Anti-Tumor Effect of the Mammalian Target of Rapamycin Inhibitor Everolimus in Oral Squamous Cell Carcinoma

The mammalian target of rapamycin (mTOR) has recently emerged as a promising target for therapeutic anti-cancer interventions in several human tumors. In present study, we investigated the expression of mTOR, and subsequently examined its relationship with clinicopathological factors and the anti-tumor effect of everolimus (also known as RAD001) in oral squamous cell carcinoma (OSCC). The expression of phosphorylated mTOR (p-mTOR) was immunohistochemically evaluated in specimens obtained from 70 OSCC patients who underwent radical surgery. The relationships between the expression of p-mTOR and clinicopathological factors and survival were determined. We also investigated the effect of everolimus on the OSCC cell lines, SAS, HSC-2, HSC-3, HSC-4, OSC-20, SCC25 and Ca9-22 by the MTT assay. We further evaluated whether mTOR contributed to cell functions by blocking its activity with everolimus, and confirmed the direct target by the Matrigel invasion assay, wound healing assay and Western blotting. p-mTOR was overexpressed in 37 tumors (52.8 %), and correlated with the T classification, N classification, and survival rate (P < 0.05). The treatment with everolimus significantly inhibited cell growth, and significantly reduced the expression of p-mTOR, downstream signaling proteins, and hypoxic related proteins as well as invasion and migration potentials (P < 0.05). The results of the present study suggest that everolimus may represent an attractive approach for the future treatment of OSCC

A pathogenic role for germline PTEN variants which accumulate into the nucleus.

The PTEN gene encodes a master regulator protein that exerts essential functions both in the cytoplasm and in the nucleus. PTEN is mutated in the germline of both patients with heterogeneous tumor syndromic diseases, categorized as PTEN hamartoma tumor syndrome (PHTS), and a group affected with autism spectrum disorders (ASD). Previous studies have unveiled the functional heterogeneity of PTEN variants found in both patient cohorts, making functional studies necessary to provide mechanistic insights related to their pathogenicity. Here, we have functionally characterized a PTEN missense variant [c.49C>G; p.(Gln17Glu); Q17E] associated to both PHTS and ASD patients. The PTEN Q17E variant displayed partially reduced PIP3-catalytic activity and normal stability in cells, as shown using S. cerevisiae and mammalian cell experimental models. Remarkably, PTEN Q17E accumulated in the nucleus, in a process involving the PTEN N-terminal nuclear localization sequence. The analysis of additional germline-associated PTEN N-terminal variants illustrated the existence of a PTEN N-terminal region whose targeting in disease causes PTEN nuclear accumulation, in parallel with defects in PIP3-catalytic activity in cells. Our findings highlight the frequent occurrence of PTEN gene mutations targeting PTEN N-terminus whose pathogenicity may be related, at least in part, with the retention of PTEN in the nucleus. This could be important for the implementation of precision therapies for patients with alterations in the PTEN pathway

The clinicopathologic and prognostic significance of CD44+/CD24-/low and CD44-/CD24+ tumor cells in invasive breast carcinomas

Cells with distinct phenotypes and stem cell-like properties have been reported to exist in breast cancer. The aim of the present study was to investigate the clinicopathologic and prognostic significance of the CD44+/CD24-/low and CD44-/CD24+ tumor phenotypes&apos; prevalence. Double immunohistochemistry was applied on a series of 155 paraffin-embedded breast tissue specimens to detect CD44 and CD24. Evaluation of the phenotypes was performed by image analysis. The prevalence of CD44+/CD24-/low and CD44-/CD24+ tumor cells was 58.7% and 82.6%, respectively. The dominance of the CD44+/CD24-/low tumor cells was inversely associated with lymph node metastasis (P = .019) and tended to inversely associate with the stage of the disease (P = .068). Moreover, the prevalence of CD44+/CD24-/low was found to exert no significant impact on patients&apos; prognosis although it displayed a tendency toward an increase in disease-free survival (P = .074). On the other hand, the prevalence of CD44-/CD24+ tumor cells was found to have no clinicopathologic significance. However, it was found to exert an unfavorable impact on both relapse-free (P = .009) and overall survival (P = .046) of the patients with breast carcinomas of intermediate differentiation (grade 2). In breast tissue, CD44+/CD24-/low tumor cells seem to be associated with lack of lymph node metastasis and a tendency toward an increase of the relapse-free survival of the patients. On the contrary, tumor cells with the phenotype CD44-/CD24+ seem to identify patients with worse disease-free and overall survival within the group of intermediate-grade differentiation patients whose prognosis is difficult to assess. © 2008

Peroxisome proliferator-activated receptor gamma expression in urothelial carcinomas of the bladder: Association with differentiation, proliferation and clinical outcome

