Compound SLXM-2, a derivative of cyclophosphamide （CTX）, has shown potent growth-inhibitory effect on tumor cells with low toxicity in previous studies. However, the mechanism of its anti-tumor effect, especially on DNA damage, remains largely unclear. This study investigated the effect of SLXM-2 on the survival time of mice transplanted with the ascitie fluid-type hepatocarcinoma 22 （H22）. We also evaluated the correlation between DNA damaging effect of SLXM-2 and its anti-tumor effect, and to probe the possible molecular mechanism for its effect on H22 cells. The results suggested that SLXM-2 significantly （P〈0.05） prolonged the survival time of mice bearing the ascitic fluid-type H22. Furthermore, SLXM-2 induced DNA damage in a dose-dependent manner in H22 cells. Further investigation revealed that SLXM-2 significantly （P〈0.05） up-regulated the expression levels of a series of DNA damage-related proteins, such as γH2AX （Ser139）, p-Chkl （Ser296）, p-Chk2 （Thr68）, p-p53 （Ser15）, p-p53 （Ser20） and p21, and down-regulated the expression of p-ATR （Ser428） and p-ATM （Ser1981）. In conclusion, SLXM-2 showed a remarkable anti-tumor activity on ascitic fluid-type H22 cells, and its molecular mechanism is related to its DNA damaging effect.
As a novel proteasome inhibitor, remarkable proliferation inhibitory effect of compound YSY-01A was shown on tumor cells in previous studies. However, few studies has reported its effect on gastric cancer and related mechanism. We evaluated the anti-proliferative effect of compound YSY-01A using MGC-803 cells and its anti-tumor effect using xenograft nu-BALB/c mouse model. Cell proliferation inhibition was assessed by SRB assay. Related protein expression levels were determined by Western blot assay. We observed that the compound YSY-01A had a significant proliferation inhibitory effect on MGC-803 cells in vitro. Experiment in vivo showed that the compound YSY-01A had a remarkable growth inhibitory effect on MGC-803 cells xenograft tumor when it was used either alone or in combination with the conventional chemotherapeutic agent 5-fluorouracil （5-FU）. Furthermore, YSY-01A and 5-FU had a synergistic effect on xenograft tumor. Results of molecular experiment showed that the compound YSY-01A had a remarkable inhibitory effect on TNF-c~ and IFN induced NF-KB nuclear translocation. At the same time, the compound YSY-01A could reduce the expression of IKK-~, IL-I~ and iNOS, while it significantly enhanced the expression of COX-2 in MGC-803 ceils. Taken together, compound YSY-01A had an impressive tumor inhibitory effect, and it worked in NF-KB-related pathway, suggesting that the compound YSY-01A was an effective therapeutic drug for patients with gastric cancer. Higher tumor cell growth inhibition after the treatment in a combination with 5-FU indicated that combining YSY-01A with 5-FU might be more effective for displaying tumor cell growth inhibitory effects on gastric cancer cells.
Compound YSY-01A, a recently synthesized proteasome inhibitor, has shown potent growth-inhibitory effect on tumor cells in previous researches. However, the mechanism of its inhibitory effects, especially on cell cycle, remains largely unclear. This study aims to evaluate the correlation between cell cycle arrest effect of YSY-01A and its anti-cancer effect, and to probe the possible molecular mechanisms for its effects on human colorectal adenocarcinoma cells HT-29. The results suggested that YSY-01A significantly （P0.05） inhibited cellular proliferation of HT-29 cells in a time and concentration-dependent manner. Furthermore, YSY-01A suppressed the G 2 /M transition of HT-29 cells, whereas the mitotic inhibitor paclitaxel induced M phase accumulation. Further investigation revealed that YSY-01A significantly （P0.05） up-regulated the expression levels of a series of cell cycle related protein, such as cyclin B1, Wee1, p-cdc2 （Tyr15）, p53, p21, and p27. The HT-29 cells only exhibited typical cytotoxic symptom when YSY-01A concentration reached 0.5 μM （P0.05）, which was above the dose we used in the mechanism research. In conclusion, YSY-01A showed remarkable anti-cancer activity on HT-29 cells, and its molecular mechanisms are related to G 2 /M cell cycle transition arrest.
