A Novel Pan-RAS Inhibitor with a Unique Mechanism of Action Blocks Tumor Growth in Mouse Models of GI Cancer.

Here, we describe a novel pan-RAS inhibitor, ADT-007, that potently inhibited the growth of RAS mutant cancer cells irrespective of the RAS mutation or isozyme. RAS WT cancer cells with activated RAS from upstream mutations were equally sensitive. Conversely, cells from normal tissues or RAS WT cancer cells harboring downstream BRAF mutations were insensitive. Insensitivity to ADT-007 was attributed to low activated RAS levels and metabolic deactivation by UDP-glucuronosyltransferases expressed in normal cells but repressed in RAS mutant cancer cells. Cellular, biochemical, and biophysical experiments show ADT-007 binds nucleotide-free RAS to block GTP activation of RAS and MAPK/AKT signaling. Local administration of ADT-007 strongly inhibited tumor growth in syngeneic immune-competent and xenogeneic immune-deficient mouse models of colorectal and pancreatic cancer while activating innate and adaptive immunity in the tumor immune microenvironment. Oral administration of ADT-007 prodrug inhibited tumor growth, supporting further development of this novel class of pan-RAS inhibitors for treating RAS-driven cancers. SIGNIFICANCE: ADT-007 is a 1 st -in-class pan-RAS inhibitor with ultra-high potency and unique selectivity for cancer cells with mutant or activated RAS capable of circumventing resistance and activating antitumor immunity. Further development of ADT-007 analogs or prodrugs with oral bioavailability as a generalizable monotherapy or combined with immunotherapy is warranted.

Targeting the metabolism and immune system in pancreatic ductal adenocarcinoma: Insights and future directions.

Pancreatic cancer, specifically pancreatic ductal adenocarcinoma (PDAC), presents a challenging landscape due to its complex nature and the highly immunosuppressive tumor microenvironment (TME). This immunosuppression severely limits the effectiveness of immune-based therapies. Studies have revealed the critical role of immunometabolism in shaping the TME and influencing PDAC progression. Genetic alterations, lysosomal dysfunction, gut microbiome dysbiosis, and altered metabolic pathways have been shown to modulate immunometabolism in PDAC. These metabolic alterations can significantly impact immune cell functions, including T-cells, myeloid-derived suppressor cells (MDSCs), and macrophages, evading anti-tumor immunity. Advances in immunotherapy offer promising avenues for overcoming immunosuppressive TME and enhancing patient outcomes. This review highlights the challenges and opportunities for future research in this evolving field. By exploring the connections between immunometabolism, genetic alterations, and the microbiome in PDAC, it is possible to tailor novel approaches capable of improving immunotherapy outcomes and addressing the limitations posed by immunosuppressive TME. Ultimately, these insights may pave the way for improved treatment options and better outcomes for PDAC patients.

Adherence patterns in naïve and prevalent use of infliximab and its biosimilar.

INTRODUCTION: Although short-term clinical trials have demonstrated that switching from infliximab (INF) bio-originator to its biosimilar is safe with no significant loss of efficacy, there are limited real-world data comparing their patterns of use and adherence. METHODS: Using 2015-2018 IBM Marketscan data, we established 4 cohorts of patients with at least one administration or pharmacy claim for INF bio-originator or biosimilar in 2017, including INF naïve biosimilar users, INF prevalent biosimilar users, INF naïve bio-originator users, and INF prevalent bio-originator users, defined according to their prior use of INF from 2015 to their first INF administration in 2017. The proportion of days covered (PDC) was calculated for patients with at least 6, 12, or 18 months of follow-up time. Factors associated with optimal adherence (PDC > 80%) were evaluated using log-binomial models. RESULTS: We identified 96 INF naïve biosimilar users, 223 INF prevalent biosimilar users, 2,149 INF naïve bio-originator users, and 10,970 INF prevalent bio-originator users. At the end of 18 months of follow-up, 64% of INF prevalent bio-originators, 48% of INF naïve biosimilars, 41% of INF naïve bio-originators, and 36% of INF prevalent biosimilars had optimal adherence. Depression, previous hospitalization, and greater use of prior biologics were negatively associated with adherence, whereas IBD diagnoses (referent to RA) and age 55-64 (referent to < 35) were positively associated with high adherence. CONCLUSION: INF prevalent users had higher adherence in our analyses than INF naïve users. However, further studies with larger sample size are needed to evaluate INF biosimilar users' adherence.

Cytokine profiling of tumor-infiltrating T lymphocytes by flow cytometry.

Intracellular cytokine staining (ICS) utilizing fluorescently labeled, cytokine-specific antibodies is a powerful technique utilized to evaluate cytokine expression that provides resolution at the single cell level. Combined with multi-parameter flow cytometry, ICS can provide detailed information on complex cytokine profiles and cellular phenotypes within the tumor microenvironment, particularly for the CD4+ T helper and CD8+ cytotoxic T cell compartments. This technique provides critical information concerning tumor-infiltrating T cell function that is essential for evaluating existing or therapeutically-induced tumor antigen-specific T cell responses in both preclinical models and cancer patients. In this chapter we will discuss in detail the critical steps necessary for a successful ICS assay and outline common protocols for the evaluation of cytokine production from T cell subsets present within the tumor microenvironment.