diethoxyphosphoryloxymethyl-butanoate and pivalyloxymethyl-butyrate

Histone deacetylase inhibitory prodrugs that are metabolized to butyric acid and formaldehyde possess antineoplastic properties and low toxicity. We sought to characterize the antiangiogenic and antimetastatic activities of two lead prodrugs, pivaloyloxymethyl butyrate (AN-9) and butyroyloxymethyl-diethyl phosphate (AN-7) in murine cancer models. In the sc implanted human colon carcinoma HT-29 xenograft model AN-7, exhibited superior anticancer activity compared to AN-9, as was evident by the significantly greater inhibition of tumor growth and reduction of serum CEA. AN-7 was also more effective in reducing mean vessel density (MVD) by 7-fold, bFGF, Ki-67 (7-fold) and HIF-1alpha in immunohistochemically stained tumor sections. Semi-quantitative evaluation of the levels of bFGF, HDAC1 and HIF-1alpha by Western blot analysis showed a decrease in expression only in the tumors of mice treated with AN-7. The level of bFGF was reduced 3-fold in the tumor and that of TIMP1 was elevated (by 3-fold) in the serum of AN-7 treated mice. In a 4T1 metastatic breast carcinoma model, AN-7 inhibited the formation of lung lesions by 76% and AN-9 by 47%, further demonstrating the greater efficacy of AN-7 compared to AN-9 (P<0.02). Both AN-7 and AN-9 exhibited antimetastatic and antiangiogenic activities by reducing vascularization, bFGF expression and HIF-1alpha. Yet, AN-7 was more potent than AN-9.

Topics: Angiogenesis Inhibitors; Animals; Antigens, CD34; Antineoplastic Agents; Butyrates; Cell Differentiation; Cell Line, Tumor; Cell Proliferation; Enzyme Inhibitors; Histone Deacetylase Inhibitors; Humans; Hypoxia-Inducible Factor 1, alpha Subunit; Mice; Neoplasm Metastasis; Organophosphorus Compounds; PTEN Phosphohydrolase; Tissue Inhibitor of Metalloproteinase-1

The antiangiogenic and antineoplastic activities of the butyric acid prodrugs AN-7 and AN-9 were demonstrated in vitro with HUVEC by inhibition of proliferation and vascular tubes formation, enhanced apoptosis, and inhibition of 22Rv-1 cells migration. In the sc implanted human prostate tumors (22Rv-1) in nude mice, AN-7 significantly inhibited Ki-67, HIF-1alpha, HER-2/neu, bFGF and increased PTEN level. AN-7 and AN-9 reduced hemoglobin accumulation in matrigel plugs implanted sc in Balb-c mice. Herein, we show that the anticancer activity of AN-7 and AN-9 can be attributed in part to their antiangiogenic activities suggesting potential therapeutic benefits for prostate cancer patients.

Topics: Angiogenesis Inhibitors; Animals; Antineoplastic Agents; Apoptosis; Butyrates; Cell Proliferation; Endothelium, Vascular; Fibroblast Growth Factor 2; Humans; Hypoxia-Inducible Factor 1, alpha Subunit; Ki-67 Antigen; Male; Mice; Mice, Inbred BALB C; Mice, Nude; Neovascularization, Pathologic; Organophosphorus Compounds; Prodrugs; Prostatic Neoplasms; PTEN Phosphohydrolase; Receptor, ErbB-2; Tumor Cells, Cultured; Umbilical Veins