CS12192, a novel JAK3/JAK1/TBK1 inhibitor, attenuates autoimmune dermatoses in murine models.

OBJECTIVE: Autoimmune dermatosis (AID) occurs when the body's immune system attacks skin or tissue, leading to various types of skin disorders or injuries. Recent studies show that Janus kinases (JAKs) play critical roles in autoimmune diseases including AID by regulating multiple cytokine signaling pathways. CS12192, a novel JAK3/JAK1/TBK1 inhibitor, has been reported to exert ameliorative effects in rheumatoid arthritis. However, the efficacy of CS12192 on AID is undetermined. This study aims to investigate the therapeutic efficacy of CS12192 on psoriasis (PSO), systemic lupus erythematosus (SLE) and atopic dermatitis (AD) in mouse models. METHODS: Interleukin-23 (IL-23)-induced PSO model, spontaneous SLE model of MRL/MpJ-Faslpr/J (MRL/lpr) mice, and oxazolone (OXA) and dinitrochlorobenzene (DNCB)-induced murine AD models were used for the evaluation of curative effects of CS12192, respectively. The skin lesion, biochemical parameters, ear thickness, ear weight and histopathology were assessed accordingly. RESULTS: In PSO model, mice treated with CS12192 show reduced ear thickness and ear weight as compared with vehicle. In SLE model, CS12192 ameliorates cutaneous parameters such as lymphadenectasis and skin lesion but not systematic parameters such as proteinuria concentration and score, serum dsDNA and BUN concentration. In AD models, CS12192 dose-dependently improves ear swelling and reduces histological scores, exerting equivalent efficacy with baricitinib, a marketed JAK1/JAK2 inhibitor. CONCLUSION: Our findings suggest that the novel JAK3/JAK1/TBK1 inhibitor CS12192 is potentially to alleviate autoimmune dermatosis.

Antitumor and immunomodulatory effects of a novel multitarget inhibitor, CS2164, in mouse hepatocellular carcinoma models.

As a novel orally active multitarget small molecule inhibitor, CS2164 has shown broad antitumor activities against several human tumor xenograft models in immune-compromised mice. However, the ability of CS2164 to modulate antitumor immunity in an immune-competent mouse tumor model remains undefined, although antiangiogenic treatment has been reported to affect immune cell infiltration and remodel the tumor immune microenvironment. In the present study, the subcutaneous and ascites hepatocellular carcinoma (HCC) models in syngeneic Balb/c mice established by inoculation of an H22 hepatoma cell line were utilized to investigate the antitumor and immunomodulatory effects of CS2164. Although the antitumor effects of CS2164 were validated in both subcutaneous and ascites HCC models in syngeneic mice, CS2164 treatment consistently modulated immune cell populations, both in the periphery and in tumor microenvironments, with upregulation of CD4 and CD8 T cells in the spleen, but downregulation of immunosuppressive populations including regulatory T cells, myeloid-derived suppressor cells, and tumor-associated macrophages in the spleen and tumor tissues. Furthermore, CS2164 increased the relative gene expression and protein production of several proinflammatory cytokines in tumor-related ascites. These results indicate that CS2164 exerts an antitumor effect associated with its immunomodulatory activities in mouse HCC models, and may also provide evidence for the immunotherapy potentiation of CS2164 in future cancer treatment.

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.

Impact of chiglitazar on glycemic control in type 2 diabetic patients with metabolic syndrome and insulin resistance: A pooled data analysis from two phase III trials.

