The cation-π interaction in cysteine-rich domain of Smoothened is critical for its cholesterylation and function

A sterol analog inhibits hedgehog pathway by blocking cholesterylation of smoothened

The hedgehog (Hh) signaling pathway has long been a hotspot for anti-cancer drug development due to its important role in cell proliferation and tumorigenesis. However, most clinically available Hh pathway inhibitors target the seven-transmembrane region (7TM) of smoothened (SMO), and the acquired drug resistance is an urgent problem in SMO inhibitory therapy. Here, we identify a sterol analog Q29 and show that it can inhibit the Hh pathway through binding to the cysteine-rich domain (CRD) of SMO and blocking its cholesterylation. Q29 suppresses Hh signaling-dependent cell proliferation and arrests Hh-dependent medulloblastoma growth. Q29 exhibits an additive inhibitory effect on medulloblastoma with vismodegib, a clinically used SMO-7TM inhibitor for treating basal cell carcinoma (BCC). Importantly, Q29 overcomes resistance caused by SMO mutants against SMO-7TM inhibitors and inhibits the activity of SMO oncogenic variants. Our work demonstrates that the SMO-CRD inhibitor can be a new way to treat Hh pathway-driven cancers.

Protein lipidation in health and disease: molecular basis, physiological function and pathological implication

Posttranslational modifications increase the complexity and functional diversity of proteins in response to complex external stimuli and internal changes. Among these, protein lipidations which refer to lipid attachment to proteins are prominent, which primarily encompassing five types including S-palmitoylation, N-myristoylation, S-prenylation, glycosylphosphatidylinositol (GPI) anchor and cholesterylation. Lipid attachment to proteins plays an essential role in the regulation of protein trafficking, localisation, stability, conformation, interactions and signal transduction by enhancing hydrophobicity. Accumulating evidence from genetic, structural, and biomedical studies has consistently shown that protein lipidation is pivotal in the regulation of broad physiological functions and is inextricably linked to a variety of diseases. Decades of dedicated research have driven the development of a wide range of drugs targeting protein lipidation, and several agents have been developed and tested in preclinical and clinical studies, some of which, such as asciminib and lonafarnib are FDA-approved for therapeutic use, indicating that targeting protein lipidations represents a promising therapeutic strategy. Here, we comprehensively review the known regulatory enzymes and catalytic mechanisms of various protein lipidation types, outline the impact of protein lipidations on physiology and disease, and highlight potential therapeutic targets and clinical research progress, aiming to provide a comprehensive reference for future protein lipidation research.

Hedgehog signaling in tissue homeostasis, cancers, and targeted therapies

The past decade has seen significant advances in our understanding of Hedgehog (HH) signaling pathway in various biological events. HH signaling pathway exerts its biological effects through a complex signaling cascade involved with primary cilium. HH signaling pathway has important functions in embryonic development and tissue homeostasis. It plays a central role in the regulation of the proliferation and differentiation of adult stem cells. Importantly, it has become increasingly clear that HH signaling pathway is associated with increased cancer prevalence, malignant progression, poor prognosis and even increased mortality. Understanding the integrative nature of HH signaling pathway has opened up the potential for new therapeutic targets for cancer. A variety of drugs have been developed, including small molecule inhibitors, natural compounds, and long non-coding RNA (LncRNA), some of which are approved for clinical use. This review outlines recent discoveries of HH signaling in tissue homeostasis and cancer and discusses how these advances are paving the way for the development of new biologically based therapies for cancer. Furthermore, we address status quo and limitations of targeted therapies of HH signaling pathway. Insights from this review will help readers understand the function of HH signaling in homeostasis and cancer, as well as opportunities and challenges of therapeutic targets for cancer.