Inhibition of CCN6 (WISP3) expression promotes neoplastic progression and enhances the effects of insulin-like growth factor-1 on breast epithelial cells

INTRODUCTION: CCN6/WISP3 belongs to the CCN (Cyr61, CTGF, Nov) family of genes that contains a conserved insulin-like growth factor (IGF) binding protein motif. CCN6 is a secreted protein lost in 80% of the aggressive inflammatory breast cancers, and can decrease mammary tumor growth in vitro and in vivo. We hypothesized that inhibition of CCN6 might result in the loss of a growth regulatory function that protects mammary epithelial cells from the tumorigenic effects of growth factors, particularly IGF-1. METHOD: We treated human mammary epithelial (HME) cells with a CCN6 hairpin short interfering RNA. RESULTS: CCN6-deficient cells showed increased motility and invasiveness, and developed features of epithelial-mesenchymal transition (EMT). Inhibition of CCN6 expression promoted anchorage-independent growth of HME cells and rendered them more responsive to the growth effects of IGF-1, which was coupled with the increased phosphorylation of IGF-1 receptor and insulin receptor substrate-1 (IRS-1). CONCLUSION: Specific stable inhibition of CCN6 expression in HME cells induces EMT, promotes anchorage-independent growth, motility and invasiveness, and sensitizes mammary epithelial cells to the growth effects of IGF-1

CDH1 promoter hypermethylation and E-cadherin protein expression in infiltrating breast cancer

BACKGROUND: The E-cadherin gene (CDH1) maps, at chromosome 16q22.1, a region often associated with loss of heterozygosity (LOH) in human breast cancer. LOH at this site is thought to lead to loss of function of this tumor suppressor gene and was correlated with decreased disease-free survival, poor prognosis, and metastasis. Differential CpG island methylation in the promoter region of the CDH1 gene might be an alternative way for the loss of expression and function of E-cadherin, leading to loss of tissue integrity, an essential step in tumor progression. METHODS: The aim of our study was to assess, by Methylation-Specific Polymerase Chain Reaction (MSP), the methylation pattern of the CDH1 gene and its possible correlation with the expression of E-cadherin and other standard immunohistochemical parameters (Her-2, ER, PgR, p53, and K-67) in a series of 79 primary breast cancers (71 infiltrating ductal, 5 infiltrating lobular, 1 metaplastic, 1 apocrine, and 1 papillary carcinoma). RESULTS: CDH1 hypermethylation was observed in 72% of the cases including 52/71 ductal, 4/5 lobular carcinomas and 1 apocrine carcinoma. Reduced levels of E-cadherin protein were observed in 85% of our samples. Although not statistically significant, the levels of E-cadherin expression tended to diminish with the CDH1 promoter region methylation. In the group of 71 ductal cancinomas, most of the cases of showing CDH1 hypermethylation also presented reduced levels of expression of ER and PgR proteins, and a possible association was observed between CDH1 methylation and ER expression (p = 0.0301, Fisher's exact test). However, this finding was not considered significant after Bonferroni correction of p-value. CONCLUSION: Our preliminary findings suggested that abnormal CDH1 methylation occurs in high frequencies in infiltrating breast cancers associated with a decrease in E-cadherin expression in a subgroup of cases characterized by loss of expression of other important genes to the mammary carcinogenesis process, probably due to the disruption of the mechanism of maintenance of DNA methylation in tumoral cells

Aspects of molecular phenotype and its correlations with breast cancer behaviour and taxonomy

The assessment of breast cancer morphology remains an important element in the evaluation of prognosis and therapeutic planning for this disease. The tumour morphology reflects the molecular profile that produced it and consequently each can be predictive of the other

Multiple ways of silencing E-cadherin gene expression in lobular carcinoma of the breast.

