Design, synthesis and molecular mechanisms of novel dual inhibitors of heat shock protein 90/phosphoinositide 3-kinase alpha (Hsp90/PI3Kα) against cutaneous melanoma

Advancements in dual-target inhibitors of PI3K for tumor therapy: Clinical progress, development strategies, prospects

Phosphoinositide 3-kinases (PI3Ks) modify lipids by the phosphorylation of inositol phospholipids at the 3'-OH position, thereby participating in signal transduction and exerting effects on various physiological processes such as cell growth, metabolism, and organism development. PI3K activation also drives cancer cell growth, survival, and metabolism, with genetic dysregulation of this pathway observed in diverse human cancers. Therefore, this target is considered a promising potential therapeutic target for various types of cancer. Currently, several selective PI3K inhibitors and one dual-target PI3K inhibitor have been approved and launched on the market. However, the majority of these inhibitors have faced revocation or voluntary withdrawal of indications due to concerns regarding their adverse effects. This article provides a comprehensive review of the structure and biological functions, and clinical status of PI3K inhibitors, with a specific emphasis on the development strategies and structure-activity relationships of dual-target PI3K inhibitors. The findings offer valuable insights and future directions for the development of highly promising dual-target drugs targeting PI3K.

Synthesis, in silico modelling, and in vitro biological evaluation of substituted pyrazole derivatives as potential anti-skin cancer, anti-tyrosinase, and antioxidant agents

Twenty-five azole compounds (P1-P25) were synthesised using regioselective base-metal catalysed and microwave-assisted approaches, fully characterised by high-resolution mass spectrometry (HRMS), nuclear magnetic resonance (NMR), and infrared spectra (IR) analyses, and evaluated for anticancer, anti-tyrosinase, and anti-oxidant activities in silico and in vitro. P25 exhibited potent anticancer activity against cells of four skin cancer (SC) lines, with selectivity for melanoma (A375, SK-Mel-28) or non-melanoma (A431, SCC-12) SC cells over non-cancerous HaCaT-keratinocytes. Clonogenic, scratch-wound, and immunoblotting assay data were consistent with anti-proliferative results, expression profiling therewith implicating intrinsic and extrinsic apoptosis activation. In a mushroom tyrosinase inhibition assay, P14 was most potent among the compounds (half-maximal inhibitory concentration where 50% of cells are dead, IC50 15.9 μM), with activity greater than arbutin and kojic acid. Also, P6 exhibited noteworthy free radical-scavenging activity. Furthermore, in silico docking and absorption, distribution, metabolism, excretion, and toxicity (ADMET) simulations predicted prominent-phenotypic actives to engage diverse cancer/hyperpigmentation-related targets with relatively high affinities. Altogether, promising early-stage hits were identified - some with multiple activities - warranting further hit-to-lead optimisation chemistry with further biological evaluations, towards identifying new skin-cancer and skin-pigmentation renormalising agents.

Small-molecule dual inhibitors targeting heat shock protein 90 for cancer targeted therapy

Heat shock protein 90, also known as Hsp90, is an extensively preserved molecular chaperone that performs a critical function in organizing various biological pathways and cellular operations. As a potential drug target, Hsp90 is closely linked to cancer. Hsp90 inhibitors are a class of drugs that have been extensively studied in preclinical models and have shown promise in a variety of diseases, especially cancer. However, Hsp90 inhibitors have encountered several challenges in clinical development, such as low efficacy, toxicity, or drug resistance, few Hsp90 small molecule inhibitors have been approved worldwide. Nonetheless, combining Hsp90 inhibitors with other tumor inhibitors, such as HDAC inhibitors, tubulin inhibitors, and Topo II inhibitors, has been shown to have synergistic antitumor effects. Consequently, the development of Hsp90 dual-target inhibitors is an effective strategy in cancer treatment, as it enhances potency while reducing drug resistance. This article provides an overview of Hsp90's domain structure and biological functions, as well as a discussion of the design, discovery, and structure-activity relationships of Hsp90 dual inhibitors, aiming to provide insights into clinical drug research from a medicinal chemistry perspective and discover novel Hsp90 dual inhibitors.

Targeting the PI3K/AKT/mTOR Signaling Pathway in the Treatment of Human Diseases: Current Status, Trends, and Solutions

The phosphoinositide 3-kinase (PI3K)/protein kinase B (AKT)/mammalian target of rapamycin (mTOR) pathway is one of the most important intracellular pathways involved in cell proliferation, growth, differentiation, and survival. Therefore, this route is a prospective biological target for treating various human diseases, such as tumors, neurodegenerative diseases, pulmonary fibrosis, and diabetes. An increasing number of clinical studies emphasize the necessity of developing novel molecules targeting the PI3K/AKT/mTOR pathway. This review focuses on recent advances in ATP-competitive inhibitors, allosteric inhibitors, covalent inhibitors, and proteolysis-targeting chimeras against the PI3K/AKT/mTOR pathway, and highlights possible solutions for overcoming the toxicities and acquired drug resistance of currently available drugs. We also provide recommendations for the future design and development of promising drugs targeting this pathway.

