Role and mechanism of action of LAPTM4B in EGFR-mediated autophagy.

LAPTM4B is upregulated in the majority of types of cancer and associated with cancer cell proliferation, survival and drug resistance, as well as poor patient prognosis. LAPTM4B knockdown inhibits autophagosome maturation in the context of metabolic stress. Autophagy is a homeostatic process that degrades and recycles intracellular components in response to metabolic stress. The function of autophagy is dual, as this process can either have a tumor suppressor or an oncogenic role. EGFR serves an important role in determining the tumor-suppressive or oncogenic roles of autophagy. EGFR family members regulate autophagy through various signaling pathways, including PI3K/AKT signaling. Notably, LAPTM4B also promotes cancer cell proliferation via the PI3K/AKT signaling pathway. In addition, LAPTM4B can enhance and prolong EGFR signal transduction by blocking active EGFR intraluminal sorting and lysosomal degradation. Thus, LAPTM4B may be associated with autophagy through EGFR signaling. The present review proposed that LAPTM4B participates in regulating autophagy through the EGFR pathway.