Advances in targeting histone deacetylase for treatment of solid tumors.

Histone deacetylase (HDAC) serves as a critical molecular regulator in the pathobiology of various malignancies and have garnered attention as a viable target for therapeutic intervention. A variety of HDAC inhibitors (HDACis) have been developed to target HDACs. Many preclinical studies have conclusively demonstrated the antitumor effects of HDACis, whether used as monotherapy or in combination treatments. On this basis, researchers have conducted various clinical studies to evaluate the potential of selective and pan-HDACis in clinical settings. In our work, we extensively summarized and organized current clinical trials, providing a comprehensive overview of the current clinical advancements in targeting HDAC therapy. Furthermore, we engaged in discussions about several clinical trials that did not yield positive outcomes, analyzing the factors that led to their lack of anticipated therapeutic effectiveness. Apart from the experimental design factors, issues such as toxicological side effects, tumor heterogeneity, and unexpected off-target effects also contributed to these less-than-expected results. These challenges have naturally become significant barriers to the application of HDACis. Despite these challenges, we believe that advancements in HDACi research and improvements in combination therapies will pave the way or lead to a broad and hopeful future in the treatment of solid tumors.

Chiglitazar Preferentially Regulates Gene Expression via Configuration-Restricted Binding and Phosphorylation Inhibition of PPARγ.

Type 2 diabetes mellitus is often treated with insulin-sensitizing drugs called thiazolidinediones (TZD), which improve insulin resistance and glycemic control. Despite their effectiveness in treating diabetes, these drugs provide little protection from eminent cardiovascular disease associated with diabetes. Here we demonstrate how chiglitazar, a configuration-restricted non-TZD peroxisome proliferator-activated receptor (PPAR) pan agonist with moderate transcription activity, preferentially regulates ANGPTL4 and PDK4, which are involved in glucose and lipid metabolism. CDK5-mediated phosphorylation at serine 273 (S273) is a unique regulatory mechanism reserved for PPARγ, and this event is linked to insulin resistance in type 2 diabetes mellitus. Our data demonstrates that chiglitazar modulates gene expression differently from two TZDs, rosiglitazone and pioglitazone, via its configuration-restricted binding and phosphorylation inhibition of PPARγ. Chiglitazar induced significantly greater expression of ANGPTL4 and PDK4 than rosiglitazone and pioglitazone in different cell models. These increased expressions were dependent on the phosphorylation status of PPARγ at S273. Furthermore, ChIP and AlphaScreen assays showed that phosphorylation at S273 inhibited promoter binding and cofactor recruitment by PPARγ. Based on these results, activities from pan agonist chiglitazar can be an effective part of a long-term therapeutic strategy for treating type 2 diabetes in a more balanced action among its targeted organs.

CS2164, a novel multi-target inhibitor against tumor angiogenesis, mitosis and chronic inflammation with anti-tumor potency.

Although inhibitors targeting tumor angiogenic pathway have provided improvement for clinical treatment in patients with various solid tumors, the still very limited anti-cancer efficacy and acquired drug resistance demand new agents that may offer better clinical benefits. In the effort to find a small molecule potentially targeting several key pathways for tumor development, we designed, discovered and evaluated a novel multi-kinase inhibitor, CS2164. CS2164 inhibited the angiogenesis-related kinases (VEGFR2, VEGFR1, VEGFR3, PDGFRα and c-Kit), mitosis-related kinase Aurora B and chronic inflammation-related kinase CSF-1R in a high potency manner with the IC50 at a single-digit nanomolar range. Consequently, CS2164 displayed anti-angiogenic activities through suppression of VEGFR/PDGFR phosphorylation, inhibition of ligand-dependent cell proliferation and capillary tube formation, and prevention of vasculature formation in tumor tissues. CS2164 also showed induction of G2/M cell cycle arrest and suppression of cell proliferation in tumor tissues through the inhibition of Aurora B-mediated H3 phosphorylation. Furthermore, CS2164 demonstrated the inhibitory effect on CSF-1R phosphorylation that led to the suppression of ligand-stimulated monocyte-to-macrophage differentiation and reduced CSF-1R+ cells in tumor tissues. The in vivo animal efficacy studies revealed that CS2164 induced remarkable regression or complete inhibition of tumor growth at well-tolerated oral doses in several human tumor xenograft models. Collectively, these results indicate that CS2164 is a highly selective multi-kinase inhibitor with potent anti-tumor activities against tumor angiogenesis, mitosis and chronic inflammation, which may provide the rationale for further clinical assessment of CS2164 as a therapeutic agent in the treatment of cancer.

