A protumorigenic secretory pathway activated by p53 deficiency in lung adenocarcinoma
Xiaochao Tan, … , Chad J. Creighton, Jonathan M. Kurie
Xiaochao Tan, … , Chad J. Creighton, Jonathan M. Kurie
Published September 15, 2020
Citation Information: J Clin Invest. 2021;131(1):e137186. https://doi.org/10.1172/JCI137186.
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Research Article Cell biology Oncology

A protumorigenic secretory pathway activated by p53 deficiency in lung adenocarcinoma

Abstract

Therapeutic strategies designed to target TP53-deficient cancer cells remain elusive. Here, we showed that TP53 loss initiated a pharmacologically actionable secretory process that drove lung adenocarcinoma (LUAD) progression. Molecular, biochemical, and cell biological studies showed that TP53 loss increased the expression of Golgi reassembly and stacking protein 55 kDa (G55), a Golgi stacking protein that maintains Golgi organelle integrity and is part of a GOLGIN45 (G45)–myosin IIA–containing protein complex that activates secretory vesicle biogenesis in the Golgi. TP53 loss activated G55-dependent secretion by relieving G55 and myosin IIA from miR-34a–dependent silencing. G55-dependent secreted proteins enhanced the proliferative and invasive activities of TP53-deficient LUAD cells and promoted angiogenesis and CD8+ T cell exhaustion in the tumor microenvironment. A small molecule that blocks G55-G45 interactions impaired secretion and reduced TP53-deficient LUAD growth and metastasis. These results identified a targetable secretory vulnerability in TP53-deficient LUAD cells.

Authors

Xiaochao Tan, Lei Shi, Priyam Banerjee, Xin Liu, Hou-Fu Guo, Jiang Yu, Neus Bota-Rabassedas, B. Leticia Rodriguez, Don L. Gibbons, William K. Russell, Chad J. Creighton, Jonathan M. Kurie

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Figure 6

G55-dependent secretion and LUAD progression require G55/G45 interactions.

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G55-dependent secretion and LUAD progression require G55/G45 interaction...
(A) Co-IP of G55 and G45. IP/WB assays on H1299 cells cotransfected with GFP-tagged G55 (GFP-G55) and HA-tagged WT or mutant (L400R) G45 (HA-G45). (B) WB analysis of H1299 cells cotransfected with G45 shRNA and WT or mutant (L400R) G45 (G45). Control vectors indicated by (–). Arrow indicates endogenous G45. (C) Anchorage-independent colony formation using cells in B. (D) Co-IP of G55 and G45. IP/WB analysis of H1299 cells cotransfected with HA-tagged G45 and GFP-tagged WT or mutant (G97D) G55. (E) WB analysis of H1299 cells cotransfected with G55 shRNA (shG55) and WT or mutant (G97D) G55. Endogenous (G55) and ectopic (G55-EGFP) G55. (F) WB analysis of CM samples from cells in E. (G) Anchorage-independent colony formation assays on cells in E. (H) Primary tumor weights and lung metastasis numbers at necropsy 5 weeks after subcutaneously injecting 1 × 106 344SQ cells into syngeneic, immunocompetent mice. Transfectants generated using the same vectors described in E. (I) Co-IP of G55 and G45. IP/WB assays on H1299 cells cotransfected with GFP-tagged G55 and a G45 peptide that blocks G55/G45 interactions (G45 BP). Empty vector indicated by (–). Arrow indicates endogenous G45. (J) Anchorage-independent colony formation using H1299 cells or 344SQ cells transfected with G45 BP or empty vector (–). (K) Primary tumor weights and lung metastasis numbers at necropsy 5 weeks after subcutaneous injection of 344SQ cells in J. (L) Kaplan-Meier analysis of nu/nu mice bearing orthotopic lung tumors generated by H1299 cells in J. Results represent mean ± SD. n = 3, unless otherwise indicated. P values: ANOVA (C, G, and H), log-rank test (L), 2-sided t test (all others).