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Objective: To study how the combined effects of various differentiation inducers and heat stress on the expression of JWA protein in K562 cell, the relationship between JWA and Hsp70 expression, and the signal regulation mechanism possibly involved., Methods: The experimental model was established in K562 cells. Various directional differentiation inducers (TPA, Ara-C, hemin, adriamycin, ATRA and As(2)O(3)) were used alone or combined with heat shock treatment (42 degrees C, 2 h). Western blot was used for detecting expressions of JWA, Hsp70, heat stress factor 1 (HSF1) and HSF2., Results: (1) The expressions of both JWA protein and Hsp70 were significantly up-regulated after K562 cells treated by TPA (100, 200 ng/ml) or adriamycin (4 x 10(-8) mol/L) 48 h, and followed by heat shock (42 degrees C, 2 h). However, the opposite effects were observed when the cells treated by hemin (3 x 10(-5) mol/L, 48 h), Ara-C (80 ng/ml, 48 h) and As(2)O(3) (1 x 10(-6) mol/L, 48 h) followed by 2 h heat shock. No obvious changes were found when the cells treated by ATRA (1 x 10(-6) mol/L, 48 h) alone or followed by heat shock. (2) Both the heat shock transcriptional factors HSF1 and HSF2 did not show any significant changes when K562 cells were treated with various differentiation inducers and followed by heat stress., Conclusion: JWA not only takes part in the regulation of K562 cellular differentiation, but also of heat stress, it might be the co-target gene of several differentiation inducers and heat stress. The expression of Hsp70 seems not mediated by both HSF1 and HSF2 in K562 cells undergoing directional differentiation or heat stress treatment. JWA is likely to be a new signal molecule similar to Hsp70 signal pathways. The results show that JWA takes part in the mechanism of K562 cell response to heat stress.

Objective: To study the expression of JWA protein and heat shock protein (Hsp70), and to explore these relationship and the possible mechanism of JWA gene involved in induced differentiation and heat stress (42 degrees C) of K562 cells., Methods: The models of differentiation and heat stress of K562 cells were established. Western blot was used for detecting expressed proteins of JWA gene, Hsp70, heat shock factor (HSF1 and HSF2)., Results: (1) Under the condition of differentiations induced by TPA (100 ng/ml), hemin (3 x 10(-5) mol/L), Ara-C (80 ng/ml), adriamycin (4 x 10(-8) mol/L), ATRA (1 x 10(-6) mol/L) and As(2)O(3) (1 x 10(-6) mol/L) for 48 h respectively, the expression of JWA protein and Hsp70 were more significantly increased than control; the level of HSF2 protein was increased by inductions of hemin, Ara-C and adriamycin, respectively. (2) After heat exposure to 42 degrees C for 10, 20, 30, 45, 60, 90 min, and heat exposure to 39 degrees C, 42 degrees C, 45 degrees C, the trend of changing in expression of Hsp70 was similar to that of JWA protein, and HSF1 was expressed in earlier stage., Conclusion: The expression of JWA protein and Hsp70 were upregulated in induced differentiation and in heat stress, and the change of expression of JWA protein were similar to that of Hsp70, but the intracellular transduction signal pathways involved may be various. JWA might not be specifically related with both HSF1 and HSF2.