Table 3: Drugs, their mode of action, and reported effects on GJIC and breast tumor.

DrugMode of actionAnti-breast tumor effect

Organochlorine compound TCDDNonspecific, increases phosphorylated Cx43 and GJICDecreases GJIC
PQ1 quinolone derivativeNonspecific, increases Cx43 expression and increases GJICDecreases colony formation ability and xenograft tumor growth of T47D cells
PQ1 + cisplatinCombination treatment, bystander effectReduces T47D cell proliferation synergizing with cytotoxic effects of cisplatin
Peptide ACT1Increases gap junction aggregation by redirecting uncoupled Cx43 hemichannels into the membraneReduces MCF-7 and MDA-MB-231 cell proliferation in vitro
ACT1 + tamoxifenCombination treatment, bystander effectAugments tamoxifen cytotoxic effects on MCF-7 cells
All-trans-retinoic acid (ATRA) + VEGFP-TK/CD gene suicide systemATRA increases GJIC and mediates bystander effects to induce cell killing by gene suicide systemIncreases apoptotic MCF-7 cell death
Anti-Cx46Knocks down Cx46Reduces MCF-7 viability under hypoxia and inhibits xenograft tumor growth