BACKGROUND: To evaluate the glycemic control effects of vhiglitazar (carfloglitazar), a novel peroxisome proliferator-activated receptor pan-agonist, in patients with type 2 diabetes mellitus (T2DM) with metabolic syndrome (MetS) or insulin resistance (IR) using pooled data analysis of two phase III clinical trials. METHODS: Data were collected from two randomized phase III clinical trials in China, comparing chiglitazar to placebo or sitagliptin in T2DM patients. The MetS was defined by the Adult Treatment Panel III MetS criteria, and IR was defined by homeostatic model assessment for insulin resistance (HOMA-IR) ≥4.31 (male) or 4.51 (female). The main end point of this analysis was glycemic control in the different arms within each subgroup. RESULTS: In the MetS subgroup, changes in glycated hemoglobin (HbA1c) from baseline at week 24 in the chiglitazar 32 mg, chiglitazar 48 mg, and sitagliptin 100 mg arms were -1.44%, -1.68%, and -1.37%, respectively; p < .05 was obtained when chiglitazar 48 mg was compared with sitagliptin. In the IR subgroup, the changes in HbA1c were -1.58%, -1.56%, and -1.26% in chiglitazar 32 mg, chiglitazar 48 mg, and sitagliptin 100 mg arms, respectively; p < .05 was obtained when chiglitazar 32 mg was compared with sitaligptin. The two doses of chiglitazar demonstrated a greater reduction in fasting plasma glucose and 2 h postprandial plasma glucose than sitagliptin in the pooled population and in the MetS and IR subgroups. CONCLUSIONS: Chiglitazar shows promising efficacy for glycemic control in patients with T2DM associated with MetS or IR. Further prospective trials are required to validate these findings.

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.

Plasma proteome profiling reveals the therapeutic effects of the PPAR pan-agonist chiglitazar on insulin sensitivity, lipid metabolism, and inflammation in type 2 diabetes.

Chiglitazar is a novel peroxisome proliferator-activated receptor (PPAR) pan-agonist, which passed phase III clinical trials and was newly approved in China for use as an adjunct to diet and exercise in glycemic control in adult patients with Type 2 Diabetes (T2D). To explore the circulating protein signatures associated with the administration of chiglitazar in T2D patients, we conducted a comparative longitudinal study using plasma proteome profiling. Of the 157 T2D patients included in the study, we administered chiglitazar to a specific group, while the controls were given either placebo or sitagliptin. The plasma proteomes were profiled at baseline and 12 and 24 weeks post-treatment using data-independent acquisition mass spectrometry (DIA-MS). Our study indicated that 13 proteins were associated with chiglitazar treatment in T2D patients, including 10 up-regulated proteins (SHBG, TF, APOA2, APOD, GSN, MBL2, CFD, PGLYRP2, A2M, and APOA1) and 3 down-regulated proteins (PRG4, FETUB, and C2) after treatment, which were implicated in the regulation of insulin sensitivity, lipid metabolism, and inflammation response. Our study provides insight into the response of chiglitazar treatment from a proteome perspective and demonstrates the multi-faceted effects of chiglitazar in T2D patients, which will help the clinical application of chiglitazar and further study of its action mechanism.

CS27109, A Selective Thyroid Hormone Receptor-ß Agonist Alleviates Metabolic-Associated Fatty Liver Disease in Murine Models.

Background/Aim: Thyroid hormone receptor-ß (THR-ß) agonists play crucial roles in dyslipidemia and metabolic associated fatty liver disease (MAFLD). We developed a novel oral and liver-targeted THR-ß agonist, CS27109, and evaluated its efficacy in the treatment of metabolic disorders. Materials and Methods: We evaluated in vitro and in vivo efficacy and/or safety of CS27109 along with MGL3196 (a phase III THR-ß agonist). Results: CS27109 showed pronounced activity and selectivity to THR-ß and favorable PK properties, which was equivalent to MGL3196. In the hamster model, animals treated with a high dose of CS27109 showed equivalent reductions in serum TC and LDL-c with groups treated with MGL3196. In the rat model, CS27109 and MGL3196 reduced serum ALT, TC, TG, LDL-c, liver weight ratio, and liver steatosis. CS27109 simultaneously decreased liver TG and TC, and MGL3196 additionally reduced AST. In the mouse model, CS27109 dose-dependently reduced serum AST, ALT, liver inflammation, and NAS score, and also downregulated TC, LDL-c, liver steatosis, and fibrosis, but not in a dose-dependent manner. MGL3196 revealed an equivalent effect with CS27109 in that model. CS27109 also exhibited tolerable toxicity to the heart. Conclusions: CS27109 shows comparative in vitro and in vivo efficacy with MGL3196, suggesting its potential therapeutic application in the treatment of MAFLD such as dyslipidemia and steatohepatitis.

