The Effect of Aurora Kinase Inhibitor on Adhesion and Migration in Human Breast Cancer Cells and Clinical Implications.

BACKGROUND: The Aurora kinase family is comprised of highly conserved serine/threonine protein kinases that are known to be crucial in the regulation of the cell cycle. Aberrant expression of Aurora kinases has been demonstrated in certain malignancies. We aimed to examine the expression of Aurora kinases in human breast cancer tissues and to investigate the cellular impact of Aurora kinases inhibitor on breast cancer cells. METHODS: The expression of Aurora kinase A/B/C was individually examined in tumor specimens (n = 106) and normal tissues (n = 29) from breast cancer patients using quantitative real-time PCR (Q-PCR) and immunohistochemistry. Cells were treated with the corresponding inhibitor, and then migration and adhesion were evaluated by electric cell impedance sensing assay. The proliferation of breast cancer cells treated with the inhibitor was examined using in vitro models. RESULTS: High levels of Aurora kinase B and C were found in the tumor tissues from breast cancer patients, but low levels of Aurora kinase A were seen in normal tissues at the mRNA level and immunohistochemistry. The mRNA expression level of Aurora kinase B and C had a negative correlation with grade staging, staging and survival rate in breast cancer patients, whilst Aurora kinase A exhibited a converse expression. The inhibitor ZM447439 promoted adhesion of the human breast cancer cell line MDA-MB-231 and inhibited the migration of MCF-7 human breast cancer cells. CONCLUSION: Taken together, the expression of Aurora kinase B and C was down-regulated in breast tumor tissues but Aurora kinase A was not. Aurora kinase may have a key role in the progression and metastasis of breast cancer.

Clinical Significance of PD1 and PDL1 in Human Breast Cancer.

BACKGROUND/AIM: Programmed death 1 (PD1) and its ligand programmed death ligand 1 (PDL1) form a pathway which when activated is thought to result in suppression of antitumor adaptive responses, influencing antitumor immunity. With potential targeted therapies emerging against PDL1, we investigated the clinical significance of mRNA expression levels of PD1 and PDL1 in our breast cancer cohort to explore its association with disease progression and prognosis. Previous studies evaluating the expression of PD1 and PDL1 (mRNA or protein) and its association with prognosis in breast cancer showed both positive and negative correlations and hence remain controversial. MATERIALS AND METHODS: Quantitative polymerase chain reaction was used to determine transcript expression levels of PD1 and PDL1 in a cohort consisting of primary breast cancer tissues (n=127) and matching non-neoplastic background tissues (n=33) with available clinical and pathological information. Two-sample two-tailed t-test, Kaplan-Meier survival analysis and Wilcoxon tests were performed. RESULTS: Significant PDL1 transcript level reductions were seen in patients who developed metastases, as well as those who had local recurrence, compared to patients who remained disease-free. Higher PDL1 transcript levels were also associated with better overall and disease-free survival. Significantly higher transcript expression levels of PD1 were found in tumor tissue, whilst a general increase in PDL1 expression was found in tumor tissues, although this did not reach statistical significance. CONCLUSION: Our study demonstrates higher levels of expression of PDL1 are associated with favorable clinical outcome.

Expression of phospholipase C isozymes in human breast cancer and their clinical significance.

Phospholipase C (PLC) regulates a number of cellular behaviours including cell motility, cell transformation, differentiation and cell growth. PLC plays a regulatory role in cancer cells partly by acting as signalling intermediates for cytokines such as EGF and interleukins. The current study examined the expression of the PLC isozymes in human breast cancer and corresponding clinical relevance. Transcript levels of human PLC-α, -ß1, -δ, -ε, and -γ1 in human breast cancer tissues were quantitatively determined by real-time PCR. Immunochemical staining was performed for PLC-δ. The clinical relevance was analysed with clinic pathological information. Mammary tissues widely expressed PLC-α, -ß1, -δ, -ε, and -γ1. Significantly high levels of PLC -ß1 and -ε were seen in breast cancer tissues in comparison with normal mammary gland tissues. PLC-γ1 however, showed marginally low levels in tumour tissues. No significant difference was seen in the expression of the PLC isozymes in tumours with lymph node metastases. Moderately and poorly differentiated breast tumours (grade 2 and grade 3) had significantly higher levels of PLC-γ1, compared with well differentiated tumours. High levels of PLC-δ were significantly correlated with a shorter disease-free survival. The altered expression of other isozymes had no correlation with the survival. It is concluded that mammary tissues differentially expressed PLC isozymes. These isozymes have certain implications in the disease development and progression, with PLC-δ showing a significant correlation with shorter disease-free survival.

