👤 Callum McGrath

BRAF, when mutated at V600E, is a well-known potent early oncogenic driver in papillary thyroid carcinoma (PTC), with potential prognostic and therapeutic implications. Non-V600E mutations are less common and without clear functional or therapeutic significance. One class of non-V600E mutations is BRAF gene fusions, which typically involve the C-terminal kinase domain of BRAF joined to a wide repertoire of potential N-terminal fusion partners. The aim of this study was to employ a sequential algorithmic approach to identify patients with BRAF fusions based on an integrated analysis of histologic, immunohistochemistry (IHC), and molecular (NGS) features of BRAF-rearranged PTCs. Nine patients with PTC previously scrutinized as BRAF V600E negative by IHC were analyzed by NGS. The studied 9 cases showed conventional PTC growth; 2 cases displayed a minor high-grade component (tall cell and hobnailing, < 20%), 1 case qualified as high-grade differentiated thyroid carcinoma (presence of necrosis and mitotic activity > 5 MF/ 2 mm Show less

Several KRASG12D inhibitors (KRASG12Di) are under clinical evaluation for pancreatic ductal adenocarcinoma (PDAC). However, as seen with other first generation KRAS inhibitors, resistance may limit their long-term efficacy, necessitating combination strategies to enhance therapeutic outcomes. Exportin 1 (XPO1), a nuclear transport protein overexpressed in PDAC, represents a therapeutic vulnerability in KRAS-mutant cancers. Here, we demonstrate that the second-generation XPO1 inhibitor Eltanexor synergizes with MRTX1133 to enhance its efficacy in multiple PDAC models. We generated KRASG12Di-resistant PDAC cells and assessed their response to Eltanexor. The antiproliferative effects of MRTX1133 and Eltanexor combinations were evaluated in 2D and 3D Eltanexor sensitized MRTX1133-resistant PDAC cells to growth inhibition. In both 2D and 3D culture models, the combination of Eltanexor and MRTX1133 significantly reduced cell viability. Mechanistically, the combination treatment suppressed key KRAS downstream signaling molecules, including p-ERK, mTOR, p-4EBP1, DUSP6, and cyclin D1. Kinome analysis further revealed reduced MAPK-related kinase activity. Combining subtherapeutic doses of Eltanexor and MRTX1133 resulted in significant tumor regression and prolonged survival in PDAC xenograft and immunocompetent orthotopic allograft models. Moreover, maintenance therapy with Eltanexor prevented tumor relapse, yielding a durable antitumor response. This study demonstrates that Eltanexor overcomes resistance to MRTX1133 and enhances its efficacy in PDAC. The combination regimen may provide a durable therapeutic response while reducing the required dose of KRASG12D inhibitors, potentially delaying resistance and improving patient outcomes. Show less

Macroautophagy/autophagy occurs basally under nutrient-rich conditions in most mammalian cells, contributing to protein and organelle quality control, and protection against aging and neurodegeneration. During autophagy, lysosomes are heavily utilized via their fusion with autophagosomes and must be repopulated to maintain autophagic degradative capacity. During starvation-induced autophagy, lysosomes are generated via Show less