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Sophoridine is a quinolizidine natural product and the exploration of its derivatives has been carried out, and the potent anticancer compound IMB-HDC was acquired. Although previous studies have revealed that some sophoridine derivatives could induce DNA breakage, the underlying mechanisms of inhibition of DNA damage repair (ATR inactivation) and the apoptosis independent of p53, have not been elucidated. Our research reveals a novel DNA response mechanism different from general DNA-damaging agents, and that sophoridine derivate inhibits the phosphorylation of Tyr694 and Ser780 of STAT5a to induce the lessened shuttle from the cytoplasm to the nucleus, and leads to the decreased nuclear STAT5a and subsequently inhibits the expression of STAT5a target gene RAD51 that contributes to the checkpoint activation, thus inhibiting ATR activation. Meanwhile, IMB-HDC that induced the diminished expression of STAT5a target gene contributes to proliferation and leads to apoptosis. More importantly, we give the first evidence that promoting the effect of Tyr694 phosphorylation on nuclear location and subsequent STAT5a target gene transcription depends on Ser780 increased or unchanged phosphorylation and was not correlated with Ser726 phosphorylation.

Twenty-nine 12 N-substituted aloperine derivatives were synthesized and screened for suppression on PD-L1 expression in H460 cells, as a continuation of our work. Systematic structural modifications led to the identification of compound 6b as the most active PD-L1 modulator. Compound 6b could significantly down-regulate both constitutive and inductive PD-L1 expression in NSCLC cells, and successively enhance the cytotoxicity of co-cultured T cells against tumor cells at the concentration of 20 μM. Also, it exhibited a moderate in vivo anticancer efficacy against Lewis tumor xenograft with a stable PK and safety profile. The mechanism study indicated that 6b mediated the degradation of PD-L1 through a proteasome pathway, rather than a lysosome route. These results provided the powerful information for cancer immunotherapy of aloperine derivatives with unique endocyclic skeleton by targeting PD-L1 to activate immune cells to kill cancer cells.

Proprotein convertase subtilisin/kexin type 9 (PCSK9) is a secreted protein and its deficiency markedly enhanced the survival rate of patient with cardiovascular diseases (CVDs). Forty berberine (BBR) derivatives were synthesized and evaluated for their activities on down-regulating the transcription of PCSK9 in HepG2 cells, taking BBR as the lead. Structure–activity relationship (SAR) analysis revealed that 2,3-dimethoxy moiety might be beneficial for activity. Among them, 9k displayed the most potent activity with IC50 value of 9.5 ± 0.5 μM, better than that of BBR. Also, it significantly decreased PCSK9 protein level at cellular level, as well as in the liver and serum of mice in vivo. Furthermore, 9k markedly increased LDLR expression and LDL-C clearance via down-regulating PCSK9 protein. The mechanism of action of 9k is targeting HNF1α and/or Sp1 cluster modulation upstream of PCSK9, a different one from BBR. Therefore, 9k might have the potential to be a novel PCSK9 transcriptional inhibitor for the treatment of atherosclerosis, worthy for further investigation.

Berberine (BBR), a traditional Chinese medicine, has therapeutic effects on a variety of inflammation-related diseases, but its direct proteomic targets remain unknown. Using activity-based protein profiling, we first demonstrated that BBR directly targets the NEK7 protein via the hydrogen bond between the 2,3-methylenedioxy and 121-arginine (R121) residues. The fact that R121 is located precisely within the key domain involved in the NEK7-NLRP3 interaction allows BBR to specifically block the NEK7-NLRP3 interaction and successively inhibit IL-1β release, independent of the NF-κB and TLR4 signaling pathways. Moreover, BBR displays in vivo anti-inflammatory efficacy in a NEK7-dependent manner. Therefore, we consider NEK7 to be a key target of BBR in the treatment of NLRP3-related inflammatory diseases, and the development of novel NEK7-NLRP3 interaction inhibitors might be easily achieved using NEK7 as a target.

Graphic abstract Compound 8a exhibited the promising activity against anti-SARS-CoV-2 via inhibiting host Cat B activity, and had the advantage of broad-spectrum anti-coronavirus and anti-cytokine activity in the treatment of COVID-19., So far, there is still no specific drug against COVID-19. Taking compound 1 with anti-EBOV activity as the lead, fifty-four 12N-substituted aloperine derivatives were synthesized and evaluated for the anti-SARS-CoV-2 activities using pseudotyped virus model. Among them, 8a exhibited the most potential effects against both pseudotyped and authentic SARS-CoV-2, as well as SARS-CoV and MERS-CoV, indicating a broad-spectrum anti-coronavirus profile. The mechanism study disclosed that 8a might block a late stage of viral entry, mainly via inhibiting host cathepsin B activity rather than directly targeting cathepsin B protein. Also, 8a could significantly reduce the release of multiple inflammatory cytokines in a time- and dose-dependent manner, such as IL-6, IL-1β, IL-8 and MCP-1, the major contributors to cytokine storm. Therefore, 8a is a promising agent with the advantages of broad-spectrum anti-coronavirus and anti-cytokine effects, thus worthy of further investigation.

Twenty-seven novel 12N-substituted aloperine derivatives were synthesized and investigated for their inhibitory effects on collagen &alpha, 1 (I) (COL1A1) promotor in human hepatic stellate LX-2 cells, taking aloperine (1) as the hit. A structure-activity relationship (SAR) study disclosed that the introduction of suitable substituents on the 12N atom might enhance the activity. Compound 4p exhibited a good promise on down-regulating COL1A1 expression with the IC50 value of 16.5 &mu, M. Its inhibitory activity against COL1A1 was further confirmed on both mRNA and protein levels. Meanwhile, it effectively inhibited the expression of other fibrogenic proteins, such as transforming growth factor &beta, 1 (TGF-&beta, 1) and smooth muscle actin (&alpha, SMA). It also exhibited good in vivo safety profile with the oral LD50 value of 400 mg kg&minus, 1 in mice. The results initiated the anti-liver fibrogenic study of aloperine derivatives, and the key compound 4p was selected as a novel lead for further investigation against liver fibrogenesis.

Twenty 9O-substituted palmatine derivatives were prepared and tested for their biological effect against collagen &alpha, 1 (I) (COL1A1) promotor in human hepatic stellate LX-2 cells. The structure&minus, activity relationship (SAR) indicated that the introduction of a benzyl motif on the 9O atom was favorable for activity. Among them, compound 6c provided the highest inhibitory effect against COL1A1 with an IC50 value of 3.98 &mu, M, and it also dose-dependently inhibited the expression of fibrogenic COL1A1, &alpha, soomth muscle actin (&alpha, SMA), matrix metalloprotein 2 (MMP2) in both mRNA and protein levels, indicating extensive inhibitory activity against fibrogenesis. A further primary mechanism study indicated that it might repress the hepatic fibrogenesis via inhibiting both canonical transforming growth factor-beta 1 (TGF-&beta, 1)/Smads and non-canonical janus-activated kinase 1 (JAK1)/singal transducer and activator of transcription 3 (STAT3) signaling pathways. Additionally, 6c owned a high safety profile with the LD50 value of over 1000 mg&middot, kg-1 in mice. These results identified palmatine derivatives as a novel class of anti-fibrogenic agents, and provided powerful information for further structure optimization.

