ß2-microglobulin induced apoptosis of tumor cells via the ERK signaling pathway by directly interacting with HFE in HER2-overexpressing breast cancer.

BACKGROUND: Our previous study demonstrated that ß2-microglobulin (ß2M) promoted ER+/HER2- breast cancer survival via the SGK1/Bcl-2 signaling pathway. However, the role of ß2M has not been investigated in ER-/HER2+ breast cancer. Here, we aimed to determine the role of ß2M in ER-/HER2+ breast cancer. METHODS: The interaction between ß2M and HFE was confirmed by co-immunoprecipitation, mass spectrometry, yeast two-hybrid screening, and His pull-down. The knockdown and overexpression of ß2M or HFE were performed in MDA-MB-453 cells, and ERK signaling pathway was subsequently analyzed via western blotting. Apoptotic cells were detected using flow cytometer. ß2M, HFE, and p-ERK1/2 were examined in tumor and paired adjacent tissues via immunohistochemistry. RESULTS: HFE was found to be an interacting protein of ß2M in ER-/HER2+ breast cancer cells MDA-MB-453 by co-immunoprecipitation and mass spectrometry. A yeast two-hybrid system and His-pull down experiments verified that ß2M directly interacted with HFE. ß2M and HFE as a complex were mainly located in the cytoplasm, with some on the cytomembrane of MDA-MB-453 cells. In addition to breast cancer cells BT474, endogenous ß2M directly interacted with HFE in breast cancer cells MDA-MB-453, MDA-MB-231, and MCF-7. ß2M activated the ERK signaling pathway by interacting with HFE and induced apoptosis of MDA-MB-453 cells. The expression of HFE and p-ERK1/2 showed significantly high levels in HER2-overexpressing breast cancer tumor tissue compared with adjacent normal tissue, consistent with the results obtained from the cell experiments. CONCLUSIONS: ß2M induced apoptosis of tumor cells via activation of the ERK signal pathway by directly interacting with HFE in HER2-overexpressing breast cancer.

ß2-microglobulin has a different regulatory molecular mechanism between ER+ and ER- breast cancer with HER2.

BACKGROUND: Previous studies have demonstrated that ß2-microglobulin (ß2M) promotes the growth and survival of a variety of cancer cells and has different regulatory effects on the expression of Bcl-2 and HER2 in HER2- breast cancer cells. However, ß2M-mediated signaling in ER+ and ER- breast cancer with HER2- remains unclear. METHODS: ß2M expression vector and siRNA were transfected into two types of HER2- breast cancer cells, and the possible relevant signaling molecules were subsequently analyzed by real-time PCR and western blotting. These signaling molecules were also analyzed by real-time PCR and immunohistochemistry (IHC) in two types of HER2- breast cancer tissues, and the associations between ß2M and these signaling molecules were assessed using Spearman's correlation analysis. RESULTS: ß2M silencing downregulated p-SGK1/SGK1 levels and Bcl-2 expression, and ß2M overexpression downregulated p-CREB/CREB and significantly upregulated p-SGK1/SGK1 levels and Bcl-2 expression, and both resulting processes did not affect HER2, HIF-1α, VEGF, and ERK signaling in ER+ breast cancer cells with HER2-. ß2M silencing upregulated p-CREB/CREB and VEGF protein and significantly downregulated p-ERK/ERK levels, and ß2M overexpression downregulated p-CREB/CREB and VEGF, significantly upregulated p-ERK/ERK levels, and both resulting processes did not affect HIF-1α and SGK1 signaling in ER- breast cancer cells with HER2-. ß2M expression was positively correlated with p-CREB, p-SGK1, and Bcl-2 expression and had no correlation with HIF-1α, VEGF, and p-ERK1/2, whereas p-SGK1 exhibited a significantly positive correlation with Bcl-2 expression in cancer tissues of patients with luminal A breast cancer, which coincide with the results obtained from the same molecular types of breast cancer cells except CREB signaling. However, ß2M expression did not show a significant correlation with HIF-1α, p-CREB, VEGF, p-SGK1, p-ERK1/2, and Bcl-2 expression in cancer tissues of patients with basal-like breast cancer, which was discordant with the results obtained from the same molecular types of breast cancer cells. CONCLUSIONS: ß2M has a different molecular regulatory mechanism between ER+ and ER- breast cancer with HER2-, and it may promote tumor survival through the SGK1/Bcl-2 signaling pathway in ER+ breast cancer with HER2- and has no regulatory effects on ER- breast cancer with HER2-.