Follow-up and evaluation of the pregnancy outcome in women of reproductive age with Graves' disease after 131Iodine treatment.

The aims of the present study were to analyze the outcomes of pregnancy, after 131I treatment, in patients of reproductive age with Graves' hyperthyroidism and to investigate the effects, if any, of the 131I treatment on the mothers and newborns. From 2009 to 2014, 257 pregnant female patients with Graves' hyperthyroidism in the outpatients at the Department of Nuclear Medicine and 166 healthy pregnant women from the Department of Obstetrics at Sun Yat-Sen Memorial Hospital were included in our study. They were divided into a 131I therapy group (n = 130) and an anti-thyroid drug (ATD) group (n = 127) according to their therapy before conception. The neonatal gender, rate of preterm birth, body weight ratio and occurrence of low birth weight [except for higher rates of abortion (odds ratio; OR = 2.023) and cesarean delivery (OR = 1.552) in patients with Graves' hyperthyroidism] showed no statistically significant differences from those of the healthy group (P > 0.05). The level of intrauterine growth restriction did not differ between the Graves' hyperthyroidism group and the healthy group (8 vs 2, 3.0% vs 1.2%). The outcomes of pregnancy among the 131I therapy group, ATD group and healthy group also showed no significant differences. Of the patients treated with 131I, no significant differences were observed in the outcomes of their pregnancies, whether they received propylthiouracil (PTU), levothyroxine or no additional drug treatment during pregnancy. Women with hyperthyroidism who were treated with 131I therapy could have normal delivery if they ceased 131I treatment for at least six months prior to conception and if their thyroid function was reasonably controlled and maintained using the medication: anti-thyroid drug and levothyroxine before and during pregnancy.

Non-toxic dose chidamide synergistically enhances platinum-induced DNA damage responses and apoptosis in Non-Small-Cell lung cancer cells.

Combination of low doses of histone deacetylases inhibitors and chemotherapy drugs is considered as one of the most promising strategies to increase the anticancer efficacy. Chidamide is a novel benzamide chemical class of HDAC inhibitor that selectively inhibited HDAC1, 2, 3 and 10. We sought to determine whether chidamide may enhance platinum-induced cytotoxicity in NSCLC cells. In this study, the combination of chidamide with carboplatin showed a good synergism on growth inhibition with the mean combination index value as 0.712 and 0.639 in A549 and NCI-H157 cells, respectively. The used concentration of chidamide was non-toxic on cells by itself as low as 0.3µM. All of our experiments were comparisons between combination regimen and single carboplatin regimen in A549 and NCI-H157 cell lines. Phosphorylated histone H2A.X (γH2A.X), a hall marker of DNA damage response, was dramatically increased by the combination treatment. Cell cycle analysis by flow cytometry and phosphorylation level analysis of histone H3 (Ser10) by western blotting showed that combination treatment significantly increased the percentage of G2/M phase of cells. Mitochondrial membrane potential and cleaved-PARP1 level analysis indicate that chidamide synergistically enhances carboplatin-induced apoptosis. Additionally, synergistic effects of chidamide were found when it was combined with two other platinum drugs (cisplatin and oxaliplatin). The results suggest that Chidamide in combination with platinum drugs may be a novel therapeutic option for NSCLC.

