Showing papers by "Paul D. Smith published in 2022"

Anti–PD-L1 and anti-CD73 combination therapy promotes T cell response to EGFR-mutated NSCLC

Abstract: Treatment with anti–PD-1 and anti-PD-L1 therapies has shown durable clinical benefit in non–small cell lung cancer (NSCLC). However, patients with NSCLC with epidermal growth factor receptor (EGFR) mutations do not respond as well to treatment as patients without an EGFR mutation. We show that EGFR-mutated NSCLC expressed higher levels of CD73 compared with EGFR WT tumors and that CD73 expression was regulated by EGFR signaling. EGFR-mutated cell lines were significantly more resistant to T cell killing compared with WT cell lines through suppression of T cell proliferation and function. In a xenograft mouse model of EGFR-mutated NSCLC, neither anti–PD-L1 nor anti-CD73 antibody alone inhibited tumor growth compared with the isotype control. In contrast, the combination of both antibodies significantly inhibited tumor growth, increased the number of tumor-infiltrating CD8+ T cells, and enhanced IFN-γ and TNF-α production of these T cells. Consistently, there were increases in gene expression that corresponded to inflammation and T cell function in tumors treated with the combination of anti–PD-L1 and anti-CD73. Together, these results further support the combination of anti-CD73 and anti–PD-L1 therapies in treating EGFR-mutated NSCLC, while suggesting that increased T cell activity may play a role in response to therapy.

Decrease of the amount of fat in chocolate at constant viscosity by optimizing the particle size distribution of chocolate

Abstract: The objective of this paper is the formulation of fat-reduced chocolate without affecting the viscosity of chocolate suspension. To achieve this objective, we control the rheological behaviour of dark chocolate suspension by optimizing the morphological properties (particle size distribution and maximum packing fraction) of sugar and cocoa powders. It is shown that the maximum packing fraction of cocoa and sugar powders can be predicted by the compressive packing model developed for the optimization of cement-based materials in the construction industry. Further an accurate control of maximum packing fraction by adding “fine” cocoa particles with mean diameter of few micrometres, well below the usual range in conventional chocolate, allows for the decrease of the amount of fat in dark chocolate without affecting viscosity. Then the viscosity of dark chocolate can be related to the solid volume fraction and the maximum packing fraction by a phenomenological Krieger-Dougherty type equation. Thus, new opportunities exist for reducing the fat content of chocolates.

Escape from G1 arrest during acute MEK inhibition drives the acquisition of drug resistance

Abstract: Abstract Mutations and gene amplifications that confer drug resistance emerge frequently during chemotherapy, but their mechanism and timing are poorly understood. Here, we investigate BRAFV600E amplification events that underlie resistance to the MEK inhibitor selumetinib (AZD6244/ARRY-142886) in COLO205 cells, a well-characterized model for reproducible emergence of drug resistance, and show that BRAF amplifications acquired de novo are the primary cause of resistance. Selumetinib causes long-term G1 arrest accompanied by reduced expression of DNA replication and repair genes, but cells stochastically re-enter the cell cycle during treatment despite continued repression of pERK1/2. Most DNA replication and repair genes are re-expressed as cells enter S and G2; however, mRNAs encoding a subset of factors important for error-free replication and chromosome segregation, including TIPIN, PLK2 and PLK3, remain at low abundance. This suggests that DNA replication following escape from G1 arrest in drug is more error prone and provides a potential explanation for the DNA damage observed under long-term RAF–MEK–ERK1/2 pathway inhibition. To test the hypothesis that escape from G1 arrest in drug promotes de novo BRAF amplification, we exploited the combination of palbociclib and selumetinib. Combined treatment with selumetinib and a dose of palbociclib sufficient to reinforce G1 arrest in selumetinib-sensitive cells, but not to impair proliferation of resistant cells, delays the emergence of resistant colonies, meaning that escape from G1 arrest is critical in the formation of resistant clones. Our findings demonstrate that acquisition of MEK inhibitor resistance often occurs through de novo gene amplification and can be suppressed by impeding cell cycle entry in drug.