Integrin α7 high expression correlates with deteriorative tumor features and worse overall survival, and its knockdown inhibits cell proliferation and invasion but increases apoptosis in breast cancer.

BACKGROUND: This study aimed to investigate the correlation of integrin α7 (ITGA7) expression with clinical/pathological characteristics and overall survival (OS), and its knockdown on inhibiting cell activities in breast cancer. METHODS: A total of 191 breast cancer patients underwent surgery were retrospectively reviewed, and ITGA7 expression in tumor tissues was determined by immunofluorescence and real-time quantitative polymerase chain reaction. Patients' clinical/pathological data were recorded, and OS was calculated. In vitro, control shRNA and ITGA7 shRNA plasmids were transfected into MCF7 cells to evaluate the influence of ITGA7 knockdown on cell proliferation, apoptosis, and invasion. RESULTS: Ninety-two (48.2%) patients presented with ITGA7 high expression, and 99 patients (51.8%) presented with ITGA7 low expression. ITGA7 expression was positively correlated with T stage, tumor-node metastasis (TNM) stage, and pathological grade. Kaplan-Meier curves showed that ITGA7 high expression was associated with shorter OS, and multivariate Cox's proportional hazards regression displayed that ITGA7 high expression was an independent predictive factor for poor OS. Moreover, in vitro experiments disclosed that cell proliferation (by Cell Counting Kit-8 assay) and cell invasion (by Matrigel invasion assay) were reduced, while cell apoptosis rate (by Annexin V/propidium iodide assay) was enhanced by ITGA7 knockdown in MCF-7 cells. CONCLUSION: Integrin α7 high expression correlates with increased T stage, TNM stage, and pathological grade as well as worse OS, and its knockdown enhances cell apoptosis but inhibits cell proliferation and invasion in breast cancer.

Association of APEX1 and OGG1 gene polymorphisms with breast cancer risk among Han women in the Gansu Province of China.

BACKGROUND: Genetic variations in key DNA repair genes may influence DNA repair capacity, DNA damage and breast carcinogenesis. The current study aimed to estimate the association of APEX1 and OGG1 polymorphisms with the risk of breast cancer development. METHODS: A total of 518 patients with histopathologically confirmed breast cancer and 921 region- and age-matched cancer-free controls were genotyped for the APEX1 polymorphisms rs3136817 and rs1130409 and the OGG1 polymorphisms rs1052133 and rs2072668 using a QuantStudio™ 12 K Flex Real-Time PCR System. RESULTS: The rs3136817 heterozygous TC genotype along with the rs3136817 dominant model (TC + CC) was strongly associated with breast cancer susceptibility (odds ratio [OR] = 0.670, 95% confidence interval [95% CI]: 0.513 - 0.873, P = 0.003; OR = 0.682, 95% CI: 0.526 - 0.883, P = 0.004, respectively). No significant associations were observed among rs1130409, rs1052133, rs2072668 and breast cancer risk. Furthermore, an allele combination analysis revealed that APEX1 haplotypes containing C-T (alleles rs3136817 and rs1130409) conferred a significantly lower risk (corrected P < 0.001). CONCLUSION: This research is the latest report showing that an APEX1 rs3136817 heterozygous genotype may have a positive influence on DNA repair capacity in patients with breast cancer and thus may have a potential protective effect for Chinese Han women.

Relationship between mammographic calcifications and the clinicopathologic characteristics of breast cancer in Western China: a retrospective multi-center study of 7317 female patients.

BACKGROUND AND PURPOSE: Limited information is available regarding the correlations between mammographic calcifications and the epidemiological features of patients with breast cancer living different lifestyles in Western China. Thus, this study aimed to investigate the relationship between mammographic calcifications and the epidemiological characteristics of female patients with breast cancer in Western China. METHODS: This was a hospital-based, retrospective, multi-center epidemiological study of patients with breast cancer. Using the Western China Clinical Cooperation Group (WCCCG) database, we obtained the records of 7317 patients (with mammographic data) diagnosed with breast cancer between March 2011 and June 2016. These patients were divided into Groups I (mass alone) and II (mass combined with calcification), and their clinical and pathological data were compared. RESULTS: A total of 4211 patients were enrolled in Group I, and 3106 patients were enrolled in Group II. The tumors in Group II were more likely to be larger (P < 0.0001), higher grade (P = 0.0029), estrogen receptor (ER)+/progesterone receptor (PR)- (P = 0.0319), and human epidermal growth factor receptor 2 (HER-2)-positive (P < 0.0001), and to have axillary lymph node metastasis (P = 0.0033) than those in Group I. Regarding treatment, patients in Group II were more likely to have undergone chemotherapy (P = 0.0108) and anti-HER2 therapy (P = 0.0102), whereas patients in Group I were more likely to have undergone endocrine therapy (P < 0.0001). CONCLUSIONS: In conclusion, mammographic calcifications in tumors were associated with distinct clinicopathologic characteristics and aggressive treatments.

