Cytosolic pro-apoptotic SPIKE induces mitochondrial apoptosis in cancer

Low-Molecular-Weight β-1,3-1,6-Glucan Derived from Aureobasidium pullulans Exhibits Anticancer Activity by Inducing Apoptosis in Colorectal Cancer Cells

β-glucan, a plant polysaccharide, mainly exists in plant cell walls of oats, barley, and wheat. It is attracting attention due to its high potential for use as functional foods and pharmaceuticals. We have previously reported that low-molecular-weight Aureobasidium pullulans-fermented β-D-glucan (LMW-AP-FBG) could inhibit inflammatory responses by inhibiting mitogen-activated protein kinases and nuclear factor-κB signaling pathways. Bases on previous results, the objective of the present study was to investigate the therapeutic potential of LMW-AP-FBG in BALB/c mice intracutaneously transplanted with CT-26 colon cancer cells onto their backs. Daily intraperitoneal injections of LMW-AP-FBG (5 mg/kg) for two weeks significantly suppressed tumor growth in mice bearing CT-26 tumors by reducing tumor proliferation and inducing apoptosis as compared to phosphate buffer-treated control mice. In addition, LMW-AP-FBG treatment reduced the viability of CT-26 cells in a dose-dependent manner by inducing apoptosis with loss of mitochondrial transmembrane potential and increased activated caspases. Taken together, LMW-AP-FBG exhibits anticancer properties both in vivo and in vitro.

BAP31: Physiological functions and roles in disease

B-cell receptor-associated protein 31 (BAP31 or BCAP31) is a ubiquitously expressed transmembrane protein found mainly in the endoplasmic reticulum (ER), including in mitochondria-associated membranes (MAMs). It acts as a broad-specificity membrane protein chaperone and quality control factor, which can promote different fates for its clients, including ER retention, ER export, ER-associated degradation (ERAD), or evasion of degradation, and it also acts as a MAM tetherer and regulatory protein. It is involved in several cellular processes - it supports ER and mitochondrial homeostasis, promotes proliferation and migration, plays several roles in metabolism and the immune system, and regulates autophagy and apoptosis. Full-length BAP31 can be anti-apoptotic, but can also mediate activation of caspase-8, and itself be cleaved by caspase-8 into p20-BAP31, which promotes apoptosis by mobilizing ER calcium stores at MAMs. BAP31 loss-of-function mutations is the cause of 'deafness, dystonia, and central hypomyelination' (DDCH) syndrome, characterized by severe neurological symptoms and early death. BAP31 is furthermore implicated in a growing number of cancers and other diseases, and several viruses have been found to target it to promote their survival or life cycle progression. The purpose of this review is to provide an overview and examination of the basic properties, functions, mechanisms, and roles in disease of BAP31.

Induction of mitochondrial apoptotic pathway by raloxifene and estrogen in human endometrial stromal ThESC cell line

INTRODUCTION

Endometrial hyperplasia is a condition that occurs as a result of hormonal imbalance between estrogen and progesterone. Morphological disturbance of endometrial cells occurs consequently leading towards endometrial cancer. In therapy of endometrial hyperplasia SERMs are used to supress effects of locally high estrogen level in uterus. There is strong evidence suggesting that estrogen could be involved in cell death - apoptosis. There are no experimental data demstrating the direct apoptotic effect of both raloxifene and estrogen on the ThESC cell line. The aim of our study wa sto investigate both cytotoxic and apototic mechanism of raloxifene and estrogen - induced death in the ThESC cell line.

MATERIAL AND METHODS

In order to determine their cytotoxic and apoptotic effects, various doses of raloxifene and estrogen were applied to the ThESC cell line for 24 h. After the treatment MTT assay, FACS analysis and immunofluoroscence method were conducted.

RESULTS

The results of this study for the first time demonstrated the cytotoxic and apoptotic effects of raloxifene and estrogen on human endometrial stromal cell line suggesting the involvement of the inner, mitochondrial apoptotic pathway.

CONCLUSIONS

Our results demonstrated apoptotic effects of investigated drugs in the ThESC cell line through increasing the Bax/Bcl-2 ratio and activation of caspase 3.