Cleavage of parallel-stranded DNA duplex by peplomycin metal complexes.
Peplomycin-mediated degradation of parallel-stranded (ps) duplex was investigated. It was found that Co- and Fe-peplomycins degraded ps DNA duplex by 4'-hydrogen abstraction at 5'-GPy (pyrimidine) site in a similar manner to that of antiparallel B-DNA. While the orientation of two strands of ps and B-form DNA duplexes are reversed, peplomycin metal complex can bind to ps DNA duplex to cause oxidative DNA damage. These results indicate that peplomycin metal complex mainly interacts with one strand which is damaged. (+info)
Amplification of bleomycin-induced DNA cleavage by pyrrole triamide.
We investigated the amplification of bleomycin-induced DNA cleavage by synthetic pyrrole triamide (PyPyPy) using 32P-labeled DNA fragments obtained from human genes. Peplomycin, a kind of bleomycins, plus Fe(II) caused DNA cleavage at the 5'-GC-3' and 5'-GT-3' sequences (damaged bases are underlined). The addition of PyPyPy enhanced the cleavage at cytosine and thymine residues 3' to consecutive guanines, particularly at the 5'-GGGGC-3' and 5'-GGGGT-3' sequences. These results suggest that PyPyPy binds to DNA to induce its conformational change, resulting in alteration of the site specificity and amplification of DNA cleavage. The present study on amplifiers of antitumor drugs would show a novel approach to the establishment of more effective chemotherapy. (+info)
Peplomycin, a bleomycin derivative, induces myofibroblasts in pulmonary fibrosis.
To analyse the mechanism by which a bleomycin derivative, peplomycin (PLM) induces pulmonary fibrosis, we investigated differentiation of rat pulmonary fibroblasts to myofibroblasts (MF). In intraperitoneally PLM (5 mg/kg/day)-injected rats, the peripheries of lungs adjacent to the pleura revealed advanced fibrosis with a small number of alpha-smooth muscle actin (alpha-SMA)-positive MF, which ultrastructurally possessed abundant microfilaments and cellular organelles. In the fibrotic tissue, the expression of alpha-SMA-mRNA was detected by in situ reverse transcription-polymerase (RT-PCR). The message was strong just after a 2-week administration of PLM then decreased thereafter, although fibrosis advanced. When pulmonary fibroblasts were separated from saline-injected rats (N-Fib) and cultivated for 7 days in the presence of 5 mg/mL PLM, alpha-SMA protein was weakly expressed, while the majority of pulmonary fibroblasts separated from PLM-injected rats (P-Fib) became positive for alpha-SMA in 7-day cultivation and the expression of alpha-SMA in P-Fib was strongly increased by cultivation in the presence of PLM and transforming growth factor-beta (TGF-beta), but not basic fibroblast growth factor (bFGF) or platelet-derived growth factor (PDGF), although the cell proliferation was most strongly enhanced by bFGF and only slightly by PLM and TGF-beta. The alpha-SMA-positive cells expressed vimentin, but only weakly expressed desmin. Additionally, P-Fib generated larger amounts of TGF-beta and bFGF than were generated by N-Fib. These results indicate that PLM induces pulmonary fibrosis by differentiating fibroblasts to alpha-SMA-positive MF, and that bFGF and TGF-beta play each critical role in the different phases of PLM-induced pulmonary fibrosis by inducing fibroblast proliferation and transformation, respectively. (+info)
The upregulation by peplomycin of signal transduction in human cells.
To explore the mechanism of pulmonary fibrosis by bleomycin and its derivative, peplomycin (PLM), we examined the influence of PLM on signal transduction in human peripheral blood lymphocytes (HL), monocytes (HM) and fibroblasts (HF). Tyrosine phosphorylation of multiple proteins in HL and HM were induced by 0.001 to 0.05 microg/ml and by 0.01 to 0.5 microg/ml of PLM, respectively. In HF, 116-kDa protein was phosphorylated 0.2 to 5 microg/ml of PLM. When HL were treated with 0.01 microg/ml of PLM, phosphorylation of p56lck and activation of extracellular-signal related kinase-2 (ERK2) were induced. ERK2 was also activated in HM. Coordinately, the ratio of p21ras-binding GTP/GDP was increased by PLM. As well as interleukin-2, PLM induced tyrosine phosphorylation of JAK-3. In addition, PLM upregulated the nuclear translocation of nuclear factor-kappa B and the expression of c-myc-mRNA in HL, HM and HF. Furthermore, 0.01 to 0.001 microg/ml PLM enhanced the cytokine generation by HL and HM, and 1 to 5 microg/ml PLM increased cytokine generation and collagen synthesis by HF. These upregulatory effects of PLM were abrogated by pretreatment of the cells with a tyrosine kinase inhibitor. These results indicate that PLM upregulates signal transduction in a variety of cell types and the upregulation may induce pulmonary fibrosis. (+info)
Peplomycin induces G1-phase specific apoptosis in liver carcinoma cell line Bel-7402 involving G2-phase arrest.