YSY01-A, as a novel proteasome inhibitor, has shown remarkable proliferation inhibitory effect on certain types of tumor cells. However, few studies have reported its effect on non-small cell lung cancer （NSCLC）, and its underlying mechanism remains unknown. In our present study, we aimed to figure out the inhibitory effects as well as the mechanism of proteasome inhibitor YSY01-A against A549 cells both individually and in combination with cisplatin. A549 cell proliferation inhibition was assessed by SRB assay. Its related protein expression levels were determined by western blot assay. Moreover, the change of intracellular cisplatin accumulation was examined by ICP-MS assay. The results suggested that YSY01-A significantly （P〈0.001） inhibited the proliferation of A549 cells （IC50 was 36.2 nM for 72 h） in a concentration-dependent and time-dependent manner. Compared with the negative control group, YSY01-A （60 nM, 48 h） down-regulated PI3K/Akt pathway in A549 cells by increasing the expression level of PTEN （P〈0.01）, and decreasing the expression level of PI3K （P〈0.001） and p-Akt/Akt （P〈0.001）. When combined with cisplatin, YSY01-A of different concentrations （5, 10, 20 nM） could significantly increase the inhibition effects on A549 cells compared with the cisplatin alone treatment, showing a synergistic effect. At the same time, YSY01-A could remarkably block the cisplatin-induced down-regulation of hCTR1 in a concentration-dependent manner and increase cisplatin uptake from 2.01 to 2.47 fold （P〈0.001）. In conclusion, compound YSY01-A could significantly inhibit proliferation of NSCLC A549 cells, showing a strong synergistic effect when combined with cisplatin. Down-regulation of PI3K/Akt pathway might be the mechanism of inhibitory effect of YSY0 l-A, and the combination with cisplatin might increase the expression of CTR1 and intracellular cisplatin accumulation.
Compound YSY-01A, a recently synthesized proteasome inhibitor, has shown potent growth-inhibitory effect on tumor cells in previous researches. However, the mechanism of its inhibitory effects, especially on cell cycle, remains largely unclear. This study aimed to evaluate the correlation between cell cycle arrest effect of YSY-01A and its anti-cancer effect, and to probe the possible molecular mechanisms for its effects on human ovarian cancer SK-OV-3 cells. The results suggested that YSY-01A significantly （P〈0.05） inhibited cellular proliferation of SK-OV-3 cells in a concentration-dependent and time-dependent manner. Furthermore, YSY-01A induced a G2/M cell cycle arrest of SK-OV-3 cells. Further investigation revealed that YSY-01A significantly （P〈0.05） changed the expression levels of a series of cell cycle related protein, such as cyclin B1, cdc2, and p-cdc2 （T14）. Meanwhile, YSY-01A could inhibit the TNF-a-induced NF-kB nuclear translocation and lead to the increase of 1kBa as well as the decrease of IKK and Gadd45a In conclusion, YSY-01A showed remarkable anti-cancer activity on SK-OV-3 cells, and its molecular mechanisms were related to G2/M cell cycle arrest.
Compound 209 is a newly synthesized dithiocarbamate derivative with antiproliferation activity in vitro, however, its antitumor effect in vivo and the underlying mechanisms have yet to be identified. We explored the antitumor effect of compound 209 and the possible mechanisms for its inhibition of the growth of HT-29 xenograff tumor and proliferation of HT-29 cells. Cell proliferation was evaluated with SRB assay in vitro. The results showed that compound 209 had significant antiproliferation activity on HT-29 cells. Furthermore, the xenograff HT-29 nude mouse model was used to study the antitumor effect of compound 209 in vivo. We found that compound 209 significantly inhibited tumor growth and did not cause loss of body weight or leukocytopenia. Analysis by flow cytometry indicated that compound 209 arrested HT-29 cell cycle in G~ phase. Western blotting analysis suggested that compound 209 increased the expression of p27, cyclin E, CDK2, cyclin D1 and CDK4. These results demonstrated the antitumor effect of compound 209 and its potential use as an anticancer drug.
YSY-01A has shown proliferation inhibitory activity to certain types of tumor cells by inhibiting proteasome. How- ever, its effect on autophagy, which is related with the ubiquitin proteasome pathway （UPP）, remains unclear. Our study aimed to find out its effect on autophagy and possible molecular mechanisms. The results suggested that YSY-0 l A significantly （P〈0.001） inhibited proliferation of PC-3M cells （IC50 was 287 nM for 48 h） in a concentration-dependent and time-dependent manner. YSY-01A （100 nM, 3 h） also induced autophagy in PC-3M ceils through increasing the expression of P53 （P〈0.001）, Beclin-1 （P〈0.001） and LC3 （P〈0.001）, and decreasing the expression of p-roTOR （P〈0.001） as compared with the negative control group. Autophagy stayed at a final stage in PC-3M cells after treated with YSY-01A （400 nM） for 12 h. Meanwhile inhibition of autophagy with chloroquine increased the sensitivity to YSY-01A in PC-3M cells. In conclusion, YSY-01A showed high proliferation inhibitory activity of PC-3M cells and it could induce autophagy in PC-3M cells. Inhibiting autophagy increased the cytotoxic activity of YSY-01A in PC-3M cells.
