Estrogen Receptor Mediates the Radiosensitivity of Triple-Negative Breast Cancer Cells

Unveiling the Mechanism of the ChaiShao Shugan Formula Against Triple-Negative Breast Cancer

Background

The ChaiShao Shugan Formula (CSSGF) is a traditional Chinese medicine formula with recently identified therapeutic value in triple-negative breast cancer (TNBC). This study aimed to elucidate the underlying mechanism of CSSGF in TNBC treatment.

Methods

TNBC targets were analyzed using R and data were from The Cancer Genome Atlas (TCGA) and Gene Expression Omnibus (GEO) databases. The major ingredients and related protein targets of CSSGF were explored via the Traditional Chinese Medicine Systems Pharmacology database, and an ingredient-target network was constructed via Cytoscape to identify hub genes. The STRING database was used to construct the PPI network. GO and KEGG enrichment analyses were performed via R to obtain the main targets. The online tool Kaplan‒Meier plotter was used to identify the prognostic genes. Molecular docking was applied to the core target genes and active ingredients. MDA-MB-231 and MCF-7 cell lines were used to verify the efficacy of the various drugs.

Results

A total of 4562 genes were screened as TNBC target genes. The PPI network consisted of 89 nodes and 845 edges. Our study indicated that quercetin, beta-sitosterol, luteolin and catechin might be the core ingredients of CSSGF, and EGFR and c-Myc might be the latent therapeutic targets of CSSGF in the treatment of TNBC. GO and KEGG analyses indicated that the anticancer effect of CSSGF on TNBC was mainly associated with DNA binding, transcription factor binding, and other biological processes. The related signaling pathways mainly involved the TNF-a, IL-17, and apoptosis pathways. The molecular docking data indicated that quercetin, beta-sitosterol, luteolin, and catechin had high affinity for EGFR, JUN, Caspase-3 and ESR1, respectively. In vitro, we found that CSSGF could suppress the expression of c-Myc or promote the expression of EGFR. In addition, we found that quercetin downregulates c-Myc expression in two BC cell lines.

Conclusion

This study revealed the effective ingredients and latent molecular mechanism of action of CSSGF against TNBC and confirmed that quercetin could target c-Myc to induce anti-BC effects.

Novel insights on perils and promises of miRNA in understanding colon cancer metastasis and progression

Colorectal cancer (CRC) is the third highest frequent malignancy and ultimate critical source of cancer-associated mortality around the world. Regardless of latest advances in molecular and surgical targeted medicines that have increased remedial effects in CRC patients, the 5-year mortality rate for CRC patients remains dismally low. Evidence suggests that microRNAs (miRNAs) execute an essential part in the development and spread of CRC. The miRNAs are a type of short non-coding RNA that exhibited to control the appearance of tumor suppressor genes and oncogenes. miRNA expression profiling is already being utilized in clinical practice as analytical and prognostic biomarkers to evaluate cancer patients' tumor genesis, advancement, and counteraction to drugs. By modulating their target genes, dysregulated miRNAs are linked to malignant characteristics (e.g., improved proliferative and invasive capabilities, cell cycle aberration, evasion of apoptosis, and promotion of angiogenesis). This review presents an updated summary of circulatory miRNAs, tumor-suppressive and oncogenic miRNAs, and the potential reasons for dysregulated miRNAs in CRC. Further we will explore the critical role of miRNAs in CRC drug resistance.

The Detection of DNA Damage Response in MCF7 and MDA-MB-231 Breast Cancer Cell Lines after X-ray Exposure