Brain metastatic outgrowth and osimertinib resistance are potentiated by RhoA in EGFR-mutant lung cancer

Abstract: The brain is a major sanctuary site for metastatic cancer cells that evade systemic therapies. Through pre-clinical pharmacological, biological, and molecular studies, we characterize the functional link between drug resistance and central nervous system (CNS) relapse in Epidermal Growth Factor Receptor- (EGFR-) mutant non-small cell lung cancer, which can progress in the brain when treated with the CNS-penetrant EGFR inhibitor osimertinib. Despite widespread osimertinib distribution in vivo, the brain microvascular tumor microenvironment (TME) is associated with the persistence of malignant cell sub-populations, which are poised to proliferate in the brain as osimertinib-resistant lesions over time. Cellular and molecular features of this poised state are regulated through a Ras homolog family member A (RhoA) and Serum Responsive Factor (SRF) gene expression program. RhoA potentiates the outgrowth of disseminated tumor cells on osimertinib treatment, preferentially in response to extracellular laminin and in the brain. Thus, we identify pre-existing and adaptive features of metastatic and drug-resistant cancer cells, which are enhanced by RhoA/SRF signaling and the brain TME during the evolution of osimertinib-resistant disease.

Combinatorial approaches for mitigating resistance to KRAS-targeted therapies

Abstract: Approximately 15% of all cancer patients harbor mutated KRAS. Direct inhibitors of KRAS have now been generated and are beginning to make progress through clinical trials. These include a suite of inhibitors targeting the KRASG12C mutation commonly found in lung cancer. We investigated emergent resistance to representative examples of different classes of Ras targeted therapies. They all exhibited rapid reactivation of Ras signaling within days of exposure and adaptive responses continued to change over long-term treatment schedules. Whilst the gene signatures were distinct for each inhibitor, they commonly involved up-regulation of upstream nodes promoting mutant and wild-type Ras activation. Experiments to reverse resistance unfortunately revealed frequent desensitization to members of a panel of anti-cancer therapeutics, suggesting that salvage approaches are unlikely to be feasible. Instead, we identified triple inhibitor combinations that resulted in more durable responses to KRAS inhibitors and that may benefit from further pre-clinical evaluation.

Polymorphic and microstructural behaviors of palm oil/lecithin blends crystallized under shear

Abstract: There has been much work on polymorphism and crystal habit of quiescently crystallized palm oil. However, researchers have found it difficult to probe the process of sheared crystallization. The effect of surface-active molecules as nucleation agents or habit modifiers was demonstrated in quiescent systems. The aim of this work is to explore the effects of shear and specific lecithins (soy and sunflower) on palm oil crystallization by monitoring crystallization under shear using a synchrotron radiation source, as well as microscopy and DSC. It was found that increasing shear led to increasing β′ stabilization in all situations. Soybean lecithin had little effect on behavior. Sunflower lecithin led to even greater β′ stabilization. The different lecithins interact with the crystallizing fat changing rates of nucleation and crystal growth. Thus, the structure of the overall system can be dramatically altered. Microscopy revealed very different structures even if the polymorphism of the different systems was similar. Consequently, specific interactions can be manipulated in order to control the system. In particular, control of lecithin composition affects the stability of the different polymorphs. Palm oil crystallization under realistic processing conditions has been characterized. Under these conditions, increasing shear rates give higher β′ stability. Specific lecithins have different effects. In particular, soybean lecithin is β′ stabilizing, whereas sunflower lecithin has limited effects. Thus the overall structure of lecithin is important in determining the efficacy. This can be applied to control the structure and properties of different systems such as shortenings or spreads where crystalline interactions create the macro-structure that determines product properties.

Abstract 4217: MEKi in combination with anti-OX40 generates metabolically fit effector CD8+ T cells, enhances stem cell-like memory CD8+ T cells, and leads to strong anti-tumor activity

