Activation of PKC? and Rac1 promotes invadopodia reassembly through optogenetically engineered Ca2+ oscillations

Abstract

Calcium (Ca2+) plays an important role in the signal transduction of cells regulating the physiological activities of cells such as fertilization cell proliferation cell contraction cell migration and apoptosis Invadopodia is a protrusion on the cell membrane that uses metalloproteinases to degrade the extracellular matrix Invadopodia plays an important role in the invasion and metastasis of cancer cells Ca2+ has also been shown to be important for the formation of invadopodia and the disintegration of extracellular matrices by cancer cells However in the previous literature on this topic there has been no precise study to indicate what kind of Ca2+ signal causes invadopodia assembly Optogenetic technology is a research method that provides high temporal and spatial resolution and has been developed and applied to many precise biological and medical studies Therefore we use optogenetic techniques combining 470 nm of blue light to activate light-sensitive channels (Ca2+ translocating channelrhodopsin CatCh) expressed on human melanoma cancer cells (A375) to create different oscillating waves so that Ca2+ signals can flow into cells in different oscillating waves In this study we explore how Ca2+ signals affect the formation of invadopodia Our research showed that low frequency (0 01 Hz 0 1 Hz) Ca2+ oscillations promoted reassembly of invadopodia while high frequency (1 Hz) Ca2+ oscillations caused the collapse of invadopodia In addition we also found that low frequency Ca2+ oscillation caused by light stimulation promotes the reassembly of invadopodia by activating PKC? (protein kinase C alpha) and Rac1 (Ras-related C3 botulinum toxin substrate 1) As for the role of RhoA (Ras homolog gene family member A) and Cdc42 (Cell division control protein 42 homolog) in this process we need further research to prove it

Date of Award	2019
Original language	English
Supervisor	Wen-Tai Chiu (Supervisor)