DHFR-IN-3 (7-bromoquinazoline-2,4-diamine) is a dihydrofolate reductase (DHFR) inhibitor.

EGFR/HER2/DHFR-IN-3 (compound 4c) serves as an efficacious dual inhibitor specifically targeting EGFR/HER2, exhibiting IC50 values of 0.138 μM for EGFR and 0.092 μM for HER2, respectively. Moreover, it demonstrates inhibition of DHFR with an IC50 of 0.193 μM. Notably, this compound induces cell cycle arrest in the S phase and triggers apoptosis in MCF7 breast cancer cells [1].

EGFR/HER2/DHFR-IN-2 (Compound 4b) serves as an inhibitor for EGFR, HER2, and DHFR, with IC50 values of 0.248, 0.156, and 0.138 μM, respectively. It exhibits anticancer activity, displaying IC50 values of 9.14, 7.33, 14.18, 24.87, 20.07, and 6.16 μM in Hep G2, HeLa, HEp-2, HCT 116, PC-3, and MCF7 cancer cell lines, respectively. Additionally, EGFR/HER2/DHFR-IN-2 has been shown to reduce the growth of breast cancer tumors [1].

DHFR-IN-9 (compound 8A), a dihydrofolate reductase (DHFR) inhibitor, impedes purine and thymidylate biosynthesis, pivotal in cell proliferation and growth. It demonstrates potency against methicillin-resistant Staphylococcus aureus (MRSA) ATCC 43300 with an IC50 of 0.25 μg/mL and exhibits anti-infective properties in mouse systemic and thigh infection models at doses of 2.5 mg/kg and 5 mg/kg administered intraperitoneally (ip). Furthermore, DHFR-IN-9 shows greater anticancer efficacy in a mouse breast cancer model compared to paclitaxel (Y-B0015), at a regimented dosage of 2.5 mg/kg ip every three days [1].

Brivudine monophosphate is a phosphate ester of Brivudine. Brivudine, also known as bromovinyl-deoxyuridine, is a uridine derivative and nucleoside analog with pro-apoptotic and chemosensitizing properties. In vitro, bromovinyl-deoxyuridine (BVDU) has been shown to downregulate the multifunctional DNA repair enzyme APEX nuclease 1, resulting in the inhibition of DNA repair and the induction of apoptosis. In addition, this agent may inhibit the expression of STAT3 (signal transducer and activator of transcription 3), which may result in the downregulation of vascular endothelial growth factor (VEGF). BVDU has also been found to inhibit the upregulation of chemoresistance genes (Mdr1 and DHFR) during chemotherapy.