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The Src homology-2 domain-containing tyrosine phosphatase 2 (SHP-2) regulates many cellular processes, including proliferation, differentiation and survival. Polymorphisms in the gene encoding SHP-2 are associated with an increased susceptibility to develop ulcerative colitis. We recently reported that intestinal epithelial cell (IEC)-specific deletion of Shp-2 in mice (Shp-2IEC-KO ) leads to chronic colitis and colitis-associated cancer. This suggests that SHP-2-dependent signaling protects the colonic epithelium against inflammation and colitis-associated cancer development. To verify this hypothesis, we generated mice expressing the Shp-2 E76K activated form specifically in IEC. Our results showed that sustained Shp-2 activation in IEC increased intestine and crypt length, correlating with increased cell proliferation and migration. Crypt regeneration capacity was also markedly enhanced, as revealed by ex vivo organoid culture. Shp-2 activation alters the secretory cell lineage, as evidenced by increased goblet cell numbers and mucus secretion. Notably, these mice also demonstrated elevated ERK signaling in IEC and exhibited resistance against both chemical- and Citrobacter rodentium-induced colitis. In contrast, mice with IEC-specific Shp-2 deletion displayed reduced ERK signaling and rapidly developed chronic colitis. Remarkably, expression of an activated form of Braf in Shp-2-deficient mice restored ERK activation, goblet cell production and prevented colitis. Altogether, our results indicate that chronic activation of Shp-2/ERK signaling in the colonic epithelium confers resistance to mucosal erosion and colitis. © 2018 The Authors. The Journal of Pathology published by John Wiley & Sons Ltd on behalf of Pathological Society of Great Britain and Ireland.

Fabry disease is an X-linked lysosomal storage disorder caused by α-galactosidase A (α-GAL A) deficiency. This enzyme contributes to the cellular recycling of glycosphingolipids such as galabiosylceramide (Ga2), globotriaosylceramide (Gb3), and globotriaosylsphingosine (lyso-Gb3) by hydrolyzing the terminal α-galactosyl moiety. Urine and plasma α-GAL A substrates are currently analyzed as biomarkers for the detection, monitoring, and follow-up of Fabry disease patients. The sensitivity of the analysis of Ga2 is decreased by the co-analysis of its structural isomer, lactosylceramide (LacCer), which is not an α-GAL A substrate. A normal-phase ultraperformance liquid chromatography coupled to tandem mass spectrometry (UPLC-MS/MS) methodology, allowing the baseline separation of 12 Ga2 isoforms/analogues from their lactosylceramide counterparts, was developed and validated in urine. The method was multiplexed with the analysis of 12 Gb3 isoforms/analogues having the same fatty acid moieties as those of Ga2 fo...

Autophagy has both tumor-promoting and -suppressing effects in cancer, including colorectal cancer (CRC), with transformed cells often exhibiting high autophagic flux. In established tumors, autophagy inhibition can lead to opposite responses resulting in either tumor cell death or hyperproliferation. The functional mechanisms underlying these differences are poorly understood. The present study aimed to investigate the relationship between the autophagic capacities of CRC cells and their sensitivities to autophagy inhibition. All studied CRC cell lines showed high basal autophagic flux. However, only HCT116 and Caco-2/15 cells displayed regulated autophagic flux upon starvation. Knockdown of ATG5 (which disrupts autophagosome elongation) or RAB21 (which decreases autophagosome/lysosome fusion) had little effect on CRC cell proliferation in vitro. Nonetheless, inhibition of autophagy in vivo had a substantial cell line-dependent impact on tumor growth, with some cells displaying decreased (HCT116 and Caco-2/15) or increased (SW480 and LoVo) proliferation. RNA sequencing and Western blot analyses in hyperproliferative SW480 tumors revealed that the mTORC2 and AKT pathways were hyperactivated following autophagy impairment. Inhibition of either mTOR or AKT activities rescued the observed hyperproliferation in autophagy-inhibited SW480 and reduced tumor growth. These results highlight that autophagy inhibition can lead, in specific cellular contexts, to compensatory mechanisms promoting tumor growth.

