Louisiana Via Research Day Book 2026

Biomedical Research: Section 2

Biomedical Research: Section 2

Gabriel N. Stephen 2 ; Sophia R. Voth 3 ; Lin Kang, PhD 1 ; Melissa E.H. Lipsmeyer, MS, PhD 1 ; K. Adam Morrow, PhD 1 1 VCOM-Louisiana; 2 University of Louisiana at Monroe; 3 Delta Community College, Monroe, Louisiana 22 INDOLE 3 PROPIONIC ACID MODULATES OBESOGENIC SIGNALING THROUGH SUBTYPE SPECIFIC PATHWAYS IN BREAST CANCER CELLS

Mohammad Nurul Amin, PhD Student 1 ; Md Saqline Mostaq, PhD 1 ; Lin Kang, PhD 1,2 ; Yong-Yu Liu, PhD 1 1 School of Basic Pharmaceutical and Toxicological Sciences, University of Louisiana at Monroe; 2 VCOM-Louisiana 23 TARGETING M6A METHYLATION OF TP53 R273H RESTORES NATURAL KILLER CELLS AGAINST BREAST CANCER

Background: Breast cancer is a heterogeneous disease comprised of distinct molecular subtypes that differ in hormone receptor status, aggressiveness, and response to metabolic cues from the tumor microenvironment. Obesity is associated with worse breast cancer outcomes and promotes tumor progression through adipocyte-derived factors that alter inflammation, metabolism, and cell signaling. Adipocyte-conditioned media (ACM) is commonly used to model this obesogenic environment in vitro. In parallel, obesity associated gut microbiome dysbiosis leads to reduced circulating levels of indole-3-propionic acid (IPA), a tryptophan-derived microbial metabolite with reported anti-inflammatory and cytostatic effects in breast cancer cells. While ACM and IPA have been studied independently in hormone receptor–positive and triple-negative breast cancer models, direct comparisons of their effects across distinct subtypes remain limited. Objective/Hypothesis: The objective of this study was to compare the transcriptional responses to ACM and IPA between the triple negative breast cancer cell line MDA-MB-231

and the hormone receptor–positive breast cancer cell line MCF-7, to determine whether obesity-associated and microbiome-derived signals differentially impact these subtypes. Methods: MDA-MB-231 and MCF-7 cells were cultured in control media, ACM, IPA (1 µM), or ACM+IPA for 72 hours using an established in vitro model of obesity. Following treatment, next-generation RNA sequencing was performed to identify global gene expression changes induced by ACM and to assess the ability of IPA to modify these responses. Genes with a significant p-value (<0.05) and a log-fold change greater than 2 or less than 0.5 were selected for pathway enrichment analysis using a public bioinformatic platform. Results: ACM exposure induced distinct, subtype-specific transcriptional programs in the two cell lines. In MDA-MB-231 cells, ACM predominantly altered pathways associated with apoptosis, inflammation, cellular senescence, and cytoskeletal organization. In contrast, ACM-treated MCF-7 cells exhibited significant changes in estrogen and insulin signaling, tight junctions, and focal adhesion pathways,

consistent with enhanced hormone- and metabolism-driven survival signaling. IPA treatment modulated these ACM-induced effects in both models but in divergent ways in MDA MB-231 cells, IPA primarily altered extracellular matrix organization and actin cytoskeleton– related pathways, whereas in MCF-7 cells IPA reduced hormone receptor–mediated and insulin signaling networks. Conclusion: These findings demonstrate that adipocyte-derived factors and the gut microbiome metabolite IPA exert differential effects on triple-negative versus hormone receptor–positive breast cancer cells. IPA appears to partially mitigate obesogenic, pro tumorigenic signaling in both models, though through distinct molecular pathways. This comparative analysis highlights the importance of breast cancer subtype in shaping responses to obesity and microbiome-associated metabolites and supports further investigation into IPA as a modulator of obesity-driven breast cancer progression.

Context: Missense mutation of tumor suppressor gene TP53 expresses oncogenic proteins and promotes tumor progression. It is far to understand how p53 mutant proteins mask cancer cells from anticancer immunity. p53 mutation (m-p53) is highly correlated to tumor growth and treatment failure of triple negative breast cancer. Objective and/or Hypothesis: The objective of our project is to examine the effects of inhibiting N6-methyladenosine methylation (m6A) of TP53 R273H on reinstating NK cell based immunity against breast tumors. Previous studies indicate murine p53 missense mutant G242A (corresponding to human G245A) suppress the activation of host natural killer (NK) cells in protection of breast cancer cells from immune destruction. Methods: We did Imaging Flowcytometric Analysis for NK cells and ELISA for IFN- γ level in co-culture. We performed Tumor Organoid with NK cell to determine NK cell cytotoxicity. We did proteomics analysis for characterizing RNA-binding proteins that are highly associated with m6A methylation at mp53R273H codon.

Moreover, we performed Western blotting to test several m6A readers including hnRNPG, IGFBP1, SRSF10 and YTHDF2. Results: Using human MDA-MB-468 breast cancer cells (p53 R273H) co-cultured with NK-92-MI cells, we observed that mutant p53 deactivates NK cells, leading to a significant reduction in interferon- γ (IFN- γ ) production compared with wild-type p53 (MCF-7) and non cancerous MCF-10A cells. Organoid co-culture assays confirmed reduced NK cytotoxicity and enhanced tumor organoid growth in the presence of p53 R273H. Treatment with the m6A methylation inhibitor Neplanocin A (NPC) reversed these effects, restoring NK activity and IFN- γ secretion. Proteomics and validation experiments identified that YTHDF-2 is a key m6A reader involved in modulating the effects of m6A at the R273 mutant codon on expression of p53 mutant and deactivation of NK cells. Conclusions: Human p53 missense mutation R273H deactivates human NK cells, and further inhibition of N6-methyladenosine (m6A) modification at the mutant cordon reactivates NK cell-based cytotoxicity against cancer.

Altogether, our study indicates targeting m6A modification at the mutant codon might selectively reactivate NK cell-based anticancer immunity.

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2026 Research Recognition Day