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.
View: Text | PDF
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

×

Figure 2

G55 is a driver of TP53-mutant LUAD progression.

Options: View larger image (or click on image) Download as PowerPoint
G55 is a driver of TP53-mutant LUAD progression. (A) WB analysis of TP53...
(A) WB analysis of TP53-mutant LUAD cell lines transfected with G55 (siG55#1, #2) or control (siCTL) siRNA. (B) Cell proliferation in monolayer culture quantified at 4 days by WST-1 assays. Results relative to siCTL controls. n = 5. (C) Anchorage-independent colony formation quantified after 10 days in soft agarose. Results relative to siCTL controls. (D) Boyden chamber assays. FBS (10%) added to bottom chamber as chemoattractant. Cells that migrated or invaded through porous filter (Matrigel-coated for invasion assays) photographed 8 hours after seeding in upper chamber and counted manually. Results relative to siCTL controls. (E) qPCR analysis of TP53-WT and TP53-mutant (MT) LUAD cell lines. Results relative to siCTL. (F and G) Anchorage-dependent colony formation. Cells seeded at low density on plastic. Results expressed as fractions (F) or percentage reductions (G) relative to siCTL in TP53-WT and TP53-mutant (MT) cell lines (G). (H) WB analysis of 344SQ cells transfected with G55 (shG55#1, #2, #3) or control (shCTL) shRNAs. G55 densitometric values relative to shCTL. (I) Primary subcutaneous tumor weight (left plot) and lung metastasis numbers (right plot) per mouse (dots). Necropsies performed 5 weeks after subcutaneous injection of 344SQ cells into syngeneic, immunocompetent mice. (J) Kaplan-Meier analysis of mouse cohorts bearing G55-deficient (shG55) or G55-replete (shCTL) 344SQ orthotopic lung tumors (n = 10 mice per cohort). (K) WB analysis of 344P LUAD cells transfected with GFP-tagged G55 or empty (Vec) expression vectors. (L) Primary tumor weights (left plot) and lung metastasis numbers (right plot) determined at necropsy 5 weeks after subcutaneous injection of tumor cells. Results represent mean ± SD. n = 3, unless otherwise indicated. P values: ANOVA (B–D and I), log-rank test (J), 2-sided t test (all others).