To discover small-molecule cancer immunotherapy candidates through targeting Indoleamine 2,3-dioxygenase 1 (IDO1), twenty-five new berberine (BBR) derivatives defined with substituents on position 3 or 9 were synthesized and examined for repression of IFN-γ-induced IDO1 promoter activities. Structure-activity relationship (SAR) indicated that large volume groups at the 9-position might be beneficial for potency. Among them, compounds 2f, 2i, 2n, 2o and 8b exhibited increased activities, with inhibition rate of 71-90% compared with BBR. Their effects on IDO1 expression were further confirmed by protein level as well. Furthermore, compounds 2i and 2n exhibited anticancer activity by enhancing the specific lysis of NK cells to A549 through IDO1, but not cytotoxicity. Preliminary mechanism revealed that both of them inhibited IFN-γ-induced IDO1 expression through activating AMPK and subsequent inhibition of STAT1 phosphorylation. Therefore, compounds 2i and 2n have been selected as IDO1 modulators for small-molecule cancer immunotherapy for next investigation.

Twenty new 12N-substituted matrinol derivatives were synthesized and evaluated for their inhibitory effects on collagen &alpha, 1 (I) (COL1A1) promotor in human hepatic stellate LX-2 cells. The structure-activity relationship (SAR) revealed that introducing a 12N-benzeneaminoacylmethyl substitution might significantly enhance the activity. Compound 8a exhibited the highest inhibitory potency against COL1A1, and its inhibition activity against COL1A1 was further confirmed on both the mRNA and protein levels. It also effectively inhibited the expression of &alpha, smooth muscle actin (&alpha, SMA), fibronectin and transforming growth factor &beta, 1 (TGF&beta, 1), indicating an extensive inhibitory effect on the expression of fibrogenic genes. The primary mechanism study indicated that it might take action via the Integrin/FAK/PI3K/Akt signaling pathway. The results provided powerful information for further structure optimization, and compound 8a was selected as a novel anti-fibrogenic lead for further investigation.

Twenty eight 7-substitued fangchinoline analogues, of which twenty two were novel, were synthesized and evaluated for their effect to inhibit lipopolysaccharide/nigericin (LPS/NIG)-induced IL-1&beta, release at both cell and protein levels at the concentration of 5 &mu, M. Among them, compound 6 exhibited promising inhibitory potency against IL-&beta, activation with an IC50 value of 3.7 &mu, M. Preliminary mechanism study revealed that 6 might target NLRP3 protein, and then block ASC pyroptosome formation with-NLRP3, rather than acting on the activation of the NLRP3 inflammasome (NF-&kappa, B and MAPK pathways) or caspase-1 protein. Our current study supported the potential role of compound 6 against IL-&beta, activation, and provided powerful information for developing fangchinoline derivatives into a novel class of anti-inflammatory agents.

A series of novel tricyclic matrinic derivatives with 11-adamantyl substitution were designed, synthesized, and evaluated for their activities against Influenza A H3N2 virus, based on the privileged structure strategy. Structure-activity relationship (SAR) analysis indicated that the introduction of an 11-adamantyl might be helpful for the potency. Among them, compounds 9f and 9j exhibited the promising anti-H3N2 activities with IC50 values of 7.2 &mu, M and 10.2 &mu, M, respectively, better than that of lead 1. Their activities were further confirmed at the protein level. Moreover, compound 9f displayed a high pharmacokinetic (PK) stability profile in whole blood and a safety profile in vivo. In primary mechanism, compound 9f could inhibit the virus replication cycle at early stage by targeting M2 protein, consistent with that of the parent amantadine. This study provided powerful information for further strategic optimization to develop these compounds into a new class of anti-influenza agents.

Materials & methods: Fifty-one novel 12N-substituted matrinic acid derivatives were synthesized and evaluated for their anti-coxsackievirus B3 activities. Results: Structure–activity relationship studies revealed that the 11-side chain could be determinant for the selectivity index by adjusting overall lipophilicity, and 11-butane was the best one for both potency and druggability. The optimized 35d showed the broad-spectrum anti-coxsackieviruse effects, an excellent pharmacokinetics and a good safety profile. More importantly, it displayed a potential effect for the pleconaril-resistant coxsackievirus B3 as well. Its mode of action is targeting on the viral transcription and translation stage, a different mechanism from that of pleconaril. Conclusion: Thus, we considered that 35d is a promising anti-enteroviral candidate for the treatment of various diseases infected with coxsackieviruses.

Sophoridinic acid derivatives have received considerable attentions for their potencies in cancer therapy. IMB-6G is a novel N-substituted sophoridinic acid derivative with potent cytotoxicity against tumor cells. In the present study, we explored the antitumor abilities of IMB-6G in human hepatocellular carcinoma (HCC) cells and investigated the underlying mechanisms. We found that IMB-6G inhibited cell growth and induced mitochondrial-dependent apoptosis in HepG2 and SMMC7721 cells. Analyses of the molecular mechanism of IMB-6G-induced apoptosis indicated IMB-6G induced endoplasmic reticulum (ER) stress activation. Incubation of HCC cells with IMB-6G induced increase in Bip and CHOP levels, which precede induction of apoptosis. Further study showed IMB-6G activated IRE1α and PERK pathways but did not stimulated ATF6 pathway in HCC cells. Moreover, silencing of IRE1α dramatically abrogated IMB-6G-induced pro-apoptotic ASK1-JNK signaling. Importantly, interruption of CHOP rendered HCC cells sensitive to IMB-6G-induced apoptosis via inactivation of Bim, PUMA and Bax. Thus, the IRE1α-ASK1 and PERK-CHOP pathways may be a novel molecular mechanism of IMB-6G-induced apoptosis. Collectively, our study demonstrates that IMB-6G induces ER stress-mediated apoptosis by activating IRE1α and PERK pathways. Our findings provide a rationale for the potential application of IMB-6G in HCC therapy.

Forty-three tricyclic matrinic derivatives with a unique scaffold were prepared and evaluated for their stimulation effects on glucose consumption in HepG2 cells. The structure-activity relationship was systematically elucidated for the first time. Among them, compound 17a exhibited the most promising potency, and dose-dependently increased glucose consumption in L6 myotubes. It significantly lowered blood glucose, glucosylated haemoglobin and AGE level, and improved glucose tolerance and insulin resistance in KK-Ay mice as well. More importantly, 17a effectively ameliorated diabetic nephropathy (DN), as indicated by the improvement of renal function and pathological changes, and decrease of urinary protein. Furthermore, 17a could induce glycolysis but suppressed aerobic oxidation of glucose, in a similar mechanism to Metform. Our results indicated that in addition to hyperglycemia, 17a may be developed to treat diabetic complication such as DN.

