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Lau, A. P. Y.

Publications and source records attributed to Lau, A. P. Y..

2 recordsLinked to original sources

Upregulation of PD-L1 as a putative mechanism of resistance to CD47 inhibition in non-small cell lung cancer

CD47 is a "dont eat me" signal that suppresses macrophage-mediated phagocytosis. Its upregulation in lung and other cancers facilitates tumour immune escape, making CD47 a promising immunotherapeutic target. Studies have demonstrated anti-tumour efficacy of CD47 blockade in preclinical lung cancer models, but monoclonal antibodies targeting CD47 have had limited efficacy as monotherapy in solid tumour patients to date. This discrepancy may in part reflect the use of human tumour xenografts in mice that do not have fully-functioning immune systems in preclinical efficacy studies. Thus, understanding tumour responses to CD47 inhibition using immune competent lung cancer models is needed to inform strategies to harness its therapeutic potential. Here, we characterized the effects of CD47 knockout (KO) on tumour growth and immune responses in two syngeneic, orthotopic murine lung cancer models, LLC-Luc (LLC) and CMT167 (CMT). As expected, CD47 KO impaired the fitness of LLC and CMT cells in vivo. Mice with CD47-deficient tumours exhibited prolonged survival and increased infiltration of anti-tumour leukocytes. However, although CD47 KO impaired lung tumour growth in syngeneic mice, KO tumours were ultimately lethal. Immunophenotyping revealed an increased prevalence of PD-L1+ cells in CD47-deficient tumours, nominating PD-L1-mediated suppression of tumour immunity as an acquired mechanism of resistance to CD47 blockade. Concordantly, dual inhibition of CD47 and PD-L1 extended the survival of CMT tumour-bearing mice compared to inhibition of either alone. These findings suggest that PD-L1 blockade could be leveraged to overcome resistance and potentiate the efficacy of CD47-targeted immunotherapy in lung cancer.

cancer biology↗

CD47 regulates pro-metastatic phenotypes through an ERK-dependent epithelial-to-mesenchymal transition program in non-small cell lung cancer

CD47 is best known for its role in tumor immune evasion; however, studies in diverse cell models indicate that it also has cell-autonomous, tumor-promoting functions which are cell type- and context-specific. Motivated by the prognostic and therapeutic significance of CD47 and the limited knowledge regarding its roles beyond immune evasion in non-small cell lung cancer (NSCLC), we sought to define the cellular and molecular processes driven by intrinsic CD47 signaling in NSCLC. Transcriptome profiling of CD47 wildtype and knockout NSCLC cells implicated its regulation of genes enriched for signatures of MAPK signaling and epithelial-to-mesenchymal transition (EMT). A significant positive association between CD47 and MAPK/EMT expression signatures was also evident in large cohorts of NSCLC cell lines and tumor tissues. Functional studies indicated that CD47 does not regulate cell proliferation in NSCLC cells like it does in other cancer types. Instead, CD47 regulates cell adhesion and migration through an ERK and EMT axis, validating our transcriptomic findings. Moreover, CD47 loss-of-function significantly diminished the ability of NSCLC cells to metastasize in vivo, demonstrating the physiological relevance of cell-intrinsic CD47 signaling in lung cancer cells. Our data reveal a novel role for CD47 in relaying signals through ERK to promote EMT expression programs and pro-metastatic phenotypes in NSCLC. Although additional mechanistic studies are needed to further decipher the CD47-ERK-EMT signaling pathway, our findings reinforce the therapeutic potential of CD47, rationalizing further research to develop CD47 blockade as a multimodal therapy for NSCLC.

cancer biology↗