| 1. |
- Li, Shuijie, et al.
(författare)
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Impaired oxygen-sensitive regulation of mitochondrial biogenesis within the von Hippel–Lindau syndrome
- 2022
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Ingår i: Nature Metabolism. - : Nature Publishing Group. - 2522-5812. ; 4:6, s. 739-758
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Tidskriftsartikel (refereegranskat)abstract
- Mitochondria are the main consumers of oxygen within the cell. How mitochondria sense oxygen levels remains unknown. Here we show an oxygen-sensitive regulation of TFAM, an activator of mitochondrial transcription and replication, whose alteration is linked to tumours arising in the von Hippel–Lindau syndrome. TFAM is hydroxylated by EGLN3 and subsequently bound by the von Hippel–Lindau tumour-suppressor protein, which stabilizes TFAM by preventing mitochondrial proteolysis. Cells lacking wild-type VHL or in which EGLN3 is inactivated have reduced mitochondrial mass. Tumorigenic VHL variants leading to different clinical manifestations fail to bind hydroxylated TFAM. In contrast, cells harbouring the Chuvash polycythaemia VHLR200W mutation, involved in hypoxia-sensing disorders without tumour development, are capable of binding hydroxylated TFAM. Accordingly, VHL-related tumours, such as pheochromocytoma and renal cell carcinoma cells, display low mitochondrial content, suggesting that impaired mitochondrial biogenesis is linked to VHL tumorigenesis. Finally, inhibiting proteolysis by targeting LONP1 increases mitochondrial content in VHL-deficient cells and sensitizes therapy-resistant tumours to sorafenib treatment. Our results offer pharmacological avenues to sensitize therapy-resistant VHL tumours by focusing on the mitochondria.
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| 2. |
- Sarhan, Dhifaf, et al.
(författare)
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Antibody targeting of tumor associated macrophages in lung cancer remodel the tumor microenvironment and revives immune targeting of tumor cells
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Annan publikation (övrigt vetenskapligt/konstnärligt)abstract
- Immunotherapy for cancer has revolutionized clinical practice and enabled cures for previously lethal cancers. However, the clinical responses are variable and highly influenced by immune regulatory compartments in the tumor microenvironment. This is especially true for immune-excluded tumors, where clinical trials aiming to recover T cell anti-tumor activity have been disappointing. Thus, in NSCLC and other cancers there is a clinical need for additional and combinatory treatments. We have previously shown that antibodies targeting scavenger receptors expressed on tumor-associated macrophages (TAMs), reduces tumor growth and impair metastasis in murine cancer models. Here we investigated targeting of the scavenger receptor MARCO on human TAMs in NSCLC. We found that expression of this receptor in the tumor correlated with immune-exclusion phenotype. Also, we found that lung cancer cell lines converted healthy myeloid cells towards TAM like cells with high expression of MARCO. These human MARCO+ myeloid cells stopped cytotoxic T cells and natural killer (NK) cells from killing tumors and inhibited their overall activity. We then generated anti-human MARCO antibodies and found that these could repolarize TAMs leading to augmented cytolytic ability of NK cells and T cells to kill tumor cells and recovered their proliferation and IFNγ production capacity. Overall, our data demonstrate that it is feasible to use antibodies to alter human TAM immune suppression of NK and T cell anti-tumor activities.
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| 3. |
- Sarhan, Dhifaf, et al.
(författare)
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Targeting myeloid suppressive cells revives cytotoxic anti-tumor responses in pancreatic cancer
- 2022
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Ingår i: ISCIENCE. - : Elsevier BV. - 2589-0042. ; 25:11, s. 105317-
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Tidskriftsartikel (refereegranskat)abstract
- Immunotherapy for cancer that aims to promote T cell anti-tumor activity has changed current clinical practice, where some previously lethal cancers have now become treatable. However, clinical trials with low response rates have been disappointing for pancreatic ductal adenocarcinoma (PDAC). One suggested explanation is the accumulation of dominantly immunosuppressive tumor-associated macrophages and myeloid-derived suppressor cells in the tumor microenvironment (TME). Using retrospectively collected tumor specimens and transcriptomic data from PDAC, we demonstrate that expression of the scavenger receptor MARCO correlates with poor prognosis and a lymphocyte-excluding tumor phenotype. PDAC cell lines produce IL-10 and induce high expression of MARCO in myeloid cells, and this was further enhanced during hypoxic conditions. These myeloid cells suppressed effector T and natural killer (NK) cells and blocked NK cell tumor infiltration and tumor killing in a PDAC 3D-spheroid model. Anti-human MARCO (anti-hMARCO) antibody targeting triggered the repolarization of tumor-associated macrophages and activated the inflammasome machinery, resulting in IL-18 production. This in turn enhanced T cell and NK cell functions. The targeting of MARCO thus remodels the TME and represents a rational approach to make immunotherapy more efficient in PDAC patients.
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