Phase I study of chidamide (CS055/HBI-8000), a new histone deacetylase inhibitor, in patients with advanced solid tumors and lymphomas.

PURPOSE: Chidamide (CS055/HBI-8000) is a new benzamide class of histone deacetylase inhibitor with marked anti-tumor activity. This study reports the phase I results. METHODS: Patients with advanced solid tumors or lymphomas received oral doses of 5, 10, 17.5, 25, 32.5, or 50 mg chidamide either twice (BIW) or three times (TIW) per week for 4 consecutive weeks every 6 weeks. Safety, characteristics of pharmacokinetics (PK) and pharmacodynamics (PD), and preliminary efficacy were evaluated. RESULTS: A total of 31 patients were enrolled. No DLTs were identified in the BIW cohorts up to 50 mg. DLTs were grade 3 diarrhea and vomiting in two patients in the TIW cohort at 50 mg, respectively. PK analysis revealed t(1/2) of 16.8-18.3 h, T(max) of 1-2 h in most cases, and a dose-related increase in C(max) and AUC. Significant induction of histone H3 acetylation in peripheral white blood cells was observed after a single dose of chidamide. Four patients with T-cell lymphomas and 1 patient with submandibular adenoid cystic carcinoma achieved a partial response. CONCLUSIONS: Chidamide was generally well tolerated in patients with advanced solid tumors or lymphomas in the tested regimens. Favorable PK and PD profiles, as well as encouraging preliminary anti-tumor activity, were demonstrated.

Chidamide (CS055/HBI-8000): a new histone deacetylase inhibitor of the benzamide class with antitumor activity and the ability to enhance immune cell-mediated tumor cell cytotoxicity.

PURPOSE: Chidamide (CS055/HBI-8000) is a new histone deacetylase (HDAC) inhibitor of the benzamide class currently under clinical development in cancer indications. This study reports the in vitro and in vivo antitumor characteristics of the compound. METHODS: Selectivity and potency of chidamide in inhibition of HDAC isotypes were analyzed by using a panel of human recombinant HDAC proteins. Tumor cell lines either in culture or inoculated in nude mice were used for the evaluation of the compound's antitumor activity. To investigate the immune cell-mediated antitumor effect, isolated peripheral blood mononuclear cells from healthy donors were treated with chidamide, and cytotoxicity and expression of relevant surface proteins were analyzed. Microarray gene expression studies were performed on peripheral white blood cells from two T-cell lymphoma patients treated with chidamide. RESULTS: Chidamide was found to be a low nanomolar inhibitor of HDAC1, 2, 3, and 10, the HDAC isotypes well documented to be associated with the malignant phenotype. Significant and broad spectrum in vitro and in vivo antitumor activity, including a wide therapeutic index, was observed. Chidamide was also shown to enhance the cytotoxic effect of human peripheral mononuclear cells ex vivo on K562 target cells, accompanied by the upregulation of proteins involved in NK cell functions. Furthermore, the expression of a number of genes involved in immune cell-mediated antitumor activity was observed to be upregulated in peripheral white blood cells from two T-cell lymphoma patients who responded to chidamide administration. CONCLUSIONS: The results presented in this study provide evidence that chidamide has potential applicability for the treatment of a variety of tumor types, either as a single agent or in combination therapies.

Relationship between cerebral hypoxic tissue volume and prognosis after stroke.

