Polycystin-1 downregulation induces ERK-dependent mTOR pathway activation in a cellular model of psoriasis

Psoriatic plaques tend to localize to the knees and elbows, areas that are particularly subject to mechanical stress resulting from bending and friction. Moreover, plaques often develop at sites of mechanical trauma or injury (Koebner phenomenon). Nevertheless, mechanotransduction has never been linked to psoriasis. Polycystins (polycystin-1, PC1; polycystin-2, PC2) are mechanosensitive molecules that function as key regulators of cellular mechanosensitivity and mechanotransduction. The aim of this in vitro study was to investigate the role of polycystins in the development of psoriasis. We showed that PC1 knockdown in HaCaT cells led to an elevated mRNA expression of psoriasis-related biomarkers Ki-67, IL-6, TNF-α, VEGF and Bcl-2, while PC1 functional inhibition was accompanied by increased cell proliferation and migration of HaCaT cells. In addition, PC1 knockdown via siRNA in HaCaT cells was followed by activation of critical molecules of the mTOR and MAPK pathways and this mTOR pathway activation was ERK-dependent. Furthermore, loss of PC1 protein expression and elevated levels of activated mTOR substrates were also observed in human samples of psoriatic plaques. Overall, our study suggests that the PC1/ERK/mTOR signaling axis represents a novel potential mechanism in psoriasis pathogenesis.

Effect of BRCA1 immunohistochemical localizations on prognosis of patients with sporadic breast carcinomas

Our purpose was to investigate the expression pattern of BRCA1 protein in sporadic breast carcinomas, as well as the clinicopathological and prognostic value of its subcellular localizations. Immunohistochemistry was performed on paraffin embedded tissue specimens from 111 sporadic, invasive breast carcinomas to detect the expression of the proteins BRCA1, ER, PR, erbB2, p53 and Ki67. BRCA1 protein was detected in the nuclei and the cytoplasm of the tumor cells. Nuclear BRCA1 immunoreactivity showed no relation with the classic clinicopathological markers and the expression of cerbB2, p53 and Ki67. Reduced expression of nuclear BRCA1 protein was found to exert an independent favorable impact on both the overall and relapse-free (RF) survival of the patients (p=0.019 and p=0.043, respectively). Cytoplasmic BRCA1 was associated with none of the classic histomorphological indices, except from the lymph node metastasis, with which its relation was found to be inverse (p=0.05), prolonging the RF survival of the patients (p=0.05). Our findings suggest that BRCA1 protein depicts different prognostic significance, according to its subcellular distribution. Nuclear detection of the protein was associated with a worse prognosis, while the cytoplasmic one was related to fewer recurrences as a result of fewer lymph node metastases.

An immunohistochemical evaluation of the proteins Wnt1 and glycogen synthase kinase (GSK)-3β in invasive breast carcinomas

AIMS

Our purpose was to investigate, in breast carcinomas, the prognostic importance of the proteins Wnt1 and glycogen synthasekinase (GSK)-3β, and their associations with classic clinicopathological indices.

METHODS AND RESULTS

Immunohistochemistry was performed on paraffin-embedded tissue specimens from 288 invasive breast carcinomas to detect the expression of the proteins Wnt1, GSK3β, oestrogen receptor (ER), progesterone receptor (PR), erbB2, p53, Ki67, caspase-3 and β-catenin. Both Wnt1 and GSK3β were detected predominantly in the cytoplasm of the invasive tumour cells and the in-situ component, while GSK3β was also detected in the stromal fibroblasts. Wnt1 immunoreactivity in the invasive tumour cells showed an inverse association with histological grade (P = 0.002), Ki67 (P = 0.008) and p53 (P = 0.031), while its relation with ER, erbB2 and caspase-3 was found to be positive (P = 0.007, P = 0.018 and P = 0.03, respectively). Cytoplasmic Wnt1 expression was related to a favourable prognosis within the subgroup of patients with stage II disease (P = 0.032).

CONCLUSIONS

Wnt1 expression in the invasive tumour cells seems to promote differentiation and apoptosis, while being related inversely to proliferation. Therefore, this suggests its participation in the primary stages of breast carcinogenesis. The latter is supported further by the immunodetection of Wnt1 in in-situ carcinomas.

Cyclin D1 in invasive breast carcinoma: favourable prognostic significance in unselected patients and within subgroups with an aggressive phenotype

AIMS

  To study the clinicopathological and prognostic value of cyclin D1 overexpression in patients with breast carcinoma.

METHODS AND RESULTS

  Immunohistochemistry was performed on paraffin-embedded tissue specimens from 290 invasive breast carcinomas to detect the proteins cyclin D1, oestrogen receptor (ER), progesterone receptor (PR), p53, c-erbB2, and topoisomerase IIα (topoIIα). Cyclin D1 staining was quantified using a computerized image analysis method. Cyclin D1 overexpression characterized smaller, ER-positive and PR-positive tumours (P = 0.017, P < 0.0001, and P < 0.0001, respectively), of a lower histological and nuclear grade (P = 0.011 and P < 0.0001, respectively), and with reduced expression of topoIIα (P = 0.001) and p53 (P < 0.001). Cyclin D1 was found to have an independent favourable impact on the overall survival of both the unselected cohort of patients (P = 0.011) and of patients with ER-negative and lymph node-positive tumours (P = 0.034 and P = 0.015, respectively). In triple-negative tumours, cyclin D1 overexpression was found to have independent favourable impacts on both overall and relapse-free survival (P = 0.002 for both).

CONCLUSIONS

  This is the first immunohistochemical study to dissociate the advantageous prognostic effect of cyclin D1 overexpression from its association with ER expression, and to provide evidence that cyclin D1 overexpression may be a marker of prolonged survival in patient subgroups with aggressive phenotypes.

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' 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 detected 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 < 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' 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.

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 χ² test. 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.

An immunohistochemical evaluation of phosphorylated Akt at threonine 308 [pAkt(Thr308)] in invasive breast cancer

BACKGROUND

Akt is a serine/threonine kinase which is fully activated when phosphorylated (pAkt). The aim of this study was to investigate the expression pattern of phosphorylated Akt at Threonine 308 [pAkt(Thr308)] in association with clinicopathological parameters and various biological markers.

MATERIALS AND METHODS

Immunohistochemistry was performed on paraffin-embedded tissue specimens from 152 invasive breast carcinomas to detect the expression of the proteins pAkt(Thr308), estrogen (ER) and progesterone (PR) receptors, p53, Ki-67 and c-erbB-2.

RESULTS

pAkt(Thr308) protein was immunodetected in the cytoplasm and the nuclei of the malignant cells. pAkt was found to be positively associated with the lobular histological type, while it was found to exert no impact on patients' survival. pAkt(Thr308) immunopositivity was inversely related to Ki-67 and p53 (p=0.013 and p=0.020, respectively), while being positively associated with cerbB2 expression (p=0.005).

CONCLUSION

This is the first study to show a frequent detection of pAkt(Thr308) in lobular breast carcinomas and an association of its expression with indices of proliferation (c-erbB2, Ki-67) and apoptosis (p53).