Serum starvation drives ALIX-dependent extracellular vesicle biogenesis and determines tumor progression
Xueqiang Peng, Jiaxing Liu, Guolong Zeng, Yafei Xiao, Zhixiong Hao, Guangpeng He, Hongyuan Jin, Yu Gao, Shilei Tang, Shibo Wei, Yan Li, Yifan Yu, Liang Yang, Hangyu Li
Xueqiang Peng, Jiaxing Liu, Guolong Zeng, Yafei Xiao, Zhixiong Hao, Guangpeng He, Hongyuan Jin, Yu Gao, Shilei Tang, Shibo Wei, Yan Li, Yifan Yu, Liang Yang, Hangyu Li
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Research Article Cell biology Oncology

Serum starvation drives ALIX-dependent extracellular vesicle biogenesis and determines tumor progression

Abstract

Tumor cells are constantly confronted with nutrient deprivation; however, the effect of serum starvation on the remodeling of endosomal compartments and extracellular vesicles (EVs) in tumor cells remains unclear. Here, we found that serum starvation pronouncedly promotes multivesicular body (MVB) biogenesis, EV formation, and cargo selection. Specifically, by generating a constitutively active Rab5Q79L mutant to induce the enlargement of MVB, we revealed for the first time to our knowledge that ANXA3 is sorted into intraluminal vesicles (ILVs) of MVB. Mechanistically, we confirmed that serum starvation regulates the endosomal sorting complex required for transport–associated (ESCRT-associated) protein ALG-2 interacting protein X (ALIX), which recruits ESCRT-III to MVB and binds to annexin A3 (ANXA3) to mediate its sorting into ILVs of MVB. Our study highlights that serum starvation promotes an ALIX-dependent ESCRT-III recruitment pathway, which loads protumor ANXA3 cargo to exert a profound effect on tumor progression.

Authors

Xueqiang Peng, Jiaxing Liu, Guolong Zeng, Yafei Xiao, Zhixiong Hao, Guangpeng He, Hongyuan Jin, Yu Gao, Shilei Tang, Shibo Wei, Yan Li, Yifan Yu, Liang Yang, Hangyu Li

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Figure 7

ANXA3+ EVs promote s.c. tumor growth in mice.

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ANXA3+ EVs promote s.c. tumor growth in mice. (A) Schematic of the anima...
(A) Schematic of the animal experiment. Huh7 cells were s.c. injected into nude mice. Three days later, EVs from the indicated groups were administered by tail vein injection every 3 days, and tumors were collected on day 21. (B) Representative tumor images from mice treated with EVs from NC, SS-sgCtrl, SS-sgANXA3, SS-ALIX-WT, and SS-ALIXΔPRR groups. (C and D) Quantification of tumor volume (C) and tumor weight (D). n = 8. (E) Representative IHC images of tumor tissues, including H&E, Ki-67, cleaved caspase-3, and ANXA3 staining. Scale bar: 100 μm. (F) Quantification of Ki-67+ cells in tumor tissues. n = 8. (G) Quantification of cleaved caspase-3+ cells in tumor tissues. n = 8. (H) Quantification of ANXA3 staining intensity in tumor tissues. n = 8. Data are presented as mean ± SD. Statistical analysis was performed using ordinary 1-way ANOVA followed by Tukey’s multiple-comparison test. *P < 0.05, **P < 0.01, ***P < 0.001.