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Biology subjects

Bale, T.

Publications and source records attributed to Bale, T..

6 recordsLinked to original sources

Mechanoimmunological Control of Metastatic Site Selection

Cancer cells alter their mechanical properties in response to the rigidity of their environment. Here, we explored the implications of this environmental mechanosensing for anti-tumor immunosurveillance using single cell biophysical profiling and metastasis models. Cancer cells stiffened in more rigid environments, a biophysical change that sensitized them to cytotoxic lymphocytes. In immunodeficient mice, this behavior manifested in the outgrowth of stiffer metastatic cells in the rigid bone than in the soft lung, while in immunocompetent hosts, it led to preferential elimination of stiffer cancer cells and suppression of bone metastasis. Environmentally-induced cell stiffening and immune sensitization both required Osteopontin, a secreted glycoprotein that is upregulated during bone colonization. Analysis of patient metastases spanning mechanically distinct tissues revealed associations between environmental rigidity, immune infiltration, and cancer cell stiffness consistent with mechanically driven immunosurveillance. These results demonstrate how environmental mechanosensing modulates anti-tumor immunity and suggest a mechanoimmunological basis for metastatic site selection.

cancer biology↗

A diverse landscape of FGFR alterations and co-mutations defines novel therapeutic strategies in pediatric low-grade gliomas

Alterations in Fibroblast growth factor receptor (FGFR)-family proteins frequently occur as oncogenes in many cancers, including a subset of pediatric gliomas. Here, we performed a genomic analysis of 11,635 gliomas across ages and found that 4.5% of all gliomas harbor FGFR alterations including structural variants (SV) and single nucleotide variants (SNV), with an incidence of almost 10% in pediatric gliomas. FGFR family members are differentially enriched by age, tumor grade, and histological subtype, with FGFR1-alterations associated with glioneuronal histologies and pediatric low-grade gliomas. Across development, we find FGFR1 expression in both neuronal and glial precursors, while FGFR3 expression is largely restricted to astrocytic lineages. Leveraging novel isogenic model systems, we confirm FGFR1 alterations to be sufficient to activate MAPK and mTOR signaling, drive gliomagenesis, activate neuronal transcriptional programs and exhibit sensitivity to MAPK pathway inhibitors, including pan-FGFR inhibitors. Models driven by FGFR1 SVs exhibited different patterns of sensitivity compared to those driven by SNVs. Finally, we performed a retrospective analysis of clinical responses in children diagnosed with FGFR-driven gliomas and found that targeted MAPK or FGFR-inhibition with currently available inhibitors is largely associated with stability of disease. This study provides key insights into the biology of FGFR1-altered gliomas, therapeutic strategies to target them and associated challenges that still need to be overcome.

cancer biology↗

Leptomeningeal anti-tumor immunity follows unique signaling principles

Metastasis to the cerebrospinal fluid (CSF)-filled leptomeninges, or leptomeningeal metastasis (LM), represents a fatal complication of cancer. Proteomic and transcriptomic analyses of human CSF reveal a substantial inflammatory infiltrate in LM. We find the solute and immune composition of CSF in the setting of LM changes dramatically, with notable enrichment in IFN-{gamma} signaling. To investigate the mechanistic relationships between immune cell signaling and cancer cells within the leptomeninges, we developed syngeneic lung, breast, and melanoma LM mouse models. Here we show that transgenic host mice, lacking IFN-{gamma} or its receptor, fail to control LM growth. Overexpression of Ifng through a targeted AAV system controls cancer cell growth independent of adaptive immunity. Instead, leptomeningeal IFN-{gamma} actively recruits and activates peripheral myeloid cells, generating a diverse spectrum of dendritic cell subsets. These migratory, CCR7+ dendritic cells orchestrate the influx, proliferation, and cytotoxic action of natural killer cells to control cancer cell growth in the leptomeninges. This work uncovers leptomeningeal-specific IFN-{gamma} signaling and suggests a novel immune-therapeutic approach against tumors within this space.

cancer biology↗

Dual inhibition of SHP2 and autophagy suppresses NF1-associated Malignant Peripheral Nerve Sheath Tumors

