Discovery of Novel Indazoles as Potent and Selective PI3Kδ Inhibitors with High Efficacy for Treatment of Hepatocellular Carcinoma

The petroleum ether extracts of Chloranthus fortunei(A. Gray) Solms-Laub.with bioactivities: A rising source in HCC drug treatment

ETHNOPHARMACOLOGICAL RELEVANCE

Hepatocellular Carcinoma (HCC) is an aggressive killer worldwide with high incidence and mortality. The herb Chloranthus fortunei (A. Gray) Solms-Laub is known as "Si Ji Feng" and is classified as a Feng-type medicine in classic Yao medicines. According to Yao's medical beliefs, Chloranthus fortunei has the functions of dispelling Feng, regulating qi, detoxifying, promoting blood circulation, etc. Folk uses its decoctions to treat stagnant liver conditions, such as liver abscesses, cirrhosis, hepatitis, and liver cancer. However, the bioactivity and mechanisms of Chloranthus fortunei extract against HCC have not been reported.

AIM OF THE STUDY

To investigate the anti-HCC bioactivity and potential mechanism of the extract of Chloranthus fortunei (CFS).

MATERIALS AND METHODS

Using 70% ethanol for reflux extraction of CFS resulted in the CFS ethanol extract, followed by sequential extractions with petroleum ether, chloroform, ethyl acetate, and n-butanol, yielding four fractions. The CCK-8 assay was utilized to examine the cytotoxic effects of 4 fractions on MHCC97-H and HepG2 cells, exploring the most effective component, namely petroleum ether extracts of CFS (PECFS). The major active ingredients of PECFS were identified using LC/MS technology, and the impact on cell proliferation and apoptosis in HCC cells was studied. The key genes and proteins in the pathway were validated using RT-PCR and Western blotting. BALB/c nude mice were chosen for tumor xenotransplantation and PECFS therapy. hinders the proliferation of HCC cells and promotes apoptosis.

RESULTS

Among the four fractions, it was found that PECFS have the highest antiproliferative activity against MHCC97-H and HepG2 cells (IC50 = 13.86, 10.55 μg/mL), with sesquiterpene compounds being the primary active constituents. The antiproliferative activity of PECFS on HCC cells was linked to the inhibition of cell cloning, invasion, and metastasis abilities, as well as the arrest of the cell cycle at the G2/M phase. Additionally, exerts pro-apoptotic effects on HCC cells by upregulating the pro-apoptotic protein Bax, downregulating the anti-apoptotic protein Bcl-2, and activating the expression of the Caspase family. Moreover, protein and m-RNA expression data showed that PECFS inhibits HCC cell proliferation and promotes apoptosis by regulating the PI3K/AKT/mTOR pathway. Besides, after PECFS treatment, tumor growth in nude mice was suppressed.

CONCLUSION

PECFS can inhibit the viability of HCC cells by acting on the PI3K/AKT/mTOR pathway, demonstrating anti-tumor potential. This study's findings suggest that PECFS may represent a promising source of novel agents for liver cancer treatment, providing scientific evidence for the traditional application of CFS in treating HCC.

TYM-3-98, a novel selective inhibitor of PI3Kδ, demonstrates promising preclinical antitumor activity in B-cell lymphomas

AIMS

PI3Kδ is expressed predominately in leukocytes and is commonly found to be aberrantly activated in human B-cell lymphomas. Although PI3Kδ has been intensively targeted for discovering anti-lymphoma drugs, the application of currently approved PI3Kδ inhibitors has been limited due to unwanted systemic toxicities, thus warranting the development of novel PI3Kδ inhibitors with new scaffolds.

MAIN METHODS

We designed TYM-3-98, an indazole derivative, and evaluated its selectivity for all four PI3K isoforms, as well as its efficacy against various B-cell lymphomas both in vitro and in vivo.

KEY FINDINGS

We identified TYM-3-98 as a highly selective PI3Kδ inhibitor over other PI3K isoforms at both molecular and cellular levels. It showed superior antiproliferative activity in several B-lymphoma cell lines compared with the approved first-generation PI3Kδ inhibitor idelalisib. TYM-3-98 demonstrated a concentration-dependent PI3K/AKT/mTOR signaling blockage followed by apoptosis induction. In vivo, TYM-3-98 showed good pharmaceutical properties and remarkably reduced tumor growth in a human lymphoma xenograft model and a mouse lymphoma model.