Phosphoinositide-3-Kinase Enhancers, PIKEs: Their Biological Functions and Roles in Cancer.

Phosphoinositide 3-kinase enhancer (PIKE) belongs to a family of GTP-binding proteins, including three isoforms, PIKE-S, PIKE-L and PIKE-A. PIKE-S and PIKE-L interact with PI3K to enhance the activity of PI3K, but PIKE-A directly binds to AKT and up-regulates its activity. PIKEs also interacts with a variety of signaling molecules in addition to PI3K and AKT, to trigger multiple physiological functions. Overexpression or mutation of PIKE has been observed in a variety of tumors, especially PIKE-A, which acts as a proto-oncogene, promoting cancer cell growth, transformation and invasion through AKT signaling. Knockdown of PIKE-A or blocking of PIKE-A/AKT interactions enhances apoptosis, inhibits cancer cell proliferation, migration and invasion. Moreover, PIKE plays an important role in tumorigenesis through other signaling pathways, such as focal adhesion kinase, signal transducer and activator of transcription 5A, and nuclear factor kappa-light-chain-enhancer of activated B cells. The current review explores the functional role of PIKE and its potential in cancer therapy.

The Clinical Implications of RSK1-3 in Human Breast Cancer.

BACKGROUND/AIM: The ribosomal S6 protein kinase (RSK) family is an important effector of extracellular signal-regulated kinase/mitogen-activated protein kinase (ERK/MAPK) that could influence tumour metastasis by phosphorylating proteins in both the nuclear and cytoplasmic compartments. Aberrant expression of RSK is evident in certain malignancies but the role played by RSK in breast cancer is still not clear. This study aimed to examine the expression of RSK in human breast cancer specimens and its role to breast cancer metastasis. MATERIALS AND METHODS: The expression of RSK1 to -3 were separately examined in human breast cancer tissues (normal, n=33; cancer, n=112) using quantitative real-time polymerase chain reaction (Q-PCR) and immunohistochemistry. Migration and adhesion of breast cancer cells treated with the RSK inhibitor SL0101 were investigated by electric cell impedance sensing (ECIS). The effect on growth and invasion of RSK1-3 was then investigated using in vitro models. RESULTS: The clinical data and immunohistochemistry revealed that expression of RSK1 and RSK3 were less in tumour tissues than normal. mRNA expression of RSK2 was negatively correlated with grade, TNM staging, and survival rate. SL0101 inhibited adhesion of the MCF-7 and MDA-231 breast cancer cell lines. SL0101 suppressed MDA-231 invasion and the alternate RSK inhibitor BRD7389 inhibited the invasion of MCF-7 and MDA-231 cells. CONCLUSION: RSK1 and 3 but not RSK2 are down-regulated in breast tumour and are associated with disease progression. RSK may be a key component in the progression and metastasis of breast cancer.

Expression of Semaphorin 3C in Breast Cancer and its Impact on Adhesion and Invasion of Breast Cancer Cells.

BACKGROUND: The aim of the current study was to examine the role of semaphorin 3C (SEMA3C) in breast cancer. MATERIALS AND METHODS: SEMA3C transcripts expressed by breast tissues were determined using real-time polymerase chain reaction (PCR). Knock-down of SEMA3C was performed in MDA-MB-231 and MCF-7 breast cancer cell lines using anti-SEMA3C hammerhead ribozyme transgenes. The effect of SEMA3C knockdown on cancer cells was determined using in vitro cellular function assays. RESULTS: Higher SEMA3C transcript levels were significantly associated with poor differentiation of cancer cells, and transcript levels were significantly reduced in oestrogen receptor-positive tumours. Knock-down of SEMA3C expression resulted in a decrease in cell proliferation, adhesion and invasion of breast cancer cells. CONCLUSION: Higher SEMA3C expression is correlated with tumour differentiation. Inhibition of SEMA3C reduces adhesion and invasion of breast cancer cells. This suggests that SEMA3C may play a significant role in morphological changes of cancer cells, leading to enhanced growth and dissemination.