A series of novel berberine (BBR) analogues were prepared and tested for their antiviral potencies against six different genotype Coxsackievirus B (CVB1–6) strains, taking BBR core for structural modification. Structure-activity relationship (SAR) research revealed that introduction of a primary amine through a linker at position 3 might be beneficial for both antiviral activity and safety. Compound 14c displayed most promising inhibitory potency with IC50 values of 3.08–9.94 µM against tested CVBs 2–6 strains and satisfactory SI value of 34.3 on CVB3, better than that of BBR. Also, 14c could inhibit CVB3 replication through down-regulating the expression of VP1 protein and VP1 RNA. The mechanism revealed that 14c could suppress host components JNK-MAPK, ERK-MAPK and p38-MAPK activation. Therefore, BBR derivatives were considered to be a new class of anti-CVB agents with an advantage of broad-spectrum anti-CVB potency.

Lysosome has a crucial role in clearance of endocytosed pathogens from the cell. Small molecules that can boost lysosome function and bactericidal ability to cope with subsequent infection are urgently needed. Here, we report that MPB, a novel berberine derivative, induced lysosome-based degradation and clearance of methicillin-resistant Staphylococcus aureus and enteroinvasive Escherichia coli in macrophages. MPB caused nuclear translocation of transcription factor EB (TFEB), which boosted expression of lysosome genes. TFEB silencing repressed the MPB-mediated enhancements in degradation and bacterial eradication. MPB switched on TFEB nuclear translocation by coupling 2 parallel signaling pathways. MPB-triggered JNK activation led to 14-3-3δ being released from TFEB, which, in turn, caused TFEB nuclear translocation. In addition, MPB induced AMPK activation and subsequent inhibition of mechanistic target of rapamycin activity, which also contributed to TFEB nuclear translocation. Importantly, genetical or pharmaceutical inhibition of TGF-β-activated kinase 1 (TAK1) reduced MPB action remarkably. MPB acted through TAK1 at lysine 158 to activate JNK and AMPK and, thus, induced TFEB-dependent bactericidal activity in macrophages. Therefore, our study reveals a novel mechanism by which MPB controls JNK and AMPK phosphorylation cascades to activate lysosomal function and bactericidal activity via TAK1 K158-dependent manner, which may offer insight into novel therapeutic strategies to control bacterial infection.-Liu, X., Zhang, N., Liu, Y., Liu, L., Zeng, Q., Yin, M., Wang, Y., Song, D., Deng, H. MPB, a novel berberine derivative, enhances lysosomal and bactericidal properties via TGF-β-activated kinase 1-dependent activation of the transcription factor EB.

Resibufogenin (RB), one of the major active compounds of the traditional Chinese medicine Chansu, has received considerable attention for its potency in cancer therapy. However, the anticancer effects and the underlying mechanisms of RB on pancreatic cancer remain elusive. Here, we found that RB inhibited the viability and induces caspase‐dependent apoptosis in human pancreatic cancer cells Panc‐1 and Aspc. Resibufogenin‐induced apoptosis was through inhibition of constitutive nuclear factor‐κB (NF‐κB) activity and its target genes’ expression, which was caused by downregulation of transforming growth factor‐β‐activated kinase 1 (TAK1) levels and suppression of IκB kinase activity in Panc‐1 and Aspc cells. This induction of TAK1‐mediated NF‐κB inactivation by RB was associated with increased glycogen synthase kinase‐3 (GSK‐3) phosphorylation and subsequent suppression of its activity. Moreover, RB‐induced GSK‐3 phosphorylation/inactivation acted through activation of protein kinase C but not Akt. Finally, RB suppressed human pancreatic tumor xenograft growth in athymic nude mice. Thus, our findings reveal a novel mechanism by which RB suppresses TAK1‐mediated NF‐κB activity through protein kinase C‐dependent inhibition of GSK‐3. Our findings provide a rationale for the potential application of RB in pancreatic cancer therapy.

Glycogen synthase kinase-3β (GSK-3β) is a ubiquitously expressed serine/threonine kinase involved in a variety of functions ranging from the control of glycogen metabolism to transcriptional regulation. We recently demonstrated that GSK-3β inhibition triggered ASK1-JNK-dependent apoptosis in human hepatocellular carcinoma (HCC) cells. However, the comprehensive picture of downstream GSK-3β-regulated pathways/functions remains elusive. In this study, we showed that GSK-3β was aberrantly activated in HCC. Pharmacological inhibition and genetic depletion of GSK-3β suppressed the growth and induced caspase-dependent apoptosis in HCC cells. In addition, GSK-3β inhibition-induced apoptosis through downregulation of c-FLIPL in HCC, which was caused by biogenesis of functional lysosomes and subsequently c-FLIPL translocated to lysosome for degradation. This induction of the lysosome-dependent c-FLIPL degradation was associated with nuclear translocation of transcription factor EB (TFEB), a master regulator of lysosomal biogenesis. Moreover, GSK-3β inhibition-induced TFEB translocation acts through activation of AMPK and subsequently suppression of mTOR activity. Thus our findings reveal a novel mechanism by which inhibition of GSK-3β promotes lysosome-dependent degradation of c-FLIPL. Our study shows that GSK-3β may become a promising therapeutic target for HCC.

Background Programmed death-ligand 1 (PD-L1) is a T-cell inhibitory checkpoint molecule that suppresses antitumor immunity. Anti-PD-L1 antibodies have shown remarkable promise in treating tumors, but the patient response rate is low. Therefore, small-molecule checkpoint inhibitors blocking PD-L1 function are urgently needed. Methods Changes of protein expression and phosphorylation levels were determined by immunoblotting. The level of Membrane PD-L1 was examined by flow cytometer. Cytotoxicity of T cells and NK cells toward tumor cells were detected using LDH and cell index assays. Lysosome function was investigated by NAG assay. Changes in lysosomal-related genes were measured by RT-PCR. In vivo anti-NSCLC cancer effects were assessed using C57BL/6 mice bearing Lewis tumor xenografts. Findings We identified SA-49 as a new regulator of PD-L1 expression from a series of novel aloperine derivatives. SA-49 decreased the expression of PD-L1 in NSCLC cells and enhanced the cytotoxicity of co-cultured T and NK cells toward tumor cells. Importantly, lysosomal pathway contributed to SA-49-mediated down-regulation of PD-L1. SA-49 increased the biogenesis of lysosome and promoted translocation of PD-L1 to lysosome for proteolysis, which was associated with nuclear translocation of MITF. SA-49-induced MITF translocation acted through activation of PKCα and subsequently suppression of GSK3β activity. Furthermore, SA-49 suppressed Lewis tumor xenograft growth by activating immune microenvironment in C57BL/6 mice. Interpretation Our data demonstrate that SA-49 can be used to regulate PD-L1 in cancer cells and trigger its degradation by activating lysosome function.