Radiotherapy is one of the main options to cure and control breast cancer. The aim of this study was to investigate the sensitivity of two human breast cancer cell lines, MCF7 and MDA-MD-231, to radiation exposure at timepoints 4 h and 24 h after radiation. MCF7 and MDA-MD-231 were irradiated with different radiation doses using a Gilardoni CHF 320 G X-ray generator (Mandello del Lario, Italy) at 250 kVp, 15 mA [with half-value layer (HVL) = 1.6 mm copper]. The ApoTox-Glo triplex assay combines three assays used to assess viability, cytotoxicity, and apoptosis. The expression of γH2AX and BAX was analyzed by Western blotting. Viability and cytotoxicity did not change 4 h and 24 h after irradiation in either cell line, but we found a significant increase in the expression of cleaved caspase-3/7 at 24 h after irradiation with 8.5 Gy in MDA-MB231. The expression of γH2AX and BAX was low in MCF7, whereas the expression of γH2AX and BAX increased with radiation dose in a dose-dependent manner in MDA-MB231. The results show that the MCF7 cell line is more radioresistant than the MDA-MB 231 cell line at 4 h and 24 h after X-ray irradiation. In contrast, MDA-MB-231 cells were radiosensitive at a high radiation dose of 8.5 Gy at 24 h after irradiation. γH2AX and BAX indicated the radiosensitivity in both cell lines. These results open the possibility of using these cancer cell lines as models for testing new therapeutic strategies to improve radiation therapy.

P2Y2R-Mediated PAK1 Activation Is Involved in ESM-1 Overexpression in RT-R-MDA-MB-231 through FoxO1 Regulation

ESM-1, overexpressed in several cancer types, is a potential cancer diagnostic and prognostic indicator. In our previous study, we determined that RT-R-TNBC cells were more aggressive than TNBC cells, and this difference was associated with ESM-1 overexpression. However, the mechanism explaining upregulated ESM-1 expression in RT-R-TNBC cells compared to TNBC cells was unclear. Therefore, we aimed to identify the mechanism by which ESM-1 is overexpressed in RT-R-MDA-MB-231 cells. RT-R-MDA-MB-231 cells were treated with various ESM-1 transcription factor inhibitors, and only the FoxO1 inhibitor downregulated ESM-1 expression. FoxO1 nuclear localization was modulated by JNK and p38 MAPKs, which were differentially regulated by PKC, PDK1 and PAK1. PAK1 profoundly modulated JNK and p38 MAPKs, whereas PKC and PDK1 affected only p38 MAPK. P2Y2R activated by ATP, which is highly released from RT-R-BC cells, was involved in PAK1 activation, subsequent JNK and p38 MAPK activation, FoxO1 induction, and ESM-1 expression in RT-R-MDA-MB-231 cells. These findings suggest for the first time that ESM-1 was overexpressed in RT-R-MDA-MB-231 cells and regulated through the P2Y2R-PAK1-FoxO1 signaling pathway.

Survival comparison between postoperative and preoperative radiotherapy for stage I-III non-inflammatory breast cancer

To compare the survival benefit between preoperative and postoperative radiotherapy for stage I-III non-inflammatory breast cancer patients, we conducted a retrospective cohort study using surveillance, epidemiology and end results databases. Our study recruited patients who had been diagnosed with stage I-III breast cancer and underwent surgery and radiotherapy. The overall survival was calculated by Kaplan-Meier method. Cox risk model was used to determine the impact of radiotherapy according to stage, molecular subtype and other risk factors. Propensity score matching was used to balance measurable confounding factors. Of all the 411,279 enrolled patients varying from 1975 to 2016, 1712 patients received preoperative radiotherapy, and 409,567 patients received postoperative radiotherapy. Compared with the postoperative radiotherapy group, the preoperative radiotherapy group showed significantly higher risks of overall mortality and breast cancer-specific mortality. Survival differences in treatment sequences were correlated with stage, molecular subtypes and other risk factors. According to the results of this study, preoperative radiotherapy did not show a survival advantage, and postoperative radiotherapy is still the primary treatment. However, preoperative radiotherapy also has some theoretical advantages, such as phase reduction and recurrence reduction. Therefore, it is still worthy of further exploration.