Aims: Peroxisome proliferator-activated receptor γ (PPARγ) is a ligand-activated transcriptional factor that regulates the transcription of various target genes. Our purpose is to investigate the clinicopathologic and prognostic significance of PPARγ expression in human urothelial bladder cancer (BUC). Methods: Immunohistochemistry was applied in 117 paraffin-embedded specimens of human BUC to detect the proteins PPARγ and Ki67. The image analysis method was used for the evaluation of the immunohistochemical staining. Results: PPARγ protein was localized in the nuclei of the malignant cells. Its expression was inversely associated with the stage of BUCs (p &lt; 0.001), tumor grade (p = 0.007) and the expression of the proliferation marker Ki67 (p = 0.015) while it was found to exert a favorable effect on patients&apos; overall survival (p = 0.001). Conclusion: The findings of the present study suggest that in BUC, PPARγ expression can identify patients with a better prognosis who suffer from more differentiated, non-invasive tumors, of a low proliferative potential. © 2008 Elsevier Ltd. All rights reserved

Expression of the epidermal growth factor receptor (EGFR) and the phosphorylated EGFR in invasive breast carcinomas

Introduction: Epidermal growth factor receptor (EGFR) is involved in regulating cell growth in breast carcinomas. Its activated form, phosphorylated EGFR (pEGFR), is correlated with poor prognosis in lung cancer, but it has not yet been fully investigated in breast cancer. The aim of this study was to investigate the expressions of EGFR and pEGFR and their correlation with overall and disease-free survival, clinicopathological parameters and biological markers of invasion and angiogenesis (phosphorylated Akt [pAkt], urokinase plasminogen activator receptor [uPAR], matrix metalloproteinase [MMP]-14, vascular endothelial growth factor receptor [VEGFR]-1/Flt-1).Methods: A three-step immunohistochemical method was applied to paraffin-embedded sections from 154 patients with invasive breast carcinoma in order to detect expressions of the proteins EGFR, pEGFR, oestrogen receptor, progesterone receptor, c-erbB-2, pAkt, VEGFR-1/Flt-1, MMP-14 and uPAR. The results were evaluated statistically using the χ2test. Overall and disease-free survival distribution curves were assessed using the Kaplan-Meier test and log-rank statistics, followed by Cox proportional hazards regression model.Results: EGFR and pEGFR proteins were immunodetected in the membrane of the malignant cells (11.3% and 35.7%, respectively). EGFR expression was positively correlated with nuclear grade (P = 0.001) and negatively correlated with the hormonal receptor oestrogen receptor (P = 0.005). pEGFR was positively related to the Akt pathway (P = 0.008) and appeared to participate in invasion and metastasis (uPAR, P = 0.049; MMP-14, P = 0.025; VEGFR-1/Flt-1, P = 0.016). Univariate analysis showed that the EGFR/pEGFR phenotype was associated with poor overall survival (P = 0.019), a finding further supported by multivariate analysis (P = 0.013).Conclusion: These data provide evidence that pEGFR expression is related to angiogenesis (via VEGFR-1/Flt-1, MMP-14 and pAkt pathways) and invasiveness (via uPAR, MMP-14 and pAkt pathways) and that the EGFR/pEGFR phenotype is associated with poor patient survival in invasive breast cancer. © 2008 Magkou et al.; licensee BioMed Central Ltd

Immunohistochemical study of PTEN and phosphorylated mTOR proteins in familial and sporadic invasive breast carcinomas

Aims: Loss of phosphatase and tensin homologue (PTEN) leads to activation of several kinases, including mammalian target of rapamycin (mTOR), which promotes cell cycle progression. The aim was to study the expression of PTEN and phosphorylated (p)-mTOR in familial and sporadic invasive breast carcinomas and their relation to clinicopathological features, molecular indices (Wnt1) and patients&apos; survival. Methods and results: PTEN and p-mTOR were detected immunohistochemically in 215 sections of invasive breast carcinomas (112 with a familial history of breast cancer). Image analysis was used and univariate and multivariate analyses employed for statistical evaluation of results. PTEN was detecte5d in the nucleus (73.5%) and p-mTOR in the cytoplasm (44.2%) of cancer cells. Loss of PTEN protein was more frequently detected in women with a familial history of breast cancer (72%) (P &lt; 0.0001), while its expression was negatively correlated with Wnt1, in total (P = 0.049). p-mTOR showed a positive association with lymph node status (P = 0.010) and was found to have a negative impact on patients&apos; overall survival (P = 0.016). Conclusions: Loss of PTEN protein expression appears to occur more frequently in women with a family history of breast cancer, whereas activation of mTOR protein seems to be related to a more aggressive phenotype. © 2010 Blackwell Publishing Limited