BACKGROUND/AIMS: Between 50 and 70% of stroke survivors suffer from severe disabilities such as paralysis and aphasia. Poor stroke outcome is a reflection of our incomplete understanding of the underlying mechanisms, and hence the capacity to implement appropriate treatment(s). We evaluated hypoxic tissue after stroke and patient condition severity and prognosis. METHODS: Hypoxic tissue volume was quantified within 14 days after stroke. Patients were classified as hypoxic positive or negative. Patients were evaluated at imaging and 21 days later. Prognosis was assessed at 30 and 90 days. RESULTS: Significant improvement was shown in hypoxia-positive (vs. hypoxia-negative) patients (p < 0.05). There were significant positive relationships between the volume of hypoxic tissue and the improvement in specialized test scores at 90 days (p < 0.05 for both). Presence of hypoxic tissue within 14 days after cerebral stroke was related to recovery at 3 weeks and prognosis at 90 days. CONCLUSIONS: The assessment of hypoxic tissue volume after stroke may be useful in predicting patient recovery.

Naringenin and hesperetin, two flavonoids derived from Citrus aurantium up-regulate transcription of adiponectin.

The dried, immature fruit of Citrus aurantium L., 'Zhiqiao' in Chinese, has been used to treat cardiovascular diseases in traditional Chinese medicine for centuries. Naringenin and hesperetin and their glycosides present in considerable amounts (about 10 approximately 15%) in the herb. The aim of this study is to test whether naringenin and hesperetin influence adiponectin expression, which plays an important role in glucose and lipid metabolism with antiatherogenic and anti-inflammatory properties. Treatment with naringenin and hesperetin enhanced adiponectin transcription in differentiated 3T3-L1 cells. Both naringenin and hesperetin induced peroxisome proliferator-activated receptor (PPAR)gamma-controlled luciferase expression in a dose-dependent manner (20-160 microM), whereas only naringenin possessed significant activity to activate PPARalpha. These results suggested the two flavonoids might exert antiatherogenic effects partly through activating PPAR and up-regulating adiponectin expression in adipocytes. Our findings give new insight for the molecular explanations for the therapeutic effects of Zhiqiao.

[Preliminary study on the value of 99Tc(m)-HL91 imaging in predicting sensitivity to radiotherapy in patients with nasopharyngeal carcinoma].

OBJECTIVE: To investigate the feasibility of 9Tc(m)-HL91 imaging in prediction of 34 radiotherapy sensitivity of naqsopharyngeal cancer( NPC) and its relationship with prognosis. METHODS: patients with NPC confirmed by pathology, staging from II-IVa, underwent 99Tc(m)-HL91 SPECT imaging one week before radiotherapy. 18 of them received adjuvant chemotherapy. The hypoxia in primary nasopharyngeal lesions and cervical lymph node metastases were calculated semi-quantitatively, and compared with clinical findings in medium-term therapy at 4 months and 1 year post therapy. RESULTS: (1) There was no significant relationship between the total preliminary curative effect of adjuvant chemotherapy and the degree of nasopharyngeal lesion hypoxia (T/Mu, gamma = -0.394, P = 0.145; T/ Ce gamma = -0.510, P = 0.052). But there was a significant difference between the partial curative effect group and significant curative effect group. (2) The degree of NPC regression in the medium-term radiotherapy group was negatively correlated with the degree of hypoxia (T/Mu, gamma = -0.602; T/Ce, gamma = -0.643, P < 0.01). (3) 23 patients had good local control except one case with lung and bone metastasis 4 months post-therapy. The lesions disappeared or not developed in 6 patients (T/Mu 1.30 +/- 0.23, T/Ce 3.61 +/- 0.84). Two patients at stage III and IVa relapsed (T/Mu were 1.40 and 1.27, respectively; T/Ce were 4.10 and 3.85, respectively), there was no significant difference. (4) The degree of lymph node hypoxia had no correlation with the curative effect on medium-term radiotherapy. CONCLUSION: 99 Tc(m)-HL91 hypoxia imaging may predict sensitivity to radiotherapy in patients with NPC, with a potential help to carry out individual therapy. However, further investigation is needed to ascertain whether it could predict the long-time curative effect on NPC radiotherapy.

[Biodistribution of (99m)Tc-labeled anti-VEGF mAb 5-FU loaded polylactic acid nanoparticles in human gastric carcinoma xenografts].

