title: Long-term culture of HIV-1-infected cells with the transcription inhibitor K-37.
abstract: We have previously reported that the fluoroquinoline derivative K-37 is a potent and selective inhibitor of HIV-1 replication in both acutely and chronically infected cells. K-37 blocks the HIV-1 transcription process through the inhibition of still unknown cellular factor(s). To gain further insight into the target of K-37 for HIV-1 replication, we have conducted long-term culture of acutely infected cells in the presence of K-37. When MOLT-4 and U937 cells were infected with HIV-1 and cultured in the absence of K-37, the p24 antigen levels in the culture supernatants reached a plateau within 12 days. In the presence of K-37 (0.25 and 0.5 microM), the elevation of p24 antigen levels was delayed but reached a similar plateau level on day 16 or later. At a concentration of 1 microM, K-37 markedly suppressed HIV-1 replication. However, viral breakthrough was observed after 1 month of the culture period in both MOLT-4 and U937 cells. We established MOLT-4 cell lines chronically infected with the breakthrough viruses (M(1) and U(1)) or the corresponding wild-type strains (M(0) and U(0), respectively), and K-37 was examined for its inhibitory effects on HIV-1 replication in these cell lines. No substantial difference in anti-HIV-1 activity was observed between the two cell lines. However, acute infection experiments revealed that the infectivity of M(1) and U(1) was much lower than that of M(0) and U(0), respectively. Furthermore, both M(1) and U(1) had a G to T nucleotide mutation at position -215 in the second nuclear factor of activated T-cells-binding domain (-215 to -203) of the HIV-1 long terminal repeat.
mesh_terms: D019380:Anti-HIV Agents / Q000494:pharmacology*; D000890:Anti-Infective Agents / Q000494:pharmacology*; D002460:Cell Line; D024841:Fluoroquinolones; D015497:HIV-1 / Q000187:drug effects* / Q000502:physiology; D006801:Humans; D012692:Serial Passage; D013601:T-Lymphocytes / Q000821:virology; D020298:U937 Cells / Q000821:virology; D014779:Virus Replication / Q000187:drug effects*
chemical_list: D019380:Anti-HIV Agents; D000890:Anti-Infective Agents; D024841:Fluoroquinolones