Malignant peripheral nerve sheath tumors (MPNSTs) are aggressive sarcomas and the primary cause of mortality in patients with neurofibromatosis type 1 (NF1). MPNSTs develop within pre-existing benign plexiform neurofibromas (PNs). PNs are driven solely by biallelic NF1 loss eliciting RAS pathway activation and respond favorably to MEK inhibitor therapy. Our analysis of genetically engineered and orthotopic patient-derived xenograft MPNST indicates that MEK inhibition has poor anti-tumor efficacy. By contrast, upstream inhibition of RAS through the protein-tyrosine phosphatase SHP2 reduced downstream signaling and suppressed NF1 MPNST growth, although resistance eventually emerged. To investigate possible mechanisms of acquired resistance, kinomic analyses of resistant tumors was performed, and data analysis identified enrichment of activated autophagy pathway protein kinases. Combining pharmacological blockade of autophagy and SHP2 inhibition resulted in durable responses in NF1 MPNSTs in both genetic and orthotopic xenograft mouse models. Our studies can be rapidly translated into a clinical trial to evaluate SHP2 inhibition in conjunction with autophagy inhibitors as a novel treatment approach for NF1 MPNSTs. Statement of significanceCurrently, no effective therapies exist for MPNST. We demonstrate intrinsic MPNST resistance to MEKi monotherapy and identify SHP2 inhibition as an actionable vulnerability upstream of RAS. Furthermore, anti-tumor effects are extended and enhanced by dual exposure to autophagy pathway inhibition. Validation of these results as the most effective therapy to date in multiple genetically engineered models and in orthotopic patient-derived xenografts justify a clinical trial to evaluate SHP2i in conjunction with autophagy inhibitors as a novel treatment approach for NF1 MPNSTs.

cancer biology↗

Enhanced specificity of high sensitivity somatic variant profiling in cell-free DNA via paired normal sequencing: design, validation, and clinical experience of the MSK-ACCESS liquid biopsy assay

Circulating cell-free DNA (cfDNA) from blood plasma of cancer patients can be used to interrogate somatic tumor alterations non-invasively or when adequate tissue is unavailable. We have developed and clinically implemented MSK-ACCESS (Analysis of Circulating cfDNA to Evaluate Somatic Status), an NGS assay for detection of very low frequency somatic alterations in select exons and introns of 129 genes. Analytical validation demonstrated 92% sensitivity in de-novo mutation calling down to 0.5% allele frequency and 98% for a priori mutation profiling. To evaluate the performance and utility of MSK-ACCESS, we report results from the first 681 prospective blood samples (617 patients) that underwent clinical analysis to guide patient management. Somatic mutations, copy number, and/or structural variants were detected in 73% of the samples, and 56% of these circulating-tumor DNA (ctDNA) positive samples had clinically actionable alterations. The utilization of matched white blood cell sequencing allowed retention of somatic alterations while filtering out over 10,000 germline and clonal hematopoiesis variants, thereby greatly enhancing the specificity of the assay. Taken together, our experience illustrates the importance of analyzing a matched normal sample when interpreting cfDNA results and highlights the potential of cfDNA profiling to guide treatment selection, monitor treatment response, and identify mechanisms of treatment resistance.

genomics↗

It’s the fiber, not the fat: Significant effects of dietary challenge on the gut microbiome

BackgroundDietary effects on the gut microbiome has been shown to play a key role in the pathophysiology of behavioral dysregulation, inflammatory disorders, metabolic syndrome, and obesity. Often overlooked is that experimental diets vary significantly in the proportion and source of dietary fiber. Commonly, treatment comparisons are made between animals that are fed refined diets that lack soluble fiber and animals fed vivarium-provided chow diet that contain a rich source of soluble fiber. Despite the well-established role of soluble fiber on metabolism, immunity, and behavior via the gut microbiome, the extent to which measured outcomes may be driven by differences in dietary fiber is unclear. Further, the significant impact of sex and age in response to dietary challenge is likely important and should also be considered.\n\nResultsWe compared the impact of transitioning young and aged male and female mice from a chow diet to a refined low soluble fiber diet on body weight and gut microbiota. Then, to determine the contribution of dietary fat, we examined the impact of transitioning a subset of animals from refined low fat to refined high fat diet. Serial tracking of body weights revealed that consumption of low fat or high fat refined diet increased body weight in young and aged adult male mice. Young adult females showed resistance to body weight gain, while high fat diet-fed aged females had significant body weight gain. Transition from a chow diet to low soluble fiber refined diet accounted for most of the variance in community structure and composition across all groups. This dietary transition was characterized by a loss of taxa within the phylum Bacteroidetes and a concurrent bloom of Clostridia and Proteobacteria in a sex- and age-specific manner. Most notably, no changes to gut microbiota community structure and composition were observed between mice consuming either low- or high-fat diet, suggesting that transition to the refined diet that lacks soluble fiber is the primary driver of gut microbiota alterations, with limited additional impact of dietary fat on gut microbiota.\n\nConclusionCollectively, our results show that the choice of control diet has a significant impact on outcomes and interpretation related to body weight and gut microbiota. These data also have broad implications for rodent studies that draw comparisons between refined high fat diets and chow diets to examine dietary fat effects on metabolic, immune, behavioral, and neurobiological outcomes.

systems biology↗