Cyclopentenylcytosine

Cyclopentenylcytosine (CPEC), a carbocyclic nucleoside analog of cytosine, is a potent inhibitor of CTP synthetase and causes depletion of CTP and dCTP pools. Cyclopentenylcytosine shows broad-spectrum (both DNA and RNA viruses) antiviral activity. Cyclopentenyl cytosine increases Gemcitabine (HY-17026) radiosensitisation in human pancreatic cancer cells. Cyclopentenylcytosine shows effective antiviral activity in the Ad5/NZW rabbit ocular replication model and shows anti-tumor activity in various tumor xenografts model. Cyclopentenylcytosine can be used for the study of infection and cancer^[1][2][3][4]. In Vitro:Cyclopentenylcytosine (0.001-100 µg/mL) exhibits potent antiviral activity against nine common ocular adenovirus types (HAdV8, HAdV19/64, HAdV37 (EKC), HAdV3, HAdV4, HAdV7a,HAdV1, HAdV2, HAdV5) in A549 cells using plaque reduction assays with EC₅₀ values ranging from 0.03 to 0.059 µg/mL ^[1].
Cyclopentenylcytosine induces rapid and complete differentiation of HL-60 promyelocytic cells, with a concomitant reduction in c-myc RNA levels preceding the appearance of differentiated cells^[2].
Cyclopentenylcytosine (0.1 µg/mL, 4 days) reduces the number of viable Vero cells^[2].
Cyclopentenylcytosine shows potent activity against HSV-1 (TK+ and TK-) with ID₅₀ values of 0.3 μg/mL and 0.6 μg/mL respectively, against HSV-2 (ID₅₀ = 2.7 μg/mL), vaccinia virus (ID₅₀ = 0.1 μg/mL), Japanese encephalitis virus (ID₅₀ = 0.10 μg/mL), vesicular stomatitis virus (ID₅₀ = 0.25-0.57 μg/mL), yellow fever (ID₅₀ = 5.05 μg/mL), Punta Toro virus (ID₅₀ = 1.01 μg/mL), and Hong Kong influenza virus (ID₅₀ = 18.2 μg/mL) in vitro^[2].
Cyclopentenylcytosine (100 nM, 0-4 days) causes accumulation of cells in the S phase and inhibits DNA synthesis in SK-N-BE(2)c cells^[3].
Cyclopentenylcytosine (100 nM, 1-4 days) increases caspase-3 activity in SK-N-BE(2)c cells, indicating induction of apoptosis^[3].
Cyclopentenylcytosine (30-1000 nM, 4-72 h) specifically reduces CTP levels and increases gemcitabine (dFdC) incorporation into DNA in a dose-dependent manner in human pancreatic cancer cells (Panc-1, Miapaca-2, BxPC-3) and NSCLC cells (SWp)^[4].
Cyclopentenylcytosine (100 nM, 48 h) enhances the cytotoxicity of dFdC (300 nM, 4 h) in dFdC-sensitive cells (Panc-1, Miapaca-2, BxPC-3, SWp), increasing growth inhibition, reducing clonogenic capacity, and promoting apoptosis^[4].
In Vivo:Cyclopentenylcytosine (3% ointment, topical application, 2 or 4 times daily, 7 days) exhibits effective antiviral activity in Ad5/NZW rabbit ocular replication model^[1].
Cyclopentenylcytosine (0.5-4 mg/kg, intraperitoneal injection, daily on days 1-9or every 4 times day on days 1, 5, 9 or every 3 hours for 8 times on days 1, 5, 9) exhibits an increase in life span (ILS) with a log cell kill (LCK) in CD2F1 mice bearing L1210 leukemia^[2].
Cyclopentenylcytosine (1.0-2.25 mg/kg, subrenal capsule injection, daily on days 1-9) inhibits the growth of tumor in mice bearing A549 lung tumor xenografts, LOX melanoma xenografts and MX-1 mammary xenografts^[2].