FOXC1 Regulation of miR-31-5p Confers Oxaliplatin Resistance by Targeting LATS2 in Colorectal Cancer.

Colorectal cancer (CRC) is the second leading cause of cancer-related illness worldwide and one of the most common malignancies. Therefore, colorectal cancer research and cases have gained increasing attention. Oxaliplatin (OXA) is currently used in first-line chemotherapy to treat stage III and stage IV metastatic CRC. However, patients undergoing chemotherapy often develop resistance to chemo drugs being used. Evidence has confirmed that microRNAs regulate downstream genes in cancer biology and thereby have roles related to tumor growth, proliferation, invasion, angiogenesis, and multi-drug resistance. The aim of our study is to establish whether miR-31-5p is an oncogene in human colorectal cancers that are resistant to OXA and further confirm its malignant phenotype-associated target molecule. From the results of miRNA microarray assay, we establish that miR-31-5p expression was upregulated in oxaliplatin-resistant (OR)-LoVo cells compared with parental LoVo cells. Moreover, through in vitro and in vivo experiments, we demonstrate that miR-31-5p and large tumor suppressor kinase 2 (LATS2) were inversely related and that miR-31-5p and Forkhead box C1 (FOXC1) were positively correlated in the same LoVo or OR-LoVo cells. Importantly, we reveal a novel drug-resistance mechanism in which the transcription factor FOXC1 binds to the miR-31 promoter to increase the expression of miR31-5p and regulate LATS2 expression, resulting in cancer cell resistance to OXA. These results suggest that miR-31-5p may be a novel biomarker involved in drug resistance progression in CRC patients. Moreover, the FOXC1/miR31-5p/LATS2 drug-resistance mechanism provides new treatment strategies for CRC in clinical trials.

Anti-Apoptosis and Anti-Fibrosis Effects of Eriobotrya Japonica in Spontaneously Hypertensive Rat Hearts.

Myocardial apoptosis and fibrosis represent important contributing factors for development of hypertension-induced heart failure. The present study aims to investigate the potential effects of Eriobotrya japonica leaf extract (EJLE) against hypertension-induced cardiac apoptosis and fibrosis in spontaneously hypertensive rats (SHRs). Twelve-week-old male rats were randomly divided into four different groups; control Wistar Kyoto (WKY) rats, hypertensive SHR rats, SHR rats treated with a low dose (100 mg/kg body weight) of EJLE and SHR rats treated with a high dose (300 mg/kg body weight) of EJLE. Animals were acclimatized for 4 weeks and thereafter were gastric fed for 8 weeks with two doses of EJLE per week. The rats were then euthanized following cardiac functional analysis by echocardiography. The cardiac tissue sections were examined by Terminal Deoxynucleotidyl Transferase-Mediated Deoxyuridine Triphosphate (dUTP) Nick End-Labeling (TUNEL) assay, histological staining and Western blotting to assess the cardio-protective effects of EJ in SHR animals. Echocardiographic measurements provided convincing evidence to support the ability of EJ to ameliorate crucial cardiac functional characteristics. Furthermore, our results reveal that supplementation of EJLE effectively attenuated cardiac apoptosis and fibrosis and also enhanced cell survival in hypertensive SHR hearts. Thus, the present study concludes that EJLE potentially provides cardio-protective effects against hypertension-induced cardiac apoptosis and fibrosis in SHR animals.

Lupeol alters ER stress-signaling pathway by downregulating ABCG2 expression to induce Oxaliplatin-resistant LoVo colorectal cancer cell apoptosis.

Colorectal cancer (CRC) is one of the most common cancers and causes of cancer-related death. There are several first-line chemotherapeutic drugs used to treat CRC. Oxaliplatin (OXA) is an alkylating cytotoxic agent that is usually combined with other chemotherapeutic drugs to treat stage II and stage III CRC. However, cancer cells commonly acquire multidrug resistance (MDR), which is a major obstruction to cancer treatment. Recent studies have shown that natural components from traditional Chinese medicine or foods that have many biological functions may be new adjuvant therapies in clinical trials. We challenged LoVo CRC cell lines with OXA in a dose-dependent manner to create an OXA-resistant model. The expression of ABCG2 was significantly higher, and levels of endoplasmic reticulum (ER) stress markers were lower than those Parental cells. However, Lupeol, which is found in fruits and vegetables, has been shown to have bioactive properties, including anti-tumor properties that are relevant to many diseases. In our study, Lupeol downregulated cell viability and activated cell apoptosis. Moreover, Lupeol decreased the expression of ABCG2 and activated ER stress to induce OXA-resistant cell death. Importantly, the anti-tumor effect of Lupeol in OXA-resistant cells was higher than that of LoVo Parental cells. In addition, we also confirmed our results with a xenograft animal model, and the tumor size significantly decreased after Lupeol injections. Our findings show that Lupeol served as a strong chemoresistant sensitizer and could be a new adjuvant therapy method for chemoresistant patients.

