Antimicrobial and antitumor activity and diversity of endophytic fungi from traditional Chinese medicinal plant Cephalotaxus hainanensis Li.

Endophytes from Cephalotaxus hainanensis Li, an important source of anti-leukemia drugs, have not been widely explored. In this study, 265 endophytic fungal isolates from C. hainanensis Li were screened for antimicrobial activities against tilapia, banana, rice, and rape and for antitumor activities against human leukemia cell lines (K562, NB4, and HL-60). Diversity was also analyzed. The results showed that 17.7% of the endophytic fungi had antimicrobial activities against at least three different test microbes, and activity against Fusarium oxysporum RKY102 was the highest at 15.8%. Cytotoxicity against at least one tumor cell line tested was observed in 18.5% of the endophytic fungi; with the highest value of 10.6% against K562. The endophytic fungal strains also showed relatively high activities against K562, NB4, and HL-60 while relatively fewer strains were cytotoxic against the human hepatic Hep-G2 and colon LoVo cancer cell lines. Thirty endophytic fungal strains showed both high antimicrobial and antitumor activities. Moreover, the analyses of the diversity of the 30 highly active strains showed they belonged to 20 species from 14 genera, and this is the first report of endophytic fungi Albonectria rigidiuscula, Colletotrichum magnisporum, and Nemania diffusa being isolated from Cephalotaxus plants. These findings suggest that natural antibacterial products for humans and tilapia; antifungal compounds for rice, rape, and banana; and antitumor compounds for leukemia therapy could be isolated from fungal strains derived from C. hainanensis Li.

Decreased miR-452 expression in human colorectal cancer and its tumor suppressive function.

MicroRNA-452 (miR-452) is dysregulated in some human malignancies, and is correlated with tumor progression. However, its expression and function in human colorectal cancer (CRC) remain unclear. The aim of our study was to explore the effects of miR-452 in CRC tumorigenesis and development. Using reverse transcription quantitative real-time polymerase chain reaction, we detected miR-452 expression in CRC cell lines and primary tumor tissues. We also examined the association between miR-452 expression and clinicopathological factors. We then investigated the effects of miR-452 on the biological behavior of CRC cells. miR-452 expression was significantly downregulated in CRC compared with the adjacent noncancerous tissues. A low level of miR-452 was associated with larger tumor size, deeper invasion depth, and advanced TNM stage. Multivariate Cox regression analysis identified decreased miR-452 expression as an independent factor predicting poor prognosis for CRC patients. In addition, in vitro functional analysis showed that overexpression of miR-452 in HCT116 cells reduced cell proliferation, promoted cell apoptosis, and inhibited cell invasion and migration. These findings indicate that miR-452acts as a tumor suppressor in CRC, and would serve as a novel molecular therapeutic agent for the treatment of the disease.