Therapeutic potential of tucidinostat, a subtype-selective HDAC inhibitor, in cancer treatment.

Histone deacetylase (HDAC) is one of the most characterized epigenetic modifiers, modulating chromatin structure and gene expression, which plays an important role in cell cycle, differentiation and apoptosis. Dysregulation of HDAC promotes cancer progression, thus inhibitors targeting HDACs have evidently shown therapeutic efficacy in multiple cancers. Tucidinostat (formerly known as chidamide), a novel subtype-selective HDAC inhibitor, inhibits Class I HDAC1, HDAC2, HDAC3, as well as Class IIb HDAC10. Tucidinostat is approved in relapsed or refractory (R/R) peripheral T-cell lymphoma (PTCL), advanced breast cancer and R/R adult T-cell leukemia-lymphoma (ATLL). Compared with other HDAC inhibitors, tucidinostat shows notable antitumor activity, remarkable synergistic effect with immunotherapy, and manageable toxicity. Here, we comprehensively summarize recent advances in tucidinostat as both monotherapy and a regimen of combination therapy in both hematological and solid malignancies in clinic. Further studies will endeavor to identify more combination strategies with tucidinostat and to identify specific clinical biomarkers to predict the therapeutic effect.

Application of p21 and klf2 reporter gene assays to identify selective histone deacetylase inhibitors for cancer therapy.

Novel 2-aminoanilide histone deacetylase (HDAC) inhibitors were designed to increase their contact with surface residues surrounding the HDAC active site compared to the contacts made by existing clinical 2-aminoanilides such as SNDX-275, MGCD0103, and Chidamide. Their HDAC selectivity was assessed using p21 and klf2 reporter gene assays in HeLa and A204 cells, respectively, which provide a cell-based readout for the inhibition of HDACs associated either with the p21 or klf2 promoter. A subset of the designed compounds selectively induced p21 over klf2 relative to the clinical reference compound SNDX-275. A representative lead compound from this subset had antiproliferative effects in cancer cells associated with induction of acetylated histone H4, endogenous p21, cell cycle arrest, and apoptosis. The p21- versus klf2-selective compounds described herein may provide a chemical starting point for developing clinically-differentiated HDAC inhibitors for cancer therapy.

Chidamide and Radiotherapy Synergistically Induce Cell Apoptosis and Suppress Tumor Growth and Cancer Stemness by Regulating the MiR-375-EIF4G3 Axis in Lung Squamous Cell Carcinomas.

As a selective histone deacetylase (HDAC) inhibitor developed in China, chidamide has been applied for the treatment of refractory peripheral T-cell lymphoma (PTCL) and multiple solid tumors, including lung cancer. However, the underlying mechanisms are not well elucidated. In our present study, we found that chidamide and radiation acted synergistically to suppress cell and xenograft growth of lung squamous cell carcinoma cells by inducing cell apoptosis. Moreover, chidamide alone or a combination of chidamide and radiation treatment inhibited cancer cell stemness. miRNA microarray analysis demonstrated that miR-375 was the highest upregulated microRNA (miRNA) in NCI-2170 and NCI-H226 cells treated with chidamide alone or treated with chidamide plus radiation, compared with normal control. Inhibition of miR-375 attenuated the promoting effect of chidamide alone and chidamide plus radiation-induced NCI-2170 and NCI-H226 cell apoptosis and reverted the suppression of cancer stemness caused by chidamide alone or chidamide plus radiation treatment. Moreover, EIF4G3, a scaffold protein in the translation initiation complex, was found to be a direct target of miR-375 based on the luciferase reporter assay and western blot analysis. Interestingly, both chidamide alone and chidamide plus radiation treatments suppressed the mRNA and protein expression of EIF4G3. Silence of EIF4G3 also induced cell apoptosis and suppressed tumor growth in NCI-2170 and NCI-H226 cells. These data suggest that chidamide shows a synergistic effect with radiation therapy on lung squamous cell carcinomas by modulating the miR-375-EIF4G3 axis, which may afford an effective strategy to overcome the drug resistance of chidamide in clinical cancer therapy.

