A methodological approach to unravel organ-specific breast cancer metastasis

Potentials of CCL21 and CBS as Therapeutic Approaches for Breast Cancer

OBJECTIVE

The present research set out to ascertain the roles of CC chemokine ligand 21 (CCL21) and cystathionine beta-synthase (CBS) in breast cancer (BC) cell biological behaviors and the relationship of CCL21 and CBS expression with the clinicopathological features of patients with BC.

METHODS

Immunohistochemistry of CCL21 or CBS was performed in 18 intraductal cancer tissues, 124 invasive BC tissues, 50 paraneoplastic tissues, 50 lobular hyperplasia tissues, and 30 normal breast tissues. For cell experiments, two human BC cell lines (MDA-MB-231 and MCF-7) and a human breast epithelial cell line (MCF-10A) were utilized to detect the expression of CCL21 and CBS. After loss- and gain-of-function assays for CCL21 or CBS, the expression of CBS and CCL21 was measured by quantitative real-time polymerase chain reaction and western blot. Additionally, BC cell proliferation was assessed by 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide assay and 5-ethynyl-2'-deoxyuridine staining, and BC cell migration was determined by scratch test and Transwell assay.

RESULTS

In the clinical data, the positive rate of CCL21 or CBS was significantly higher in invasive BC tissues than in intraductal BC tissues, lobular hyperplasia tissues, paraneoplastic tissues, and normal breast tissues (p < 0.05 or p < 0.01). CBS or CCL21 expression shared close association with the clinicopathological characteristics and the poor prognosis of BC patients. In cell experiments, overexpression of CCL21 or CBS enhanced the proliferative and migratory abilities of BC cells.

CONCLUSION

CCL21 and CBS promoted BC cell migration and proliferation. CCL21 or CBS expression was strongly related to the poor prognosis of BC patients.

Coexpression of EphA10 and Gli3 promotes breast cancer cell proliferation, invasion and migration

This study investigated the influences of EphA10 and Gli3 on breast cancer (BC) cell proliferation, invasion and migration. Immunohistochemistry was used to reveal the expressions of EphA10 and Gli3 in 18 intraductal carcinomas, 124 invasive carcinomas, 50 paracancerous tissues (2 cm away from the tumor, when possible or available), 50 lobular hyperplastic tissues and 30 normal breast tissues. qRT-PCR and Western blotting were applied to detect the expressions of EphA10 and Gli3 in invasive BC cells (MDA-MB-231, BT20 and Hs578T) and normal human mammary epithelial cells (MCF10A). MDA-MB-231 and BT20 cells were transfected with sh-EphA10, sh-Gli3 or sh-EphA10+sh-Gli3. CCK-8 was used to test the proliferation of transfected MDA-MB-231 and BT20 cells. Transwell and scratch assays were used for evaluation of invasion and migration of the transfected cells. EphA10 and Gli3 were highly expressed in invasive carcinomas and invasive BC cells. The expressions of EphA10 and Gli3 were associated with the clinicopathological characteristics and poor prognosis of patients with invasive BC. Knockdown of EphA10 or Gli3 suppressed activities of BC cells. Knockdown of both EphA10 and Gli3 was more effective than knockdown of Gli3 alone. Taken together, coexpression of EphA10 and Gli3 promotes BC cell proliferation, invasion and migration.

kshv-mir-k12-1-5p promotes cell growth and metastasis by targeting SOCS6 in Kaposi's sarcoma cells

Background: Kaposi’s sarcoma (KS) is a highly disseminated angiogenic tumour of endothelial cells. Many deregulated miRNAs, including kshv-mir-k12-1-5p, have been identified in KS. kshv-mir-k12-1-5p plays important roles in KS. However, the underlying mechanism is not fully understood. The aim of this study was to investigate the exact functions of kshv-mir-k12-1-5p in KS cells.