Increased FOXA1 levels induce apoptosis and inhibit proliferation in FOXA1-low expressing basal breast cancer cells

The transcription factor FOXA1, which is a member of the forkhead class of DNA-binding proteins, interacts with Estrogen Receptor (ER) to mediate breast cancer progression. However, its role in basal breast cancer cells remains unclear. Although the overall levels of FOXA1 are decreased in the basal subtype of clinical TCGA breast cancer samples, the high levels of FOXA1 improve the survival of the patients from this subtype. This clinical phenomenon is consistent with that of FOXA1 stimulating apoptosis in FOXA1-low expressing basal breast cancer cells, such as MDA-MB-231, and MDA-MB-468 cells. In this study, we have constructed an inducible expression system of FOXA1 and demonstrated the induced expression of FOXA1 resulting in apoptosis and cell cycle arrest in MDA-MB-231 cells, as confirmed by transcriptomic analysis and in vivo tumor-grafted models. Furthermore, the low levels of Estrogen Receptor-1 (ESR1) are critical for FOXA1 in terms of its repressive roles in the cells, as evidenced by clinical data analysis indicating that the high levels of FOXA1 improve the survival of ESR1^Low patients, but worsen the survival of ESR1^High patients of breast cancer. When introduced into MDA-MB-231 cells, ESR1 counteracts the tumor suppressor roles of FOXA1 by altering the FOXA1-regulated gene transcription and the two proteins together maintain the tumor progression in vivo. Our cumulative results suggest that FOXA1 suppresses the basal breast cancer cells with FOXA1-low expressing status independent of ESR1 by inducing apoptosis and inhibiting cell proliferation, thereby implicating its potential therapeutic role in this group of breast cancer.

Activated ERK Signaling Is One of the Major Hub Signals Related to the Acquisition of Radiotherapy-Resistant MDA-MB-231 Breast Cancer Cells

Breast cancer is one of the major causes of deaths due to cancer, especially in women. The crucial barrier for breast cancer treatment is resistance to radiation therapy, one of the important local regional therapies. We previously established and characterized radio-resistant MDA-MB-231 breast cancer cells (RT-R-MDA-MB-231 cells) that harbor a high expression of cancer stem cells (CSCs) and the EMT phenotype. In this study, we performed antibody array analysis to identify the hub signaling mechanism for the radiation resistance of RT-R-MDA-MB-231 cells by comparing parental MDA-MB-231 (p-MDA-MB-231) and RT-R-MDA-MB-231 cells. Antibody array analysis unveiled that the MAPK1 protein was the most upregulated protein in RT-R-MDA-MB-231 cells compared to in p-MDA-MB-231 cells. The pathway enrichment analysis also revealed the presence of MAPK1 in almost all enriched pathways. Thus, we used an MEK/ERK inhibitor, PD98059, to block the MEK/ERK pathway and to identify the role of MAPK1 in the radio-resistance of RT-R-MDA-MB-231 cells. MEK/ERK inhibition induced cell death in both p-MDA-MB-231 and RT-R-MDA-MB-231 cells, but the death mechanism for each cell was different; p-MDA-MB-231 cells underwent apoptosis, showing cell shrinkage and PARP-1 cleavage, while RT-R-MDA-MB-231 cells underwent necroptosis, showing mitochondrial dissipation, nuclear swelling, and an increase in the expressions of CypA and AIF. In addition, MEK/ERK inhibition reversed the radio-resistance of RT-R-MDA-MB-231 cells and suppressed the increased expression of CSC markers (CD44 and OCT3/4) and the EMT phenotype (β-catenin and N-cadherin/E-cadherin). Taken together, this study suggests that activated ERK signaling is one of the major hub signals related to the radio-resistance of MDA-MB-231 breast cancer cells.

New Insight into Triple-Negative Breast Cancer Therapy: The Potential Roles of Endoplasmic Reticulum Stress and Autophagy Mechanisms

BACKGROUND

Breast cancer is accounted as the fifth leading cause of mortality among the other cancers. Notwithstanding, Triple Negative Breast Cancer (TNBC) is responsible for 15-20% of breast cancer mortality. Despite many investigations, it remains incurable in part due to insufficient understanding of its exact mechanisms.

METHODS

A literature search was performed in PubMed, SCOPUS and Web of Science databases using the keywords autophagy, Endoplasmic Reticulum (ER) stress, apoptosis, TNBC and the combinations of these keywords.

