The compound C-3399, which inhibited PDIA1 and PDIA3 rather unselectively, with some preferences to the inhibition of PDIA3 was the most potent inhibitor of adhesion of MDA-MB-231 cells to collagen, underscoring the therapeutic value of non-selective inhibition of PDIA3 and PDIA1 in the regulation of cancer cell adhesion to the cellular matrix. The gene discussed is P4HB; the disease is cancer.