EB1 protein alteration characterizes sporadic but not ulcerative colitis associated colorectal cancer

Panomics reveals patient individuality as the major driver of colorectal cancer progression

BACKGROUND

Colorectal cancer (CRC) is one of the most prevalent cancers, with over one million new cases per year. Overall, prognosis of CRC largely depends on the disease stage and metastatic status. As precision oncology for patients with CRC continues to improve, this study aimed to integrate genomic, transcriptomic, and proteomic analyses to identify significant differences in expression during CRC progression using a unique set of paired patient samples while considering tumour heterogeneity.

METHODS

We analysed fresh-frozen tissue samples prepared under strict cryogenic conditions of matched healthy colon mucosa, colorectal carcinoma, and liver metastasis from the same patients. Somatic mutations of known cancer-related genes were analysed using Illumina's TruSeq Amplicon Cancer Panel; the transcriptome was assessed comprehensively using Clariom D microarrays. The global proteome was evaluated by liquid chromatography-coupled mass spectrometry (LC‒MS/MS) and validated by two-dimensional difference in-gel electrophoresis. Subsequent unsupervised principal component clustering, statistical comparisons, and gene set enrichment analyses were calculated based on differential expression results.

RESULTS

Although panomics revealed low RNA and protein expression of CA1, CLCA1, MATN2, AHCYL2, and FCGBP in malignant tissues compared to healthy colon mucosa, no differentially expressed RNA or protein targets were detected between tumour and metastatic tissues. Subsequent intra-patient comparisons revealed highly specific expression differences (e.g., SRSF3, OLFM4, and CEACAM5) associated with patient-specific transcriptomes and proteomes.

CONCLUSION

Our research results highlight the importance of inter- and intra-tumour heterogeneity as well as individual, patient-paired evaluations for clinical studies. In addition to changes among groups reflecting CRC progression, we identified significant expression differences between normal colon mucosa, primary tumour, and liver metastasis samples from individuals, which might accelerate implementation of precision oncology in the future.

TLR9 induces colitis-associated colorectal carcinogenesis by regulating NF-κB expression levels

Chronic colorectal inflammation has been associated with colorectal cancer (CRC); however, its exact molecular mechanisms remain unclear. The present study aimed to investigate the effect of Toll-like receptor 9 (TLR9) on the development of colitis-associated CRC (CAC) through its regulation of the NF-κB signaling pathway. By using a CAC mouse model and immunohistochemistry, the present study discovered that the protein expression levels of TLR9 were gradually upregulated during the development of CRC. In addition, the expression levels of TLR9 were revealed to be positively correlated with NF-κB and Ki67 expression levels. In vitro, inhibiting TLR9 expression levels using chloroquine decreased the cell viability, proliferation and migration of the CRC cell line HT29, and further experiments indicated that this may occur through downregulating the expression levels of NF-κB, proliferating cell nuclear antigen and Bcl-xl. In conclusion, the findings of the present study suggested that TLR9 may serve an important role in the development of CAC by regulating NF-κB signaling.

Protein Profiling of Serum Extracellular Vesicles Reveals Qualitative and Quantitative Differences After Differential Ultracentrifugation and ExoQuickTM Isolation

Solid tumor biopsies are the current standard for precision medicine. However, the procedure is invasive and not always feasible. In contrast, liquid biopsies, such as serum enriched for extracellular vesicles (EVs) represent a non-invasive source of cancer biomarkers. In this study, we compared two EV isolation methods in the context of the protein biomarker detection in inflammatory bowel disease (IBD) and colorectal cancer (CRC). Using serum samples of a healthy cohort as well as CRC and IBD patients, EVs were isolated by ultracentrifugation and ExoQuick™ in parallel. EV associated protein profiles were compared by multiplex-fluorescence two-dimensional difference gel electrophoresis (2D-DIGE) and subsequent identification by mass spectrometry. Validation of gelsolin (GSN) was performed using fluorescence-quantitative western blot. 2D-DIGE resolved 936 protein spots in all serum-enriched EVs isolated by ultracentrifugation or ExoQuick™. Hereof, 93 spots were differently expressed between isolation approaches. Higher levels of GSN in EVs obtained with ExoQuick™ compared to ultracentrifugation were confirmed by western blot (p = 0.0006). Although patient groups were distinguishable after both EV isolation approaches, sample preparation strongly influences EVs’ protein profile and thus impacts on inter-study reproducibility, biomarker identification and validation. The results stress the need for strict SOPs in EV research before clinical implementation can be reached.

Tumor Necrosis Factor Ligand-Related Molecule 1A Regulates the Occurrence of Colitis-Associated Colorectal Cancer

BACKGROUND

Tumor necrosis factor ligand-related molecule 1 A (TLlA) is closely related to the occurrence and development of inflammatory bowel disease.

AIMS

We aimed to explore whether TLlA was involved in the occurrence of colitis-associated colorectal cancer (CAC).

METHODS

Firstly, azoxymethane (AOM) and dextran sulfate sodium (DSS) were used to construct the CAC mice model in wild-type (WT) and TL1A transgenic (Tg) mice with TL1A high expression. The histopathological analysis was used for the evaluation of inflammation level, and the immunohistochemistry staining analysis was used to test the expression and location of proliferating cell nuclear antigen (PCNA) and β-catenin. Secondly, the HCT116 and HT29 cell lines were used for knockdown of TL1A gene for further assay including cell viability, cell clone, cell apoptosis and matrigel invasion. Western blot were used for quantitative protein expression of β-catenin and downstream oncogenes including c-myc and Cyclin D1 after knockdown of TL1A gene.

RESULTS

The evaluation of inflammation level showed that the disease activity index score and tumor formation rate were significantly higher in AOM + DSS/Tg group than that in AOM + DSS/WT group. The expression of PCNA, β-catenin, c-myc, and Cyclin D1 in AOM + DSS/Tg group was significantly higher than that in AOM + DSS/WT group. The cell experiment showed that TL1A knockdown inhibited the cell proliferation, invasion, and migration. Moreover, the expression of c-myc and Cyclin D1 was significantly decreased after TL1A knockdown.

CONCLUSIONS

TL1A can induce tumor cell proliferation and promote the occurrence of CAC by activating Wnt/β-catenin pathway.