RESULTS

It was found that autophagy plays a dual role in cancer, so that it may decrease the viability of tumor cells or act as a cytoprotective mechanism. It then appears that using compounds having modulatory effects on autophagy is of importance in terms of induction of autophagic cell death and diminishing the proliferation and metastasis of tumor cells. Also, ER stress can be modulated in order to stimulate apoptotic and autophagic cell death in tumor cells.

CONCLUSION

Perturbation in the signaling pathways related to cell survival leads to the initiation and progression of cancer. Regarding the advancement in the cancer pathology, it seems that modulation of autophagy and ER stress are promising.

Controversies of radiotherapy in human epidermal growth factor receptor (HER)-2 positive breast cancer patients

Tumor biology plays a crucial role in the systemic treatment, specifically in HER2-positive tumors. Distinct biological behavior of breast cancer subtypes is associated with different rates of locoregional recurrence (LRR). HER2- positive breast cancer patients treated with surgery in combination with radiation, without trastuzumab have poor outcome, including high LRR. The efficacy of radiotherapy in HER-2-positive breast cancer appears to be associated with the expression of estrogen receptors. In patients with HER-2-positive breast cancer, studies conducted before the introduction of trastuzumab indicated higher benefit of adjuvant radiation in patients with hormone receptor-positive tumors compared to patients with tumors not expressing hormone receptors. The introduction of agents targeting HER-2 has transformed the management of these patients, resulting in improved outcomes. The data of clinical studies show that the administration of trastuzumab as part of a multimodality approach (with radiation based on standard guidelines) results in improved outcomes, including lower locoregional recurrence. The risk of cardiac toxicity associated with radiation to the heart and administration of potential cardiotoxic trastuzumab is not clear. In patients treated concomitantly with regional lymph node irradiation and anti-HER-2 agents after prior anthracycline-based chemotherapy minimizing the dose to the myocardium, e.g. respiratory gating or proton beam radiotherapy, have been suggested.

CLPTM1L induces estrogen receptor β signaling-mediated radioresistance in non-small cell lung cancer cells

INTRODUCTION

Radioresistance is a major challenge in lung cancer radiotherapy, and new radiosensitizers are urgently needed. Estrogen receptor β (ERβ) is involved in the progression of non-small cell lung cancer (NSCLC), however, the role of ERβ in the response to radiotherapy in lung cancer remains elusive. In the present study, we investigated the mechanism underlying ERβ-mediated transcriptional activation and radioresistance of NSCLC cells.

METHODS

Quantitative real-time PCR, western blot and immunohistochemistry were used to detect the expression of CLPTM1L, ERβ and other target genes. The mechanism of CLPTM1L in modulation of radiosensitivity was investigated by chromatin immunoprecipitation assay, luciferase reporter gene assay, immunofluorescence staining, confocal microscopy, coimmunoprecipitation and GST pull-down assays. The functional role of CLPTM1L was detected by function assays in vitro and in vivo.

RESULTS

CLPTM1L expression was negatively correlated with the radiosensitivity of NSCLC cell lines, and irradiation upregulated CLPTM1L in radioresistant (A549) but not in radiosensitive (H460) NSCLC cells. Meanwhile, IR induced the translocation of CLPTM1L from the cytoplasm into the nucleus in NSCLC cells. Moreover, CLPTM1L induced radioresistance in NSCLC cells. iTRAQ-based analysis and cDNA microarray identified irradiation-related genes commonly targeted by CLPTM1L and ERβ, and CLPTM1L upregulated ERβ-induced genes CDC25A, c-Jun, and BCL2. Mechanistically, CLPTM1L coactivated ERβ by directly interacting with ERβ through the LXXLL NR (nuclear receptor)-binding motif. Functionally, ERβ silencing was sufficient to block CLPTM1L-enhanced radioresistance of NSCLC cells in vitro. CLPTM1L shRNA treatment in combination with irradiation significantly inhibited cancer cell growth in NSCLC xenograft tumors in vivo.

CONCLUSIONS

The present results indicate that CLPTM1L acts as a critical coactivator of ERβ to promote the transcription of its target genes and induce radioresistance of NSCLC cells, suggesting a new target for radiosensitization in NSCLC therapy. Video Abstract.

