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Chong-lou, the rhizome of Paris polyphylla, has been used in herbal regimes to treat parotitis, mastitis and certain malignant tumors for thousands of years in traditional medicine. Polyphyllin I (PPI) is the main bioactive component in Paris polyphylla. Recent studies of PPI in various types of cancers have shown that PPI may exert a broad spectrum of anti-tumor effects, including inducing cell cycle arrest, inducing cell apoptosis, inducing autophagy, anti-angiogenesis, sensitizing tumors to chemotherapy, and participating in the modulation of inflammatory and immune response. Along with the growing research interest in PPI as well as accumulation of experimental evidences, this review periodically summarized the recent advances in regard to PPI's anti-tumor propensities in various cancers and the underlying mechanisms for future prospective research., Competing Interests: Declaration of competing interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2019 Elsevier B.V. All rights reserved.)

Polyphyllin I (PPI), a bioactive component extracted from Paris polyphylla, was reported to have potent anticancer activities in previous studies. However, there were few reports on the effects and underlying mechanism of PPI in human acute myeloid leukemia cells. The present study demonstrated that PPI had an inhibitory effect through inducing apoptosis and autophagy in THP-1 and NB4 cells. PPI induced apoptosis via activating JNK pathway, as evidenced by the decreased Bcl-2 levels and increased Bax, cleaved-caspase-3 and phosphorylated-JNK expressions. In addition, PPI promoted autophagy as evidenced with increased expressions of LC3-II and Beclin-1 in western blot and autophagic vacuoles in MDC staining, which was associated with the inhibition of AKT-mTOR pathway. Furthermore, JNK inhibitor SP600125 and autophagy inhibitor 3-MA were employed to evaluate the role of apoptosis and autophagy in PPI-induced cell death. We found that autophagy and apoptosis were both causes of cell death induced by PPI. These data suggested that PPI could be a potent therapeutic agent for the treatment of human acute myeloid leukemia., (Copyright © 2019 Elsevier B.V. All rights reserved.)

The study was supposed to investigate the inhibitory effect of antisense phosphorothioate oligodeoxynucleotide (ASPSODN) targeting hTERT mRNA on gene of interest in K562 cells and influence of ASPSODN on telomerase activity and apoptosis of K562 cells. Human leukemia cell line K562 was transfected by liposome with ASPSODN and SPSODN (sense phosphorothioate oligodeoxynucleotide) at different concentrations (0.2, 0.6, 1.0 micromol/L). At the same time, blank control, liposome control and SPSODN groups were designed for comparison. The transfected cells were collected and detected at 24 and 48 hours; the expression of target gene hTERT mRNA and telomerase activity were detected by RT-PCR and TRAP-ELISA respectively, and cell apoptosis was assayed by flow cytometry. The results showed that after K562 cells were transfected for 24 hours, the expression of hTERT mRNA had no difference between liposome control (0.80+/-0.24), 0.2 micromol/L ASPSODN (0.69+/-0.12), 0.2 micromol/L SPSODN (0.72+/-0.25) and blank control (0.85+/-0.28), but the expression of hTERT mRNA in 0.6 micromol/L ASPSODN group (0.42+/-0.16) remarkably decreased as compared with liposome control group, 0.6 micromol/L SPSODN (0.69 +/- 0.26) had no obvious effect on the expression of hTERT mRNA, the expression of hTERT mRNA in 1.0 micromol/L ASPSODN and SPSODN groups both decreased; mortality of K562 cells transfected by liposome with 1.0 micromol/L ASPSODN and SPSODN remarkably increased. After 24 hours, telomerase relative activity of K562 cells showed no significant difference between blank control (88.9%) and liposome control (77.7%). The telomerase relative activities of K562 cells treated with 0.2, 0.6, 1.0 micromol/L ASPSODN were 60.6%, 52%, 58.2% respectively. There was significant difference as compared with blank control; 0.6 micromol/L ASPSODN showed significant difference (p=0.037), as compared with liposome control group. The telomerase relative activities in K562 cells treated with 0.2, 0.6, 1.0 micromol/L SPSODN were 76.1%, 72.2%, 65.7% respectively, but the telomerase relative activities of K562 cells in 0.2, 0.6 micromol/L SPSODN groups was not inhibited obviously. When K562 cells were treated for 48 hours, telomerase relative activity of K562 cells in each ASPSODN groups restored. It showed that telomerase relative activities of K562 cells treated with 0.2, 0.6, 1.0 micromol/L ASPSODN were 84.1%, 82.3%, 79.6% respectively, while telomerase relative activities of K562 cells treated with 0.2, 0.6, 1.0 micromol/L SPSODN for 48 hours were 74.8%, 74.5%, 67.9% respectively. Telomerase activity of K562 cells could not be inhibited by 0.2 and 0.6 micromol/L SPSODN. After culturing for 48 hours, the cell apoptosis rates of K562 in 0.6 micromol/L ASPSODN, 0.6 micromol/L SPSODN, liposome control and blank control groups were (4.82+/-0.39)%, (1.83+/-0.34)%, 1.84+/-1.04)%, (1.07+/-0.74)% respectively. There was difference between ASPSODN and SPSODN groups (p<0.05), but the significant difference was found in ASPSODN group as compared with liposome control and blank control (p<0.01). It is concluded that the ASPSODN targeting hTERT can specifically inhibit the expression of hTERT mRNA in K562 cells and significantly suppress the telomerase activity of K562 cells at 0.6 micromol/L, which inhibitory time is short. The ASPSODN at high concentration (1.0 micromol/L) shows definite cytotoxicity. 0.6 micromol/L of ASPSODN significantly induces cell apoptosis, while no such effect was seen in SPSODN group.