Metastasis to Bone in Human Cancer Is Associated with Loss of Occludin Expression.

BACKGROUND: Occludin is an integral membrane protein localised at tight junctions (TJ). There is no consensus regarding its paramount role in TJ. In previous work we showed that occludin is aberrantly expressed in both human breast tissues and cancer cell lines. This study demonstrates a link to bone metastasis in human cancer. MATERIALS AND METHODS: Primary breast tumours (n=124) and matched normal tissues (n=30) were processed for quantitative polymerase chain reaction (QPCR) analysis. A hammerhead ribozyme was constructed to create occludin knockdown cell lines, MDA-MB-231(ΔOcc) and PC-3(ΔOcc). The effect of human bone matrix extract (BME) was investigated using cell growth and electric cell impedance sensing (ECIS) technology to measure changes in attachment/migration. Trans-epithelial resistance (TER) was measured for assessing changes in TJ function. Cells used were MDA-MB-231, PC-3, CORL-23, SKMES-1 and A-549 human cancer cell lines. RESULTS: Tumours from patients with bone metastasis had significantly lower occludin expression compared to those remaining alive/well (60.7±21 vs. 331±98, respectively, p=0.008). This was striking in ductal carcinomas, where patients alive/well had significantly higher occludin expression compared to those with bone metastasis (391±12.5 vs. 67.9±28, respectively, p=0.0014). ECIS demonstrated that MDA-MB-231(ΔOcc) showed reduced attachment to 5% BME compared to controls (84% vs. 100%) that prevented closure of wounded cell layers. Moreover, these cells had reduced growth on BME. In addition, BME changed the TER of a number of human cell lines and was able to effect changes in the growth of MDA-MB-241 and PC-3 cells, with greater effect on knockdown cells. CONCLUSION: This is the first study to demonstrate that occludin expression has a clear relationship with bone metastasis in human cancer. The discrepancy between this and the in vitro data indicating a reduction in migration/growth rate of occludin knockdown indicates that loss of occludin leads to complex changes in human cancer cell phenotype.

Selective magnetic resonance imaging (MRI) in invasive lobular breast cancer based on mammographic density: does it lead to an appropriate change in surgical treatment?

OBJECTIVE: The purpose of this study was to evaluate whether high mammographic density can be used as one of the selection criteria for MRI in invasive lobular breast cancer (ILC). METHODS: In our institute, high breast density has been used as one of the indications for performing MRI scan in patients with ILC. We divided the patients in two groups, one with MRI performed pre-operatively and other without MRI. We compared their surgical procedures and analyzed whether surgical plan was altered after MRI. In case of alteration of plan, we analyzed whether the change was adequate by comparing post-operative histological findings. RESULTS: Between 2011 and 2015, there were a total of 1601 breast cancers with 97 lobular cancers, out of which 36 had pre-operative MRI and 61 had no MRI scan. 12 (33.3%) had mastectomy following MRI, out of which 9 (25%) had change in surgical plan from conservation to mastectomy following MRI. There were no unnecessary mastectomies in the MRI group. However, utilization of MRI in this cohort of patients did not reduce reoperation rate (19.3%). Lobular carcinoma in situ (LCIS) was identified in 60% of reoperations on post-surgical histology. Patients in the "No MRI" group had higher mastectomy rate 26 (42.6%), which was again appropriate. CONCLUSION: High mammographic density is a useful risk stratification criterion for selective MRI in ILC within a multidisciplinary team meeting setting. Provided additional lesions identified on MRI are confirmed with biopsy, pre-operative MRI does not cause unnecessary mastectomies. Used in this selective manner, reoperation rates were not eliminated, albeit reduced when compared to literature. ADVANCES IN KNOWLEDGE: High mammographic breast density can be used as one of the selection criteria for pre-operative MRI in ILC without an increase in inappropriate mastectomies with potential time and cost savings. In this cohort, re-excisions were not reduced markedly with pre-operative MRI.