Heat shock proteins HSPA1/Hsp70α and HSP90AA1/Hsp90α are crucial for cancer growth but their expression pattern in colorectal polyps or whether they can be modulated by oxicams is unknown. We quantified (RTqPCR) HSPA1 and HSP90AA1 expression in 50 polyp-normal pairs in relation to polyp malignancy potential and examined the effect of piroxicam, meloxicam and five novel analogues on HSPA1 and HSP90AA1 expression (mRNA/protein) in colorectal adenocarcinoma lines. HSPA1 and HSP90AA1 were upregulated in polyps by 3- and 2.9-fold. Expression ratios were higher in polyps with higher dysplasia grade and dominant villous growth pattern, mostly a result of diminished gene expression in normal tissue. Classic oxicams had negligible/non-significant effect on HSP expression. Their most effective analogue inhibited HSPA1 protein and gene by 2.5-fold and 5.7-fold in Caco-2 and by 11.5-fold and 6.8-fold in HCT116 and HSPA1 protein in HT-29 by 1.9-fold. It downregulated HSP90AA1 protein and gene by 1.9-fold and 3.7-fold in Caco-2 and by 2-fold and 5.0-fold in HCT116. HSPA1 and HSP90AA1 are upregulated in colorectal polyps reflecting their potential for malignancy. HSPA1 in cancer cells and, to lesser degree, HSP90AA1 can be reduced by oxicam analogues with thiazine ring substituted via propylene linker by arylpiperazine pharmacophore with fluorine substituents and by benzoyl moiety.
Keywords: chemoprevention; colorectal adenomas; colorectal cancer; drug repurposing; meloxicam; molecular-targeted therapies; nonsteroidal anti-inflammatory drugs; piroxicam; proteostasis.