BACKGROUND: The protein tyrosine phosphatase SHP-2 is known to regulate many cellular functions including growth, differentiation and survival. Interestingly, a gain-of-function mutation (residue E76K) in the gene encoding SHP-2 has been found in some colorectal cancers. Importantly, intestinal epithelial cell (IEC)-specific expression of SHP-2(E76K) mutant in mice was not sufficient to induce tumorigenesis but markedly promoted tumor growth under the Apc(Min/+) background. Conversely, SHP-2 silencing inhibited anchorage-independent growth of human CRC cells (Gagné-Sansfaçon et al., Oncotarget 2016). However, the molecular mechanisms involved in the pro-oncogenic action of SHP-2 remained to be identified. AIMS: To determine a possible role of the protein tyrosine phosphatase SHP-2 in the development of senescence. METHODS: Non immortalized human intestinal epithelial cells (HIEC) and human colorectal cancer cells (HCT116) were infected with lentiviruses encoding a shRNA directed against SHP-2. The impact on growth was assessed by BrdU incorporation, SA-β-galactosidase staining and qPCR or immunoblot analyses of regulatory proteins and signaling pathways regulating the cell cycle. SHP-2 deletion was induced ex vivo in intestinal organoids and the impact on organoid development was analyzed. RESULTS: SHP-2 silencing in HIEC changes cell morphology and results in the activation of the Wnt/β-catenin pathway and in the decreased activation of ERK1/2 MAP Kinases. Few days after silencing, the number of cells in S phase is significantly decreased and senescence (SA-β-galactosidase staining) as well as DNA damage (γH2AX) are observed. Western blot and qPCR analyses demonstrate increased expression of the cell cycle inhibitor p27 and increased phosphorylation of p53 on serine 15. Finally, deletion of SHP-2 in enteroids clearly limits their proliferative capacity and development; notably, few days after, organoids loose their integrity and degenerate in contrast to control organoids that continue to develop. CONCLUSIONS: In summary, our results suggest that SHP-2 protects intestinal epithelial cells against an oncogenic stress leading to senescence. FUNDING AGENCIES: CIHRCRS

Shp-1 (Src homology region 2 domain-containing protein tyrosine phosphatase-1) is a phosphatase that is highly expressed in hematopoietic and epithelial cells. Whereas its function is largely characterized in hematopoietic cells, its role in epithelial cells, such as intestinal epithelial cells (IECs), is not well known. Here, we generated mice with an IEC-specific knockout of Shp-1 (Src homology region 2 domain-containing phosphatase-1; Shp-1IEC-KO). We showed that the loss of epithelial Shp-1 leads to an intestinalomegaly that is associated with an increase in epithelial cell proliferation and size. Histologic analysis demonstrates significant perturbation of the crypt-villus architecture with an apparent increase in the number of goblet and Paneth cells and increased expression of their respective markers {Muc2 (mucin 2), αDef, and Sox9 [SRY (sex determining region Y)-box 9]}. Expansion of intermediate cells-common progenitors of goblet and Paneth cell lineages-is also observed in Shp-1IEC-KO mice. Although sustained activation of Wnt/β-catenin and PI3K/Akt/mammalian target of rapamycin signaling is observed, Shp-1IEC-KO mice fail to develop any intestinal tumors after 15 mo; however, the loss of Shp-1 in IECs markedly enhances tumor load ApcMin/+ mice. These findings show a novel role for Shp-1 in the regulation of IEC growth and secretory lineage allocation, possibly via modulation of PI3K/Akt-dependent signaling pathways. Finally, Shp-1 does not function as a classic tumor suppressor gene in the intestinal epithelium.-Leblanc, C., Langlois, M.-J., Coulombe, G., Vaillancourt-Lavigueur, V., Jones, C., Carrier, J. C., Boudreau, F., Rivard, N. Epithelial Src homology region 2 domain-containing phosphatase-1 restrains intestinal growth, secretory cell differentiation, and tumorigenesis.