Homeobox genes constitute a large family of transcription factors that are essential during normal development and are often dysregulated in cancer. However, the molecular mechanisms by which homeobox genes influence cancer remain largely unknown. Here we show that the tissue-restricted cyclin A1 is a transcriptional target of the Six1 homeoprotein. Both genes are expressed in the embryonic but not the terminally differentiated mammary gland, and Six1-knockout mice show a dramatic reduction of cyclin A1 in the embryonic mammary gland. In addition, both genes are reexpressed in breast cancers. Six1 overexpression increases cyclin A1 mRNA levels and activity, cell proliferation, and tumor volume, whereas Six1 down-regulation decreases cyclin A1 mRNA levels and proliferation. Overexpression of Six1 in wild-type mouse embryonic fibroblasts, but not in knockout variants lacking the cyclin A1 gene, induces cell proliferation. Furthermore, inhibition of cyclin A1 in Six1-overexpressing mammary carcinoma cells decreases proliferation. Together these results demonstrate that cyclin A1 is required for the proliferative effect of Six1. We conclude that Six1 overexpression reinstates an embryonic pathway of proliferation in breast cancer by up-regulating cyclin A1.

The development and progression of oral cavity squamous cell carcinoma (OSCC) involves complex cellular mechanisms that contribute to the low five-year survival rate of approximately 20% among diagnosed patients. However, the biological processes essential to tumor progression are not completely understood. Therefore, detecting alterations in the salivary proteome may assist in elucidating the cellular mechanisms modulated in OSCC and improve the clinical prognosis of the disease. The proteome of whole saliva and salivary extracellular vesicles (EVs) from patients with OSCC and healthy individuals were analyzed by LC-MS/MS and label-free protein quantification. Proteome data analysis was performed using statistical, machine learning and feature selection methods with additional functional annotation. Biological processes related to immune responses, peptidase inhibitor activity, iron coordination and protease binding were overrepresented in the group of differentially expressed proteins. Proteins related to the inflammatory system, transport of metals and cellular growth and proliferation were identified in the proteome of salivary EVs. The proteomics data were robust and could classify OSCC with 90% accuracy. The saliva proteome analysis revealed that immune processes are related to the presence of OSCC and indicate that proteomics data can contribute to determining OSCC prognosis.

A significant association between the BD model and outcome of OSCC patients was observed, indicating this new histopathological grading system as a possible prognostic tool.

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Myofibroblasts are frequent in the stroma of neoplasm and by the expression of proteinases they can influence tumor infiltration and progression. In the present study, presence of myofibroblasts and expression of matrix metalloproteinase-2 (MMP-2) and urokinase plasminogen activator (uPA) were examined in intra-osseous solid multicystic ameloblastomas to determine their roles in the clinicopathological features of the tumors. Fifty seven ameloblastomas were analyzed immunohistochemically with antibodies against the isoform alpha of the smooth muscle actin (alpha-SMA), a specific marker of myofibroblasts, MMP-2 and uPA. Myofibroblasts were found in the stroma, in close contact with neoplastic cell islands, of approximately 58% (n = 33) of the ameloblastomas. MMP-2 and uPA were found in the cytoplasm of both neoplastic and stromal cells. A significant correlation between presence of myofibroblasts and MMP-2 expression was observed. Abundant presence of myofibroblast in the stroma of the tumors and expression of MMP-2 in the neoplastic or stromal cells were significantly correlated with rupture of the osseous cortical, which has been considered an important prognostic marker of ameloblastoma aggressiveness. Ours results suggest that abundant presence of myofibroblasts and expression of MMP-2 in solid ameloblastomas may be associated with a more aggressive infiltrative behavior.

Considering the clinical, histopathological, and immunohistochemical characteristics, oral eosinophilic ulcers must be considered a self-limiting reactive condition.

The purpose of the current study was to develop and test a theoretical model that could explain the mechanism of action of gallic acid (GA) in the oral squamous cell carcinoma context for the first time. The theoretical model was developed using bioinformatics and interaction network analysis to evaluate the effect of GA on oral squamous cell carcinoma. In a second step to confirm theoretical results, migration, invasion, proliferation, and gene expression (Col1A1, E-cadherin, HIF-1α, and caspase-3) were performed under normoxic and hypoxic conditions. Our study indicated that treatment with GA resulted in the inhibition of cell proliferation, migration, and invasion in neoplastic cells. Observation of the molecular mechanism showed that GA upregulates E-cadherin expression and downregulates Col1A1 and HIF-1α expression, suggesting that GA might be a potential anticancer compound. In conclusion, the present study demonstrated that GA significantly reduces cell proliferation, invasion, and migration by increasing E-cadherin and repressing Col1A1.