SIGNIFICANCE

Our findings establish TYM-3-98 as a promising PI3Kδ inhibitor for the treatment of B-cell lymphoma.

Discovery of Novel Azaindoles as Potent and Selective PI3Kδ Inhibitors for Treatment of Multiple Sclerosis

Multiple sclerosis (MS) is a chronic autoimmune disorder of the central nervous system and the unmet need for MS treatment demands new therapeutic development. Particularly, PI3Kδ is a high-value target for autoimmune disease, while the investigation of PI3Kδ inhibitors for MS therapy is relatively scarce. Herein, we report a novel class of azaindoles as PI3Kδ inhibitors for MS treatment. Compound 31, designed via nitrogen bioisosterism, displayed excellent PI3Kδ inhibitory activity and selectivity. In vitro assay showed that 31 exhibited superior activity on T lymphocytes to inhibit the proliferation of CD4+, CD8+, and CD3+ T cells. In the experimental autoimmune encephalomyelitis (EAE) model, 31 showed a comparable therapeutical efficacy with Dexamethasone to significantly ameliorate EAE symptoms. Mechanistic studies showed that compound 31 could significantly inhibit the PI3K/AKT/mTOR signaling pathway and inhibited T-cell proliferation and differentiation. Overall, this work provides a new structural PI3Kδ inhibitor and a new vision for MS therapy.

Design, synthesis and biological activity evaluation of novel covalent S-acylation inhibitors

In order to obtain diverse S-acylation inhibitors and address the defects of existing S-acylation inhibitors, a series of novel covalent S-acylation inhibitors are designed through synthesis. According to the results of MTT assay, most compounds produce a better anti-proliferation effect on MCF-7, MGC-803 and U937 cell lines than 2-BP. Among them, 8d, 8i, 8j and 10e exert a significant inhibitory effect on MCF-7 cell, with the IC50 values falling below 20 μM. Besides, the toxic effects of some compounds on 3T3 cell line are less significant than 2-BP. According to the results of acyl-biotin exchange (ABE) experiment, most of them could inhibit S-acylation, and 8i performs best in this respect, with the inhibitory rate reaching 89.3% at the concentration of 20 μM. The results of molecular docking show the conjugation of 8i with surrounding amino acids. Additionally, 8i could not only suppress the migration of MCF-7 cell line, but also cause it to stagnate in G0/G1 phase, thus promoting cell apoptosis.

Discovery of Potent and Selective PI3Kδ Inhibitors for the Treatment of Acute Myeloid Leukemia

PI3Kδ is an essential target correlated to the occurrence and development of acute myeloid leukemia (AML). Herein, we investigated the pyrazolo[3,4-d]pyrimidine derivatives as potent and selective PI3Kδ inhibitors with high therapeutic efficacy toward AML. There were 44 compounds designed and prepared in a four-round optimization, and the biological evaluation showed that (S)-36 exhibited potent PI3Kδ inhibitory activity, high selectivity, and high antiproliferative activities against MV-4-11 and MOLM-13 cells, coupled with high oral bioavailability (F = 59.6%). In the MOLM-13 subcutaneous xenograft model, (S)-36 could significantly suppress the tumor progression with a TGI of 67.81% at an oral administration dosage of 10 mg/kg without exhibiting obvious toxicity. Mechanistically, (S)-36 could robustly inhibit the PI3K/AKT pathway for significant suppression of cell proliferation and remarkable induction of apoptosis both in vitro and in vivo. Thus, compound (S)-36 represents a promising PI3Kδ inhibitor for the treatment of acute myeloid leukemia with high efficacy.

Highly oxygenated guaiane-type sesquiterpene lactones from Artemisia sacrorum and their antihepatoma activity

The ethanol and EtOAc extracts of Artemisia sacrorum exhibited inhibitory effect against HepG2, Huh7, and SK-Hep-1 cell lines with inhibitory ratios of 65.5%, 28.1%, 84.6%, and 93.5%, 82.0%, 89.0% at 200 μg/mL. Twenty-three undescribed guaiane-type sesquiterpene lactones, artemisacrolides A‒W, were isolated from A. sacrorum under the guidance of antihepatoma activity. Their structures were elucidated by spectral data (HRESIMS, IR, UV, 1D and 2D NMR), ECD calculations, and a single-crystal X-ray diffraction. Artemisacrolides A‒U were guaiane-type sesquiterpene lactones possessing α-methylene-γ-lactone and containing acetoxyl groups at C-8, and artemisacrolides V and W represented the first report from the genus Artemisia with a 1,10-rearranged guaiane-type sesquiterpene lactone. Antihepatoma assay suggested that artemisacrolides A‒U demonstrated better inhibitory activity in Huh7 and SK-Hep-1 cells than those of HepG2 cells. Among them, nine compounds exhibited significant inhibitory activity against Huh7 cells with IC50 values of 8.2-14.3 μM, superior or equal to that of sorafenib; seven compounds demonstrated obvious activity against SK-Hep-1 cells with IC50 values of 13.5-19.2 μM, which were equivalent to that of sorafenib. Artemisacrolides B and E were the most active ones in three human hepatoma cell lines with IC50 values of 21.9, 8.2, 16.9 and 22.6, 9.0, 17.3 μM.

