1,4-DPCA is a competitive inhibitor of prolyl 4-hydroxylase with IC50 value of 3.6 μM [1].

Prolyl hydroxylase catalyzes the formation of hydroxyproline, which has a significant impact on the stability of collagen- the major connective tissue of the human body. Increased collagen deposition produces physical and biochemical signals to sustain tumor growth, resulting in tumor invasion and development. Therefore, 1,4-DPCA has been considered as a treatment strategy to suppress cancer progression as it inhibits collagen synthesis and deposition.

The suppression effect of 1,4-DPCA had been shown in human breast cancer cells. The activity of prolyl-4-hydroxylase was inhibited by 1, 4-DPCA, resulting in decreased deposition of collagen I and IV. In breast tumor cell lines ZR-75-1, T4-2, MDA-MB-157 and MDA-MB-231, treatment with 1,4-DPCA reduced cell proliferation and colony sizes, and formed smaller and less aggressive structures of these four cell lines[2].

References:
[1].  T. J. Franklin, W. P. Morris, P. N. Edwards, et al. Inhibition of prolyl 4-hydroxylase in vitro and in vivo by members of a novel series of phenanthrolinones. Biochemistry Journal 353, 333-338 (2001).
[2].  Xiong G, Deng L, Zhu J, et al. Prolyl-4-hydroxylase α subunit 2 promotes breast cancer progression and metastasis by regulating collagen deposition. BMC Cancer, 2014 Jan 2; 14:1.