Efficacy and safety of chiglitazar, a novel peroxisome proliferator-activated receptor pan-agonist, in patients with type 2 diabetes: a randomized, double-blind, placebo-controlled, phase 3 trial (CMAP).

Chiglitazar (Carfloglitazar) is a novel non-thiazolidinedione (TZD) structured peroxisome proliferator-activated receptor (PPAR) pan-agonist that has shown promising effects on glycemic control and lipid regulation in patients with type 2 diabetes in previous clinical studies. This randomized phase 3 trial aimed to compare the efficacy and safety of chiglitazar with placebo in patients with type 2 diabetes with insufficient glycemic control by strict diet and exercise alone. Eligible patients were randomly assigned to receive chiglitazar 32 mg (n = 167), chiglitazar 48 mg (n = 166), or placebo (n = 202) once daily. The primary endpoint was the change in glycosylated hemoglobin A1c (HbA1c) at week 24 with superiority of chiglitazar over placebo. The results showed that both chiglitazar 32 and 48 mg resulted in significant and clinically meaningful reductions in HbA1c, and placebo-adjusted estimated treatment differences at week 24 for chiglitazar 32 and 48 mg were -0.87% (95% confidential interval (CI): -1.10 to -0.65; P < 0.0001) and -1.05% (95% CI: -1.29 to -0.81; P < 0.0001), respectively. Secondary efficacy parameters including glycemic control, insulin sensitivity and triglyceride reduction were also significantly improved in the chiglitazar groups. The overall frequency of adverse events and study discontinuation attributable to adverse events were similar among the groups. Low incidences of mild edema and body weight gain were reported in the chiglitazar dose groups. The results from this phase 3 trial demonstrated that the PPAR pan-agonist chiglitazar possesses an overall good efficacy and safety profile in patients with type 2 diabetes inadequately controlled with lifestyle interventions, thereby providing adequate supporting evidence for using this PPAR pan-agonist as a treatment option for type 2 diabetes.

Chiglitazar monotherapy with sitagliptin as an active comparator in patients with type 2 diabetes: a randomized, double-blind, phase 3 trial (CMAS).

Chiglitazar (Carfloglitazar) is a novel peroxisome proliferator-activated receptor (PPAR) pan-agonist that has shown promising effects on glycemic control and lipid regulation in patients with type 2 diabetes. In this randomized phase 3 trial, we compared the efficacy and safety of chiglitazar with sitagliptin in patients with type 2 diabetes who had insufficient glycemic control despite a strict diet and exercise regimen. Eligible patients were randomized (1:1:1) to receive chiglitazar 32 mg (n = 245), chiglitazar 48 mg (n = 246), or sitagliptin 100 mg (n = 248) once daily for 24 weeks. The primary endpoint was the change in glycosylated hemoglobin A1C (HbA1c) from baseline at week 24 with the non-inferiority of chiglitazar over sitagliptin. Both chiglitazar and sitagliptin significantly reduced HbA1c at week 24 with values of -1.40%, -1.47%, and -1.39% for chiglitazar 32 mg, chiglitazar 48 mg, and sitagliptin 100 mg, respectively. Chiglitazar 32 and 48 mg were both non-inferior to sitagliptin 100 mg, with mean differences of -0.04% (95% confidential interval (CI) -0.22 to 0.15) and -0.08% (95% CI -0.27 to 0.10), respectively. Compared with sitagliptin, greater reduction in fasting and 2-h postprandial plasma glucose and fasting insulin was observed with chiglitazar. Overall adverse event rates were similar between the groups. A small increase in mild edema in the chiglitazar 48 mg group and slight weight gain in both chiglitazar groups were reported. The overall results demonstrated that chiglitazar possesses good efficacy and safety profile in patients with type 2 diabetes inadequately controlled with lifestyle interventions, thereby providing adequate supporting evidence for using this PPAR pan-agonist as a treatment option for type 2 diabetes.

