Biology subjects

Buon, L.

Publications and source records attributed to Buon, L..

4 recordsLinked to original sources

bioRxiv2026

A glycosaminoglycan degrading Polysaccharide Utilization Locus in the oral microbiota species Segatella oris

The human gut microbiota has been explored for the last two decades and studies have uncovered its major role in the degradation of complex glycans from the diet as well as the host tissues. Strikingly, until very recently, no similar investigation has been carried out on the human oral cavity microbiota, which is increasingly recognized has an important parameter in gastrointestinal health. Prevotellaceae are an important and under-investigated family of bacteria in both the gut and the oral cavity microbiota. The oral cavity is particularly rich in glycosaminoglycans which could provide an abundant carbon source for the inhabiting microorganisms, and play a significant role in host-pathogen interactions. Hence, we analyzed Polysaccharide Utilization Loci in oral microbiota species and we identified a glycosaminoglycan-degrading Polysaccharide Utilization Locus in Segatella oris. We produced and characterized the four enzymes, confirmed their ability to degrade glycosaminoglycans, and we focused our efforts on the biochemical and structural characterization of the first reported Prevotellaceae endosulfatase.

biochemistry↗

bioRxiv2025

Optimal Cannabinoid-Terpene Combination Ratios Suppress Mutagenicity of Gastric Reflux in Normal and Metaplastic Esophageal Cells

BackgroundEsophageal adenocarcinoma (EAC) frequently arises from chronic exposure to acid and bile reflux, with secondary bile acids, such as deoxycholic acid (DCA), contributing to its pathogenesis through mechanisms involving reactive oxygen species (ROS), oxidative DNA damage, and resistance to apoptosis. The human endocannabinoid system (ECS) regulates diverse anti-inflammatory, antioxidant, and analgesic pathways implicated in disease modulation. Despite its therapeutic promise, effective pharmacological activation of the ECS remains challenging. ObjectivesThis study aimed to evaluate whether specific cannabinoid-terpene combinations targeting the ECS could attenuate the mutagenic and cytotoxic effects of bile acid-induced stress in esophageal cell models. Additionally, we assessed the clinical significance of ECS-related protein receptors in the progression of EAC. DesignIn vitro experimental models combined with clinical samples analyses. MethodsWe utilized in vitro models, including human esophageal epithelial cell lines exposed to DCA and a Barretts esophagus gastroesophageal reflux (GER) model subjected to low pH and a bile acid cocktail. Patient-derived samples were analyzed to investigate the clinical association of ECS pathway markers with EAC progression. Experimental models were treated with varying ratios of phyto-cannabinoids and terpenes. Endpoints included assessment of DNA damage, mitochondrial membrane potential, and ROS production to identify optimal compound combinations. Expression of ECS-related protein receptors was evaluated in clinical samples to elucidate their role in EAC development. ResultsA 1:5 ratio of cannabigerol (CBG) to Phytol (Phy) was found to significantly reduce DCA-induced DNA damage, preserve mitochondrial membrane potential, and decrease ROS levels. This combination also enhanced apoptosis in damaged cells and diminished mutagenicity. Analysis of patient samples revealed that the expression of the ECS-associated receptor protein CB1 correlated with EAC progression, suggesting a broader clinical role for ECS modulation in cancer prevention. ConclusionModulation of the ECS through carefully selected cannabinoid-terpene ratios can mitigate bile acid-induced esophageal damage and may reduce carcinogenic progression. These findings support further in vivo investigations and raise the possibility of expanding cannabinoid-terpene therapeutics to other conditions involving similar pathogenic processes.

cancer biology↗

bioRxiv2022

ABL1 Kinase plays an important role in spontaneous and chemotherapy-induced genomic instability in multiple myeloma

Genomic instability contributes to cancer progression and is at least partly due to dysregulated homologous recombination. Here, we show that an elevated level of ABL1 kinase overactivates the HR pathway and causes genomic instability in multiple myeloma (MM) cells. Inhibiting ABL1 with either shRNA or a pharmacological inhibitor (nilotinib) inhibits HR activity, reduces genomic instability, and slows MM cell growth. Moreover, inhibiting ABL1 rescues the HR dysregulation and genomic instability caused by melphalan, a chemotherapeutic agent used in MM treatment, and increases melphalans efficacy and cytotoxicity in vivo in a subcutaneous tumor model. In these tumors, nilotinib inhibits endogenous as well as melphalan-induced HR activity. These data demonstrate that inhibiting ABL1 using the clinically approved drug nilotinib reduces MM cell growth, promotes genome stability, increases the cytotoxicity of melphalan (and similar chemotherapeutic agents), and can potentially prevent or delay progression in MM patients.

cancer biology↗

bioRxiv2020

Integrated genomics and comprehensive validation reveal novel drivers of genomic evolution in esophageal adenocarcinoma

Identification of genes driving genomic evolution can provide novel targets for cancer treatment and prevention. Here we show identification of a genomic instability gene signature, using an integrated genomics approach. Elevated expression of this signature correlated with poor survival in esophageal adenocarcinoma (EAC) as well as three other human cancers. Knockout and overexpression screens confirmed the relevance of this signature to genomic instability. Indepth evaluation of TTK (a kinase), TPX2 (spindle assembly factor) and RAD54B (recombination protein) further confirmed their role in genomic instability and tumor growth. Mutational signatures identified by whole genome sequencing and functional studies demonstrated that DNA damage and homologous recombination were common mechanisms of genomic instability induced by these genes. Consistently, a TTK inhibitor impaired EAC cell growth in vivo, and increased chemotherapy-induced cytotoxicity while inhibiting genomic instability in surviving cells. Thus inhibitors of TTK and other genes identified in this study have potential to inhibit/delay genomic evolution and tumor growth. Such inhibitors also have potential to increase chemotherapy-induced cytotoxicity while reducing its harmful genomic impact in EAC and possibly other cancers.

cancer biology↗