Design, synthesis, and biological evaluation of novel dual inhibitors of heat shock protein 90/mammalian target of rapamycin (Hsp90/mTOR) against bladder cancer cells

In this study, a novel class of thieno [2,3-d] pyrimidine derivatives containing resorcinol and morpholine fragments as Hsp90/mTOR dual inhibitors was designed, synthesized, and evaluated. In vitro anti-tumor assay results: the obtained compounds demonstrated effectiveness in suppressing the enzymatic activities of the Hsp90 and mTOR and inhibiting the proliferation of J82, T24, and SW780 cancer cell lines. Among these dual inhibitors, the most potent compound 17o, confirmed remarkable inhibitory activities on Hsp90, mTOR, and SW780 cell. Furthermore, the molecular dynamics simulation and a panel of mechanism studies revealed that inhibitor 17o suppressed the proliferation of SW780 cells through the over-activation of the PI3K/AKT/mTOR pathway regulated by mTOR inhibition and apoptosis regulated by the mitochondrial pathway. In subcutaneous J82 xenograft models, the compound 17o also presented considerable in vivo anti-tumor activity. Therefore, our investigations highlight that a new-found dual Hsp90/mTOR inhibitor by rational drug design strategies could be a promising lead compound for targeted bladder cancer therapy and deserves further studies.

Molecular hybrids: A five-year survey on structures of multiple targeted hybrids of protein kinase inhibitors for cancer therapy

Protein kinases have grown over the past few years as a crucial target for different cancer types. With the multifactorial nature of cancer, and the fast development of drug resistance for conventional chemotherapeutics, a strategy for designing multi-target agents was suggested to potentially increase drug efficacy, minimize side effects and retain the proper pharmacokinetic properties. Kinase inhibitors were used extensively in such strategy. Different kinase inhibitor agents which target EGFR, VEGFR, c-Met, CDK, PDK and other targets were merged into hybrids with conventional chemotherapeutics such as tubulin polymerization and topoisomerase inhibitors. Other hybrids were designed gathering kinase inhibitors with targeted cancer therapy such as HDAC, PARP, HSP 90 inhibitors. Nitric oxide donor molecules were also merged with kinase inhibitors for cancer therapy. The current review presents the hybrids designed in the past five years discussing their design principles, results and highlights their future perspectives.

Discovery of novel TNNI3K inhibitor suppresses pyroptosis and apoptosis in murine myocardial infarction injury

Myocardial infarction (MI) injury is a highly lethal syndrome that has, until recently, suffered from a lack of clinically efficient targeted therapeutics. The cardiac troponin I interacting kinase (TNNI3K) exacerbates ischemia-reperfusion (IR) injury via oxidative stress, thereby promoting cardiomyocyte death. In this current study, we designed and synthesized 35 novel TNNI3K inhibitors with a pyrido[4,5]thieno[2,3-d] pyrimidine scaffold. In vitro results indicated that some of the inhibitors exhibited sub-micromolar TNNI3K inhibitory capacity and good kinase selectivity, as well as cytoprotective activity, in an oxygen-glucose deprivation (OGD) injury cardiomyocyte model. Furthermore, investigation of the mechanism of the representative derivative compound 6o suggested it suppresses pyroptosis and apoptosis in cardiomyocytes by interfering with p38MAPK activation, which was further confirmed in a murine myocardial infarction injury model. In vivo results indicate that compound 6o can markedly reduce myocardial infarction size and alleviate cardiac tissue damage in rats. In brief, our results provide the basis for further development of novel TNNI3K inhibitors for targeted MI therapy.

Novel HSP90-PI3K Dual Inhibitor Suppresses Melanoma Cell Proliferation by Interfering with HSP90-EGFR Interaction and Downstream Signaling Pathways

Melanoma is the deadliest form of skin cancer, and its incidence has continuously increased over the past 20 years. Therefore, the discovery of a novel targeted therapeutic strategy for melanoma is urgently needed. In our study, MTT-based cell proliferation assay, cell cycle, and apoptosis assays through flow cytometry, protein immunoblotting, protein immunoprecipitation, designing of melanoma xenograft models, and immunohistochemical/immunofluorescent assays were carried out to determine the detailed molecular mechanisms of a novel HSP90-PI3K dual inhibitor. Our compound, named DHP1808, was found to suppress A375 cell proliferation through apoptosis induction by activating the Fas/FasL signaling pathway; it also induced cell-cycle arrest and inhibited the cell migration and invasion of A375 cells by interfering with Hsp90-EGFR interactions and downstream signaling pathways. Our results indicate that DHP1808 could be a promising lead compound for the Hsp90/PI3K dual inhibitor.