Materials and methods: The biological functions of kshv-mir-k12-1-5p were studied using CCK-8, apoptosis, migration and invasion assays. Bioinformatics software was used to identify the target gene (SOCS6) of kshv-mir-k12-1-5p. A dual luciferase assay, Western blot (WB) and quantitative real-time polymerase chain reaction (q-PCR) were performed to further verify the target gene. The underlying molecular mechanisms of kshv-mir-k12-1-5p in KS cells were also explored.

Results: kshv-mir-k12-1-5p can promote the proliferation, migration and invasion of KS cells and inhibit cell apoptosis. Suppressor of cytokine signalling 6 (SOCS6) was identified as a direct target of kshv-mir-k12-1-5p, and kshv-mir-k12-1-5p can downregulate SOCS6 expression. In addition, knockdown of SOCS6 rescued the effects of kshv-mir-k12-1-5p inhibitor. Hence, a direct relationship between kshv-mir-k12-1-5p and SOCS6 was confirmed.

Conclusions: kshv-mir-k12-1-5p promotes the malignant phenotype of KS cells by targeting SOCS6, suggesting that kshv-mir-k12-1-5p could be a potential therapeutic target for KS.

Correlation of OGR1 with proliferation and apoptosis of breast cancer cells

Effects of ovarian cancer G-protein-coupled receptor 1 (OGR1) protein on proliferation and apoptosis of breast cancer cells, as well as its molecular mechanism were investigated. The MCF-7 cell line highly expressed OGR1 was constructed by transient transfection of eukaryotic expression vector using breast cancer cells. At the same time, cells were transfected with empty vector as controls. The effects of highly expressed OGR1 on cell growth, proliferation, apoptosis and other abilities were identified. In addition, the effects of highly expressed OGR1 on serine-threonine kinase (AKT), p53 and other genes were studied. It was proved in apoptosis experiment that highly expressed OGR1 protein in breast cancer cells could effectively increase the proportion of apoptosis of cells. Cell proliferation experiment revealed that the growth and proliferation abilities of breast cancer cells with highly expressed OGR1 were inhibited to some extent, compared with those of breast cancer cells with low expression of OGR1. Results of western blotting showed that the gene and protein expression levels of p53 in breast cancer cells with highly expressed OGR1 were increased. There was no significant difference in protein expression of AKT between breast cancer cells with low expression of OGR1 and those with highly expressed OGR1. However, the protein content of phosphorylated-AKT (p-AKT) in breast cancer cells with highly expressed OGR1 was lower than that in breast cancer cells with low expression of OGR1. The proliferation and apoptosis of breast cancer cells are influenced by the changes of OGR1 expression, which are correlated with the gene expression levels of AKT and p53 to some extent, but the detailed molecular mechanism requires additional study.

miR-339-5p inhibits lung adenocarcinoma invasion and migration by directly targeting BCL6

Lung adenocarcinoma (LA) is a common non-small cell lung cancer, but effective biomarkers to diagnose early LA are still lacking. Increasing evidence has indicated that the dysregulation of microRNAs (miRNAs) play crucial roles in LA progression. miR-339-5p has been recently confirmed to exert crucial functions in various cancers. Nevertheless, molecular mechanisms and effects of miR-339-5p on LA development still remain vague. In the present research, miR-339-5p expression was downregulated in human LA tissues. miR-339-5p overexpression in LA cells could remarkably suppress the LA cell invasion and migration. In addition, further studies indicated that miR-339-5p overexpression downregulated both the B-cell lymphoma 6 (BCL6) mRNA and protein expressions by targeting the BCL6 3′-UTR directly. Moreover, BCL6 knockdown could partially lessen the function of miR-339-5p in LA invasion and migration. In conclusion, the present data identified miR-339-5p as a novel LA suppressor which exerted its functions partly by negatively regulating BCL6.

