MAP3K1 expression is associated with progression and poor prognosis of hormone receptor-positive, HER2-negative early-stage breast cancer.

PURPOSE: In this study, we assessed whether the overexpression of MAP3K1 promotes the proliferation, migration, and invasion of breast cancer cells, which affect the prognosis of hormone receptor (HR)-positive, human epidermal growth factor receptor 2 (HER2)-negative early stage breast cancer. METHODS: Two HR-positive, HER2-negative breast cancer cell lines (MCF7 and T-47D) overexpressing MAP3K1 were transfected with two MAP3K1 short hairpin RNA plasmids (shMAP3K1 [#3] and shMAP3K1 [#5]). The proliferation, migration, and invasion of these cells were then examined. We assessed whether shMAP3K1 affects the cell cycle, levels of downstream signaling molecules (ERK, JNK, p38 MAPK, and NF-κB), and sensitivity to chemotherapeutic and hormonal agents. To assess the anti-tumor effect of MAP3K1 knockdown in the breast cancer orthotopic model, MCF7 and T-47D cells treated with or without shMAP3K1 (#3) and shMAP3K1 (#5) were inoculated into the mammary fat pads of mice. In total, 182 patients with HR-positive, HER2-negative T1 and T2 breast cancer and 0-3 nodal metastases were included. Additionally, 73 patients with T1 and T2 breast cancer and negative nodes who received adjuvant endocrine therapy alone were selected as an independent validation cohort. RESULTS: In both cell lines, shMAP3K1 (#3) and shMAP3K1 (#5) significantly reduced cell growth, migration, and invasion by downregulating MMP-9 and by blocking the G2/M phase of the cell cycle and its regulatory molecule cyclin B1. Moreover, both shMAP3K1 (#3) and shMAP3K1 (#5) downregulated ERK-, JNK-, p38 MAPK-, and NF-κB-dependent gene transcription and enhanced the sensitivity of both cell lines to doxorubicin, docetaxel, and tamoxifen. We observed that both shMAP3K1 (#3) and shMAP3K1 (#5) inhibited tumor growth compared with that in the scrambled group of MCF7 and T-47D cell orthotopic tumors. Patients with MAP3K1 overexpression exhibited significantly poorer 10-year disease-free survival (DFS) (70.4% vs. 88.6%, p = 0.003) and overall survival (OS) (81.9% vs. 96.3%, p = 0.001) than those without MAP3K1 overexpression. Furthermore, phospho-ERK (p < 0.001) and phospho-JNK (p < 0.001) expressions were significantly associated with MAP3K1 expression, and both phospho-ERK and phospho-JNK expressions were significantly correlated with poor 10-year DFS and OS. These biological findings, including a significant association between DFS and OS, and the expressions of MAP3K1, phospho-ERK, and phospho-JNK were further validated in an independent cohort. Multivariate analysis identified MAP3K1 expression as an independent poor prognostic factor for DFS and OS. CONCLUSION: Our results indicate that the overexpression of MAP3K1 plays a major role in the poor prognosis of HR-positive, HER2-negative early stage breast cancer.

Atorvastatin Attenuates Radiotherapy-Induced Intestinal Damage through Activation of Autophagy and Antioxidant Effects.

Abdominal or pelvic radiotherapy (RT) often results in small intestinal injury, such as apoptosis of epithelial cells and shortening of the villi. Atorvastatin, a 3-hydroxy-3-methylglutaryl coenzyme A reductase inhibitor, has many biological effects including cholesterol reduction, protection from cell damage, and autophagy activation. To reduce the extent of radiotherapy- (RT-) induced enteritis, we investigated the protective effects of atorvastatin against RT-induced damage of the intestinal tract. In this study, C57BL/6 mice were randomly distributed into the following groups (n = 8 per group): (1) control group: mice were fed water only, (2) atorvastatin group (Ator): mice were administered atorvastatin, (3) irradiation group (IR): mice received abdominal RT, (4) Ator+IR group: mice received abdominal RT following atorvastatin administration, and (5) Ator+IR+3-MA group: abdominal RT following atorvastatin and 3-methyladenine (an autophagy inhibitor) administration. Based on the assessment of modified Chiu's injury score and villus/crypt ratio, we found that atorvastatin administration significantly reduced intestinal mucosal damage induced by RT. Atorvastatin treatment reduced apoptosis (cleaved caspase-3 and cleaved poly (ADP-ribose) polymerase), DNA damage (γH2AX and 53BP1), oxidative stress (OS, 4-hydroxynonenal), inflammatory molecules (phospho-NF-κB p65 and TGF-ß), fibrosis (collagen I and collagen III), barrier leakage (claudin-2 and fluorescein isothiocyanate-dextran), disintegrity (fatty acid-binding protein 2), and dysfunction (lipopolysaccharide) caused by RT in small intestinal tissue. In addition, atorvastatin upregulated the expression of autophagy-active molecules (LC3B), antioxidants (heme oxygenase 1 and thioredoxin 1), and tight junction proteins (occludin and zonula occludens 1). However, the biological functions of atorvastatin in decreasing RT-induced enteritis were reversed after the administration of 3-MA; the function of antioxidant molecules and activity of thioredoxin reductase were independent of autophagy activation. Our results indicate that atorvastatin can effectively relieve RT-induced enteritis through autophagy activation and associated biological functions, including maintaining integrity and function and decreasing apoptosis, DNA damage, inflammation, OS, and fibrosis. It also acts via its antioxidative capabilities.