Human ST3Gal II and ST6GalNAc IV genes increase human serum-mediated cytotoxicity to xenogeneic cells.

Carbohydrate-antigens widely existed on glycoproteins and glycosphingolipids of all mammalian cells play a crucial role in self-defense and immunity. Xeno-reactive antibodies included in natural human sera play a protecting role in an acute phase-rejection of xenotransplantation. In this study, we investigated the effect of an alteration of glycosylation-pattern, caused by human sialyltransferases such as hST3Gal II or hST6GalNAc IV, on human serum mediated cytotoxicity in pig kidney PK15 cells. From LDH cytotoxicity assay, cytotoxicity to human serum was significantly increased in hST3Gal II and hST6GalNAc IV-transfected PK15 cells, as compared to the control. In the hST6Gal I-carrying cells, the cytotoxicity to human serum was rather decreased. Moreover, flow cytometry analysis revealed that an alteration of pig glycosylation-pattern by hST3Gal II or hST6GalNAc IV influences on a binding of human IgM or IgG, respectively, in pig kidney cells, regardless of Gal antigen alteration. Finally, we found that hST6GalNAc IV contributed to increase of terminal disialylated tetrasaccharide structure, disialyl T antigen, as evidenced by increase of the MAL II lectin binding capacity in the hST6GalNAc IV-transfected PK15 cells, compared with control. Therefore, our results suggest that carbohydrate antigens, such as disialyl T antigen, newly synthesized by the ST3Gal II- and ST6GalNAc IV are potentially believed to be new xeno-reactive elements.

4-O-Methylascochlorin Synergistically Enhances 5-Fluorouracil-Induced Apoptosis by Inhibiting the Wnt/ß-Catenin Signaling Pathway in Colorectal Cancer Cells.

4-O-Methyl-ascochlorin (MAC), a derivative of the prenyl-phenol antibiotic ascochlorin extracted from the fungus Ascochyta viciae, shows anticarcinogenic effects on various cancer cells. 5-Fluorouracil (5-FU) is used to treat colorectal cancer (CRC); however, its efficacy must be enhanced. In this study, we investigated the molecular mechanisms by which MAC acts synergistically with 5-FU to inhibit cell proliferation and induce apoptosis in CRC cells. MAC enhanced the cytotoxic effects of 5-FU by suppressing the Akt/mTOR/p70S6K and Wnt/ß-catenin signaling pathways. It also reduced the viability of 5-FU-resistant (5-FU-R) cells. Furthermore, expression of anti-apoptosis-related proteins and cancer stem-like cell (CSC) markers by 5-FU-R cells decreased in response to MAC. Similar to MAC, the knockdown of CTNNB1 induced apoptosis and reduced expression of mRNA encoding CRC markers in 5-FU-R cells. In summary, these results suggest that MAC and other ß-catenin modulators may be useful in overcoming the 5-FU resistance of CRC cells.

PPIB/Cyclophilin B expression associates with tumor progression and unfavorable survival in patients with pulmonary adenocarcinoma.

Cyclophilin B (CypB), encoded by peptidylprolyl isomerase B (PPIB), is involved in cellular transcriptional regulation, immune responses, chemotaxis, and proliferation. Recent studies have shown that PPIB/CypB is associated with tumor progression and chemoresistance in various cancers. However, the clinicopathologic significance and mechanism of action of PPIB/CypB in non-small cell lung cancer (NSCLC) remain unclear. In this study, we used RNA in situ hybridization to examine PPIB expression in 431 NSCLC tissue microarrays consisting of 295 adenocarcinomas (ADCs) and 136 squamous cell carcinomas (SCCs). Additionally, Ki-67 expression was evaluated using immunohistochemistry. The role of PPIB/CypB was assessed in five human NSCLC cell lines. There was a significant correlation between PPIB/CypB expression and Ki-67 expression in ADC (Spearman correlation r=0.374, P<0.001) and a weak correlation in SCC (r=0.229, P=0.007). In ADCs, high PPIB expression (PPIBhigh) was associated with lymph node metastasis (P=0.023), advanced disease stage (P=0.014), disease recurrence (P=0.013), and patient mortality (P=0.015). Meanwhile, high Ki-67 expression (Ki-67high) was correlated with male sex, smoking history, high pT stage, lymph node metastasis, advanced stage, disease recurrence, and patient mortality in ADC (all P<0.001). However, there was no association between either marker or clinicopathological factors, except for old age and PPIBhigh (P=0.038) in SCC. Survival analyses revealed that the combined expression of PPIBhigh/Ki-67high was an independent prognosis factor for poor disease-free survival (HR 1.424, 95% CI 1.177-1.723, P<0.001) and overall survival (HR 1.266, 95% CI 1.036-1.548, P=0.021) in ADC, but not in SCC. Furthermore, PPIB/CypB promoted the proliferation, colony formation, and migration of NSCLC cells. We also observed the oncogenic properties of PPIB/CypB expression in human bronchial epithelial cells. In conclusion, PPIB/CypB contributes to tumor growth in NSCLC, and elevated PPIB/Ki-67 levels are linked to unfavorable survival, especially in ADC.

Rg3-enriched red ginseng extracts enhance apoptosis in CoCl2-stimulated breast cancer cells by suppressing autophagy.

Background: Ginsenoside Rg3, a primary bioactive component of red ginseng, has anti-cancer effects. However, the effects of Rg3-enriched ginseng extract (Rg3RGE) on apoptosis and autophagy in breast cancer have not yet been investigated. In the present study, we explored the anti-tumor effects of Rg3RGE on breast cancer cells stimulated CoCl2, a mimetic of the chronic hypoxic response, and determined the operative mechanisms of action. Methods: The inhibitory mechanisms of Rg3RGE on breast cancer cells, such as apoptosis, autophagy and ROS levels, were detected both in vitro. To determine the anti-cancer effects of Rg3RGE in vivo, the cancer xenograft model was used. Results: Rg3RGE suppressed CoCl2-induced spheroid formation and cell viability in 3D culture of breast cancer cells. Rg3RGE promoted apoptosis by increasing cleaved caspase 3 and cleaved PARP and decreasing Bcl2 under the hypoxia mimetic conditions. Further, we identified that Rg3RGE promoted apoptosis by inhibiting lysosomal degradation of autophagosome contents in CoCl2-induced autophagy. We further identified that Rg3RGE-induced apoptotic cell death and autophagy inhibition was mediated by increased intracellular ROS levels. Similarly, in the in vivo xenograft model, Rg3RGE induced apoptosis and inhibited cell proliferation and autophagy. Conclusion: Rg3RGE-stimulated ROS production promotes apoptosis and inhibits protective autophagy under hypoxic conditions. Autophagosome accumulation is critical to the apoptotic effects of Rg3RGE. The in vivo findings also demonstrate that Rg3RGE inhibits breast cancer cell growth, suggesting that Rg3RGE has potential as potential as a putative breast cancer therapeutic.