Inhibitory effects of petasin on human colon carcinoma cells mediated by inactivation of Akt/mTOR pathway / 中华医学杂志(英文版)

Background:@#Colorectal cancer is the third most common cancer worldwide and still lack of effective therapy so far. Petasin, a natural product found in plants of the genus Petasites, has been reported to possess anticancer activity. The present study aimed to investigate the anticolon cancer activity of petasin both in vitro and in vivo. The molecular mechanism of petasin was also further explored.@*Methods:@#Caco-2, LoVo, SW-620, and HT-29 cell lines were used to detect the inhibitory effect of petasin on colon cancer proliferation. Cell viability was determined using the MTT (3-[4,5-dimethylthiazol-2-yl]-2,5-diphenyltetrazolium bromide) assay. Cell apoptosis was analyzed by flow cytometry. Hoechst 33258 staining was used to visualize morphological changes. Cell migration was assessed using a wound-healing migration assay, and cell invasion was investigated using Transwell chambers. Western blotting assays were employed to evaluate the expression levels of proteins in the protein kinase B/mammalian target of rapamycin (Akt/mTOR) signaling pathway. Finally, in vivo activity of petasin was evaluated using the SW-620 subcutaneous tumor model established in Balb/c nude mice. Twelve rats were randomly divided into control group and 10 mg/kg petasin group. The tumor volume was calculated every 7 days for 28 days. Terminal deoxynucleotidyl transferase-mediated dUTP nick end labeling (TUNEL) assay was performed to assess the apoptotic effect of petasin. Differences between two groups were assessed by analysis of independent-sample t tests.@*Results:@#Petasin significantly inhibited the proliferation of human colon carcinoma cell lines, induced apoptosis, and suppressed migration and invasion in SW-620 cells. Western blotting results showed that petasin decreased the phosphorylation of Akt (1.01 ± 0.16 vs. 0.74 ± 0.06, P = 0.042), mTOR (0.71 ± 0.12 vs. 0.32 ± 0.11, P = 0.013), and P70S6K (1.23 ± 0.21 vs. 0.85 ± 0.14, P = 0.008), elevated the expression of caspase-3 (0.41 ± 0.09 vs. 0.74 ± 0.12, P = 0.018) and caspase-9 (1.10 ± 0.27 vs. 1.98 ± 0.22, P = 0.009), decreased the Bcl-2 protein (2.75 ± 0.47 vs. 1.51 ± 0.36, P = 0.008), downregulated the expression of matrix metalloproteinase (MMP)-3 (1.51 ± 0.31 vs. 0.82 ± 0.11, P = 0.021) and MMP-9 (1.56 ± 0.32 vs. 0.94 ± 0.15, P = 0.039) in SW-620 cell. In vivo, 10 mg/kg petasin inhibited tumor growth in Balb/c nude mice (924.18 ± 101.23 vs. 577.67 ± 75.12 mm3 at day 28, P = 0.001) and induced apoptosis (3.6 ± 0.7% vs. 36.0 ± 4.9%, P = 0.001) in tumor tissues.@*Conclusions:@#Petasin inhibits the proliferation of colon cancer SW-620 cells via inactivating the Akt/mTOR pathway. Our findings suggest petasin as a potential candidate for colon cancer therapy.

Inhibitory effects of petasin on human colon carcinoma cells mediated by inactivation of Akt/mTOR pathway / 中华医学杂志(英文版)