Apoptotic effects of over-expressed estrogen receptor-beta on LoVo colon cancer cell is mediated by p53 signalings in a ligand-dependent manner.

Epidemiologic studies reported that the prevalence of hereditary non-polyposis colon cancer (HNPCC) in male is about 1.5-fold higher than that in female. Decreases in circulatory estradiol (E2) have been reported to downregulate the expression of E2 receptor (ER) and significantly increase the risk of colorectal cancer. Patients that received E2 replacement therapy were found to have a reduction in the incidence of colon adenoma and carcinoma. Furthermore, significant decreases in the expression of ER have been found in colorectal cancer specimens. These data strongly suggest the protective roles of E2 and ER against colorectal cancer. However, the mechanisms remain unexplored. LoVo cells were transient transfected to overexpress ER-beta, DNA fragmentation and caspase activity assay were performed to evaluate apoptotic effects. Western blotting was used to evaluate protein levels, and luciferase activity assay to measure the TNF-alpha promoter activity. Our data clearly demonstrated that E2 and ER-beta alone could upregulate p21 and p27 proteins, which further activate caspase-8 and caspase-9 to induce apoptosis in LoVo cell, and the ER-beta. effects were enhanced by E2. However, overexpressed ER-beta did not influence the expression and promoter activity of TNF-alpha. In addition, E2 and overexpressed ER-beta downregulated the beta-catenin proteins which cause the downregulation of its target genes, cyclin D1 and Rb, to inhibit the cell cycle and cell proliferation. The results indicate that overexpressed ER-beta may induce LoVo cell apoptosis and anti-proliferation by increasing p53 signaling in a ligand-dependent manner, and without hTNF-alpha involvement. Efforts aiming at enhancing ER-beta expression and/or activity may prove to be an attractive alternative therapy against colorectal cancer.

Over-expressed estrogen receptor-alpha up-regulates hTNF-alpha gene expression and down-regulates beta-catenin signaling activity to induce the apoptosis and inhibit proliferation of LoVo colon cancer cells.

Epidemiologic studies reported that the prevalence of hereditary non-polyposis colon cancer (HNPCC) in male is about 1.5-fold higher than that in female. Decreases in circulatory estrogen (E(2)) have been reported to downregulate the expression of E(2) receptor (ER) and significantly increase the risk of colorectal cancer. Patients that received E(2) replacement therapy were found to have a reduction in the incidence of colon adenoma and carcinoma. Furthermore, significant decreases in the expression of ER have been found in colorectal cancer specimens. Evidences strongly suggest the protective roles of E(2) and ER against colorectal cancer. However, the mechanisms of ERalpha effects on colorectal cancer cells remained un-clear. LoVo cells were transient transfected to overexpress ERalpha, DNA fragmentation and the activated caspases measurements were performed to evaluate apoptotic effects. Western blotting was used to evaluate protein levels, and luciferase activity assay to measure the Htnf-a promoter activity. The results clearly demonstrated that overexpressed ERalpha with or without E(2) (10(-8) M) treatment could activate caspase -8, -9, and 3 and induce DNA fragmentation in LoVo cell. At the same time, overexpressed ERalpha plus E(2) significantly increases the expression and promoter activity of hTNF-alpha, and the DNA fragmentation effect induced by E(2) plus ERalpha were reduced by the addition of hTNF antibody (0.1 ng(ml). In addition, E(2) plus ERalpha significantly upregulated p21 and p27 levels and downregulated the beta-catenin and its target genes, cyclin D1 and Rb, which regulate the cell cycle and cell proliferation. The results indicate that E(2) plus overexpressed ERalpha induce LoVo cell apoptosis might mediate through the increase of hTNF-alpha gene expression, which in turn activate caspase-8, -9 and caspase-3 and lead to the DNA fragmentation and apoptosis. E(2) plus ERalpha also showed the downregulation of beta-catenin signalings implicating the suppression of proliferation and metastasis of colorectal cells. Efforts aiming at enhancing ERalpha expression and(or activity may be proved to be an alternative therapy against colorectal cancer.