Discovery of Highly Selective and Orally Bioavailable PI3Kδ Inhibitors with Anti-Inflammatory Activity for Treatment of Acute Lung Injury

PI3Kδ is a promising target for the treatment of inflammatory disease; however, the application of PI3Kδ inhibitors in acute respiratory inflammatory diseases is rarely investigated. In this study, through scaffold hopping design, we report a new series of 1H-pyrazolo[3,4-d]pyrimidin-4-amine-tethered 3-methyl-1-aryl-1H-indazoles as highly selective and potent PI3Kδ inhibitors with significant anti-inflammatory activities for treatment of acute lung injury (ALI). There were 29 compounds designed, prepared, and subjected to PI3Kδ inhibitory activity evaluation and anti-inflammatory activity evaluation in macrophages. (S)-29 was identified as a candidate with high PI3Kδ inhibitory activity, isoform selectivity, and high oral bioavailability. The in vivo administration of (S)-29 at 10 mg/kg dosage could significantly ameliorate histopathological changes and attenuate lung inflammation in lung tissues of LPS-challenged mice. Molecular docking demonstrated the success of scaffold hopping design. Overall, (S)-29 is a potent PI3Kδ inhibitor which might be a promising candidate for the treatment of ALI.

Discovery of Novel 1,2,3,4-Tetrahydrobenzofuro[2,3-c]pyridine Histone Deacetylase Inhibitors for Efficient Treatment of Hepatocellular Carcinoma

The development of histone deacetylase (HDAC) inhibitors for treating hematologic malignancies has been widely investigated, while their role in hepatocellular carcinoma (HCC) remains unexplored. In this study, we employed a scaffold-hopping design and a multicomponent synthesis approach to develop a novel series of 1,2,3,4-tetrahydrobenzofuro[2,3-c]pyridines as HDAC inhibitors. There were a total of 29 compounds achieved with flexible linkers and zinc-binding groups, wherein compound 12k was identified as a promising candidate with good HDAC inhibitory activity, pharmacokinetic profiles, and potency. It exhibited significant therapeutic efficacy in HCC cell lines (IC50 = 30 nM for Bel-7402) and xenograft models (76% inhibition for Bel-7402 xenografts, P.O. at 20 mg/kg, QOD, for 14 days) and was found to upregulate the acetylation of histone H3 and α-tubulin, leading to apoptosis and autophagy in HCC models. Molecular docking studies indicated a unique T-shaped conformation of 12k with the catalytic domain of HDAC1. Therefore, this work provides a new structure design for HDAC inhibitors and also offers a promising treatment for HCC.

Solvent-Dependent Selective Synthesis of CF3-Tethered Indazole Derivatives Based on Multiple Bond Activations

Presented herein is a solvent-dependent selective synthesis of CF₃-tethered indazole derivatives via the cascade reactions of 1-arylpyrazolidinones with trifluoromethyl ynones. Mechanistically, the formation of the title products involves cascade N-H/C-H/C-N/C-C bond cleavage along with pyrazole ring formation and pyrazolidinone ring opening. For the formation of a pyrazole scaffold, 1-phenylpyrazolidinone acts as a C2N2 synthon, while trifluoromethyl ynone serves as a C1 synthon. Meanwhile, trifluoromethyl ynone also acts as an enol unit to facilitate the ring opening of the pyrazolidinone ring and provide a trifluoropropenoxy fragment via cleavage of the alkynyl triple bond and migration of the cleaved moiety. When the reaction was run in trifluoroethanol instead of DCE, it selectively afforded indazole derivatives tethered with a trifluoroethoxy moiety through in situ transesterification. To our knowledge, this is the first synthesis of CF₃-tethered indazole derivatives via concurrent alkynyl activation, pyrazole formation, and CF₃ migration.