Preventing filoviruses in the entry stage is an attractive antiviral strategy. Taking aloperine, a Chinese natural herb with an endocyclic skeleton, as the lead, 23 new aloperine derivatives were synthesized and evaluated for their anti-filovirus activities including ebola virus (EBOV) and marburg virus (MARV) using pseudotyped virus model. Structure-activity relationship (SAR) analysis indicated that the introduction of a 12N-dichlorobenzyl group was beneficial for the potency. Compound 2e exhibited the most potent anti-EBOV and anti-MARV effects both in vitro and in vivo. It also displayed a good pharmacokinetic and safety profile in vivo, indicating an ideal druglike feature. The primary mechanism study showed that 2e could block a late stage of viral entry, mainly through inhibiting cysteine cathepsin B activity of host components. We consider compound 2e to be a promising broad-spectrum anti-filovirus agent with the advantages of a unique chemical scaffold and a specific biological mechanism.

Aloperine (1), a Chinese natural product with a unique endocyclic scaffold, was first identified to be a potent hepatitis C virus (HCV) inhibitor in our laboratory. Thirty-four new aloperine derivatives were designed, synthesized and evaluated for their anti-HCV activities taking 1 as the lead. Among them, compound 7f exhibited the potential potency with EC50 values in a micromolar range against both wild-type and direct-acting antiviral agents (DAAs)-resistant variants, and synergistically inhibited HCV replication with approved DAAs. Furthermore, it also owned a good oral pharmacokinetic and safety profile, suggesting a highly druglike nature. The primary mechanism showed that 7f might target host components, distinctly different from the DAAs currently used in clinic. Therefore, we consider aloperine derivatives to be a novel class of anti-HCV agents, and compound 7f has been selected as a promising antiviral candidate for further investigation.

Twenty-three new berberine (BBR) analogues defined on substituents of ring D were synthesized and evaluated for their activity for suppression of tumor necrosis factor (TNF)-α-induced nuclear factor (NF)-κB activation. Structure–activity relationship (SAR) analysis indicated that suitable tertiary/quaternary carbon substitutions at the 9-position or rigid fragment at position 10 might be beneficial for enhancing their anti-inflammatory potency. Among them, compounds 2d, 2e, 2i and 2j exhibited satisfactory inhibitory potency against NF-κB activation, with an inhibitory rate of around 90% (5 μM), much better than BBR. A preliminary mechanism study revealed that all of them could inhibit TNF-α-induced NF-κB activation via impairing IκB kinase (IKK) phosphorylation as well as cytokines interleukin (IL)-6 and IL-8 induced by TNF-α. Therefore, the results provided powerful information on further structural modifications and development of BBR derivatives into a new class of anti-inflammatory candidates for the treatment of inflammatory diseases.

Twenty-two novel 12N-substituted matrinic ethanol derivatives were synthesized and evaluated for their antiviral activities against HCV taking compound 1 as the lead. The SAR study indicated that the shortening of the 11-butyl chain to ethyl chain did not affect the activity significantly. Out of the target compounds, matrinic ethanol 6a demonstrated a potential anti-HCV effect with an EC50 value of 3.2 μM and a SI value of 96.6. The free hydroxyl arm in 6a made it possible as a parent structure to prepare pro-drug for the potential application in HCV treatment. This study provided powerful information on further strategic optimization and development of this kind of compounds into a novel family of anti-HCV agents.

A series of new cytisine derivatives with a unique endocyclic scaffold were synthesized and evaluated for their inhibitory effect on collagen α1 (I) (COL1A1) promotor in human LX2 cells, taking cytisine as the lead. Structure-activity relationship (SAR) revealed that introducing a 12 N -benzyl substitution might significantly enhance the activity. Compound 5f exhibited a promising inhibitory potency against COL1A1 with an IC 50 value of 12.8 μM in human LX2 cells, and an inspiring inhibition activity against COL1A1 on both mRNA and protein levels. It also effectively inhibited the expression of α smooth muscle actin (α-SMA), connective tissue growth factor (CTGA), matrix metalloprotein 2 (MMP-2), and transforming growth factor β1 (TGFβ1), indicating an extensive inhibitory effect against fibrogenetic proteins. In addition, compound 5f displayed reasonable PK and safety profiles. The primary mechanism study indicated that it might repress the hepatic fibrogenesis via PI3K/Akt/Smad signaling pathway. The results provided powerful information for further structure optimization, and compound 5f was selected as a novel anti-liver fibrosis agent for further investigation.

A series of new 1,13-cycloprotoberberine derivatives defined through variations at the 9-position were designed, synthesized and evaluated for their cytotoxicities in human HepG2 (hepatoma), HT1080 (fibrosarcoma) and HCT116 (colon cancer) cells. The preliminary structure−activity relationship (SAR) revealed that the replacement of 9-methoxyl with an ester moiety might significantly enhance the antiproliferative activity in vitro . Notably, compound 7f demonstrated equipotent cytotoxicity activity against breast cancer MCF-7 (parent) and doxorubicin (DOX)-resistant MCF-7 (MCF-7/ADrR) cells, indicating a mode of action different from that of DOX. Further mechanism study showed that 7f significantly inhibited activity of DNA topoisomerase I (Top I) and Top II. G2/M phase arrest and tumor cell growth reduction was observed thereafter. Thus, we consider cycloprotoberberine analogues to be a new family of promising antitumor agents with an advantage of inhibiting drug-resistant cancer cells.

Objective Cellular efflux transporters, especially P-glycoprotein (P-gp), impel berberine (BBR) out of cells, and therefore reduce bioavailability of the compound. This study was designed to overcome efflux of BBR using P-gp as a target. Materials/methods Molecular docking study was done to identify BBR analogues that were with low affinity to P-gp. Flow cytometry was used to determine cellular efflux of chemicals. Pharmacokinetic study was performed in Wistar rats, following oral administration of the study compounds. The efficacies of chemicals on glucose homeostasis were determined both in cultured cells and diabetic KK-Ay and db/db mice. Results In the molecular docking study, we found that among BBR analogues pseudo-berberine (IMB-Y53) has low affinity to P-gp. IMB-Y53 was retained in Caco-2, HL-7702 and C2C12 cells for a significantly longer period of time than BBR did. P-gp inhibitor tetrandrine (Tet) abolished the efflux of BBR at different extent depending on the expression level of P-gp; however, Tet had no impact on IMB-Y53 efflux. BBR increased P-gp expression dose-dependently in intestinal and liver cells; IMB-Y53 also up-regulated P-gp but at a much lower level as compared with BBR. Administered at equal dose in rats, the maximum plasma concentration (Cmax) and area under concentration–time curve (AUC0–24) of IMB-Y53 were 1.61 and 2.27-fold of those of BBR, respectively, indicating an improved bioavailability. IMB-Y53 stimulated glucose utility in cultured cells with a degree similar to that of BBR, but exhibited enhanced glucose-lowering efficacy in KK-Ay and db/db diabetic mice. Conclusions These results suggest that overcoming cellular efflux especially P-gp's function improves bioavailability and hypoglycemic effect of BBR.