The survival benefit of postmastectomy radiotherapy for breast cancer patients with T1-2N1 disease according to molecular subtype

OBJECTIVE

To evaluate the significance of postmastectomy radiotherapy (PMRT) in female breast cancer patients with T1-2N1M0 disease according to molecular subtypes and other risk factors.

METHOD

We conducted a retrospective cohort-based study utilizing the Surveillance, Epidemiology, and End Results database. Patients who were diagnosed with T1-2N1M0 invasive breast cancer and received mastectomy between 2010 and 2014 were enrolled in our study. Overall survival (OS) was calculated with Kaplan-Meier method, and multivariant Cox hazard model was conducted to identify the impact of PMRT according to molecular subtypes and other risk factors. Propensity score matching (PSM) was applied to balance measurable confounders.

RESULTS

Of all the 16,521 enrolled patients, 5775 (35.0%) cases received PMRT. The distribution of molecular subtype is 71.4% for Luminal A, 13.2% for Luminal B, 5.1% for HER2 enriched, and 10.3% for TNBC. The OS was significantly better for patients in PMRT group than the Non-PMRT group (P < 0.0001). Stratified by molecular subtype, PMRT significantly prolonged survival in Luminal A patients (HR: 0.759, 95% CI: 0.651-0.884, P < 0.001), Yet it brought no significant survival advantage in Luminal B, TNBC or HER2 enriched subtype (P = 0.914, P = 0.124, P = 0.103, respectively). Also, PMRT bore prognostic significance among those patients who were older than 56 years old, single, white, exempt from reconstruction and chemotherapy, and were with ductal, GradeⅡtumor (all P < 0.05). After PSM, the survival benefit of PRMT sustained in Luminal A patients with T1 tumor concomitant with one positive lymph node.

CONCLUSION

Our study demonstrates a beneficial impact for PMRT on overall survival among Luminal A subtype breast cancer patients with T1-2N1 disease. The selection of PMRT should be stratified by molecular subtype and other risk factors.

Trametes robiniophila Murr in the treatment of breast cancer

Breast cancer is the leading cause of cancer death among women across the world. Trametes robiniophila Murr (Huaier), a traditional herbal medicine, has been used in China to protect human health for about 1600 years. Recent years, Huaier had been proven to be effective for multiple types of malignancies. This systematic review focused on breast cancer treatment, summarizing the curative function of Huaier aqueous extract and polysaccharides in preclinical researches. Huaier could markedly inhibit breast cancer progression with low toxicity, enhance immune response and increase the sensitivity to radiation and chemotherapy. The therapeutic effect of Huaier granule in clinical studies was also included. This review amalgamated the current studies and highlighted the promising role of Huaier and its polysaccharides as complementary alternative medicine in breast cancer treatment.

Preliminary study on radiosensitivity to carbon ions in human breast cancer

The aim of the study was to investigate the various effects of high linear energy transfer (LET) carbon ion (12C6+) and low LET X-ray radiation on MDA-MB-231 and MCF-7 human breast cancer cells and to explore the underlying mechanisms of radiation sensitivity. Cell proliferation, cell colony formation, cell cycle distribution, cell apoptosis and protein expression levels [double-strand break marker γ-H2AX, cell cycle-related protein cyclin B1, apoptosis-related proteins Bax and Bcl-2, and the Akt/mammalian target of rapamycin (mTOR)/ribosomal protein S6 kinase B1 (p70S6K) pathway] were detected after irradiation with carbon ions or X-rays at doses of 0, 2, 4 and 8 Gy. Our results showed that the inhibition of cell proliferation and cell colony formation and the induction of G2/M phase arrest, DNA lesions and cell apoptosis/necrosis elicited by carbon ion irradiation were more potent than the effects elicited by X-ray radiation at the same dose. Simultaneously, compared with X-ray radiation, carbon ion radiation induced a marked increase in Bax and prominent decreases in cyclin B1 and Bcl-2 in a dose-dependent manner. Furthermore, the Akt/mTOR/p70S6K pathway was significantly inhibited by carbon ion radiation in both breast cancer cell lines. These results indicate that carbon ion radiation kills MDA-MB-231 and MCF-7 breast cancer cells more effectively than X-ray radiation, which might result from the inhibition of the Akt/mTOR/p70S6K pathway.

