Penciclovir (BRL 39123) is a Herpesvirus Nucleoside Analog DNA Polymerase Inhibitor. In HSV infected cells, penciclovir is phosphorylated by viral thymidine kinase and subsequently converted by cellular kinases into the active metabolite, penciclovir triphosphate, which competitively inhibits viral HSV polymerase by blocking deoxyguanosine triphosphate substrate binding. As a result, herpes viral DNA synthesis and replication are selectively inhibited.

HSV1:0.04-1.8 μg/mL, HSV2:0.06-4.4 μg/mL

Penciclovir具有抗多种病毒疱疹的活性,如抗HHV-6A（IC50：37.9 μM）和HHV-6B（IC50：77.8 μM）。Penciclovir具有抗Ⅰ型和Ⅱ型单纯疱疹病毒的体外活性,且对水痘带状疱疹病毒也有较好作用,却不影响未感染细胞中DNA的合成。作为鸟嘌呤类似物,Penciclovir毒性低、选择性高。Penciclovir由细胞激酶转化成三磷酸盐的活性形式,与脱氧鸟苷三磷酸竞争性抑制病毒DNA聚合酶,进而抑制病毒感染细胞的DNA合成。单纯疱疹病毒Ⅰ型的相关研究显示,Penciclovir使细胞凋亡,但造成的基因毒性较小。

Penciclovir is dissolved with DMSO and diluted with appropriate media[2]. Human breast cancer cell lines MCF-7 and MDA-MB-435, glioblastoma U87 mg, and embryonic kidney cells 293T are cultured at 37°C in a humidified atmosphere containing 5% CO2 in Iscove's modified Dulbecco medium or Leibovitz's L-medium and 5% fetal bovine serum (FBS). The assays are performed with slight modifications. In brief, cells are seeded into 24-well plates (5×104 cells/well) and infected 48 h later with 103 particles per cell of unmodified virus (Adtk), PEGylated virus (PEG-Adtk), or RGD-PEG-modified virus (RGD-PEG-Adtk) in triplicates in culture medium with 2% FBS and incubated for 4 h at 37°C. The incubation medium is then replaced by normal medium and cells are further incubated for 48 h. Cells are harvested and lysed with 500 μL of TK lysis buffer that contained 0.5% Nonidet P-40 (NP-40), 20 mM N-(2-hydroxyethyl) piperazine-N′-(2-ethanesulfonic acid) (HEPES) (pH 7.6), 2 mM Mg(OAc)2, 1 mM dithiothreitol, and 50 μM thymidine. The supernatant is collected after centrifugation. The samples are kept at -80°C until use. The modified and unmodified adenovirus protein concentrations are determined by the Micro BCA assay. One microgram of cell extract is incubated with HSV1-tk substrate 8-3H-Penciclovir (8-3 H-PCV). The phosphorylated tracer is separated from unphosphorylated 8-3 H-PCV with DE-81 filters. TK activity is expressed as the percentage of conversion of substrate per minute per microgram protein[2].