Multiprobe fluorescence imaging and microspectrofluorimetry of cell transformation and differentiation: implications in terms of applied biochemistryand biotechnology

The dichotomy of cellular transformation versus differentiation does not pr eclude the hypothesis of a unified underlying mechanism that can switch eit her way as a result of growth factors, cell-membrane receptors, secondary m essengers, integrating switch kinases and/or nuclear receptors, Its study f or biopharmaceutical and biotechnological applications requires a methodolo gy capable of dealing with such pleiotropy. In the multiprobe-multiparamete r approach, one must remain wary of cumulative toxic effects and misinterpr etations. 'Smart' instrumentation does not mean 'smart' probes. It turns ou t that the cell's own endogenous probes, the fluorescent coenzymes, may be akin to 'smart' probes, open to study in site of many-fold interrelated pat hways in cell energetics and dynamics. Resolution at the micro- and even na no-compartment levels is not altogether impossible. Thus an innovative sear ch in terms of what may be called 'intracellular reconnaissance with fluore scent probes and biopharmaceuticals' necessitates recourse to multiple tent ative probings along the pleiotropic mechanisms as far in resolution as one can go, Among the characteristic findings using this approach are: (i) mor phometric alterations in the mitochondria and melanosomes of melanoma cells treated with azelaic acid; (ii) deregulation of mitochondrial control and extramitochondrial metabolism in similarly treated cells; (iii) considerabl e acceleration of NAD(P) transient kinetics in atractylate-treated L sarcom a cells; (iv) alterations of mitochondria and Golgi in fusion-deficient myo blasts; (v) tentative recognition of beta-glucosidase deficiency in Gaucher disease cells by the use of fluorescent and fluorogenic lysosomal probes; and (vi) UVA-induced accumulation of Schiff bases (a kind of accelerated ph oto-aging) in yeast and kidney epithelial cells, Because these studies util ize probing at whatever points along the concerned pathways become accessib le, at first glance they may look disconnected. What and where is the conne cting thread, for instance, between studying melanoma metabolism, melanosom e morphometry, hepatocyte organelle morphogenesis and transformation, myotu be organelle morphogenesis and fusion-non-fusion, and lysosomal activity in gene-deficient cells! In the mapping of the regulatory and deregulatory me chanisms involved in the switching of differentiation or transformation, ea ch of the above topics carries an information content towards resolution of the pleiotropic puzzle. The integration of such information with increasin g resolution and access to intracellular microdomains may ultimately allow focus on the precise target, the switch from differentiation to transformat ion or vice verse.