The Role of the LY294002 - A Non-Selective Inhibitor of Phosphatidylinositol 3-Kinase (PI3K) Pathway- in Cell Survival and Proliferation in Cell Line SCC-25.

The activation of PI3K further activates subsequent regulatory pathways, which are activated via AKT phosphorylation. AKT is closely related to the Bcl-2 family, a protein known to be involved in cell survival. AKT also has a relationship with inflammatory and glycolytic mediators. The present work aimed to evaluate the relationship between the PI3K/AKT pathway, cell survival/proliferation, inflammatory mediators and the glycolytic pathway in oral squamous cell carcinoma. All experiments were performed in the SCC25 oral squamous cell carcinoma cell line. In the presence or absence of PI3K pathway inhibitors, we analyzed the protein expression of pAKT and AKT; X-linked inhibitor of apoptosis protein; Bcl-2-associated death promoter; Bcl-2-like protein two inhibitor; cyclooxygenase 1; cyclooxygenase-2; and glycoprotein-associated glucose transporter 1. For the functional characterization of treated or untreated cells, we also performed matrix invasion assays, cell migration assays, and cell proliferation assays. Our results demonstrated that activation of the PI3K/AKT pathway is directly related to members of the Bcl-2 family and GLUT1, but not the inflammatory mediators COX1 and COX2. Our data suggest that the PI3K/AKT pathway is related to cell survival and proliferation in oral squamous cell carcinoma through its interaction with Bcl-2 family members.
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BRCA1 and γH2AX as independent prognostic markers in oral squamous cell carcinoma.

Oral squamous cell carcinomas (OSCC) are believed to originate from sequential mutations that can develop as a consequence of genetic instability acquired over time. BRCA1 are linked to DNA recombination and repair processes, being of importance for its role in regulation of RAD51 and H2AX (γH2AX). The aim of this study was to investigate the relationship between BRCA1 expression status and evaluate its prognostic impact. We selected from 150 OSCC patients, and evaluated BRCA1 expression in OSCC by immunohistochemistry and qRT-PCR, comparing its expression with homologous recombination markers (RAD51, γH2AX and p53), clinicopathological and survival data. Expression of BRCA1 was observed in 61 cases (43.88%) and was related to tumor size (T stage) (p=0.001), and gender (p=0.017). mRNA from BRCA1 showed a borderline relationship with perineural invasion (p=0.053). BRCA1 [p=0.030; HR: 2.334 (C.I.: 1.087-5.012)], γH2AX [p=0.045; HR: 0.467 (C.I.: 0.222-0.628)] and gender [p=0.001; HR: 10.386 [(C.I.: 2.679-10.623)] were independent prognostic factors for DSS. BRCA1 and γH2AX expression by OSCC cells are associated with reduced overall survival time, independent of other variables in patients, as well as gender, and our findings shed some light about DSB markers in OSCC and its role as prognostic factors.

CD44/CD24 immunophenotypes on clinicopathologic features of salivary glands malignant neoplasms.

BACKGROUND: Salivary glands malignant neoplasms (SGMNs) account for 3-6% of head and neck cancers and 0.3% of all cancers. Tumor cells that express CD44 and CD24 exhibit a stem-cell-like behavior. CD44 is the binding site for hyaluronic acid, and CD24 is a receptor that interacts with P-selectin to induce metastasis and tumor progression. The present study aims to evaluate the expression of CD44 and CD24 on SGMNs and correlated these data with several clinicopathologic features. METHODS: Immunohistochemical stains for CD44 and CD24 were performed on tissue microarrays containing SGMN samples from 69 patients. The CD44, CD24 and CD44/CD24 expression phenotypes were correlated to patient clinicopathologic features and outcome. RESULTS: CD44 expression was associated with the primary site of neoplasm (p = 0.046). CD24 was associated with clinical stage III/IV (p = 0.008), T stage (p = 0,27) and lymph node (p = 0,001). The CD44/CD24 profiles were associated with the primary site of injury (p = 0.005), lymph node (p = 0.011) and T stage (p = 0.023). Univariate analysis showed a significant relationship between clinical staging and disease- free survival (p = 0.009), and the overall survival presents relation with male gender (p = 0.011) and metastasis (p = 0.027). CONCLUSION: In summary, our investigation confirms that the clinical stage, in accordance with the literature, is the main prognostic factor for SGMN. Additionally, we have presented some evidence that the analysis of isolated CD44 and CD24 immunoexpression or the two combined markers could give prognostic information associated to clinicopathologic features in SGMN. VIRTUAL SLIDES: The virtual slide(s) for this article can be found here: http://www.diagnosticpathology.diagnomx.eu/vs/1284611098470676.

