Expression of hsp 27, hsp 60, hsc 70, and hsp 70 mRNA and protein in UROtsa cells acutely exposed to heat shock.
The similarity in response of the UROtsa cells to acute chemical stress and heat shock also extended to hsc 70 and hsp 70, the constitutive and inducible members of the 70-kDa heat shock family (Figure 6E,F).
Expression of hsp 27, hsp 60, hsc 70 and hsp 70 mRNA and protein in UROtsa cells exposed to NaAs[O.sub.2] for 16 days.
For hsc 70, there was no difference in the expression of mRNA or protein for any of the three exposures to NaAs[O.sub.2] over the 16 day period of exposure (Figure 7E,F).
The levels of the hsp 70 protein were 2-3-fold higher relative to that of hsc 70 protein in UROtsa cells exposed to the highest level of NaAs[O.sub.2] and equal to hsc 70 at the intermediate level of exposure.
The heat shock proteins are a large super-family of proteins with molecular weights ranging from 8 to 170 kDa, with the members referred to as hsp 27, hsp 60, hsc 70 (constitutive form), hsp 70 (inducible form), and hsp 90 being the proteins classically identified to be induced as a result of heat treatment of mammalian cells (Macario 1995).
The finding that hsc 70 expression was unaffected by acute exposure to heat or NaAs[O.sub.2] in the UROtsa cells was the response expected from the literature.
Only a few studies have examined the expression of hsp 27, hsp 60, hsc 70, and hsp 70 when cells are continually exposed to stressful stimuli over an extended period.
The expression of hsp 27, hsp 60, and hsc 70 in the UROtsa cells exposed to lethal and sublethal levels of NaAs[O.sub.2] for 16 days was similar to that of the HPT cells.
Abbreviations: RWC, relative water content; EL, electrolyte leakage; SDS-PAGE, sodium dodecyl sulfate-polyacrylamide gel electrophoresis; HS 70, heat shock 70 kDa; HSC 70
, heat-shock cognate 70 kDa; PMSF, phenylmethylsulfonyl fluoride; LSD, least significance difference.
This agreement between mRNA and protein expression was also demonstrated for the hsp 60 and hsc 70 protein (Figure 5).
A similar analysis of hsp 27, hsp 60, hsc 70, and hsp 70 expression demonstrated complete agreement in the basal patterns of expression of hsp 27, hsp 60, and hsc 70 between the cultured cells and in situ urothelium (9-11).