OBJECTIVE: To prepare (99m)Tc-labeled Anti-VEGF mAb 5-FU loaded polylactic acid nanoparticles ((99m)Tc-Ab-5-FU-NPs) and investigate its biodistribution in human gastric carcinoma xenografts. METHODS: (99m)Tc-Ab-5-FU-NPs were prepared by labeling Ab-5-FU-NPs with (99m)Tc using improved Schwarz method. After isolation of (99m)Tc-Ab-5-FU-NPs using SephadexG250 column, the labeling ratio and radiochemical purity were determined using chromatography. The immunocompetence of (99m)Tc- Ab-5-FU-NPs was detected by ELISA and immunohistochemistry. (99m)Tc-Ab-5-FU-NPs were then injected via the tail vein into SCID mice bearing human gastric carcinoma, and (99m)Tc labeled mice-derived monoclonal IgG loaded polylactic acid nanoparticles were used as the control, followed by radioimmunoscintigraphic imaging at 2 and 6 h. The radioactive count and radioactive ratio of the tumor and non-tumor tissue (T/NT) in the animal models were calculated using ROI technique. After imaging at 24 h, SCID mice were sacrificed and the radioactive distribution, the %ID/g, as well as the T/NT radioactive ratio were examined, respectively. The concentrations of 5-FU in the tumor and blood were also detected using HPLC method. RESULTS: The labeling ratio of (99m)Tc-Ab-5-FU-NPs was 90%-95%. (99m)Tc-Ab-5-FU-NPs were detected in the tumor tissues by radioimmunoimaging 2 h after the injection. ID%/g in the tumor tissues at 2 and 6 h were both significantly higher than that of the control group. Both the ID%/g in tumor tissues and radioactive ratio of tumor and blood at 6 h were higher than those at 2 h, and the concentration of 5-FU in experimental group increased continuously with time and was significantly higher than that in control group. CONCLUSIONS: (99m)Tc-Ab-5-FU-NPs prepared in this study can meet the demands of radioimmunoimaging, and the anti-VEGF monoclonal antibody possesses reliable immune targeting ability. Six hours after injection, (99m)Tc-Ab-5-FU-NPs can specifically accumulate in the tumor tissues in human gastric carcinoma xenografts at high concentration.

The PPARalpha/gamma dual agonist chiglitazar improves insulin resistance and dyslipidemia in MSG obese rats.

1. The aim of this study was to investigate the capacity of chiglitazar to improve insulin resistance and dyslipidemia in monosodium L-glutamate (MSG) obese rats and to determine whether its lipid-lowering effect is mediated through its activation of PPARalpha. 2. Chiglitazar is a PPARalpha/gamma dual agonist. 3. The compound improved impaired insulin and glucose tolerance; decreased plasma insulin level and increased the insulin sensitivity index and decreased HOMA index. Euglycemic hyperinsulinemic clamp studies showed chiglitazar increased the glucose infusion rate in MSG obese rats. 4. Chiglitazar inhibited alanine gluconeogenesis, lowered the hepatic glycogen level in MSG obese rats. Like rosiglitazone, chiglitazar promoted the differentiation of adipocytes and decreased the maximal diameter of adipocytes. In addition, chiglitazar decreased the fibrosis and lipid accumulation in the islets and increased the size of islets. 5. Chiglitazar reduced plasma triglyceride, total cholesterol (TCHO), nonesterified fatty acids (NEFA) and low density lipoprotein-cholesterol levels; lowered hepatic triglyceride and TCHO contents; decreased muscular NEFA level. Unlike rosiglitazone, chiglitazar showed significant increase of mRNA expression of PPARalpha, CPT1, BIFEZ, ACO and CYP4A10 in the liver of MSG obese rats. 6. These data suggest that PPARalpha/gamma coagonist, such as chiglitazar, affect lipid homeostasis with different mechanisms from rosiglitazone, chiglitazar may have better effects on lipid homeostasis in diabetic patients than selective PPARgamma agonists.

