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Background Colorectal cancer is a malignant gastrointestinal cancer, in which some advanced patients would develop cancer cachexia (CAC). CAC is defined as a multi-factorial syndrome characterized by weight loss and muscle loss (with or without fat mass), leading to progressive dysfunction, thereby increasing morbidity and mortality. ApcMin/+ mice develop spontaneous intestinal adenoma, which provides an established model of colorectal cancer for CAC study. Upon studying the ApcMin/+ mouse model, we observed a marked decrease in weight gain beginning around week 15. Such a reduction in weight gain was rescued when ApcMin/+ mice were crossed with MMP12−/− mice, indicating that MMP12 has a role in age-related ApcMin/+-associated weight loss. As a control, the weight of MMP12−/− mice on a weekly basis, their weight were not significantly different from those of WT mice. Methods ApcMin/+; MMP12−/− mice were obtained by crossing ApcMin/+ mice with MMP12 knockout (MMP12 −/−) mice. Histological scores were assessed using hematoxylin-eosin (H&E) staining. MMP12 expression was confirmed by immunohistochemistry and immunofluorescence staining. ELISA, protein microarrays and quantitative Polymerase Chain Reaction (qPCR) were used to investigate whether tumor could up-regulate IL-6. Cell-based assays and western blot were used to verify the regulatory relationship between IL-6 and MMP12. Fluorescence intensity was measured to determine whether MMP12 is associated with insulin and insulin-like growth factor 1 (IGF-1) in vitro. MMP12 inhibitors were used to explore whether MMP12 could affect the body weight of ApcMin/+ mice. Results MMP12 knockout led to weight gain and expansion of muscle fiber cross-sectional area (all mice had C57BL/6 background) in ApcMin/+ mice, while inhibiting MMP12 could suppress weight loss in ApcMin/+ mice. MMP12 was up-regulated in muscle tissues and peritoneal macrophages of ApcMin/+ mice. IL-6 in tumor cells and colorectal cancer patients is up-regulation. IL-6 stimulated MMP12 secretion of macrophage. Conclusions MMP12 is essential for controlling body weight of Apc Min/+ mice. Our study shows that it exists the crosstalk between cancer cells and macrophages in muscle tissues that tumor cells secrete IL-6 inducing macrophages to up-regulate MMP12. This study may provide a new perspective of MMP12 in the treatment for weight loss induced by CAC.

Background It has been known for years that the same genetic defects drive breast cancer formation, yet, the onset of breast cancer in different individuals among the same population differs greatly in their life spans with unknown mechanisms. Methods We used a MMTV-PyMT mouse model with different genetic backgrounds (FVB/NJ vs. C57BL/6J) to generate different cancer onset phenotypes, then profiled and analyzed the gene expression of three tumor stages in both Fvb.B6 and Fvb mice to explore the underlying mechanisms. Results We found that in contrast with the FVB/N-Tg (MMTV-PyMT) 634Mul mice (Fvb mice), mammary tumor initiation was significantly delayed and tumor progression was significantly suppressed in the Fvb.B6 mice (generated by crossing FVB/NJ with C57BL/6J mice). Transcriptome sequencing and analysis revealed that the differentially expressed genes were enriched in immune-related pathways. Flow cytometry analysis showed a higher proportion of matured dendritic cells in the Fvb.B6 mice. The plasma levels of interleukin-6 (IL-6) and vascular endothelial growth factor (VEGF) were significantly reduced in the Fvb.B6 mice. IL-6 also impaired the maturation of bone marrow dendritic cells (BMDCs) of the Fvb mice in vitro. Conclusion All these findings suggest that immunity levels (characterized by a reduced IL-6 level and intact DC maturation in Fvb.B6 mice) are the key factors affecting tumor onset in a murine mammary cancer model.

The p53 gene is well known as a key tumor suppressor gene; it is vital for hematopoietic stem cell differentiation and growth. In the present study, the change of platelets (PLTs) in p53 knockout mice (p53-/mice) was investigated. The peripheral blood cell subsets and PLT parameters in p53-/mice were compared with those in age-matched p53 +/+ mice. Bleeding time as well as the alteration of PLT levels, were analyzed with the PLT marker CD41 antibody using flow cytometry. The results revealed that the number of PLTs in p53-/mice was significantly lower than that in p53 +/+ mice. Bleeding time was prolonged in the peripheral blood of p53-/mice compared with that of p53 +/+ mice. Furthermore, the related gene expression of the PI3K signaling pathway in the bone marrow of p53-/mice was shown to be associated with plateletogenesis. PI3K inhibitor (LY294002) was also used to treat p53-/mice, and the results demonstrated that LY294002 revert the change of PLTs in these mice. In summary, PLTs were altered in p53-/mice, and the PI3K signaling pathway was involved in that process, suggesting that the p53-dependent PI3K signaling pathway is involved in thrombocytopenia or PLT diseases. PLT number is reduced in p53 deficiency; however, this reduction could be reverted by inhibiting the PI3K pathway.

Inactivation of the adenomatous polyposis coli (APC) gene is the initiating event in familial adenomatous polyposis (FAP) patients. Up to 90% of FAP patients show intestinal tumors and other extracolonic malignancies including hepatoblastomas, desmoid tumors, and brain cancer. APC mutation mice (ApcMin/+ mice) develop benign polyps in the intestinal tract. It has been reported that small numbers of ApcMin/+ mice develop breast carcinomas. Here, we found that approximately 1.6% of ApcMin/+ mice suffered skin neoplasm. The results demonstrated that these skin tumors are not derived from intestinal adenomas. Sequencing of skin tumors of ApcMin/+ mice and ApcMin/+ mice skin. The data showed that somatic mutations and gene expression levels changed greatly in skin tumors compared to control. Similarly, APC mutation accounts for 27% in the patients of nonmelanoma skin carcinomas in cancer database, and two above genes mutation coexist was observed in all patients. Furthermore, using gene mutation reagent (DMBA)–treated ApcMin/+ mice skin, the skin epithelium and glandular begin hyperplasia in ApcMin/+ mice. These findings revealed that the somatic mutation hit on the germline mutation increase the tumor incidence, suggesting that the somatic mutation should be avoided if the germline mutation exists in one body.