This study was aimed to investigate the effect of plasmid-mediated RNAi targeting hTERT on blocking hTERT gene and inhibiting telomerase activity in leukemia cell line K562. For inhibiting hTERT mRNA, three siRNA strands were chemosynthesized and transfected into K562 cells, two effective and specific siRNA strands were chosen. Then plasmid pSUPER-U6-Kan rhTERT-1, pSUPER-U6-Kan rhTERT-2 targeting hTERT mRNA were constructed and transfected into K562 cells by liposome. The expression of hTERT mRNA, telomerase activity and cell apoptosis were detected at 48 hours and 72 hours. The results showed that three chemosynthesized strands began to significantly inhibit target gene expression at 48 hours, but the inhibiting rates were different. The inhibiting effect disappeared after 72 hours. After plasmid pSUPER-U6-Kan rhTERT -1 (P-1 group) and pSUPER-U6-Kan rhTERT -2 (P-2 group) were transfected into K562 cells, the expressions of hTERT mRNA both decreased in the two groups. The expression of hTERT mRNA in P-1 group was 0.39+/-0.13 at 48 hours, 0.57+/-0.32 at 72 hours. The expression of hTERT mRNA in P-2 group was 0.55+/-0.20 at 48 hours, 0.88+/-0.23 at 72 hours. Telomerase activity in P-1 group was 0.42+/-0.07 at 48 hours, 0.31+/-0.08 at 72 hours; the telomerase activity in group P-2 was 0.49+/-0.27 at 48 hours, 0.39+/-0.03 at 72 hours while telomerase activities in both groups were significantly lower than that in negative control group (0.88+/-0.30, 0.88+/-0.32). At 48 hours, the apoptosis rates in P-1 group (18.39+/-3.08%) and P-2 group (15.5+/-3.59%) were significantly higher than that in negative control group (7.64+/-3.73%). At 72 hours the apoptosis rate in P-1 group (13.2+/-1.18%) and in P-2 group (12.86+/-3.09%) had no significant difference as compared with negative control group (8.07+/-0.19%). It is concluded that RNAi targeting hTERT inhibits the expression of hTERT mRNA, and therefore inhibits telomerase activity. The inhibiting effect is closely correlated with target site. The si-hTERT-1 effect is better than si-hTERT-2, while si-hTERT-3 almost has no effect at all. The effective time of plasmid-induced RNAi is obviously longer than that of chemosynthesized siRNA. The former is longer than 72 hours, while the latter is only 48 hours. After the telomerase activity is inhibited, cell apoptosis increases a little than control group at 48 hours. At 72 hours cell apoptosis has no difference with control group. It is supposed that some cells can be induced to differentiation when telomerase activity has been down regulated.