Understanding the role of keratins 8 and 18 in neoplastic potential of breast cancer derived cell lines.

BACKGROUND: Breast cancer is a complex disease which cannot be defined merely by clinical parameters like lymph node involvement and histological grade, or by routinely used biomarkers like estrogen receptor (ER), progesterone receptor (PGR) and epidermal growth factor receptor 2 (HER2) in diagnosis and prognosis. Breast cancer originates from the epithelial cells. Keratins (K) are cytoplasmic intermediate filament proteins of epithelial cells and changes in the expression pattern of keratins have been seen during malignant transformation in the breast. Expression of the K8/18 pair is seen in the luminal cells of the breast epithelium, and its role in prognostication of breast cancer is not well understood. METHODOLOGY/PRINCIPAL FINDINGS: In this study, we have modulated K8 expression to understand the role of the K8/18 pair in three different breast epithelium derived cell lines: non-transformed MCF10A, transformed but poorly invasive MDA MB 468 and highly invasive MDA MB 435. The up-regulation of K8 in the invasive MDA MB 435 cell line resulted in a significant decrease in proliferation, motility, in-vitro invasion, tumor volume and lung metastasis. The down-regulation of K8 in MDA MB 468 resulted in a significant increase in transformation potential, motility and invasion in-vitro, while MCF10A did not show any changes in cell transformation assays. CONCLUSIONS/SIGNIFICANCE: These results indicate the role of K8/18 in modulating invasion in breast cancer -its presence correlating with less invasive phenotype and absence correlating with highly invasive, dedifferentiated phenotype. These data may have important implications for prognostication of breast cancer.

Fascin overexpression promotes neoplastic progression in oral squamous cell carcinoma.

BACKGROUND: Fascin is a globular actin cross-linking protein, which plays a major role in forming parallel actin bundles in cell protrusions and is found to be associated with tumor cell invasion and metastasis in various type of cancers including oral squamous cell carcinoma (OSCC). Previously, we have demonstrated that fascin regulates actin polymerization and thereby promotes cell motility in K8-depleted OSCC cells. In the present study we have investigated the role of fascin in tumor progression of OSCC. METHODS: To understand the role of fascin in OSCC development and/or progression, fascin was overexpressed along with vector control in OSCC derived cells AW13516. The phenotype was studied using wound healing, Boyden chamber, cell adhesion, Hanging drop, soft agar and tumorigenicity assays. Further, fascin expression was examined in human OSCC samples (N = 131) using immunohistochemistry and level of its expression was correlated with clinico-pathological parameters of the patients. RESULTS: Fascin overexpression in OSCC derived cells led to significant increase in cell migration, cell invasion and MMP-2 activity. In addition these cells demonstrated increased levels of phosphorylated AKT, ERK1/2 and JNK1/2. Our in vitro results were consistent with correlative studies of fascin expression with the clinico-pathological parameters of the OSCC patients. Fascin expression in OSCC showed statistically significant correlation with increased tumor stage (P = 0.041), increased lymph node metastasis (P = 0.001), less differentiation (P = 0.005), increased recurrence (P = 0.038) and shorter survival (P = 0.004) of the patients. CONCLUSION: In conclusion, our results indicate that fascin promotes tumor progression and activates AKT and MAPK pathways in OSCC-derived cells. Further, our correlative studies of fascin expression in OSCC with clinico-pathological parameters of the patients indicate that fascin may prove to be useful in prognostication and treatment of OSCC.

Prognostic value of tissue polypeptide antigen in oral squamous cell carcinoma.

Human oral cancer has a high risk of locoregional relapse which is difficult to diagnose early due to lack of prognostic markers. We and others have shown aberrant expression of cytokeratin (CK) 8 and 18 in human oral cancer. Aberrant supra-basal expression of CK19 has been shown earlier. In this study, our aim was to develop a non-invasive test for prognostication of human oral cancer. Immunoradiometric assay (IRMA) was used to measure the circulating levels of TPA in the sera of 80 oral cancer patients before surgery and seven days after surgery. Elevated serum TPA levels were noted in the post surgery samples of 28 out of the 50 patients for whom clinical follow-up was available, as compared to their pre-surgery samples. TPA levels in the pre-surgery serum samples of patients were significantly higher than levels in the sera of healthy controls (p=0.001). Elevated levels in patients correlated significantly with stage (p=0.02), development of recurrence (p<0.006), and impacted survival (p<0.033). IHC analysis showed statistically significant correlation between expression of CK8, 18 and 19 in surrounding uninvolved tissues of the tumour and post surgery elevated serum TPA levels (p<0.001). This suggests the possibility that CK fragments are released from the surrounding uninvolved tissues into the sera of patients after surgical removal of the tumour. Thus, our study indicates that TPA can be a useful tumour marker for the prediction of recurrence and poor prognosis in human oral cancer.