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- Bellavia, D, et al.
(författare)
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Combined expression of pTalpha and Notch3 in T cell leukemia identifies the requirement of preTCR for leukemogenesis
- 2002
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Ingår i: Proceedings of the National Academy of Sciences of the United States of America. - : Proceedings of the National Academy of Sciences. - 0027-8424. ; 99:6, s. 3788-3793
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Tidskriftsartikel (refereegranskat)abstract
- Notch receptors are conserved regulators of cell fate and have been implicated in the regulation of T cell differentiation and lymphomagenesis. However, neither the generality of Notch involvement in leukemia, nor the molecules with which Notch may interact have been clarified. Recently, we showed that transgenic mice expressing the constitutively active intracellular domain of Notch3 in thymocytes and T cells developed early and aggressive T cell neoplasias. Although primarily splenic, the tumors sustained features of immature thymocytes, including expression of pTα, a defining component of the pre T cell receptor, known to be a potent signaling complex provoking thymocyte survival, proliferation, and activation. Thus, enforced expression of Notch3, which is ordinarily down-regulated as thymocytes mature, may sustain pre T cell receptor expression, causing dysregulated hyperplasia. This hypothesis has been successfully tested in this article by the observation that deletion of pTα in Notch3 transgenic mice abrogates tumor development, indicating a crucial role for pTα in T cell leukemogenesis. Parallel observations were made in humans, in that all T cell acute lymphoblastic leukemias examined showed expression of Notch3 and of the Notch target gene HES-1, as well as of pTα a and b transcripts, whereas the expression of all these genes was dramatically reduced or absent in remission. Together, these results suggest that the combined expression of Notch3 and pTα sustains T cell leukemogenesis and may represent pathognomonic molecular features of human T-ALL.
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- Suzuki, Toshiyasu, et al.
(författare)
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b-Catenin Drives Butyrophilin-like Molecule Loss and gd T-cell Exclusion in Colon Cancer
- 2023
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Ingår i: CANCER IMMUNOLOGY RESEARCH. - : AMER ASSOC CANCER RESEARCH. - 2326-6066. ; 11:8, s. 1137-1155
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Tidskriftsartikel (refereegranskat)abstract
- Intraepithelial lymphocytes (IEL) expressing y8 T-cell receptors (y8TCR) play key roles in elimination of colon cancer. However, the precise mechanisms by which progressing cancer cells evade immu-nosurveillance by these innate T cells are unknown. Here, we investigated how loss of the Apc tumor suppressor in gut tissue could enable nascent cancer cells to escape immunosurveillance by cytotoxic y8IELs. In contrast with healthy intestinal or colonic tissue, we found that y8IELs were largely absent from the micro-environment of both mouse and human tumors, and that butyr-ophilin-like (BTNL) molecules, which can critically regulate y8IEL through direct y8TCR interactions, were also downregulated in tumors. We then demonstrated that 13-catenin activation through loss of Apc rapidly suppressed expression of the mRNA encoding the HNF4A and HNF4G transcription factors, preventing their binding to promoter regions of Btnl genes. Reexpression of BTNL1 and BTNL6 in cancer cells increased y8IEL survival and activation in coculture assays but failed to augment their cancer-killing ability in vitro or their recruitment to orthotopic tumors. However, inhibition of 13-catenin signaling via genetic deletion of Bcl9/Bcl9L in either Apc-deficient or mutant 13-catenin mouse models restored Hnf4a, Hnf4g, and Btnl gene expression and y8 T-cell infiltration into tumors. These observations highlight an immune-evasion mechanism specific to WNT-driven colon cancer cells that disrupts y8IEL immunosurveillance and furthers cancer progression.
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