Characterization of ß2-microglobulin expression in different types of breast cancer.

BACKGROUND: Βeta-2-microglobulin (ß2-M) has been demonstrated as a growth factor and signaling molecule in breast cancer and leukemia. The purpose of the study is to characterize ß2-M expression in molecular subtypes of breast cancer, thereby investigating the mechanism of ß2-M action in breast cancer. METHODS: ß2-M and B-Cell Lymphoma/Leukemia 2 (Bcl-2) transcript expression levels in breast cancer tissue and the corresponding normal tissue were quantified using real-time PCR. The protein expression levels of ß2-M, estrogen receptor (ER), progesterone receptor (PR), human epidermal growth factor receptor 2 (HER-2), tumor protein 53 (p53) and Ki67 were determined by immunohistochemical (IHC) staining. Following silencing of the ß2-M by siRNA, the levels of Bcl-2, ER, PR and HER-2 transcripts and the protein expression levels in human breast cancer cells were measured by real-time PCR and western blotting, respectively. RESULTS: The expression of ß2-M transcripts demonstrated no significant differences between the four breast cancer molecular subtypes and no significant correlations with age, clinical stage or lymph node metastasis. ß2-M transcript expression demonstrated a positive correlation when compared to Bcl-2 transcript expression (P<0.05). The ß2-M protein expression was significantly higher in breast cancer when compared with benign breast tumors (P<0.01), and have no significant correlation with age, clinical stage or lymph node metastasis. There was a significant difference demonstrated in ß2-M protein expression in the four breast cancer molecular subtypes (P<0.05), and between the ER+ and ER- groups (P<0.01); however, no significant difference was demonstrated between the HER-2+ and HER-2- groups. ß2-M protein expression had a negative correlation with ER protein expression (P<0.01), a positive correlation with p53 protein expression (P<0.01), and no correlation with Ki67 protein expression. ß2-M silencing significantly inhibited Bcl-2 mRNA expression, but did not inhibit ER, PR and HER-2 mRNA expression in MCF-7 cells (ER+, PR+ and HER-2-). In addition, Bcl-2 and HER-2 mRNA expression were significantly up-regulated in MDA-MB-231 cells (ER-, PR- and HER-2-), which is consistent with the silencing effect seen at the protein level. CONCLUSIONS: ß2-M expression demonstrated a significant difference in the four breast cancer molecular subtypes, and may be related to apoptosis regulation in breast cancer.

Adjuvant Capecitabine With Docetaxel and Cyclophosphamide Plus Epirubicin for Triple-Negative Breast Cancer (CBCSG010): An Open-Label, Randomized, Multicenter, Phase III Trial.

PURPOSE: Standard adjuvant chemotherapy for triple-negative breast cancer (TNBC) includes a taxane and an anthracycline. Concomitant capecitabine may be beneficial, but robust data to support this are lacking. The efficacy and safety of the addition of capecitabine into the TNBC adjuvant treatment regimen was evaluated. PATIENTS AND METHODS: This randomized, open-label, phase III trial was conducted in China. Eligible female patients with early TNBC after definitive surgery were randomly assigned (1:1) to either capecitabine (3 cycles of capecitabine and docetaxel followed by 3 cycles of capecitabine, epirubicin, and cyclophosphamide) or control treatment (3 cycles of docetaxel followed by 3 cycles of fluorouracil, epirubicin, and cyclophosphamide). Randomization was centralized without stratification. The primary end point was disease-free survival (DFS). RESULTS: Between June 2012 and December 2013, 636 patients with TNBC were screened, and 585 were randomly assigned to treatment (control, 288; capecitabine, 297). Median follow-up was 67 months. The 5-year DFS rate was higher for capecitabine than for control treatment (86.3% v 80.4%; hazard ratio, 0.66; 95% CI, 0.44 to 0.99; P = .044). Five-year overall survival rates were numerically higher but not significantly improved (capecitabine, 93.3%; control, 90.7%). Overall, 39.1% of patients had capecitabine dose reductions, and 8.4% reported grade ≥ 3 hand-foot syndrome. The most common grade ≥ 3 hematologic toxicities were neutropenia (capecitabine, 136 [45.8%]; control, 118 [41.0%]) and febrile neutropenia (capecitabine, 50 [16.8%]; control, 46 [16.0%]). Safety data were similar to the known capecitabine safety profile and generally comparable between arms. CONCLUSION: Capecitabine when added to 3 cycles of docetaxel followed by 3 cycles of a 3-drug anthracycline combination containing capecitabine instead of fluorouracil significantly improved DFS in TNBC without new safety concerns.

