Therapeutic strategies to overcome taxane resistance in cancer.

Novel indazole and benzimidazole analogues were designed and synthesized as tubulin inhibitors with potent antiproliferative activities. Among them, compound 12b exhibited the strongest inhibitory effects on the growth of cancer cells with an average IC50 value of 50 nM, slightly better than colchicine. 12b exhibited nearly equal potency against both, a paclitaxel-resistant cancer cell line (A2780/T, IC50 = 9.7 nM) and the corresponding parental cell line (A2780S, IC50 = 6.2 nM), thus effectively overcoming paclitaxel resistance in vitro. The crystal structure of 12b in complex with tubulin was solved to 2.45 A resolution by X-ray crystallography, and its direct binding was confirmed to the colchicine site. Furthermore, 12b displayed significant in vivo antitumor efficacy in a melanoma tumor model with tumor growth inhibition rates of 78.70% (15 mg/kg) and 84.32% (30 mg/kg). Collectively, this work shows that 12b is a promising lead compound deserving further investigation as a potential anticancer agent.

Discovery of Novel Benzimidazole and Indazole Analogues as Tubulin Polymerization Inhibitors with Potent Anticancer Activities.

Tubulin-targeted chemotherapy has proven to be a successful and wide spectrum strategy against solid and liquid malignancies. Therefore, new ways to modulate this essential protein could lead to new antitumoral pharmacological approaches. Currently known tubulin agents bind to six distinct sites at α/β-tubulin either promoting microtubule stabilization or depolymerization. We have discovered a seventh binding site at the tubulin intradimer interface where a novel microtubule-destabilizing cyclodepsipeptide, termed gatorbulin-1 (GB1), binds. GB1 has a unique chemotype produced by a marine cyanobacterium. We have elucidated this dual, chemical and mechanistic, novelty through multidimensional characterization, starting with bioactivity-guided natural product isolation and multinuclei NMR-based structure determination, revealing the modified pentapeptide with a functionally critical hydroxamate group; and validation by total synthesis. We have investigated the pharmacology using isogenic cancer cell screening, cellular profiling, and complementary phenotypic assays, and unveiled the underlying molecular mechanism by in vitro biochemical studies and high-resolution structural determination of the α/β-tubulin-GB1 complex.

Gatorbulin-1, a distinct cyclodepsipeptide chemotype, targets a seventh tubulin pharmacological site.

Medicinal Chemistry of Indane and Its Analogues: A Mini Review

Phosphatases are a diverse family of enzymes, comprising at least 10 distinct protein folds. Like most other enzyme families, many have sequence variations that predict an impairment or loss of catalytic activity classifying them as pseudophosphatases. Research on pseudoenzymes is an emerging area of interest, with new biological functions repurposed from catalytically active relatives. Here, we provide an overview of the pseudophosphatases identified to date in all major phosphatase families. We will highlight the degeneration of the various catalytic sequence motifs and discuss the challenges associated with the experimental determination of catalytic inactivity. We will also summarize the role of pseudophosphatases in various diseases and discuss the major challenges and future directions in this field.

https://febs.onlinelibrary.wiley.com/doi/pdf/10.1111/febs.15431

The dead phosphatases society: a review of the emerging roles of pseudophosphatases.

Microtubule-targeting agents and their impact on cancer treatment.

Human myotubularin-related protein 9 regulates ER-to-Golgi trafficking and modulates WNT3A secretion.

The pentameric WASH complex facilitates endosomal protein sorting by activating Arp2/3, which in turn leads to the formation of F-actin patches specifically on the endosomal surface. It is generally accepted that WASH complex attaches to the endosomal membrane via the interaction of its subunit FAM21 with the retromer subunit VPS35. However, we observe the WASH complex and F-actin present on endosomes even in the absence of VPS35. We show that the WASH complex binds to the endosomal surface in both a retromer-dependent and a retromer-independent manner. The retromer-independent membrane anchor is directly mediated by the subunit SWIP. Furthermore, SWIP can interact with a number of phosphoinositide species. Of those, our data suggest that the interaction with phosphatidylinositol-3,5-bisphosphate (PI(3,5)P2) is crucial to the endosomal binding of SWIP. Overall, this study reveals a new role of the WASH complex subunit SWIP and highlights the WASH complex as an independent, self-sufficient trafficking regulator. Summary Dostál et al. contradict the prevailing concept that WASH complex is principally recruited to the endosome via its interaction with the retromer. They show that the WASH complex binds to the endosomal membrane via its subunit SWIP, and this interaction can be prevented by removing phosphatidylinositol-3,5-bisphosphate from cells.

Vojtěch Dostál

Papers

Microtubule-targeting agents and their impact on cancer treatment.

Human myotubularin-related protein 9 regulates ER-to-Golgi trafficking and modulates WNT3A secretion.

SWIP mediates retromer-independent membrane recruitment of the WASH complex