Targeting the autophagic pathway is currently regarded as an attractive strategy for cancer drug discovery. Our previous work showed that IMB-6G is a novel N-substituted sophoridinic acid derivative with potent cytotoxicity against tumor cells, yet the effect of IMB-6G on autophagy and pancreatic cancer cell death remains unknown. Here, we show that IMB-6G inhibits the growth of MiaPaCa-2 and HupT-3 pancreatic cancer cells and induces caspase-mediated apoptosis, which is correlated with an accumulation of autophagic vacuoles. IMB-6G promotes autophagosome accumulation from the early stage of treatment but blocks autophagic flux in the degradation stage, mainly through attenuation of lysosomal cathepsin activity in pancreatic cancer cells. Moreover, IMB-6G triggers lysosomal membrane permeabilization (LMP), followed by cathepsin B/CTSB and cathepsin D/CTSD release from lysosomes into the cytoplasm. Inhibition of autophagosome formation with siRNA against autophagy protein 5 (Atg5) attenuates IMB-6G-induced LMP and apoptosis. Furthermore, cathepsin inhibitors relieve IMB-6G-induced apoptosis as well. Altogether, our findings demonstrate that IMB-6G is a novel autophagy inhibitor, which induces autophagy-dependent apoptosis through autophagosomal-cathepsin axis in pancreatic cancer cells and indicate the potential value of IMB-6G as a novel antitumor drug candidate.

The cluster of differentiation 36 (CD36) is a membrane protein related to lipid metabolism. We show that HCV infection in vitro increased CD36 expression in either surface or soluble form. HCV attachment was facilitated through a direct interaction between CD36 and HCV E1 protein, causing enhanced entry and replication. The HCV co-receptor effect of CD36 was independent of that of SR-BI. CD36 monoclonal antibodies neutralized the effect of CD36 and reduced HCV replication. CD36 inhibitor sulfo-N-succinimidyl oleate (SSO), which directly bound CD36 but not SR-BI, significantly interrupted HCV entry, and therefore inhibited HCV replication. SSO’s antiviral effect was seen only in HCV but not in other viruses. SSO in combination with known anti-HCV drugs showed additional inhibition against HCV. SSO was considerably safe in mice. Conclusively, CD36 interacts with HCV E1 and might be a co-receptor specific for HCV entry; thus, CD36 could be a potential drug target against HCV.

Glycogen synthase kinase-3β (GSK-3β), a multifunctional kinase, is an important regulator of cancer cell survival. Apoptosis signal-regulating kinase 1 (ASK1) is also a key factor for controlling several cellular events including the cell cycle, senescence, and apoptosis, in response to reactive oxygen species (ROS). The role of GSK-3β regulating the activity and protein level of ASK1 in the cancer cells remains largely unexplored. In this study, we showed that GSK-3β inhibits ROS-induced hepatocellular carcinoma cell death by suppressing ASK1. We first found that ectopic expression of GSK-3β suppressed hydrogen peroxide (H2O2)-induced cell death in HepG2 cells and knockdown of endogenous GSK-3β expression exhibited opposite effects. Moreover, GSK-3β expression clearly inhibited H2O2-induced phosphorylation of ASK1 in HepG2 cells, in association with a decrease in ASK1 protein level. Further exploration revealed that GSK-3β induced ubiquitination and proteasome-dependent degradation of ASK1 via inhibition of ubiquitin-specific protease USP9X. Our results thus suggest that GSK-3β is a key factor involved in ASK1 activation and ROS-induced cell death.

Currently there is no approved medicine for the treatment of metabolic syndrome. A series of new derivatives of berberine (BBR) or pseudoberberine (1) was synthesized and evaluated for their activity on AMP-activated protein kinase (AMPK) activation and up-regulatory low-density-lipoprotein receptor (LDLR) gene expression, respectively. In addition, the four major metabolites of BBR in vivo were also examined for their activity on AMPK in order to further understand the chemical mechanisms responsible for its glucose-lowering efficacy. Among those BBR analogues, compound 1 exhibited the potential effect on AMPK activation and LDLR up-regulation as compared with BBR. The results suggested that compound 1 might be a multiple-target agent for the treatment of metabolic syndrome, and thus was selected as a promising drug candidate for further development.

Sophoridine (1), a natural anticancer drug, has been used in China for decades. A series of novel N-substituted sophoridinic acid derivatives were synthesized and evaluated for their cytotoxicity with 1 as the lead. The structure–activity relationship indicated that introduction of an aliphatic acyl on the nitrogen atom might significantly enhance the anticancer activity. Among the compounds, 6b bearing bromoacetyl side-chain afforded a potential effect against four human tumor cell lines (liver, colon, breast, and lung). The mechanism of action of 6b is to inhibit the activity of DNA topoisomerase I, followed by the S-phase arrest and then cause apoptotic cell death, similar to that of its parent 1. We consider 6b promising for further anticancer investigation.

By using human scavenger receptor CD36 as the target, twenty-five N-(2-arylethyl) isoquinoline derivatives were designed, synthesized and evaluated for their antagonistic activities for CD36-oxidatively low density lipoprotein (oxLDL) binding. The primary analysis of structure-activity relationship (SAR) indicated a methoxyl at the 7-position and a hydroxyl at the 6- or 8-position could afford good activities. Among these analogs, compounds 7e and 7t showed the potential CD36 antagonistic activities with IC(50) values of 0.2 and 0.8 μg/mL, respectively. Furthermore, both of them could effectively inhibit oxLDL uptake in insect Sf9 cells overexpressing human CD36, and thus have been selected for further investigation. We consider N-(2-arylethyl) isoquinoline analogs to be a family of novel CD36 antagonists.

Taking berberine (BBR) as the lead, 23 new BBR derivatives were synthesized and examined for their antiviral activities against four different genotype enterovirus 71 (EV71) strains with a cytopathic effect (CPE) assay. Structure-activity relationship (SAR) studies indicated that introduction of a suitable substituent at the 9-position might be beneficial for potency. Among them, compound 2d exhibited most potent activities with IC50 values of 7.12&ndash, 14.8 &mu, M, similar to that of BBR. The effect of 2d was further confirmed in a dose-dependent manner both in RNA and protein level. The mechanism revealed that 2d could inhibit the activation of MEK/ERK signaling pathway. Meanwhile, it could suppress the EV71-induced autophagy by activating AKT and inhibiting the phosphorylation of JNK and PI3KIII proteins. We consider BBR derivatives to be a new family of anti-EV71 agents through targeting host components, with an advantage of broad-spectrum anti-EV71 potency.