99mTc-labeled sodium phytate and stannous chloride injection accurately detects sentinel lymph node in axillary of early stage breast cancer: a randomized, controlled study.

AIM: The aim of this study was to assess the sentinel lymph node (SLN) detection rate and accuracy of 99mTc-labeled sodium phytate and stannous chloride (99mTc-PHY) injection versus 99mTc-labeled sulfur colloid (99mTc-SC) injection in sentinel lymph node biopsy (SLNB) in patients with early stage breast cancer. METHODS: A total of 146 consecutive female patients with early stage breast cancer were recruited in this open-labeled, randomized, controlled study. SLNB was conducted on all patients, and 99mTc-PHY or 99mTc-SC was used as the radioactive agent (RA). Axillary lymph node dissections were performed in all patients post SLN dissections. RESULTS: The detection rate of 99mTc-PHY group was higher compared with that of 99mTc-SC group (p=0.023), but no difference in the detection rate by dye alone (p=0.190) or by RAs alone (p=0.615) was found between the two groups, and the number of identified SLNs (p=0.100), number of identified SLNs by dye alone (p=0.161), and number of identified SLNs by RA alone (p=0.242) were similar between the two groups. In addition, the sensitivity, specificity, false-negative rate, false-positive rate, and accuracy rate of SLNB showed no difference between 99mTc-PHY and 99mTc-SC groups (sensitivity: p=0.645; specificity: p=0.511; false-negative rate: p=0.645; false-positive rate: p=0.511; accuracy rate: p=0.464). CONCLUSION: Our study revealed that 99mTc-PHY was qualified to be a convincing radiopharmaceutical in SLNB.

Clinicopathologic Factors Related to the Histological Tumor Grade of Breast Cancer in Western China: An Epidemiological Multicenter Study of 8619 Female Patients.

BACKGROUND AND PURPOSE: Breast cancer is now recognized as a clinically heterogeneous disease with a wide spectrum of epidemiological and clinicopathologic features. We aimed to evaluate whether epidemiological and clinicopathologic features are associated with the histological tumor grade of breast carcinomas in Western China. METHODS: We retrospectively collected data from the Western China Clinical Cooperation Group and assessed associations between clinicopathologic factors and histological tumor grade in 8619 female breast cancer patients. Patients were divided into two groups: Group I (tumor grade I/II) and Group II (tumor grade III). Univariable analysis and multivariable logistic regression models were used to analyze the relationships between clinicopathologic factors and tumor grade. RESULTS: Patients presenting with positive axillary lymph nodes, large tumor size (>2 cm), lymphovascular invasion, hormone receptor negativity, human epidermal growth factor receptor 2 (HER-2) positivity, and triple negativity tended to have an increased risk of a high tumor grade. However, the number of pregnancies or births was inversely correlated with the risk of a high tumor grade. In addition, patients presenting with grade III tumors were more likely to receive aggressive treatment, such as adjuvant chemotherapy, anti-HER-2 therapy, and level III axillary lymph node dissection. CONCLUSIONS: Our results suggested that several clinicopathologic factors were associated with high tumor grade of breast cancer patients in Western China.

Association analysis of ERCC5 gene polymorphisms with risk of breast cancer in Han women of northwest China.