Downregulation of TMPRSS4 Enhances Triple-Negative Breast Cancer Cell Radiosensitivity Through Cell Cycle and Cell Apoptosis Process Impairment

Background:

Radioresistance remains a challenge for cancer radiotherapy. The present study aims to investigate the role of TMPRSS4 in triple negative breast cancer (TNBC) cell radiosensitivity.

Materials and Methods:

After transfection of MDA-MD-468 triple negative breast cancer cells line by using the lentivirus vector, the effect of TMPRSS4 down-regulation on TNBC radiosensitivity was evaluated by using cloning assay and CCK-8 assay. The CCK-8 assay was also used for performing cell proliferation analysis. Western blot was carried out to detect the expression of certain proteins related to cell cycle pathways (cyclin D1), cell apoptosis pathways (Bax, Bcl2, and Caspase3), DNA damage and DNA damage repair (TRF2, Ku80 , ˠH2AX) . The cell cycle and cell apoptosis were also investigated using flow cytometer analysis.

Results:

TMPRSS4 expression was down-regulated in MDA-MB-468 cells which enhanced MDA-MB-468 cells radiosensitivity. TMPRSS4 silencing also improved IR induced cell proliferation ability reduction and promoted cell arrested at G2/M phase mediated by 6 Gy IR associated with cyclin D1 expression inhibition. Moreover, TMPRSS4 inhibition enhanced TNBC apoptosis induced by 6 Gy IR following by over-expression of (Bax, Caspase3) and down-regulation of Bcl2 as the pro-apoptotic and anti-apoptotic proteins, respectively. Otherwise, TMPRSS4 down-regulation increases DNA damage induced by 6 Gy IR and delays DNA damage repair respectively illustrated by downregulation of TRF2 and permanent increase of Ku80 and ˠH2AX expression at 1 h and 10 h post-IR.

Conclusion:

Down-regulation of TMPRSS4 increases triple negative breast cancer cell radiosensitivity and the use of TMPRSS4 inhibitor can be encouraged for improving radiotherapy effectiveness in TNBC radioresistant patients.

Co-delivery of epirubicin and paclitaxel using an estrone-targeted PEGylated liposomal nanoparticle for breast cancer

Breast cancer is one of the most frequent malignancies in the female population. Recently, the development of medical products has been advanced for this disease; however, patients still suffer from the failure of current treatments and new therapeutic strategies are urgently required. In this study, due to the overexpression of the estrogen receptor (ER) in breast cancer and the ability of ER to specifically bind to its ligand estrone (ES), an ES-targeted PEGylated epirubicin (EPI) and paclitaxel (PTX) co-loaded liposomal nanoparticle (NP) (termed as ES-SSL-EPI/PTX) was developed. Physicochemical studies demonstrated that the ES-SSL-EPI/PTX had a nanoscaled particle size (~120 nm) and a neutral zeta potential (~-5 mV) and presented favorable stability in physiological media. In vitro, the ES-SSL-EPI/PTX showed a significantly higher cellular uptake in human breast cancer MCF-7 cells mainly via the receptor-ligand mediated pathway resulting in effective cytotoxic activity. In vivo targeting study, the accumulation of targeted liposomes in tumor was significantly improved. The systemic circulation time and biodistribution in main organs of EPI and PTX delivered by ES-SSL-Liposomes were increased. Consequently, the ES-SSL-EPI/PTX significantly suppressed tumor growth in the MCF-7-derived tumor-bearing mouse model without inducing toxicity. These results suggested that the ES-SSL-EPI/PTX was a promising formulation for co-delivery of chemotherapeutics in the treatment of breast cancer.

