Yan Xu

Measles, hepatitis C, and COVID-19 are significant human diseases caused by RNA viruses. While vaccines exist to prevent infections, there are a small number of currently available therapeutic agents that can effectively treat these diseases after infection occurs. This study explores a new therapeutic strategy using a small molecule designated polyprenyl immunostimulant (PI) to increase innate immune responses and combat viral infections. Using a multi-disciplinary approach, this study quantifies the effects of PI in mice and THP-1 cells using flow cytometry to identify immune phenotypic markers and mass spectroscopy to monitor the metabolomic profiles of immune cells perturbed by PI treatment. The metabolomic studies identified that sphinganine and ceramide, which are precursors of sphingosine-1-phosphate (S1P), were the common metabolites upregulated in THP-1 and mice blood. Sphingosine-1-phosphate can mediate the trafficking of T cells, whereas ceramide can signal the activation and proliferation of T cells, thereby modulating the mammalian host’s immunity. To demonstrate proof-of-principle, a case study was conducted to examine the benefit of administering PI to improve the outcomes of a feline co-infected with two distinct RNA viruses—feline leukemia virus and feline infectious peritonitis virus. Both viruses produce deadly symptoms that closely resemble RNA viruses that infect humans. The results identify quantifiable cellular and metabolic markers arising from PI treatment that can be used to establish a platform measuring the efficacy of PI in modulating the innate immune system.

Allergic rhinitis affects millions globally, causing significant discomfort and reducing the quality of life. This study investigates the metabolic alterations in murine mast cells (MC/9) under allergic rhinitis conditions induced by lipopolysaccharide (LPS) stimulation, employing UHPLC-QTOF-MS-based untargeted and targeted metabolomics. The analysis identified 44 significantly regulated metabolites, including histamine, leukotrienes, prostaglandins, thromboxanes, and ceramides. Key metabolic pathways such as arachidonic acid, histidine, and sphingolipid metabolisms were notably modulated. The study further examined the therapeutic effects of triprolidine and zileuton, demonstrating their capacity to reverse LPS-induced metabolic shifts. Triprolidine primarily modulated histidine and sphingolipid metabolism, while zileuton targeted arachidonic acid and sphingolipid metabolism. These findings underscore the utility of metabolomics analysis in elucidating the complex biochemical pathways involved in allergic rhinitis and highlight the potential of metabolomics for evaluating therapeutic interventions. This study enhances our understanding of mast cell metabolism in allergic responses and provides a robust model for assessing the efficacy of anti-allergic agents, paving the way for more effective treatments.

Supplementary Figures 1-6 and Tables 1-3. Figure S1. PIK3CA mutant cells are more sensitive to a glutaminase inhibitor CB-839 than their WT counterparts. Figure S2. CB-839 enhances 5-FU tumor inhibitory effect in PIK3CA mutant CRC. Figure S3. Genes and pathways that are up-regulated in PIK3CA mutant cells after glutamine deprivation. Figure S4. Characterization of Nrf2 and its targets in CRC cells. Figure S5. CB-839 and 5-FU combinational treatment induces more DNA damage. Figure S6. Phase I clinical trial. Table S1: Patient Baseline Characteristics. Table S2. Patient information. Table S3. Treatment Related Adverse Events (all grade 3/4 AEs and grade 1/2 AEs seen in {greater than or equal to} 10% of patients).

PIK3CA encodes the p110α catalytic subunit of PI3K and is frequently mutated in human cancers, including ∼30% of colorectal cancer. Oncogenic mutations in PIK3CA render colorectal cancers more dependent on glutamine. Here we report that the glutaminase inhibitor CB-839 preferentially inhibits xenograft growth of PIK3CA-mutant, but not wild-type (WT), colorectal cancers. Moreover, the combination of CB-839 and 5-fluorouracil (5-FU) induces PIK3CA-mutant tumor regression in xenograft models. CB-839 treatment increased reactive oxygen species and caused nuclear translocation of Nrf2, which in turn upregulated mRNA expression of uridine phosphorylase 1 (UPP1). UPP1 facilitated the conversion of 5-FU to its active compound, thereby enhancing the inhibition of thymidylate synthase. Consistently, knockout of UPP1 abrogated the tumor inhibitory effect of combined CB-839 and 5-FU administration. A phase I clinical trial showed that the combination of CB-839 and capecitabine, a prodrug of 5-FU, was well tolerated at biologically-active doses. Although not designed to test efficacy, an exploratory analysis of the phase I data showed a trend that PIK3CA-mutant patients with colorectal cancer might derive greater benefit from this treatment strategy as compared with PIK3CA WT patients with colorectal cancer. These results effectively demonstrate that targeting glutamine metabolism may be an effective approach for treating patients with PIK3CA-mutant colorectal cancers and warrants further clinical evaluation.Significance:Preclinical and clinical trial data suggest that the combination of CB-839 with capecitabine could serve as an effective treatment for PIK3CA-mutant colorectal cancers.

Supplementary Figures 1-6 and Tables 1-3. Figure S1. PIK3CA mutant cells are more sensitive to a glutaminase inhibitor CB-839 than their WT counterparts. Figure S2. CB-839 enhances 5-FU tumor inhibitory effect in PIK3CA mutant CRC. Figure S3. Genes and pathways that are up-regulated in PIK3CA mutant cells after glutamine deprivation. Figure S4. Characterization of Nrf2 and its targets in CRC cells. Figure S5. CB-839 and 5-FU combinational treatment induces more DNA damage. Figure S6. Phase I clinical trial. Table S1: Patient Baseline Characteristics. Table S2. Patient information. Table S3. Treatment Related Adverse Events (all grade 3/4 AEs and grade 1/2 AEs seen in {greater than or equal to} 10% of patients).

PIK3CA encodes the p110α catalytic subunit of PI3K and is frequently mutated in human cancers, including ∼30% of colorectal cancer. Oncogenic mutations in PIK3CA render colorectal cancers more dependent on glutamine. Here we report that the glutaminase inhibitor CB-839 preferentially inhibits xenograft growth of PIK3CA-mutant, but not wild-type (WT), colorectal cancers. Moreover, the combination of CB-839 and 5-fluorouracil (5-FU) induces PIK3CA-mutant tumor regression in xenograft models. CB-839 treatment increased reactive oxygen species and caused nuclear translocation of Nrf2, which in turn upregulated mRNA expression of uridine phosphorylase 1 (UPP1). UPP1 facilitated the conversion of 5-FU to its active compound, thereby enhancing the inhibition of thymidylate synthase. Consistently, knockout of UPP1 abrogated the tumor inhibitory effect of combined CB-839 and 5-FU administration. A phase I clinical trial showed that the combination of CB-839 and capecitabine, a prodrug of 5-FU, was well tolerated at biologically-active doses. Although not designed to test efficacy, an exploratory analysis of the phase I data showed a trend that PIK3CA-mutant patients with colorectal cancer might derive greater benefit from this treatment strategy as compared with PIK3CA WT patients with colorectal cancer. These results effectively demonstrate that targeting glutamine metabolism may be an effective approach for treating patients with PIK3CA-mutant colorectal cancers and warrants further clinical evaluation.Significance:Preclinical and clinical trial data suggest that the combination of CB-839 with capecitabine could serve as an effective treatment for PIK3CA-mutant colorectal cancers.