The cell-cell adhesion receptor gene E-cadherin (CDH1) is expressed by epithelial cells, in which it mediates adhesion and morphogenesis. Invasive lobular carcinoma (ILC) characteristically infiltrates diffusely as single cells; by immunohistochemistry, many of these tumours lack E-cadherin expression. In the present study we investigated various ways in which loss of function of the E-cadherin gene could occur in ILCs, namely, promoter methylation, mutation and allelic loss. We analysed 22 ILCs and found 12 (55%) E-cadherin-negative samples by immunohistochemical analysis. Methylation-specific polymerase chain reaction (PCR) showed that 17/22 (77%) of these tumours had methylation of the CDH1 promoter, including 11/12 (91%) of the E-cadherin-negative tumours. All 16 exons of E-cadherin (including intron-exon boundaries) were amplified from chromosomal DNA and screened for mutations by conformation-sensitive gel electrophoresis (CSGE). Bands with altered mobility were analysed by direct sequencing. We identified five frameshift mutations, which resulted in downstream stop codons and one splice site mutation in six different tumours (29%). Loss of heterozygosity (LOH) was assessed using microsatellite markers, and 9/18 (50%) informative tumours showed LOH. We conclude that most ILCs show genetic or epigenetic changes affecting the E-cadherin gene and that many of these tumours lack E-cadherin expression. In all cases in which there was loss of expression, this was consistent with biallelic inactivation of CDH1 by promoter methylation, mutation or allelic loss in any combination

The role of E-cadherin in low-grade ductal breast tumourigenesis.

Grade I invasive ductal breast carcinomas have a specific pattern of genetic aberrations, namely gain of 1q and loss of 16q. This pattern is very similar to the changes seen in invasive lobular breast carcinomas (ILCs). The gene on 16q involved in ILC is known to be E-cadherin (CDH1). This study has investigated whether the same gene is responsible for grade I invasive ductal carcinoma (IDC), using allele imbalance analysis, mutation screening, and immunohistochemistry (IHC). The data suggest that despite the shared pattern of genetic aberrations seen in grade I IDC and ILC, CDH1 is not the target gene in low-grade ductal tumourigenesis

High prevalence of BRCA1 founder mutations in Greek breast/ovarian families

We have screened 473 breast/ovarian cancer patients with family history, aiming to define the prevalence and enrich the spectrum of BRCA1/2 pathogenic mutations occurring in the Greek population. An overall mutation prevalence of 32% was observed. Six BRCA1 recurrent/founder mutations dominate the observed spectrum (58.5% of all mutations found). These include three mutations in exon 20 and three large genomic deletions. Of the 44 different deleterious mutations found in both genes, 16 are novel and reported here for the first time. Correlation with available histopathology data showed that 80% of BRCA1 carriers presented a triple-negative breast cancer phenotype while 82% of BRCA2 carriers had oestrogen receptor positive tumours. This study provides a comprehensive view of the frequency, type and distribution of BRCA1/2 mutations in the Greek population as well as an insight of the screening strategy of choice for patients of Greek origin. We conclude that the Greek population has a diverse mutation spectrum influenced by strong founder effects

Alveolar bone histological necrosis observed prior to extractions in patients, who received bone-targeting agents

Objective: We reported the alveolar bone histology prior to dental extractions in cancer patients, who received bone-targeting agents (BTA). Subjects and Methods: Fifty-four patients were included. Patients underwent extractions, and bone biopsies were taken. Results: Extractions were performed due to pain, swelling, purulence, fistula, and numbness, not responding to treatment, in 40 patients (group A); extractions due to asymptomatic, non-restorable teeth, were performed in 14 patients (group B). Complete alveolar jaw bone histological necrosis was observed in 28 of 40 (70%) patients of group A and none of group B (p <.001). The development of clinical osteonecrosis (MRON) was assessed in 44 patients; 10 patients, who were also treated with Low Level Laser Treatments-LLLT, were excluded from this analysis, as the alternative therapies were a confounding factor. Twelve patients, with alveolar bone histological necrosis prior to extraction, developed medication-related osteonecrosis of the jaw (MRONJ) compared with two patients with vital or mixed vital/non-vital bone (p <.0007). BTAs >1 year and concurrent targeted therapy were also significantly associated with MRONJ (p =.016 and p =.050). Conclusion: Pain, swelling, purulence, fistula, and numbness were significantly associated with complete bone histological necrosis prior to extractions and increased MRONJ development. Research is justified to explore whether histological necrosis represents an early stage of osteonecrosis. © 2020 John Wiley & Sons A/S. Published by John Wiley & Sons Ltd. All rights reserve