Chromosomal radiosensitivity of triple negative breast cancer patients

Purpose: Based on clinical and molecular data, breast cancer is a heterogeneous disease. Breast cancers that have no expression of estrogen receptor (ER), progesterone receptor (PR) and human epidermal growth factor receptor 2 (HER2) are defined as triple negative breast cancers (TNBCs); luminal cancers have different expressions of ER, PR and/or HER2. TNBCs are frequently linked with advanced disease, poor prognosis and occurrence in young African women, and about 15% of the cases are associated with germline BRCA1/2 mutations. Since radiotherapy is utilized as a principle treatment in the management of TNBC, we aimed to investigate the chromosomal instability and radiosensitivity of lymphocytes in TNBC patients compared to luminal breast cancer patients and healthy controls using the micronucleus (MN) assay. The effect of mutations in breast cancer susceptibility genes on chromosomal radiosensitivity was also evaluated.Methods: Chromosomal radiosensitivity was evaluated in the G0 (83 patients and 90 controls) and S/G2 (34 patients and 17 controls) phase of the cell cycle by exposing blood samples from all patients and controls to 2 and 4 Gy ionizing radiation (IR).Results: In the G0 MN assay, the combined cohort of all breast cancer, TNBC and luminal patients' exhibit significantly elevated spontaneous MN values compared to controls indicating chromosomal instability. Chromosomal radiosensitivity is also significantly elevated in the combined cohort of all breast cancer patients compared to controls. The TNBC patients, however, do not exhibit enhanced chromosomal radiosensitivity. Similarly, in the S/G2 phase, 76% of TNBC patients do not show enhanced chromosomal radiosensitivity compared to the controls. In both the G0 and S/G2 phase, luminal breast cancer patients demonstrate a shift toward chromosomal radiosensitivity compared to TNBC patients and controls.Conclusions: The observations of the MN assay suggest increased chromosomal instability and chromosomal radiosensitivity in South African breast cancer patients. However, in TNBC patients, the irradiated MN values are not elevated. Our results suggest that the healthy lymphocytes in TNBC patients could handle higher doses of IR.

Role of estrogen and its receptors mediated-autophagy in cell fate and human diseases

Studies have shown that morbidity of several diseases varies between males and females. This difference likely arises due to sex-related hormones. Estrogen, a primary female sex steroid hormone, plays a critical role in mediating many of the physiological functions like growth, differentiation, metabolism, and cell death. Recently, it has been demonstrated that estrogen mediates autophagy through its receptors (ERs) namely ERα, ERβ, and G-protein coupled estrogen receptor (GPER). However, the specific role of estrogen and its receptors mediated-autophagy in cell fate and human diseases such as cancers, cardiovascular disease and nervous system disease remains unclear. In this review, we comprehensively summarize the complex role of estrogen and its receptors-mediated autophagy in different cell lines and human diseases. In addition, we further discuss the key signaling molecules governing the role of ERs in autophagy. This review will serve as the basis for a proposed model of autophagy constituting a new frontier in estrogen-related human diseases. Here, we discuss the dual role of ERα in classical and non-classical autophagy through B-cell lymphoma 2 (BCL2)-associated athanogene 3 (BAG3). Next, we review the role of ERβ in pro-survival pathways through the promotion of autophagy under stress conditions. We further discuss activation of GPER via estrogen often mediates autophagy or mitophagy suppression, respectively. In summary, we believe that understanding the relationship between estrogen and its receptors mediated-autophagy on cell fate and human diseases will provide insightful knowledge for future therapeutic implications.

Tumor grade and molecular subtypes on local control in breast cancer radiotherapy: Does fractionation really matter? A retrospective control study group

The aim of this current study was to assess whether the tumour grade and molecular subtypes have influenced local control in the whole breast hypofractionated radiotherapy (HRT) over standard radiotherapy (SRT) in early breast node negative cancer patients by a retrospective control group study.

Data of 215 patients treated with hypofractionated radiotherapy at our institution from 2008 to 2011 were prospectively collected and then compared with 215 pts treated with SRT in a control group study. The local relapse free survival (LRFS) in both arms was compared on the basis of variables defined by tumour grade (Nottingham Grading System), and Molecular subtypes. Kaplan-Meier method was applied to estimate the LRFS in both groups. Chi-squared and univariate Cox proportional hazards model were conducted for all variables in both groups to assess the impact on local control. Statistical significance was assumed at P < .05. Statistical significant variables at univariate analysis were then included in multivariate Cox proportional hazards model. The median follow up duration was 9.5 years (7–13 yrs); the Kaplan Meyer 8 year LRFS did not reach any statistical significant difference between the two groups (P = . 836). At univariate Cox analysis tumour grade 3 was significantly related to local relapse only in the SRT group (P = .041) while, among molecular subtypes, no differences were found for all groups; for Her2 + noL no difference was found (P = .233). Multivariate analysis confirmed Her2 non-luminal subtype as an independent variable for local relapse regardless the fractionation arm (P = .045). Breast cancer subtypes show a different radiosensitivity, which is independent by fractionation.

