Activity of insulin growth factors and shrimp neurosecretory organ extracts on a lepidopteran cell line

Abstract

Ecdysteroids, or molting hormones, have been proven to be key differentiation regulators for epidermal cells in the postembryonic development of arthropods. Regulators of cell proliferation, however, remain largely unknown. To date, no diffusible insect peptidic growth factors have been characterized. Molecules structurally related to insulin have been discovered in insects, as in other eucaryotes. We developed in vitro tests for the preliminary characterization of potential growth factors in arthropods by adapting the procedures designed to detect such factors in vertebrates to an insect cell line (IAL-PID2) established from imaginal discs of the Indian meal moth. We verified the ability of these tests to measure the proliferation of IAL-PID2 cells. We tested mammalian insulin and insulin-like growth factors (IGF-I, IGF-II). Following an arrest of cell proliferation by serum deprivation, IGF-I and IGF-II caused partial resumption of the cell cycle, evidenced by DNA synthesis. In contrast, the addition of 20-hydroxyecdysone arrested the proliferation of the IAL-PID2 cells. The cell line was then used in a test for functional characterization of potential growth factors originating from the penaeid shrimp, Penaeus vannamei. Crude extracts of neurosecretory and nervous tissues, eyestalks, and ventral neural chain compensated for serum deprivation and stimulated completion of mitosis. Arch.

MbIDGF, a novel member of the imaginal disc growth factor family in Mamestra brassicae, stimulates cell proliferation in two lepidopteran cell lines without insulin

“…However, mammalian insulin has shown different effects in other insect cell cultures. For example, insulin could not stimulate cell growth in lepidopteran cell cultures (Ferkovich and Oberlander, 1991;Hatt et al, 1997). For the SESMaBr-5 cell line derived from M. brassicae larval fat bodies, it was also proved that insulin cannot support cell proliferation (Nishino and Mitsuhashi, 1995).…”