Tri‐dimensional prostate cell cultures in simulated microgravity and induced changes in lipid second messengers and signal transduction

Abstract

The high aspect rotating‐wall vessel (HARV) was designed to cultivate cells in an environment that simulate microgravity. We studied previously the effects of HARV cultivation on DU‐145 human prostate carcinoma cells. We determined that HARV cultivation produced a less aggressive, slower growing, less proliferative, more differentiated and less pliant cell than other cell cultivation methods. The result was a 3‐dimensional (3D) growth model of prostate cancer which mimics in vivo tissue growth. This work examines the signal transduction‐second messenger pathways existing temporarily in these HARV cells and correlates these features with the special properties in growth and 3D spheroid formation. We found an initial very active ceramide, a diacylglycerol increase together with increases in PI‐PLC and PLA2 a central defect in PLD (no phosphatic acid or phosphatidylethanol at any time during 15 days of HARV cultivation). There is a cross‐talk between ceramide and PI3K pathways with activation of PI3K, after 6 days of HARV growth concomitant with down‐regulation of ceramide. At this time, there is also an increase of cAMP (seen by increases in arachidonic acid). Taken together these results can explain the 3D organoidlike growth. We therefore developed a model for growth in HARV prostate cancer cells which involve temporal “switches” between second messengers, activation and cross‐talk between multiplicity of signaling pathways and a central defect in PLD pathways. Essential to the late slow growth, and 3D organotypic formation are the apoptotic, anti‐survival, anti‐proliferation and differentiation pathways in the first days of HARV, with growth of “new” different types of prostate cancer cells which set‐up for later “switch” in ceramide‐PI3K to survival and proliferation.

Cellular adaptations to hypoxia and acidosis during somatic evolution of breast cancer

“…By maintaining the spheroids in microgravity (Doolin et al, 1999;Clejan et al, 2001;Dabos et al, 2001), we find they reliably achieve diameters of 5 -10 mm. This size has three advantages: (1) it is similar to the diameter of many clinical lobular and ductal carcinoma in situ tumours; (2) it is much greater than the predicted diffusion limit of oxygen so that central regions of hypoxia and acidosis will develop; (3) it contains a larger number of cells than conventional spheroids, increasing the probability that evolution driven by rare mutations will be manifested during the 30-day observation period.…”

Growing Tissues in Real and Simulated Microgravity: New Methods for Tissue Engineering

“…78 Clejan et al showed that the activation of apoptotic pathways during an early phase of culturing DU-145 human prostate carcinoma cells in a HARV is essential for the subsequent formation of 3D organoids. 79 Our experiments on the RPM on FTC-133 thyroid cancer cells suggested that initiation of an early phase of apoptosis, followed by an escape from the late phase, could be a step in cells that transit from a 2D to a 3D kind of growth. 80 In this process the signaling elements IL-6, IL-8, OPN, TLN1, and CTGF are involved with NF-kB p65.…”

Effects of simulated weightlessness on cellular morphology and biological characteristics of cell lines SGC-7901 and HFE-145

“…Regarding the biological characteristics of carcinoma cells, weightlessness or simulated weightlessness can cause slower growth, lower proliferation, and better differentiation in human prostate cells, as well as activation of second messengers and reciprocity between different signal transduction passages (Clejan et al, 2001). It can also cause early apoptosis, redistribution of mitochondria, and destruction of microtubules in human thyroid carcinoma cells (Kossmehl et al, 2002).…”