DNA Replication Licensing Protein MCM10 Promotes Tumor Progression and Is a Novel Prognostic Biomarker and Potential Therapeutic Target in Breast Cancer

Breast cancer is one of the most common malignancies in women worldwide. In breast cancer, the cell proliferation rate is known to influence the cancer malignancy. Recent studies have shown that DNA replication initiation/licensing factors are involved in cancer cell proliferation as well as cancer cell migration and invasion. Licensing factors have also been reported as important prognostic markers in lung, prostrate, and bladder cancers. Here, we studied the role of MCM10, a novel licensing factor, in breast cancer progression. From the public database, NCBI, we investigated six independent breast cancer patient cohorts, totaling 1283 patients. We observed a significant association between high MCM10 mRNA expression with tumor grading and patients’ survival time. Most importantly, using breast cancer cohorts with available treatment information, we also demonstrated that a high level of MCM10 is associated with a better response to conventional treatment. Similarly, in in vitro studies, the expression level of MCM10 in breast cancer cell lines is significantly higher compared to paired normal breast epithelium cells. Knockdown of MCM10 expression in the cancer cell line showed significantly decreased tumorigenic properties such as cell proliferation, migration and anchorage independence. The MCF7 breast cancer cell line, after MCM10 expression knockdown, showed significantly decreased tumorigenic properties such as cell proliferation, migration, and anchorage independent growth. Mechanistically, MCM10 expression is observed to be regulated by an Estrogen Receptor (ER) signaling pathway, where its expression is suppressed by the inhibition of the ER or serum withdrawal. Our results suggest that MCM10 plays an important role in breast cancer progression and is a potential prognostic/predictive biomarker and therapeutic target for breast cancer patients.

Study on the Mechanism of Cell Cycle Checkpoint Kinase 2 (CHEK2) Gene Dysfunction in Chemotherapeutic Drug Resistance of Triple Negative Breast Cancer Cells

Background

This study aimed to investigate the mechanism of CHEK2 gene dysfunction in drug resistance of triple negative breast cancer (TNBC) cells.

Material/Methods

To perform our study, a stable CHEK2 wild type (CHEK2 WT) or CHEK2 Y390C mutation (CHEK2 Y390C) expressed MDA-MB-231 cell line was established. MTT assay, cell apoptosis assay and cell cycle assay were carried out to analyze the cell viability, apoptosis, and cell cycle respectively. Western blotting and qRT-PCR were applied for related protein and gene expression detection.

Results

We found that the IC₅₀ value of DDP (Cisplatin) to CHEK2 Y390C expressed MDA-MB-231 cells was significantly higher than that of the CHEK2 WT expressed cells and the control cells. After treatment with DDP for 48 h, cells expressing CHEK2 WT showed lower cell viability than that of the CHEK2 Y390C expressed cells and the control cells; compared with the CHEK2 Y390C expressed cells and the control cells, cells expressing CHEK2 WT showed significant G1/S arrest. Meanwhile, we found that compared with the CHEK2 Y390C expressed cells and the control cells, cell apoptosis was significantly increased in CHEK2 WT expressed cells. Moreover, our results suggested that cells expressing CHEK2 WT showed higher level of p-CDC25A, p-p53, p21, Bax, PUMA, and Noxa than that of the CHEK2 Y390C expressed cells and the control cells.

Conclusions

Our findings indicated that CHEK2 Y390C mutation induced the drug resistance of TNBC cells to chemotherapeutic drugs through administrating cell apoptosis and cell cycle arrest via regulating p53 activation and CHEK2-p53 apoptosis pathway.