylation, leading to inhibition of OSCC cell growth. This information may be instrumental for the design of novel targeted therapeutic strategies.
CONCLUSIONS: From our data we conclude that IFITM3 is overexpressed in OSCC and may regulate the CCND1-CDK4/6-pRB axis to mediate OSCC cell growth.
OBJECTIVE: To explore the feasibility of using cyclin D1 as a prognostic marker in tongue and cheek SCC by the fluorescent-in-situ hybridization (FISH) method.
METHODS: Fifty paraffin-embedded samples (25 each of cheek and tongue SCCs) were obtained from the archives of the Oral Pathology Diagnostic Laboratory. Sociodemographic data, histopathologic diagnoses, lymph node status and survival data were obtained from the Malaysian Oral Cancer Database and Tissue Bank System (MOCDTBS)coordinated by the Oral Cancer Research and Coordinating Centre (OCRCC), University of Malaya. The FISH technique was used to detect the amplification of cyclin D1 using the Vysis protocol. Statistical correlations of cyclin D1 with site and lymph node status were analyzed using the Fisher exact test. Kaplan-Meier and Log Rank (Mantel-Cox) test were used to analyze cyclin D1 amplification and median survival time.
RESULTS: Positive amplification of cyclin D1 was detected in 72% (36) of OSCCs. Detection of positive amplification for cyclin D1 was observed in 88% (22) and 56% (14) of the tongue and cheek tumors, respectively, where the difference was statistically significant (P=0.012). Lymph node metastasis of cheek SCCs showed a trend towards a significant association (P= 0.098) with cyclin D1 amplification whereas the lymph node metastasis of tongue SCC was clearly not significant (P=0.593).There was a statistically significant correlation between cyclin D1 positivity and survival rate (P=0.009) for overall SCC cases and (P<0.001) for cheek SCC cases.
CONCLUSION: The present study found that cyclin D1 amplification may differ in different subsites of OSCC (tongue vs cheek) and its positive amplification implies an overall poor survival in OSCCs, particularly those arising in cheeks.