Abstract: In the tumor microenvironment (TME), T cell exhaustion and short persistence of effector cells are crucial factors that limit the efficacy of endogenously generated or adoptively transferred effector cells. Regenerative stem-cell memory CD62LhiCD44lowSca1+ CD8+ CD8+ T cells (TSCM) persist longer and produce cells with more vital effector functions. OX40, a member of TNFRSF4, has been shown to promote the expansion and proliferation of activated effector T cells, leading to the generation of robust anti-tumor responses and immune memory. However, treatment with anti-OX40 as a single therapeutic modality has not generated desirable clinical outcomes. A combination of immune modulators has been found to enhance the therapeutic efficacy synergistically. Recently, we reported that inhibition of MEK1/2 using selumetinib (AZD6244) leads to a significant increase in the numbers of CD8+ TSCM cells with self-renewability, enhanced multipotency and proliferative capacity, leading to potent anti-tumor effects. Therefore, here we combined selumetinib with anti-OX40 to investigate if enhanced immune-mediated anti-tumor responses could be obtained. Using three mouse tumor models (TC1, B16, and CT26), we found that combination of MEKi with anti-OX40 enhances the anti-tumor activity by increasing the expansion of total and antigen-specific CD8+ T cells in the TME. These CD8+ T cells have higher functional activity as seen by increased Granzyme B and INF-γ production. We also found similar results after adoptive cell therapy (ACT) where infusion of MEKi-treated cells in B16 tumor-bearing mice synergized with anti-OX40 agonist treatment. Interestingly, anti-OX40 treatment of MEKi-treated CD8+ T cells enhanced the metabolic fitness as demonstrated by low mitochondrial potential and enhanced Oxygen Consumption Rates (OCR), Spare Respiratory Capacity (SRC), and Extra-cellular Acidification Rates (ECAR) compared to anti-OX40 treatment alone. Furthermore, OX40 agonist significantly enhanced the longevity of MEKi-induced CD8+ TSCM cells. In summary, our data provide a novel strategy to utilize MEKi to enhance the efficacy of ACT and combination immunotherapy using anti-OX40 agonist. Citation Format: Pankaj Gaur, Vivek Verma, Mays Alreem Elayyan, Zainab Ramlaoui, Simon T. Barry, Viia E. Valge-Archer, Paul D. Smith, Seema Gupta, Samir N. Khleif. MEKi in combination with anti-OX40 generates metabolically fit effector CD8+ T cells, enhances stem cell-like memory CD8+ T cells, and leads to strong anti-tumor activity [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2022; 2022 Apr 8-13. Philadelphia (PA): AACR; Cancer Res 2022;82(12_Suppl):Abstract nr 4217.

Feasibility of a Randomized Controlled Mixed Methods Trial to Address Health Literacy, Beliefs, Medication Adherence, and Self-Efficacy (ADHERE) in a Clinical Pharmacist-Led Clinic

Abstract: Purpose To assess the feasibility and acceptability of a health literacy-psychosocial support intervention – ADHERE and explore changes in glycemic values and medication adherence. Patients and Methods Thirty-one participants with hemoglobin A1c (HbA1c) ≥ 8% were randomly allocated to control (usual care) or intervention groups (receiving usual care plus a 6-session pharmacist-led intervention focusing on the modifiable psychosocial factors that may influence medication adherence). Feasibility metrics evaluated recruitment, retention, and intervention adherence. Questionnaires were administered to collect psychosocial factors and self-reported medication adherence at baseline, the end of the intervention, 3 months, and 6 months post intervention. HbA1c values were extracted from electronic medical records. Repeated measures analysis of variance was used to compare differences in mean outcomes between the control and intervention groups. To assess intervention acceptability, eleven individuals participated in semi-structured interviews about their intervention experiences. Qualitative content analysis was used for analyzing the interviews. Results Thirty participants completed the study. Overall, the findings support the feasibility of the intervention. There were significant differences in HbA1c values. Participants in the intervention group had lower A1C (8.3 ± 1.4) than in the control group (9.2 ± 1.3) at the time of 6-month follow-up (p = 0.003). In addition, the participants in the intervention group showed improved HbA1c at 6-month follow-up (8.3 ± 1.4), compared to baseline (9.4 ± 1.5, p = 0.011) and after 6-session intervention (8.9 ± 1.6, p = 0.046). However, there were no significant differences in medication adherence between groups over time. Qualitative themes suggest participants liked the intervention and perceived the additional support from the pharmacist as beneficial. Conclusion A pharmacist-led intervention to provide additional health literacy-psychosocial support may contribute to long-term improvements in HbA1c. Equipping pharmacists with patient-specific diabetes medication adherence information and building in additional follow-up support for patients may improve patient health outcomes.

Trans fat reduction for oil suppliers

Abstract: The development of improved trans free fats is necessary in order to replicate the functionality of trans containing systems. Several different approaches are available to oil suppliers. These have different pros and cons and are at different stages of development from well known to speculative. In this presentation we will explore some of the routes that have been used or are under development. This will comprise many different possibilities such as breeding of crops (such as canola or soy), application and blending of fats (including tropical and temperate oils), processing including novel techniques and novel oils such as those produced by micro-organisms. In this talk we will explore the different options and consider how they can be applied and used to create functional systems that can be applied in different applications. We will highlight how by understanding the behavior and physical properties of fats new systems can be designed in a way that meets the requirements of the consumer and enable customers to make high quality goods that retain all the functionalities required whilst using desirable fats.