Volatile organic compounds as potential biomarkers of irritable bowel syndrome: A systematic review.

BACKGROUND: Irritable bowel syndrome (IBS) is a prevalent gastrointestinal disease characterized by intermittent abdominal pain with altered bowel habits. Due to the condition's chronicity, patients suffer from poor quality of life, while the healthcare burden continues to grow. There is currently no reliable biomarker for the diagnosis of IBS, and the current approach depends on ruling-out organic diseases such as inflammatory bowel disease (IBD) and colorectal cancer by markers of inflammation like fecal calprotectin and C-reactive protein, or invasive procedures like a colonoscopy. Volatile organic compounds (VOCs) are growing in popularity as a biomarker due to its accuracy and ease of use. PURPOSE: This systematic review of Medline and Cochrane's databases aimed to identify VOCs in the diagnosis of IBS. 57% of the studies proved that VOCs could identify IBS patients from healthy controls with AUC ranging from 0.83 to 0.99. Studies that distinguished IBS from IBD patients had slightly higher AUC of 0.87-0.98. Combining VOC into panels allowed the creation of discriminative algorithms. Though current research is limited by areas of heterogeneity in VOC sampling and small sample sizes, our review shows that VOC analysis has the potential to be a noninvasive point-of-care test that differentiates IBS from other organic gastrointestinal diseases.

Clinical relevance of PD-1 positive CD8 T-cells in gastric cancer.

BACKGROUND: We evaluated the relevance of PD-1+CD8+ T-cells in gastric cancer (GC) including prognostic significance, association with chemotherapy and immunotherapy sensitivity and correlations with the tumor microenvironment (TME). METHODS: Discovery cohort: GC samples were evaluated for AE1/3, CD8, PD-1, Ki-67 and Granzyme-B expression with fluorescence-based multiplex immunohistochemistry (mIHC). Validation cohorts: we analyzed bulk RNAseq GC datasets from TCGA, the "3G" chemotherapy trial and an immunotherapy phase 2 trial. The cox proportional hazards model was used to identify factors that influenced overall survival (OS). To study the TME, we analyzed single-cell RNAseq performed on GCs. RESULTS: In the discovery cohort of 350 GCs, increased PD-1 expression of CD8 T-cells was prognostic for OS (HR 0.822, p = 0.042). PD-1 expression in CD8 T-cells highly correlated with cytolytic [Granzyme-B+] (r = 0.714, p < 0.001) and proliferative [Ki-67+] (r = 0.798, p < 0.001) activity. Analysis of bulk RNAseq datasets showed tumors with high PD-1 and CD8A expression levels had improved OS when treated with immunotherapy (HR 0.117, p = 0.036) and chemotherapy (HR 0.475, p = 0.017). Analysis of an scRNAseq dataset of 152,423 cells from 40 GCs revealed that T-cell and NK-cell proportions were higher (24% vs 18% and 19% vs 15%, p < 0.0001), while macrophage proportions were lower (7% vs 11%, p < 0.0001) in CD8PD-1high compared to CD8PD-1low tumors. CONCLUSION: This is one of the largest GC cohorts of mIHC combined with analysis of multiple datasets providing orthogonal validation of the clinical relevance of PD-1+CD8+ T-cells being associated with improved OS. CD8PD-1high tumors have distinct features of an immunologically active, T-cell inflamed TME.

Proton NMR characterization of intact primary and metastatic melanoma cells in 2D & 3D cultures.

OBJECTIVE: To characterize the differences between the primary and metastatic melanoma cell lines grown in 2D cultures and 3D cultures. METHODS: Primary melanoma cells (WM115) and metastatic melanoma cells (WM266) extracted from a single donor was cultured in 2D as well as 3D cultures. These cells were characterized using proton NMR spectrometry, and the qualitative chemical shifts markers were identified and discussed. RESULTS: In monolayer culture (2D), we observed one qualitative chemical shift marker for primary melanoma cells. In spheroid cultures (3D), we observed nine significant chemical shifts, of which eight markers were specific for primary melanoma spheroids, whereas the other one marker was specific to metastatic melanoma spheroids. This study suggests that the glucose accumulation and phospholipid composition vary significantly between the primary and metastatic cells lines that are obtained from a single donor and also with the cell culturing methods. 14 qualitative chemical shift markers were obtained in the comparison between monolayer culture and spheroids cultures irrespective of the differences in the cell lines. Among which 4 were unique to monolayer cultures whereas 10 chemical shifts were unique to the spheroid cultures. This study also shows that the method of cell culture would drastically affect the phospholipid composition of the cells and also depicts that the cells in spheroid culture closely resembles the cells in vivo. CONCLUSION: This study shows the high specificity of proton NMR spectrometry in characterizing cancer cell lines and also shows the variations in the glucose accumulation and phospholipid composition between the primary and metastatic melanoma cell lines from the same donor. Differences in the cell culture method does plays an important role in phospholipid composition of the cells.

Proton NMR characterization of intact primary and metastatic melanoma cells in 2D & 3D cultures

OBJECTIVE: To characterize the differences between the primary and metastatic melanoma cell lines grown in 2D cultures and 3D cultures. METHODS: Primary melanoma cells (WM115) and metastatic melanoma cells (WM266) extracted from a single donor was cultured in 2D as well as 3D cultures. These cells were characterized using proton NMR spectrometry, and the qualitative chemical shifts markers were identified and discussed. RESULTS: In monolayer culture (2D), we observed one qualitative chemical shift marker for primary melanoma cells. In spheroid cultures (3D), we observed nine significant chemical shifts, of which eight markers were specific for primary melanoma spheroids, whereas the other one marker was specific to metastatic melanoma spheroids. This study suggests that the glucose accumulation and phospholipid composition vary significantly between the primary and metastatic cells lines that are obtained from a single donor and also with the cell culturing methods. 14 qualitative chemical shift markers were obtained in the comparison between monolayer culture and spheroids cultures irrespective of the differences in the cell lines. Among which 4 were unique to monolayer cultures whereas 10 chemical shifts were unique to the spheroid cultures. This study also shows that the method of cell culture would drastically affect the phospholipid composition of the cells and also depicts that the cells in spheroid culture closely resembles the cells in vivo. CONCLUSION: This study shows the high specificity of proton NMR spectrometry in characterizing cancer cell lines and also shows the variations in the glucose accumulation and phospholipid composition between the primary and metastatic melanoma cell lines from the same donor. Differences in the cell culture method does plays an important role in phospholipid composition of the cells.

Identification of Gastric Cancer Biomarkers Using 1H Nuclear Magnetic Resonance Spectrometry.

Existing gastric cancer diagnosing methods were invasive, hence, a reliable non-invasive gastric cancer diagnosing method is needed. As a starting point, we used 1H NMR for identifying gastric cancer biomarkers using a panel of gastric cancer spheroids and normal gastric spheroids. We were able to identify 8 chemical shift biomarkers for gastric cancer spheroids. Our data suggests that the cancerous and non-cancerous spheroids significantly differ in the lipid composition and energy metabolism. These results encourage the translation of these biomarkers into in-vivo gastric cancer detection methodology using MRI-MS.