Biology subjects

Shields, A. F.

Publications and source records attributed to Shields, A. F..

4 recordsLinked to original sources

bioRxiv2025

Genomic and Transcriptomic Landscapes of MEN1-Wild-Type Low-Grade Metastatic Pancreatic NETs Uncover Key Oncogenic Drivers and Targetable Pathways

Sporadic pancreatic neuroendocrine tumors (pNETs) with wild type MEN1 represent a major yet largely ignored subset whose biology and metastatic potential remain poorly understood. Because metastasis can occur despite low histologic grade and modest mutational burden, we hypothesized that metastatic competence in MEN1-wild-type pNETs reflects quantitative reinforcement of shared oncogenic pathways rather than distinct mutational processes. We profiled 75 primary low-grade pNETs by whole-exome and RNA sequencing, including 25 percent with lymph node and/or liver metastasis, and integrated genomic and transcriptomic data to connect pathway lesions with expression state. Metastatic tumors showed a slight increase in mutation frequency but conserved base-substitution spectra relative to non-metastatic cases, and adverse clinicopathologic features were enriched in Grade 2 disease. Aggregating alterations to pathways revealed broad convergence on canonical networks, with transcriptomic analyses demonstrating cohort-wide enrichment of Calcium, WNT, and KRAS/PI3K-AKT programs in metastasis. Intersection of significantly mutated genes with differentially expressed genes identified a focused 29-gene overlap, including RYR1 and ZNF273, that marks these convergent axes and distinguishes metastatic from non-metastatic tumors. Gene set enrichment confirmed preferential activation of Calcium, WNT, and PI3K-AKT signaling in metastatic tumors, consistent with a network-intensity model of progression. Finally, upstream-regulator analysis (iPathwayGuide) and gene-centric perturbation mapping (Gene2Drug) nominated candidate targeted and repurposable agents predicted to reverse the metastatic expression phenotype and flagged drugs unlikely to provide benefit, yielding a prioritized, testable therapeutic shortlist which includes fasudil and spaglumic acid. Convergent, domain-specific mutational patterns in highly mutated genes such as ZNF273 and CLCA1 define a molecular signature that could stratify metastatic risk in low-grade pNETs. Collectively, our data reframe metastasis in MEN1-wild-type low-grade pNETs as a property of pathway state rather than mutation quantity and provide a translational blueprint for biomarker-guided therapy development focused on Calcium, WNT, and KRAS/PI3K hubs.

cancer biology↗

bioRxiv2025

Co-targeting KRAS and Exportin1 as an effective therapeutic strategy for KRASG12D mutant pancreatic ductal adenocarcinoma

BackgroundSeveral 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. MethodsWe 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 in vitro PDAC models. The in vivo efficacy of the combination was tested in KRASG12D-mutant human and murine PDAC xenograft and allograft models. ResultsEltanexor 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. ConclusionThis 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. Statement of Translational RelevancePDAC remains one of the deadliest malignancies, with limited effective therapies and dismal survival rates. The emergence of KRASG12D-selective inhibitors, such as MRTX1133, marks a critical advance for nearly 40% of PDAC patients harboring this oncogenic driver. However, inevitable emergence of adaptive or acquired resistance to KRAS inhibitors remains a major barrier to achieving durable clinical benefit. This study uncovers XPO1 inhibition as a rational and synergistic strategy to augment the antitumor efficacy of MRTX1133. By enhancing KRASG12D inhibitor activity and potentially reducing the required therapeutic dose, this combination approach offers a novel means to delay or overcome resistance. These findings provide a strong preclinical rationale for clinical trials evaluating KRAS inhibitors in combination with XPO1 inhibitors and may significantly improve outcomes for a substantial subset of PDAC patients who currently lack effective targeted treatment options.

cancer biology↗

bioRxiv2023

Anticancer efficacy of KRASG12C inhibitors is potentiated by PAK4 inhibitor KPT9274 in preclinical models of KRASG12C mutant pancreatic and lung cancers