Organ-specific isogenic metastatic breast cancer cell lines exhibit distinct Raman spectral signatures and metabolomes

Molecular characterization of organ-specific metastatic lesions, which distinguish them from the primary tumor, will provide a better understanding of tissue specific adaptations that regulate metastatic progression. Using an orthotopic xenograft model, we have isolated isogenic metastatic human breast cancer cell lines directly from organ explants that are phenotypically distinct from the primary tumor cell line. Label-free Raman spectroscopy was used and informative spectral bands were ascertained as differentiators of organ-specific metastases as opposed to the presence of a single universal marker. Decision algorithms derived from the Raman spectra unambiguously identified these isogenic cell lines as unique biological entities – a finding reinforced through metabolomic analyses that indicated tissue of origin metabolite distinctions between the cell lines. Notably, complementarity of the metabolomics and Raman datasets was found. Our findings provide evidence that metastatic spread generates tissue-specific adaptations at the molecular level within cancer cells, which can be differentiated with Raman spectroscopy.

Expression of and correlation between BCL6 and ZEB family members in patients with breast cancer

B-cell lymphoma 6 (BCL6), a proto-oncogene, is an evolutionarily conserved zinc finger protein that functions as a transcriptional repressor. BCL6 is the master regulator of B-lymphocyte development, and it has been reported that BCL6 may serve an important role in breast cancer progression. The aim of the present study was to investigate the expression of BCL6, zinc finger E-box-binding homeobox (ZEB)1 and ZEB2 and their associations in breast cancer. The mRNA and protein expression of BCL6, ZEB1 and ZEB2 was assessed using in situ hybridization and immunohistochemistry, respectively, in 228 patients with breast cancer and 80 patients with benign breast disease. In addition, the association between BCL6, ZEB1 and ZEB2 expression and the clinicopathological characteristics and survival of patients with breast cancer were analyzed. The mRNA and protein expression of BCL6, ZEB1 and ZEB2 were significantly higher in breast cancer tissues compared with benign breast disease tissues (P<0.05). The expression of BCL6, ZEB1 and ZEB2 were significantly positively correlated with tumor size, lymph node metastasis and a higher tumor stage (P<0.05). Furthermore, patients with BCL6, ZEB1 and ZEB2 protein-positive primary tumors had significantly lower overall survival (P=0.001, 0.002 and 0.001, respectively) and relapse-free survival (P=0.002, 0.001 and 0.003, respectively) rates. The mRNA expressions of ZEB1 (r_s=0.326, P<0.001) and ZEB2 (r_s=0.382, P<0.001) were significantly positively correlated with BCL6 mRNA expression, and the protein expressions of ZEB1 ((r_s=0.449, P<0.001) and ZEB2 (r_s=0.669, P<0.001) were significantly positively correlated with BCL6 protein expression. These results suggest that BCL6, ZEB1 and ZEB2 are potential biomarkers for the invasion, metastasis and prognosis of breast cancer, and that BCL6 may be a regulator of the ZEB family.

EGFR and HER2 signaling in breast cancer brain metastasis

Breast cancer occurs in approximately 1 in 8 women and 1 in 37 women with breast cancer succumbed to the disease. Over the past decades, new diagnostic tools and treatments have substantially improved the prognosis of women with local diseases. However, women with metastatic disease still have a dismal prognosis without effective treatments. Among different molecular subtypes of breast cancer, the HER2-enriched and basal-like subtypes typically have higher rates of metastasis to the brain. Basal-like metastatic breast tumors frequently express EGFR. Consequently, HER2- and EGFR-targeted therapies are being used in the clinic and/or evaluated in clinical trials for treating breast cancer patients with brain metastases. In this review, we will first provide an overview of the HER2 and EGFR signaling pathways. The roles that EGFR and HER2 play in breast cancer metastasis to the brain will then be discussed. Finally, we will summarize the preclinical and clinical effects of EGFR- and HER2-targeted therapies on breast cancer metastasis.

New methods in mammary gland development and cancer: proteomics, epigenetics, symmetric division and metastasis

The European Network for Breast Development and Cancer (ENBDC) meeting on 'Methods in Mammary Gland Development and Cancer' has become an annual international rendezvous for scientists with interests in the normal and neoplastic breast. The fourth meeting in this series, held in April in Weggis, Switzerland, focused on proteomics, epigenetics, symmetric division, and metastasis.