A series of novel matrinic thiadiazole derivatives were designed, synthesized and evaluated for their inhibitory effect on COL1A1 promotor. The SAR indicated that: (i) the introduction of a thiadiazole on the 11-side chain was beneficial for activity, (ii) a 12-N-benzyl moiety was favorable for activity. Among them, compound 6n displayed a high activity with an inhibitory rate of 39.7% at a concentration of 40 &mu, M. It also effectively inhibited the expression of two representative collagen proteins (COL1A1 and &alpha, SMA) on both the mRNA and protein levels and showed a high safety profile in vivo, indicating its great promise as an anti-liver fibrosis agent. Further study indicated that it might repress hepatic fibrogenesis via the TGF&beta, /Smad pathway. This study provided powerful information for further strategic optimization and the top compound 6n was selected for further study as an ideal liver fibrosis lead for next investigation.

Host heat shock cognate 70 (Hsc70) protein is packaged into hepatitis C viral (HCV) particles as a structural component of the virus in the assembly process. It helps HCV RNA release into the cytoplasm in the next infection cycle. The goal of this study is to investigate whether chemically down-regulating host Hsc70 expression could be a novel strategy to interrupt HCV replication. Compounds were screened with an Hsc70 messenger RNA (mRNA) assay. IMB-DM122 was found to be an effective and safe inhibitor for Hsc70 mRNA/protein expression in human hepatocytes. IMB-DM122 inhibited HCV replication through destabilization of Hsc70 mRNA, and the half-life of host Hsc70 mRNA was reduced by 78% after the compound treatment. The Hsc70 mRNA 3′ untranslated region sequence is the element responsible for the effect of IMB-DM122 on Hsc70 mRNA. The compound appears to be highly efficient in inhibiting Hsc70-related HCV replication. Treatment of the HCV-infected hepatocytes with IMB-DM122 reduced the virion encapsidation of Hsc70, and therefore disrupted HCV replication and the infection cycle. IMB-DM122 showed considerable good safety in vitro as well as in vivo with no indication of harmful effect on liver and kidney functions. Conclusion: Hsc70 might be a new drug target and mechanism to inhibit HCV proliferation. (HEPATOLOGY 2010;)

CD36, a class B scavenger receptor, is an integral membrane protein that mediates the endocytosis of modified lipoproteins. The functions of CD36 are complex and have been associated with atherosclerosis. In the current study, we developed a high-throughput screening (HTS) assay to identify small molecule antagonists by expressing human CD36 using a Bac-to-Bac baculovirus expression system in Spodoptera frugiperda (Sf9) cells. Uptake of 1,1'-dioctadecyl-3,3,3',3'-tetramethylindocarbocyanine perchlorate-labeled acetylated low-density lipoprotein (DiI-AcLDL) revealed that the IC(50) values for the CD36 ligands oxidatively modified LDL (Ox-LDL), Ac-LDL, and high-density lipoprotein (HDL) were 0.039, 0.019, and 0.010 microg/ml, respectively. Using the HTS assay, two novel compounds, 2016481B and 2038751B, were found to inhibit DiI-AcLDL uptake in insect cells and exhibited IC(50) values of 17.4 and 23.7 microM, respectively. These two novel compounds also inhibited DiI-AcLDL uptake in cultured Chinese hamster ovary (CHO) cells permanently expressing human CD36. Furthermore, these two compounds inhibited lipid accumulation in RAW 264.7 murine macrophage cells in foam cell assays. This HTS assay represents a potential method for identifying more effective macrophage scavenger receptor antagonists, which may serve as starting points for the development of novel anti-atherosclerotic agents.

Antiviral chemotherapy can select for drug-resistant viral mutants (21). For chronic infections that need long-term chemotherapy, such as infection with hepatitis B virus (HBV), the challenge to clinical therapy is substantial (27, 31). Reverse transcriptase (RT) inhibitors, such as lamivudine, adefovir, entecavir, telbivudine, and tenofovir, are potent drugs for HBV infections, but their use in the clinical setting often selects for drug resistance (13, 14, 27, 31). The incidence of lamivudine resistance rises from 15 to 32% in the first year to 67 to 69% by the fifth year of treatment (7, 9, 28). Many drug-induced mutations in the HBV polymerase gene have been characterized. For instance, rtM204I/V/S (“rt” means “resistant”), rtL180M, rtL80V/I, and rtV173L are signature mutations for lamivudine; rtN236T and rtA181T/V are signature mutations for adefovir; rtS202G/I, rtI169T, rtS184G, and rtM250V are signature mutations for entecavir; rtM204I is a signature mutation for telbivudine; and rtA194T is a signature mutation for tenofovir (9, 27, 30, 31). The mutations in RT result from the intrinsic high variability due to the lack of an editing function of the enzyme (18, 20), and they alter the three-dimensional (3D) interaction between HBV polymerase and the drugs (27). This challenges the current anti-HBV strategy, which is directed at viral enzymes. However, HBV strains rely heavily on host cell machinery to complete their life cycles. Indeed, a number of host proteins have been reported to be crucial for HBV replication (10, 17, 29). Our hypothesis is that (i) these cellular components might be drug targets to control the virus, and suppression of these cellular proteins might be able to inhibit HBV replication, and (ii) unlike those that target viral enzymes, drugs utilizing this mechanism would be active against either wild-type or drug-resistant HBV strains, because the virus is not the target of chemotherapy. However, inhibition of host proteins might be harmful to the host. The key to avoiding undesirable side effects is, first, to identify host targets that are crucial for viral replication but not essential or only conditionally required for cell survival and, second, to find compounds that selectively target these proteins. Heat stress cognate 70 (Hsc70, or HspA8) is an ATP-binding protein of the heat stress protein 70 (Hsp70) family (16). It is the form of Hsp70 that is expressed in the absence of heat or other cell stress (1). This host protein was found to be required for the reverse transcription process in experiments using duck HBV DNA polymerase (2, 8). We anticipated that downregulation of this protein in the host would inhibit HBV replication in either wild-type or drug-resistant strains. Here, we report the results of testing this novel antiviral strategy that uses Hsc70 as a drug target to inhibit HBV.

Our previous work demonstrated that berberine (BBR) increases insulin receptor (InsR) expression and improves glucose utility both in vitro and in animal models. Here, we study the InsR-up-regulating and glucose-lowering activities of BBR in humans. Our results showed that BBR increased InsR messenger RNA and protein expression in a variety of human cell lines, including CEM, HCT-116, SW1990, HT1080, 293T, and hepatitis B virus-transfected human liver cells. Accordingly, insulin-stimulated phosphorylations of InsR beta-subunit and Akt were increased after BBR treatment in cultured cells. In the clinical study, BBR significantly lowered fasting blood glucose (FBG), hemoglobin A(1c), triglyceride, and insulin levels in patients with type 2 diabetes mellitus (T2DM). The FBG- and hemoglobin A(1c)-lowering efficacies of BBR were similar to those of metformin and rosiglitazone. In the BBR-treated patients, the percentages of peripheral blood lymphocytes that express InsR were significantly elevated after therapy. Berberine also lowered FBG effectively in chronic hepatitis B and hepatitis C patients with T2DM or impaired fasting glucose. Liver function was improved greatly in these patients by showing reduction of liver enzymes. Our results confirmed the activity of BBR on InsR in humans and its relationship with the glucose-lowering effect. Together with our previous report, we strongly suggest BBR as an ideal medicine for T2DM with a mechanism different from metformin and rosiglitazone.