BACKGROUND@#Colorectal cancer is the third most common cancer worldwide and still lack of effective therapy so far. Petasin, a natural product found in plants of the genus Petasites, has been reported to possess anticancer activity. The present study aimed to investigate the anticolon cancer activity of petasin both in vitro and in vivo. The molecular mechanism of petasin was also further explored.@*METHODS@#Caco-2, LoVo, SW-620, and HT-29 cell lines were used to detect the inhibitory effect of petasin on colon cancer proliferation. Cell viability was determined using the MTT (3-[4,5-dimethylthiazol-2-yl]-2,5-diphenyltetrazolium bromide) assay. Cell apoptosis was analyzed by flow cytometry. Hoechst 33258 staining was used to visualize morphological changes. Cell migration was assessed using a wound-healing migration assay, and cell invasion was investigated using Transwell chambers. Western blotting assays were employed to evaluate the expression levels of proteins in the protein kinase B/mammalian target of rapamycin (Akt/mTOR) signaling pathway. Finally, in vivo activity of petasin was evaluated using the SW-620 subcutaneous tumor model established in Balb/c nude mice. Twelve rats were randomly divided into control group and 10 mg/kg petasin group. The tumor volume was calculated every 7 days for 28 days. Terminal deoxynucleotidyl transferase-mediated dUTP nick end labeling (TUNEL) assay was performed to assess the apoptotic effect of petasin. Differences between two groups were assessed by analysis of independent-sample t tests.@*RESULTS@#Petasin significantly inhibited the proliferation of human colon carcinoma cell lines, induced apoptosis, and suppressed migration and invasion in SW-620 cells. Western blotting results showed that petasin decreased the phosphorylation of Akt (1.01 ± 0.16 vs. 0.74 ± 0.06, P = 0.042), mTOR (0.71 ± 0.12 vs. 0.32 ± 0.11, P = 0.013), and P70S6K (1.23 ± 0.21 vs. 0.85 ± 0.14, P = 0.008), elevated the expression of caspase-3 (0.41 ± 0.09 vs. 0.74 ± 0.12, P = 0.018) and caspase-9 (1.10 ± 0.27 vs. 1.98 ± 0.22, P = 0.009), decreased the Bcl-2 protein (2.75 ± 0.47 vs. 1.51 ± 0.36, P = 0.008), downregulated the expression of matrix metalloproteinase (MMP)-3 (1.51 ± 0.31 vs. 0.82 ± 0.11, P = 0.021) and MMP-9 (1.56 ± 0.32 vs. 0.94 ± 0.15, P = 0.039) in SW-620 cell. In vivo, 10 mg/kg petasin inhibited tumor growth in Balb/c nude mice (924.18 ± 101.23 vs. 577.67 ± 75.12 mm at day 28, P = 0.001) and induced apoptosis (3.6 ± 0.7% vs. 36.0 ± 4.9%, P = 0.001) in tumor tissues.@*CONCLUSIONS@#Petasin inhibits the proliferation of colon cancer SW-620 cells via inactivating the Akt/mTOR pathway. Our findings suggest petasin as a potential candidate for colon cancer therapy.

Effect of ulinastatin donor-pretreatment on liver graft during cold preservation in rats / 中华医学杂志(英文版)

<p><b>BACKGROUND</b>Donor-pretreatment with ulinastatin may influence the liver graft during cold preservation. The aim of this research was to determine whether pretreatment of donor liver with Ulinastatin can attenuate cold preservation injury, and to explore the mechanism by which Ulinastatin affects the donor liver graft.</p><p><b>METHODS</b>One hundred and forty-four Wistar rats were divided into the Ulinastatin treatment group (T group) pretreated with Ulinastatin 50 000 U/kg and control group (C group) treated with 0.9% normal saline via peritoneal injection prior to the anesthetization. After the abdominal cavity was opened and perfused with cold Ringer's lactate solution, the liver was harvested. The harvested liver was preserved in cold Ringer's lactate solution for 0, 2, 6, 24 hours, at which time the liver tissue was sampled for determination of dry weight and wet weight, Na(+)-K(+)-ATPase and Ca(2+)-ATPase activity, lactic acid dehydrogenase (LDH) activity, lactic acid and malondialdehyde levels. Light microscopy and electron microscopy were used to observe liver morphology. The liver cold-preservation solution was taken for measurement of aspartate aminotransferase (AST) and alanine transaminase (ALT) levels. Correlation between ATPase activity and lactic acid level was analyzed by SPSS 13.0 for Windows.</p><p><b>RESULTS</b>The morphology in the T group had improved cell boundaries vs. the C group at each time point. Dry weight to wet weight in the T group was lower than in the C group at 6 hours (P < 0.05), but the difference was not significant at 24 hours. ALT levels in the T group were lower than that in the C group at 6 hours (P < 0.05) and 24 hours (P < 0.01). AST levels in the T group were lower than those in the C group at 2 hours (P < 0.05), 6 hours (P < 0.01) and 24 hours (P < 0.01). Na(+)-K(+)-ATPase activity in the T group was higher than in the C group and the mean difference between two groups was significant at 0 hour (P < 0.05) and 2 hours (P < 0.05). Ca(2+)-ATPase activity in the T group was higher than in the C group with the mean difference between two groups significant at 2 hours (P < 0.05). The T group had increased lactic acid levels at 0 hour (P < 0.01) and 2 hours (P < 0.05) compared with the C group, but there was no influence on the LDH activity at the same time. There were no obvious differences in the levels of malondialdehyde between the two groups at any time point. A linear correlation between Na(+)-K(+)-ATPase activity and lactic acid levels (r = 0.295, P < 0.05) was found.</p><p><b>CONCLUSIONS</b>Donor-pretreatment with ulinastatin may protect the cells in a liver graft from ischemia injury during cold preservation; the mechanism may be due to its promotion for cell glycolysis and its preservation of ATPase activity.</p>