TIPs are tension-responsive proteins involved in myogenic versus adipogenic differentiation.

Stretch induces lung embryonic mesenchymal cells to follow a myogenic pathway. Using this system we identified a set of stretch-responsive factors, which we referred to as TIPs (tension-induced/inhibited proteins). TIPs displayed signature motifs characteristic of nuclear receptor coregulators and chromatin remodeling enzymes. A genomic BLAST search suggested that the three TIPs identified were isoforms originated by alternative splicing from a single gene. Functional studies revealed that TIP-1 and TIP-3 were involved in the cell's selection of the myogenic or the adipogenic pathway. TIP-1, induced by stretch, promoted myogenesis, while TIP-3, inhibited by stretch, stimulated adipogenesis. The selection involved TIP-mediated chromatin remodeling via a histone acetylation process and depended on TIP-1 and TIP-3 nuclear receptor binding boxes (NRBs). This study, therefore, suggests a new developmental mechanism linking the presence or absence of tension with divergent differentiation pathways.

High RhoA activity maintains the undifferentiated mesenchymal cell phenotype, whereas RhoA down-regulation by laminin-2 induces smooth muscle myogenesis.

Round embryonic mesenchymal cells have the potential to differentiate into smooth muscle (SM) cells upon spreading/elongation (Yang, Y., K.C. Palmer, N. Relan, C. Diglio, and L. Schuger. 1998. Development. 125:2621-2629; Yang, Y., N.K. Relan, D.A. Przywara, and L. Schuger. 1999. Development. 126:3027-3033; Yang, Y., S. Beqaj, P. Kemp, I. Ariel, and L. Schuger. 2000. J. Clin. Invest. 106:1321-1330). In the developing lung, this process is stimulated by peribronchial accumulation of laminin (LN)-2 (Relan, N.K., Y. Yang, S. Beqaj, J.H. Miner, and L. Schuger. 1999. J. Cell Biol. 147:1341-1350). Here we show that LN-2 stimulates bronchial myogenesis by down-regulating RhoA activity. Immunohistochemistry, immunoblotting, and reverse transcriptase-PCR indicated that RhoA, a small GTPase signaling protein, is abundant in undifferentiated embryonic mesenchymal cells and that its levels decrease along with SM myogenesis. Functional studies using agonists and antagonists of RhoA activation and dominant positive and negative plasmid constructs demonstrated that high RhoA activity was required to maintain the round undifferentiated mesenchymal cell phenotype. This was in part achieved by restricting the localization of the myogenic transcription factor serum response factor (SRF) mostly to the mesenchymal cell cytoplasm. Upon spreading on LN-2 but not on other main components of the extracellular matrix, the activity and level of RhoA decreased rapidly, resulting in translocation of SRF to the nucleus. Both cell elongation and SRF translocation were prevented by overexpression of dominant positive RhoA. Once the cells underwent SM differentiation, up-regulation of RhoA activity induced rather than inhibited SM gene expression. Therefore, our studies suggest a novel mechanism whereby LN-2 and RhoA modulate SM myogenesis.

Therapeutic treatment of a novel selective JAK3/JAK1/TBK1 inhibitor, CS12192, in rat and mouse models of rheumatoid arthritis.

