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Among patients with advanced cutaneous squamous-cell carcinoma, cemiplimab induced a response in approximately half the patients and was associated with adverse events that usually occur with immune checkpoint inhibitors. (Funded by Regeneron Pharmaceuticals and Sanofi; ClinicalTrials.gov numbers, NCT02383212 and NCT02760498 .).

Approximately 50% of melanomas harbor an activating BRAF mutation. Combined BRAF and MEK inhibitors such as dabrafenib and trametinib, vemurafenib and cobimetinib, and encorafenib and binimetinib are US Food and Drug Administration (FDA)-approved to treat patients with BRAFV600-mutated advanced melanoma. Both genetic and epigenetic alterations play a major role in resistance to BRAF inhibitors by reactivation of the MAPK and/or the PI3K–Akt pathways. The role of BRAF inhibitors in modulating the immunomicroenvironment and perhaps enhancing the efficacy of checkpoint inhibitors is gaining interest. This article provides a comprehensive review of mechanisms of resistance to BRAF and MEK inhibitors in melanoma and summarizes landmark trials that led to the FDA approval of BRAF and MEK inhibitors in metastatic melanoma.

Albumin-bound paclitaxel (nab-paclitaxel) is a solvent-free formulation of paclitaxel that was initially developed more than a decade ago to overcome toxicities associated with the solvents used in the formulation of standard paclitaxel and to potentially improve efficacy. Nab-paclitaxel has demonstrated an advantage over solvent-based paclitaxel by being able to deliver a higher dose of paclitaxel to tumors and decrease the incidence of serious toxicities, including severe allergic reactions. To date, nab-paclitaxel has been indicated for the treatment of three solid tumors in the USA. It was first approved for the treatment of metastatic breast cancer in 2005, followed by locally advanced or metastatic non-small-cell lung cancer in 2012, and most recently for metastatic pancreatic cancer in 2013. Nab-paclitaxel is also under investigation for the treatment of a number of other solid tumors. This review highlights key clinical efficacy and safety outcomes of nab-paclitaxel in the solid tumors for which it is currently indicated, discusses ongoing trials that may provide new data for the expansion of nab-paclitaxel’s indications into other solid tumors, and provides a clinical perspective on the use of nab-paclitaxel in practice.

Microtubule (MT) destabilization promotes the formation of actin stress fibers and enhances the contractility of cells; however, the mechanism involved in the coordinated regulation of MTs and the actin cytoskeleton is poorly understood. LIM kinase 1 (LIMK1) regulates actin polymerization by phosphorylating the actin depolymerization factor, cofilin. Here we report that LIMK1 is also involved in the MT destabilization. In endothelial cells endogenous LIMK1 co-localizes with MTs and forms a complex with tubulin via the PDZ domain. MT destabilization induced by thrombin or nocodazole resulted in a decrease of LIMK1 colocalization with MTs. Overexpression of wild type LIMK1 resulted in MT destabilization, whereas the kinase-dead mutant of LIMK1 (KD) did not affect MT stability. Importantly, down-regulation of endogenous LIMK1 by small interference RNA resulted in abrogation of the thrombininduced MTs destabilization and the inhibition of thrombin-induced actin polymerization. Expression of Rho kinase 2, which phosphorylates and activates LIMK1, dramatically decreases the interaction of LIMK1 with tubulin but increases its interaction with actin. Interestingly, expression of KD-LIMK1 or small interference RNA-LIMK1 prevents thrombin-induced microtubule destabilization and F-actin formation, suggesting that LIMK1 activity is required for thrombin-induced modulation of microtubule destabilization and actin polymerization. Our findings indicate that LIMK1 may coordinate microtubules and actin cytoskeleton.Microtubules, polymers of ␣-and ␤-tubulins, are key component of the cytoskeleton and are involved in multiple cellular processes such as migration, mitosis, protein, and organelle transport (1, 2). Microtubule dynamics and their spatial arrangements are affected by a number of signaling molecules. Conversely, changes in microtubule dynamics modulate intracellular signal transduction (for review, see Ref. 1).The actin cytoskeleton undergoes rearrangement under the control of various actin binding, capping, nucleating, and severing proteins, which are intimately involved in regulating the contractile status of the cells (3). Actin dynamics is regulated via transduction of extracellular signals to intracellular events primarily through the members of the Rho family of small GTPases. Rho is known to induce stress fiber formation, whereas Cdc42 and Rac are involved in formation of lamellipodia and filopodia, respectively (4).Microtubule disassembly promotes the formation of actin stress fibers and enhances the contractility of cells (5). Agents such as nocodazole or vinblastine that disrupt microtubules induce rapid assembly of actin filaments and focal adhesions (6), whereas microtubule stabilization with taxol attenuated these effects. Regulation of the actin cytoskeleton by microtubules requires the Rho GTPases (for review, see Ref. 7). However, the mechanisms involved in the coordinated regulation of microtubules and the actin cytoskeleton remain poorly understood. LIMK1 1 is a serine/threonine kinase that regulates a...