Berberine (BBR) is a natural compound with up-regulating activity on both low-density-lipoprotein receptor (LDLR) and insulin receptor (InsR). This one-drug-multiple-target characteristic might be suitable for the treatment of metabolic syndrome. In searching for up-regulators effective for both LDLR and InsR expression, the structure-activity relationship (SAR) analysis for BBR analogues was done. Fourteen BBR analogues were designed, synthesized and biologically evaluated. SAR analysis revealed that appropriate modifications on the phenyl ring A or D of BBR might retain the up-regulatory activities on the expression of both LDLR and InsR. Among these compounds, compound 13a bearing 9-methoxy and 10-hydroxyl on the ring D showed promising activities on either LDLR or InsR gene expression. The 10-hydroxyl of 13a could be an arm to connect proper chemical groups for optimizing drug-bioavailability in vivo. Thus, 13a could be considered to be a parent compound to make pro-drugs for either blood lipids or glucose.

3-Haloacylamino benzoylureas (3-HBUs) consist of a new family of tubulin ligands that kill cancer cells through mitotic arrest. In exploring the structure-activity relationship (SAR), 17 analogues defined through variations of formylurea at the 1-position of the aromatic ring were synthesized. SAR analysis revealed that (i) the p-pi conjugation between the aromatic ring and formylurea was essential; (ii) suitable aryl substitutions at the N'-end increased anticancer activity with a mechanism different from that of parent compounds; and (iii) introduction of pyridyl at the N'-end provided an opportunity of making soluble salts to improve bioavailability. Among the analogues, 16c bearing 3,4,5-trimethoxyphenyl and 16g bearing 2-pyridyl at the N'-end showed an enhanced activity and were active in hepatoma cells that were resistant to tubulin ligands including the parent compounds. Furthermore, 16c and 16g killed cancer cells with a mechanism independent of mitotic arrest, indicating a change of action mode.

Natural product berberine (BBR) has been reported to have hypoglycemic and insulin-sensitizing activities; however, its mechanism remains unclear. This study was designed to investigate the molecular mechanism of BBR against insulin resistance. Here, we identify insulin receptor (InsR) as a target of BBR to increase insulin sensitivity. In cultured human liver cells, BBR increased InsR messenger RNA (mRNA) and protein expression in a dose- and time-dependent manner. Berberine increased InsR expression in the L6 rat skeletal muscle cells as well. Berberine-enhanced InsR expression improved cellular glucose consumption only in the presence of insulin. Silencing InsR gene with small interfering RNA or blocking the phosphoinositol-3-kinase diminished this effect. Berberine induced InsR gene expression through a protein kinase C (PKC)-dependent activation of its promoter. Inhibition of PKC abolished BBR-caused InsR promoter activation and InsR mRNA transcription. In animal models, treatment of type 2 diabetes mellitus rats with BBR lowered fasting blood glucose and fasting serum insulin, increased insulin sensitivity, and elevated InsR mRNA as well as PKC activity in the liver. In addition, BBR lowered blood glucose in KK-Ay type 2 but not in NOD/LtJ type 1 diabetes mellitus mice that were insulin deficient. Our results suggest that BBR is a unique natural medicine against insulin resistance in type 2 diabetes mellitus and metabolic syndrome.

A series of monobactam derivatives were prepared and evaluated for their antibacterial activities against susceptible and resistant Gram-negative strains, taking Aztreonam and BAL30072 as the leads. Six conjugates (12a-f) bearing PIH-like siderophore moieties were created to enhance the bactericidal activities against Gram-negative bacteria based on Trojan Horse strategy, and all of them displayed potencies against susceptible Gram-negative strains with MIC ≤ 8 μg/mL. SAR revealed that the polar substituents on the oxime side chain were beneficial for activities against resistant Gram-negative bacteria. Compounds 19c and 33a-b exhibited the promising potencies against ESBLs-producing E. coli and Klebsiella pneumoniae with MICs ranging from 2 μg/mL to 8 μg/mL. These results offered powerful information for further strategic optimization in search of the antibacterial candidates against MDR Gram-negative bacteria.

DNA topoisomerases play a key role in tumor proliferation. Chemotherapeutics targeting topoisomerases have been widely used in clinical oncology, but resistance and side effects, particularly cardiotoxicity, usually limit their application. Clinical data show that a decrease in topoisomerase (top) levels is the primary factor responsible for resistance, but in cells there is compensatory effect between the levels of top1 and top2α. Here, we validated cyclizing-berberine A35, which is a dual top inhibitor and preferentially targets top2α. The impact on the top2α catalytic cycle indicated that A35 could intercalate into DNA but did not interfere with DNA-top binding and top2α ATPase activity. A35 could facilitate DNA-top2α cleavage complex formation by enhancing pre-strand and post-strand cleavage and inhibiting religation, suggesting this compound can be a topoisomerase poison and had a district mechanism from other topoisomerase inhibitors. TARDIS and comet assays showed that A35 could induce cell DNA breakage and DNA-top complexes but had no effect on the cardiac toxicity inducer top2β. Silencing top1 augmented DNA break and silencing top2α decreased DNA break. Further validation in H9c2 cardiac cells showed A35 did not disturb cell proliferation and mitochondrial membrane potency. Additionally, an assay with nude mice further demonstrated A35 did not damage the heart. Our work identifies A35 as a novel skeleton compound dually inhibits topoisomerases, and predominantly and specially targets top2α by interfering with all cleavage steps and its no cardiac toxicity was verified by cardiac cells and mice heart. A35 could be a novel and effective targeting topoisomerase agent.

Aberrant expressions of the neuronal protein synuclein gamma (SNCG) in malignant mammary epithelial cells are strongly associated with the progression of breast cancer. SNCG is not expressed in normal breast tissues but abundantly expressed in a high percentage of invasive and metastatic breast carcinomas. Several studies have demonstrated that SNCG expression significantly stimulates proliferation, invasion, and metastasis of breast cancer cells. To elucidate the molecular and cellular mechanisms underlying the tumorigenic functions of SNCG, we investigated the effects of SNCG expression on the mitotic checkpoint function of breast cancer cells. By conducting several different lines of investigations, we now demonstrate that SNCG expression in breast cancer cells overrides the mitotic checkpoint control and confers the cellular resistance to anti-microtubule drug-caused apoptosis. We further show that the inhibitory effects of SNCG on mitotic checkpoint can be overthrown by enforced overexpression of the mitotic checkpoint protein BubR1 in SNCG-expressing cells. These new findings combined with our previous observation that SNCG intracellularly associates with BubR1 together suggest that SNCG expression compromises the mitotic checkpoint control by inhibition of the normal function of BubR1, thereby promoting genetic instability. Genetic instability is recognized as an important contributing factor in tumorigenesis. Hence, our studies gain insight into the mechanisms whereby SNCG expression advances breast cancer disease progression and fasters tumor metastasis.