Relationship between B-cell-specific Moloney murine leukemia virus integration site 1 (BMI-1) and homologous recombination regulatory genes in invasive ductal breast carcinomas.

B-cell-specific Moloney murine leukemia virus integration site 1 (Bmi-1) is a Polycomb group protein that is able to induce telomerase activity, enabling the immortalization of epithelial cells. Immortalized cells are more susceptible to double-strand breaks (DSB), which are subsequently repaired by homologous recombination (HR). BRCA1 is among the HR regulatory genes involved in the response to DNA damage associated with the RAD51 protein, which accumulates in DNA damage foci after signaling H2AX, another important marker of DNA damage. Topoisomerase IIIß (topoIIIß) removes HR intermediates before chromosomal segregation, preventing damage to cellular DNA structure. In breast carcinomas positive for BMI-1 the role of proteins involved in HR remains to be investigated. The aim of this study was to evaluate the association between BMI-1 and homologous recombination proteins. Using tissue microarrays containing 239 cases of primary breast tumors, the expression of Bmi-1, BRCA-1, H2AX, Rad51, p53, Ki-67, topoIIIß, estrogen receptors (ER), progesterone receptors (PR), and HER-2 was analyzed by immunohistochemistry. We observed high Bmi-1 expression in 66 cases (27.6%). Immunohistochemical overexpression of BMI-1 was related to ER (p=0.004), PR (p<0.001), Ki-67 (p<0.001), p53 (p=0.003), BRCA-1 (p= 0.003), H2AX (p=0.024) and topoIIIß (p<0,001). Our results show a relationship between the expression of BMI-1 and HR regulatory genes, suggesting that Bmi-1 overexpression might be an important event in HR regulation. However, further studies are necessary to understand the mechanisms in which Bmi-1 could regulate HR pathways in invasive ductal breast carcinomas.

Topoisomerase expression in oral squamous cell carcinoma: relationship with cancer stem cells profiles and lymph node metastasis.

BACKGROUND: The relationship between predictive proteins and tumors presenting cancer stem cells (CSCs) profiles in oral tumors is still poorly understood. This study aims to identify the relationship between topoisomerases I, IIα, and IIIα and putative CSCs immunophenotype in oral squamous cell carcinoma (OSCC) and determine its influence on prognosis. METHODS: The following data were retrieved from 127 patients: age, gender, primary anatomic site, smoking and alcohol intake, recurrence, metastases, histologic classification, treatment, and survival. An immunohistochemical study for topoisomerases I, IIα, and IIIα was performed in a tissue microarray containing 127 paraffin blocks of OSCCs. RESULTS: In univariate analysis, topoisomerases expression showed significant differences according to CSCs profiles and p53 immunoexpression, but not with survival. Topoisomerases IIα and IIIα also showed significant relationship with lymph node metastasis. The multivariate test confirmed these associations. CONCLUSIONS: The results that all topoisomerases correlates with OSCC CSCs may indicate a role for topoisomerases in head and neck carcinogenesis. Notwithstanding, it is plausible that other members of topoisomerases family could represent novel therapeutical targets in oral squamous cell carcinoma.

The role of tumor hypoxia in MUC1-positive breast carcinomas.

Mucin 1 (MUC1) is a glycoprotein that is expressed on apical cell membranes in a variety of normal tissues. MUC1 is involved in cell signaling, inhibition of cell-cell and cell matrix adhesion, apoptosis, proliferation, and transcription. Hypoxia is an important factor that promotes cancer metastasis and stimulates angiogenesis and tumor progression. Hypoxia inducible factor 1 (HIF-1α) and carbonic anhydrase IX (CAIX) are two molecules that are involved in this process. The role of hypoxia in MUC1+ invasive ductal breast carcinomas is not well established. In this study, the expression of MUC1 was correlated with the hypoxia-associated markers HIF-1α and CAIX, as well as several immunohistochemical markers and clinicopathologic features of prognostic significance in 243 invasive ductal carcinomas. MUC1 was overexpressed in 37.0% of patients and correlated with the expression of estrogen receptor (p = 0.0001), progesterone receptor (p = 0.0001), HIF-1α (p = 0.006), VEGF (p = 0.024), and p53 (p = 0.025). In breast cancer, MUC1 expression has been associated with increased degradation of inhibitor of NF-κB (IκBα), driving NF-κB to the nucleus and blocking apoptosis and promoting cell survival. We analyzed NF-κB expression in MUC1+ breast carcinoma and found a very significant relationship between these proteins (p = 0.0001). Our findings indicate that MUC1 may play a role in the regulation of hormone receptors by increasing the inactivation of p53 and targeting NF-κB to the nucleus. Our data also support the notion that activation of HIF-1α in MUC1+ breast carcinomas may modulate VEGF expression, allowing a metabolic adaptation to hypoxia.