Levels significantly in BEL-7402 and SMMC-7721 
human hepatocarcinoma cells, as compared with the control siRNA group (Fig. 7A). Moreover, BEL-7402 and SMMC-7721 cells were transiently transfected with siSULT2B1 or siSULT2B1b-specific siRNAs and their cell proliferations assessed by CCK-8 assay. The results show that cell proliferation rates decreased significantly with SULT2B1 inhibition as compared to control cells (Fig. 7B, C). Further, we detected cyclinB1 expression by qPCR and Western-blot assays. As the results demonstrate, both cyclinB1 mRNA and protein levels decreased significantly with Lixisenatide SULT2B1b knock-down in BEL-7402 and SMMC-7721 cells as compared with vector control (Fig. 7D,E). The effect of SULT2B1b interference on tumorigenesis in an in vivo xenograft model was further studied. As can be seen in Fig. 7F, SULT2B1b knock-down in BEL-7402 cells significantly suppressed tumor growth in vivo as compared with NC-RFP-LV vector control. The tumor size and tumor weight of siSULT2B1b xenografts also was significantly smaller than the with control group (Fig. 7G, H).DiscussionIn the present study, we demonstrated that the hydroxysterol sulfotransferase, SULT2B1b, promoted proliferation in hepatocellular carcinoma cells both in vitro and in 1655472 vivo. Recently, altered expression of SULT2B1b has been demonstrated in hormonedependent cancers, such as in the breast and prostate [10,12,23,24]. However, the expression and function of SULT2B1b in liver tumors has not been addressed. Our data suggested that SULT2B1 expressed higher in the human hepatocarcinoma tumor tissues compared to those paratumor tissues, which suggested that SULT2B1 may play an important role in the hepatocarcinoma cell growth. Additionally, SULT2B1b was the only isoform expressed in both mouse and human hepatocarcinoma cell lines. The localization of SULT2B1b varies in the tissues [7]. He D et al. reported that SULT2B1b localized in the nuclei of synchiotrophoblast cells in human term placenta. Likewise, in human T47D and MCF-7 breast cancer cells, SULT2B1b is present both in cytosol and intact nuclei [8]. However, our data showed that SULT2B1b was present in the cytoplasm of hepatocarcinoma cells, but was not detected in the nuclei. There is increasing evidence that supports an association between SULT2B1b and hepatocyte proliferation. Zhang et al. reported that both 25HC3S, the biosynthetic product of SULT2B1b, and overexpression of SULT2B1b promoted liver proliferation [17,25]. Likewise, an increase of SULT2B1 mRNA has also been observed during 
liver regeneration induced by partial hepatectomy [16]. The correlation between SULT2B1b expression and the proliferative ability of hepatocarcinoma cells was demonstrated. Knock-down of SULT2B1b expression suppressed cell growth in both mouse (Hepa1-6) and human (BEL-7402 and SMMC-7721) hepatocarcinoma cells. Both the in vitro and in vivo studies indicated that the inhibition of cell growth by siSULT2B1b was due to increased apoptosis and cell cycle POR 8 arrest. Hepa1-6 cells showed an imbalance in the expression of pro-apoptotic (also anti-proliferative, FAS) and antiapoptotic (also pro-proliferative, BCL2 and MYC) proteins after SULT2B1b knock-down, promoting apoptosis and inhibiting proliferation. Our data also suggests that SULT2B1b inhibition significantly increases the apoptosis sensitivity of Hepa1-6 cells to either serum-starvation or TNFa/CHX treatment.CyclinB1 plays in integral role in many types of cancer. The cyclinB1/C.Levels significantly in BEL-7402 and SMMC-7721 human hepatocarcinoma cells, as compared with the control siRNA group (Fig. 7A). Moreover, BEL-7402 and SMMC-7721 cells were transiently transfected with siSULT2B1 or siSULT2B1b-specific siRNAs and their cell proliferations assessed by CCK-8 assay. The results show that cell proliferation rates decreased significantly with SULT2B1 inhibition as compared to control cells (Fig. 7B, C). Further, we detected cyclinB1 expression by qPCR and Western-blot assays. As the results demonstrate, both cyclinB1 mRNA and protein levels decreased significantly with SULT2B1b knock-down in BEL-7402 and SMMC-7721 cells as compared with vector control (Fig. 7D,E). The effect of SULT2B1b interference on tumorigenesis in an in vivo xenograft model was further studied. As can be seen in Fig. 7F, SULT2B1b knock-down in BEL-7402 cells significantly suppressed tumor growth in vivo as compared with NC-RFP-LV vector control. The tumor size and tumor weight of siSULT2B1b xenografts also was significantly smaller than the with control group (Fig. 7G, H).DiscussionIn the present study, we demonstrated that the hydroxysterol sulfotransferase, SULT2B1b, promoted proliferation in hepatocellular carcinoma cells both in vitro and in 1655472 vivo. Recently, altered expression of SULT2B1b has been demonstrated in hormonedependent cancers, such as in the breast and prostate [10,12,23,24]. However, the expression and function of SULT2B1b in liver tumors has not been addressed. Our data suggested that SULT2B1 expressed higher in the human hepatocarcinoma tumor tissues compared to those paratumor tissues, which suggested that SULT2B1 may play an important role in the hepatocarcinoma cell growth. Additionally, SULT2B1b was the only isoform expressed in both mouse and human hepatocarcinoma cell lines. The localization of SULT2B1b varies in the tissues [7]. He D et al. reported that SULT2B1b localized in the nuclei of synchiotrophoblast cells in human term placenta. Likewise, in human T47D and MCF-7 breast cancer cells, SULT2B1b is present both in cytosol and intact nuclei [8]. However, our data showed that SULT2B1b was present in the cytoplasm of hepatocarcinoma cells, but was not detected in the nuclei. There is increasing evidence that supports an association between SULT2B1b and hepatocyte proliferation. Zhang et al. reported that both 25HC3S, the biosynthetic product of SULT2B1b, and overexpression of SULT2B1b promoted liver proliferation [17,25]. Likewise, an increase of SULT2B1 mRNA has also been observed during liver regeneration induced by partial hepatectomy [16]. The correlation between SULT2B1b expression and the proliferative ability of hepatocarcinoma cells was demonstrated. Knock-down of SULT2B1b expression suppressed cell growth in both mouse (Hepa1-6) and human (BEL-7402 and SMMC-7721) hepatocarcinoma cells. Both the in vitro and in vivo studies indicated that the inhibition of cell growth by siSULT2B1b was due to increased apoptosis and cell cycle arrest. Hepa1-6 cells showed an imbalance in the expression of pro-apoptotic (also anti-proliferative, FAS) and antiapoptotic (also pro-proliferative, BCL2 and MYC) proteins after SULT2B1b knock-down, promoting apoptosis and inhibiting proliferation. Our data also suggests that SULT2B1b inhibition significantly increases the apoptosis sensitivity of Hepa1-6 cells to either serum-starvation or TNFa/CHX treatment.CyclinB1 plays in integral role in many types of cancer. The cyclinB1/C.