Peroxisome proliferator-activated receptor-gamma transcriptionally up-regulates hormone-sensitive lipase via the involvement of specificity protein-1.

Both peroxisome proliferator-activated receptor (PPAR)-gamma and hormone-sensitive lipase (HSL) play important roles in lipid metabolism and insulin sensitivity. We demonstrate that expression of the HSL gene is up-regulated by PPARgamma and PPARgamma agonists (rosiglitazone and pioglitazone) in the cultured hepatic cells and differentiating preadipocytes. Rosiglitazone treatment also results in up-regulation of the HSL gene in liver and skeleton muscle from an experimental obese rat model, accompanied by the decreased triglyceride content in these tissues. The proximal promoter (-87 bp of the human HSL gene) was found to be essential for PPARgamma-mediated transactivating activity. This important promoter region contains two GC-boxes and binds the transcription factor specificity protein-1 (Sp1) but not PPARgamma. The Sp1-promoter binding activity can be endogenously enhanced by PPARgamma and rosiglitazone, as demonstrated by analysis of EMSA and chromatin immunoprecipitation assay. Mutations in the GC-box sequences reduce the promoter binding activity of Sp1 and the transactivating activity of PPARgamma. In addition, mithramycin A, the specific inhibitor for Sp1-DNA binding activity, abolishes the PPARgamma-mediated up-regulation of HSL. These results indicate that PPARgamma positively regulates the HSL gene expression, and up-regulation of HSL by PPARgamma requires the involvement of Sp1. Taken together, this study suggests that HSL may be a newly identified PPARgamma target gene, and up-regulation of HSL may be an important mechanism involved in action of PPARgamma agonists in type 2 diabetes.

Phthalide Lactones from Ligusticum chuanxiong inhibit lipopolysaccharide-induced TNF-alpha production and TNF-alpha-mediated NF-kappaB Activation.

The dried rhizome of Ligusticum chuanxiong Hort. (Umbelliferae) is a traditional Chinese medicine (TCM) herb for the prevention and treatment of inflammatory and cardiovascular diseases. However, the role of phthalide lactones from Ligusticum chuanxiong in the therapeutic actions is not yet fully understood. In the present study, two phthalide lactones from the herb, Z-ligustilide and senkyunolide A, were identified and characterized as inhibitors of lipopolysaccharide (LPS)-induced TNF-alpha production in monocytes. The results of gene expression studies showed that the observed TNF-alpha suppression was related to their inhibitory activity on TNF-alpha mRNA transcription. Furthermore, the two phthalides exhibited significant suppressive effects on TNF-alpha-mediated nuclear factor-kappaB (NF-kappaB) activation in reporter gene assays. Taken together, the results suggest that Z-ligustilide and senkyunolide A may have potential applications in the treatment of inflammation and related diseases based on their inhibitory activity on TNF-alpha production and TNF-alpha bioactivity. New insights into the therapeutic basis of the TCM herb, Ligusticum chuanxiong, are presented.

A new retinoid-like compound that activates peroxisome proliferator-activated receptors and lowers blood glucose in diabetic mice.

Retinoid X receptor (RXR) forms heterodimers with peroxisome proliferator-activated receptors (PPARs, with subtypes of alpha, delta and gamma), and the heterodimers can be activated by either an RXR or a PPAR subtype-specific ligand. Based on the chemical structure of the RXR natural ligand, 9-cis-retinoic acid (9-cis-RA), we designed and synthesized a retinoid-like compound, CS018. In vitro characterizations by cell-based reporter gene assays indicated that CS018 activated RXR homodimers and the heterodimers of RXR with PPARs, but not with farnesoid X-activated receptor (FXR) and liver X-activated receptor (LXR). Furthermore, RT-PCR results showed that CS018 induced the expression of the PPARgamma target genes, CD36 and lipoprotein lipase (LPL). In vivo studies on the diabetic db/db mice demonstrated that CS018 dramatically lowered the animal blood glucose levels. CS018 thus may represent a new retinoid-like compound that activates RXR/PPARs and has potential therapeutic applications in type 2 diabetes and other metabolic diseases.