BACKGROUND: ERCC5 plays an important role in DNA damage repair. Mutations in it will lead to DNA repair defects and genomic instability. Its functional single nucleotide polymorphisms (SNPs) may alter DNA repair capacity and affect cancer susceptibility. METHODS: This study aims to evaluate the association between SNPs in ERCC5 and breast cancer susceptibility in Han women subjects genetically from northwest China. A total of 101 breast cancer patients and 101 healthy controls provided blood samples for analysis of ERCC5 rs17655 and rs751402 genotypes. RESULTS: After adjusting covariates, rs751402 homozygote AA and heterozygote AG were found to confer statistically significant protections (OR 0.052, 95% CI 0.006-0.411, P = 0.005; OR 0.145, 95% CI 0.067-0.315, P < 0.001, respectively) against breast cancer. Moreover, both of the dominant and recessive models of rs751402 also conferred a decreased risk of breast cancer (AA + AG vs. GG, OR 0.125, 95% CI 0.060-0.261, P < 0.001; AA vs. GG + AG, OR 0.082, 95% CI 0.010-0.648, P = 0.018, respectively). CONCLUSIONS: The results indicate that the rs751402 in ERCC5 may affect the risk of breast cancer and show that it is associated with breast cancer characteristics in the Han population of northwest China. However, we found no significant differences between breast cancer patients and control subjects regarding ERCC5 rs17655 polymorphism in the studied population.

DNA repair genes XRCC1 and ERCC1 polymorphisms and the risk of sporadic breast cancer in Han women in the Gansu Province of China.

AIMS: Polymorphisms in DNA damage repair genes may affect DNA repair capacity and modulate breast cancer susceptibility. In this study, we aimed to analyze two polymorphisms for each of the DNA repair genes X-ray repair cross-complementing group 1 (XRCC1) rs25487 and rs1799782 and excision repair cross-complementing group 1 (ERCC1) rs3212964 and rs11615, to evaluate their associations with the risk of sporadic breast cancer in Han women in the Gansu Province of China. METHODS: Genotypes were determined by a polymerase chain reaction-based approach for 101 patients with breast cancer and in 101 disease-free controls. RESULTS: We found that individuals with the AA genotype at XRCC1 rs25487 had a significantly increased risk of breast cancer compared with GG genotype (p<0.001, odds ratio [OR]=6.39, 95% confidence interval [CI]: 2.18-18.65). The dominant model showed that the combined rs25487 genotypes (AA+AG) increased the disease risk (p<0.001, OR=3.17, 95% CI: 1.76-5.72). However, no statistical associations were found between rs1799782 in XRCC1, or rs3212964 and rs11615 in ERCC1 and the risk of disease. In haplotype analysis, the GC haplotype in XRCC1 conferred an increased risk (p<0.001) with a 4.78-fold increase for each copy (95% CI: 2.52-8.72). Significant associations were also shown between the single nucleotide polymorphisms (SNPs) and the status of estrogen receptor (ER), progesterone receptor (PR), and HER-2. CONCLUSIONS: The results suggest that the XRCC1 rs25487 polymorphism may increase the risk of breast cancer.

Polymorphisms in the DNA repair gene ERCC2/XPD and breast cancer risk: a HapMap-based case-control study among Han Women in a Chinese less-developed area.

AIMS: Genetic variations in DNA repair genes may impact repair functions, DNA damage, and breast cancer risk. This study is aimed to assess the associations of genetic polymorphisms in excision repair cross-complementing group 2 (ERCC2) with the risk of developing breast cancer. MATERIALS AND METHODS: In total, 101 histopathologically confirmed breast cancer cases and 101 age/region-matched healthy controls were genotyped for rs 3916840, rs 1799793, and rs 238416 in ERCC2 by polymerase chain reaction-restriction fragment length polymorphism. RESULTS: The rs 238416 heterozygous GA genotype combined with the rs 238416 genotypes (GA+AA) showed a significant association with breast cancer susceptibility (corrected p<0.01, odds ratio [OR]=0.29, 95% confidence interval [CI]=0.15-0.54; corrected p<0.01, OR=0.31, 95% CI=0.17-0.56, respectively). The rs 238416 GA genotype carriers had a decreased risk of breast cancer. However, we observed no significant association between the rs 3916840 and rs 1799793 polymorphisms in ERCC2 and breast cancer risk. Moreover, haplotype analysis showed that the ACG haplotype was associated with a significantly decreased risk of breast cancer, whereas the GCG haplotype was associated with a significantly increased risk of breast cancer (corrected p=0.004 and p=0.002, respectively). Multifactor dimensionality reduction analysis demonstrated that the interactions between rs 3916840 and rs 238416 were significantly synergistic. CONCLUSION: To the best of our knowledge, this study is the first to demonstrate that the rs 238416 heterozygous genotype likely has a higher DNA repair capacity and, thus, can be protective against breast cancer in Chinese Han women.