KRASG12C inhibitors have revolutionized the treatment landscape for cancer patients harboring the G12C mutant isoform of KRAS. With the recent FDA approval of sotorasib and adagrasib, patients now have access to more promising treatment options. However, patients who receive these agents as a monotherapy usually develop drug resistance. Thus, there is a need to develop logical combination strategies that can delay or prevent the onset of resistance and simultaneously enhance the antitumor effectiveness of the treatment regimen. In this study, we aimed at pharmacologically targeting PAK4 by KPT9274 in combination with KRASG12C inhibitors in KRASG12C mutant pancreatic ductal adenocarcinoma (PDAC) and non-small cell lung cancer (NSCLC) preclinical models. PAK4 is a hub molecule that links several major signaling pathways and is known for its tumorigenic role in mutant Ras-driven cancers. We assessed the cytotoxicity of PAK4 and KRASG12C inhibitors combination in KRASG12C mutant 2D and 3D cellular models. KPT9274 synergized with both sotorasib and adagrasib in inhibiting the growth of KRASG12C mutant cancer cells. The combination was able to reduce the clonogenic potential of KRASG12C mutant PDAC cells. We also evaluated the antitumor activity of the combination in a KRASG12C mutant PDAC cell line-derived xenograft (CDX) model. Oral administration of a sub-optimal dose of KPT9274 in combination with sotorasib (at one-fourth of MTD) demonstrated significant inhibition of the tumor burden (p = 0.002). Similarly, potent antitumor efficacy was observed in an NSCLC CDX model where KPT9274, acting as an adjuvant, prevented tumor relapse following the discontinuation of sotorasib treatment (p = 0.0001). KPT9274 and sotorasib combination also resulted in enhanced survival. This is the first study showing that KRASG12C inhibitors can synergize with PAK4 inhibitor KPT9274 both in vitro and in vivo resulting in remarkably enhanced antitumor activity and survival outcomes. SignificanceKRASG12C inhibitors demonstrate limited durable response in patients with KRASG12C mutations. In this study, combining PAK4 inhibitor KPT9274 with KRASG12C inhibitors has resulted in potent antitumor effects in preclinical cancer models of PDAC and NSCLC. Our results bring forward a novel combination therapy for cancer patients that do not respond or develop resistance to KRASG12C inhibitor treatment.

cancer biology↗

bioRxiv2022

Molecular profiling of XPO1 inhibitor and gemcitabine-nab-paclitaxel combination in cellular and LSL-Kras G12D/+; Trp53 fl/+; Pdx1-Cre (KPC) pancreatic cancer model

The majority of pancreatic ductal adenocarcinoma (PDAC) patients experience disease progression while on treatment with gemcitabine and nab-Paclitaxel (GemPac) treatment indicating the need for more effective combinations for this recalcitrant disease. Earlier we showed that nuclear exporter protein exportin 1 (XPO1) is a valid therapeutic target in PDAC and the selective inhibitor of nuclear export (SINE) selinexor (Sel), synergistically enhances the efficacy of GemPac in pancreatic cancer cells, spheroids, patient derived tumors and had promising activity in a phase I study in patients with PDAC. Here we investigated the mechanisms of synergy by molecular profiling of Sel or Sel-GemPac treated PDAC cells, in vitro and by utilizing genetically modified LSL-Kras G12D/+; Trp53 fl/+; Pdx1-Cre (KPC) mouse model. In KPC model, Sel given with GemPac at a sub-MTD dose enhanced the survival compared to controls (p < 0.05). Molecular analysis of residual KPC tumors showed re-organization of tumor stromal architecture, suppression of proliferation and nuclear retention of tumor suppressors. Single cell nuclear RNA sequencing (snRNAseq) revealed significant loss of cellular clusters in the Sel-GemPac treated mice including CD44 stem cell population. RNA-seq, Gene Ontology (GO) and Gene Set Enrichment Analysis (GSEA) analysis showed inhibition of several tumor promoting molecules. Prioritized RNA-seq identified molecules were validated in in vitro or in the PDAC patient samples through siRNA mediated silencing, quantitative gene expression, cytotoxicity assays and confirmed their role in observed synergy. Sel or Sel-GemPac caused broad penetration in PDAC supporting signaling networks.

cancer biology↗