[Clinical value of combined therapy with 188Re-HEDP and pamidronate in breast cancer with bone metastasis].

OBJECTIVE: To evaluate the clinical therapeutic value of (188)Re-HEDP combined with pamidronate in breast cancer with bone metastasis. METHODS: Forty-eight patients with breast cancer with multi-bone metastases were randomly divided into three groups:15 patients received (188)Re-HEDP (group A), 15 patients received pamidronate (group B) and 18 patients were treated by (188)Re-HEDP plus pamidronate (group C). RESULTS: The overall pain relief rate was 73.3%, 80.0%, 100.0% in groups A, B and C. The response rate of bone metastasis was 40.0%, 33.3%, 66.7% in groups A, B and C respectively. The therapeutic effect of group C was better than those of groups A and B (P < 0.05), without any significance in the difference (P > 0.05). CONCLUSION: The therapeutic effect of (188)Re-HEDP combined with pamidronate for breast cancer with bone metastasis is remarkable in bone pain relief and bone metastasis control, which is better than either (188)Re-HEDP or pamidronate alone.

Construction of a virtual combinatorial library using SMILES strings to discover potential structure-diverse PPAR modulators.

Based on the structural characters of PPAR modulators, a virtual combinatorial library containing 1226,625 compounds was constructed using SMILES strings. Selected ADME filters were employed to compel compounds having poor drug-like properties from this library. This library was converted to sdf and mol2 files by CONCORD 4.0, and was then docked to PPARgamma by DOCK 4.0 to identify new chemical entities that may be potential drug leads against type 2 diabetes and other metabolic diseases. The method to construct virtual combinatorial library using SMILES strings was further visualized by Visual Basic.net that can facilitate the needs of generating other type virtual combinatorial libraries.

Design, synthesis, and evaluation of a new class of noncyclic 1,3-dicarbonyl compounds as PPARalpha selective activators.

Lipid accumulation in nonadipose tissues is increasingly linked to the development of type 2 diabetes in obese individuals. We report here the design, synthesis, and evaluation of a series of novel PPARalpha selective activators containing 1,3-dicarbonyl moieties. Structure-activity relationship studies led to the identification of PPARalpha selective activators (compounds 10, 14, 17, 18, and 21) with stronger potency and efficacy to activate PPARalpha over PPARgamma and PPARdelta. Experiments in vivo showed that compounds 10, 14, and 17 had blood glucose lowering effect in diabetic db/db mouse model after two weeks oral dosing. The data strongly support further testing of these lead compounds in other relevant disease animal models to evaluate their potential therapeutic benefits.

3D QSAR studies on peroxisome proliferator-activated receptor gamma agonists using CoMFA and CoMSIA.

The peroxisome proliferator-activated receptors (PPARs) have increasingly become attractive targets for developing novel anti-type 2 diabetic drugs. We employed comparative molecular field analysis (CoMFA) and comparative molecular similarity indices analysis (CoMSIA) to study three-dimensional quantitative structure-activity relationship (3D QSAR) based on existing agonists of PPARgamma (including five thiazolidinediones and 74 tyrosine-based compounds). Predictive 3D QSAR models with conventional r2 and cross-validated coefficient (q2) values up to 0.974 and 0.642 for CoMFA and 0.979 and 0.686 for COMSIA were established using the SYBYL package. These models were validated by a test set containing 18 compounds. The CoMFA and CoMSIA field distributions are in general agreement with the structural characteristics of the binding pockets of PPARgamma, which demonstrates that the 3D QSAR models built here are very useful in predicting activities of novel compounds for activating PPARgamma.