Rheumatoid arthritis (RA) is a representative autoimmune disease characterized by chronic inflammation and joint destruction. Although biological inhibitors such as TNF-α and IL-6 antibodies have achieved success in clinical therapy, small molecule inhibitors against the Janus kinases (JAKs) involved in the signaling pathways of various cytokine receptors have gained more attraction as safe and efficacious options. In this study, we identified CS12192 as a novel selective JAK3/JAK1/TBK1 inhibitor and investigated its pharmacological effects on the experimental arthritis models in rat and mouse. We found that CS12192 showed a more selective inhibitory activity on JAK3, and to a less extent on JAK1 and TBK1, that were verified by decreased activation of p-STATs and p-IRF3 as well as down-regulation of IFN gene expression in the cultured cells with relevant stimuli. Furthermore, oral treatment with CS12192 dose-dependently ameliorated the disease severity, hind paw swelling, body weight loss, and bone destruction in rat models of adjuvant-induced arthritis (AIA) and collagen-induced arthritis (CIA). In a mouse CIA model, CS12192 also attenuated the disease severity, which was correlated with the suppressed CD4+ T cell activation and Th17 function, as well as the reduced cytokine levels in sera and pro-inflammatory cytokine and chemokine gene expression in joint tissue. Corroboratively, RANKL-induced osteoclast formation was inhibited by CS12192. Thus, these results suggest that CS12192 as a novel selective JAK inhibitor has therapeutic potential for the treatment of RA and may provide a new strategy for the control of autoimmune diseases.

P311 induces a TGF-beta1-independent, nonfibrogenic myofibroblast phenotype.

P311, also called PTZ17, was identified by suppressive subtraction hybridization as potentially involved in smooth muscle (SM) myogenesis. P311 is an 8-kDa protein with several PEST-like motifs found in neurons and muscle. P311 transfection into two fibroblast cell lines, NIH 3T3 and C3H10 T1/2, induced phenotypic changes consistent with myofibroblast transformation, including upregulation of SM alpha-actin and SM22, induction of FGF-2, VEGF, PDGF, and PDGF receptors, upregulation of integrins alpha3 and alpha5, and increased proliferation rate. The P311-mediated changes differed, however, from the well-characterized myofibroblast in that P311 inhibited TGF-beta1, TGF-beta receptor 2, and TGF-beta1-activating MMP-2 and MMP-9, with the resultant decrease in collagen 1 and 3 expression. The effect of P311 on collagen was overcome by exogenous TGF-beta1, indicating that the cells were responsive to TGF-beta1 paracrine stimulus. In support of a role for P311 in vivo, immunohistochemical examination of human wounds showed P311 only in myofibroblasts and their activated precursors. To our knowledge, these studies are the first to implicate P311 in myofibroblast transformation, to demonstrate that transformation may occur independently of TGF-beta1, and to suggest that P311 may prevent fibrosis.

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.

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.

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.

Pharmacokinetic optimization of class-selective histone deacetylase inhibitors and identification of associated candidate predictive biomarkers of hepatocellular carcinoma tumor response.

Herein, we describe the pharmacokinetic optimization of a series of class-selective histone deacetylase (HDAC) inhibitors and the subsequent identification of candidate predictive biomarkers of hepatocellular carcinoma (HCC) tumor response for our clinical lead using patient-derived HCC tumor xenograft models. Through a combination of conformational constraint and scaffold hopping, we lowered the in vivo clearance (CL) and significantly improved the bioavailability (F) and exposure (AUC) of our HDAC inhibitors while maintaining selectivity toward the class I HDAC family with particular potency against HDAC1, resulting in clinical lead 5 (HDAC1 IC50 = 60 nM, mouse CL = 39 mL/min/kg, mouse F = 100%, mouse AUC after single oral dose at 10 mg/kg = 6316 h·ng/mL). We then evaluated 5 in a biomarker discovery pilot study using patient-derived tumor xenograft models, wherein two out of the three models responded to treatment. By comparing tumor response status to compound tumor exposure, induction of acetylated histone H3, candidate gene expression changes, and promoter DNA methylation status from all three models at various time points, we identified preliminary candidate response prediction biomarkers that warrant further validation in a larger cohort of patient-derived tumor models and through confirmatory functional studies.