Persistent infection with hepatitis C virus (HCV) is a major risk factor in the development of hepatocellular carcinoma. The elucidation of the pathogenesis of HCV-associated liver disease is hampered by the absence of an appropriate small animal model. Zebrafish exhibits high genetic homology to mammals, and is easily manipulated experimentally. In this study, we describe the use of a zebrafish model for the analysis of HCV replication mechanisms. As the 5' untranslated region (UTR), the core protein, the non-structural protein 5B (NS5B) and the 3'UTR are essential for HCV replication, we constructed a HCV sub-replicon gene construct including the 4 gene sequences and the enhanced green fluorescent protein (EGFP) reporter gene; these genes were transcribed through the mouse hepatocyte nuclear factor 4 (mHNF4) promoter. By microinjection of the subgenomic replicon vector into zebrafish larvae, the virus was easily detected by observing EGFP fluorescence in the liver. The positive core and NS5B signals showed positive expression of the HCV gene construct in zebrafish by reverse transcription-polymerase chain reaction (RT-PCR) and western blot analysis. Importantly, the negative strand sequence of the HCV subgenomic RNA was detected by RT-PCR and hybridization in situ, demonstrating that the HCV sub-replicon has positive replication activity. Furthermore, the hybridization signal mainly appeared in the liver region of larvae, as detected by the sense probe of the core protein or NS5B, which confirmed that the sub-replicon amplification occurred in the zebrafish liver. The amplification of the sub-replicon caused alterations in the expression of certain genes, which is similar to HCV infection in human liver cells. To verify the use of this zebrafish model in drug evaluation, two drugs against HCV used in clinical practice, ribavirin and oxymatrine, were tested and these drugs showed significant inhibition of replication of the HCV sub-replicon in the larvae. In conclusion, this zebrafish model of HCV may prove to be a novel and simple in vivo model for the study of the mechanisms of HCV replication and may also prove useful in the disovery of new anti-HCV drugs.

A series of cycloberberine derivatives were designed, synthesized and evaluated for their anti-cancer activities in vitro. Among these analogs, compounds 6c, 6e and 6g showed strong inhibition on human HepG2 cells. They afforded a potent effect against DOX-resistant MCF-7 breast cells as well. The primary mechanism showed that cell cycle was blocked at G2/M phase of HepG2 cells treated with 6g using flow cytometry assay. It significantly inhibited the activity of DNA Top I at the concentration of 0.1 mg mL-1. Our results provided a basis for the development of this kind of compounds as novel anti-cancer agents.

Using sophoridine (1) as the lead compound, a series of new N-substituted sophoridinic acid derivatives were designed, synthesized and evaluated for their cytotoxicity. SAR analysis indicated that introduction of a chlorobenzyl on the 12-nitrogen atom of sophoridinol might significantly enhance the antiproliferative activity. Of the newly synthesized compounds, sophoridinol analogue 9k exhibited a potent effect against six human tumor cell lines (liver, colon, breast, lung, glioma and nasopharyngeal). The mode of action of 9k was to inhibit the DNA topoisomerase I activity, followed by the G0/G1 phase arrest. It also showed a moderate oral bioavailability and good safety in vivo. Therefore, compound 9k has been selected as a novel-scaffold lead for further structural optimizations or as a chemical probe for exploring anticancer pathways of this kinds of compounds.

This study was designed to improve the absorption and hypoglycemic efficacy of berberine (BBR), which is a substrate of P-glycoprotein (P-gp), by combination with a P-gp inhibitor tetrandrine (Tet). Flow cytometry and LC-MS/MS were used to determine the cellular efflux or retention of chemicals. Pharmacokinetic study was performed in ICR mice following oral administration of the study compounds. The hypoglycemic efficacies of the compounds were evaluated in diabetic KK-Ay mice. In the in vitro experiments, Tet significantly inhibited the efflux and increased the uptake of P-gp substrates rhodamine-123 as well as BBR in MCF7/DOX cells and Caco-2 intestinal cells. Meanwhile, Tet greatly reduced the expression of P-gp in Caco-2 cells. The inhibition of BBR efflux by Tet was translated into improved pharmacokinetics in vivo. When co-administered, Tet dose-dependently increased the average maximum concentration (C(max)) and area under concentration-time curve (AUC₀₋₂₄) of BBR in mice. Tet itself had no impact on glucose metabolism. However, it greatly potentiated the hypoglycemic efficacy of BBR in diabetic KK-Ay mice. In addition, we found that Tet had moderate inhibitory effect on the catalytic activity of CYP3A4, which played a role in the bio-transformation of BBR, and this may also take part in the improvement of the pharmacokinetics of BBR. In summary, combination with P-gp inhibitors such as Tet can improve the pharmacokinetics and hypoglycemic efficacy of BBR greatly; this implicates a feasible strategy for exploring the therapeutic effects of BBR and other pharmaceuticals which are substrates of P-gp.

The lack of small animal models for hepatitis C virus has impeded the discovery and development of anti-HCV drugs. HCV-IRES plays an important role in HCV gene expression, and is an attractive target for antiviral therapy. In this study, we report a zebrafish model with a biscistron expression construct that can co-transcribe GFP and HCV-core genes by human hepatic lipase promoter and zebrafish liver fatty acid binding protein enhancer. HCV core translation was designed mediated by HCV-IRES sequence and gfp was by a canonical cap-dependent mechanism. Results of fluorescence image and in situ hybridization indicate that expression of HCV core and GFP is liver-specific; RT-PCR and Western blotting show that both core and gfp expression are elevated in a time-dependent manner for both transcription and translation. It means that the HCV-IRES exerted its role in this zebrafish model. Furthermore, the liver-pathological impact associated with HCV-infection was detected by examination of gene markers and some of them were elevated, such as adiponectin receptor, heparanase, TGF-β, PDGF-α, etc. The model was used to evaluate three clinical drugs, ribavirin, IFNα-2b and vitamin B12. The results show that vitamin B12 inhibited core expression in mRNA and protein levels in dose-dependent manner, but failed to impact gfp expression. Also VB12 down-regulated some gene transcriptions involved in fat liver, liver fibrosis and HCV-associated pathological process in the larvae. It reveals that HCV-IRES responds to vitamin B12 sensitively in the zebrafish model. Ribavirin did not disturb core expression, hinting that HCV-IRES is not a target site of ribavirin. IFNα-2b was not active, which maybe resulted from its degradation in vivo for the long time. These findings demonstrate the feasibility of the zebrafish model for screening of anti-HCV drugs targeting to HCV-IRES. The zebrafish system provides a novel evidence of using zebrafish as a HCV model organism.