AIM: To investigate the mechanism of peplomycin (PEP)-induced apoptosis in liver carcinoma cell line (Bel-7402). METHODS: Growth inhibition by PEP was analyzed using 3- 4,5-Dimethylthiazol-2-yl-2,5-diphenyltetrazolium bromide (MTT) assay. Apoptotic cells were detected using Hoechest 33258 staining, and confirmed by flow cytometric analysis and DNA fragmentation analysis. The expression of cyclin A and B1 were determined by flow cytometry and Western blot. Annexin V assay was measured by flow cytometric analysis. RESULTS: PEP induced apoptosis and then inhibited cell proliferation in liver carcinoma cell line Bel-7402. Cells treated with PEP 50 mumol/L for 15 h were arrested in G2-phase with dramatical expression of cyclin A and a little change in cyclin B1. Almost all the apoptosis occurred in cells undergoing the G1-phase after treatment for 24 h. CONCLUSION: Peplomycin induced G1-phase specific apoptosis in Bel-7402 involving G2-phase arrest. (+info)
Radiotherapy for uterine cervical cancer: results of the 1995-1997 patterns of care process survey in Japan.
OBJECTIVE: The aim of this study is to establish Japanese national practice patterns for uterine cervical cancer patients who received radiotherapy without surgery. METHODS: The Japanese Patterns of Care Study (JPCS) conducted a national survey of 73 institutions using two-stage cluster sampling, and collected specific information on 591 patients with uterine cervical cancer treated by radiotherapy without planned surgery between 1995 and 1997. RESULTS: The median age of the patients was 70 years. Karnofsky performance status (KPS) was >/=90 for 37%. Most patients (95%) had histology of squamous cell carcinoma. Ten percent were stage I, 29% stage II, 48% stage III and 13% stage IVA. Photon beams of 10-14 MV were the most used for external beam radiotherapy (EBRT). The beam energy utilized varied significantly by institution strata. Midline block was used in approximately 70% of institutions. Intracavitary brachytherapy (ICBT) was performed in 77%. Institution strata correlated significantly with the ICBT application. The majority of patients (89%) were treated with high-dose-rate (HDR) ICBT. The median single point A dose of HDR-ICBT was 600 cGy. The median summated point A dose from EBRT and HDR-ICBT was 5800 cGy (range: 1196-8600). The median overall treatment time including ICBT was 49 days. Twenty-four percent of the patients received chemotherapy. Concurrent chemoradiation was performed in 5%. CONCLUSIONS: The JPCS established the Japanese national practice patterns of care for uterine cervical cancer patients treated with radiotherapy without planned surgery between 1995 and 1997. This survey demonstrated that the institutional strata significantly affected several practice patterns. (+info)
Preoperative chemotherapy and radiation therapy for squamous cell carcinoma of the maxillary sinus.
OBJECTIVE: This study was undertaken to assess the prognostic factors for the management of squamous cell carcinoma (SCC) of the maxillary sinus, who received preoperative chemotherapy and radiation therapy (RT). We also elucidated the appropriate sequence of chemotherapy. METHODS: A total of 124 patients (median age 62 years) with SCC of the maxillary sinus were analysed retrospectively. T3 or T4 disease was found in 93% of the patients. Thirty-nine patients received neoadjuvant chemotherapy (NA), 38 patients received concurrent chemoradiotherapy (CRT) and 47 patients received NA followed by CRT. The median dose of RT was 60 Gy. Maxillectomy was undertaken in 98 patients. RESULTS: The 5 year overall survival (OAS) and local control probability (LCP) were 56.6 and 73.7%, respectively. On univariate analysis, surgery (P < 0.0001) and T classification (P < 0.04) were significant prognostic factors for OAS and LCP. Histological grade and nodal status were also related to OAS. However, any chemotherapy sequence was not associated with the treatment outcome. On multivariate analysis, surgery (P < 0.0005) and T classification (P < 0.05) were identified as significant prognostic factors for LCP and OAS. CONCLUSIONS: This study suggests that both surgery and T stage are important prognostic factors for LCP and OAS in the management of SCC of the maxillary sinus. The appropriate sequence of chemotherapy remains to be elucidated in the future study. (+info)
Apoptosis in cervical cancer after balloon-occluded arterial infusion of anticancer drugs.
BACKGROUND: This study was designed to investigate the relationship between apoptosis and Bcl-2 and Bax expressions in uterine cervical cancer after balloon-occluded arterial infusion (BOAI). MATERIALS AND METHODS: Twenty-four specimens were obtained before and after BOAI. The occurrence of apoptosis was examined with molecular biochemical techniques. The expressions of Bcl-2 and Bax proteins were investigated by immunohistochemical staining. RESULTS: Labelling of DNA in situ indicated that apoptotic cells were sporadically seen before BOAI (6.1 +/- 1.9). Apoptotic cells apparently increased at 5 days (25.1 +/- 6.4) after BOAI The autoradiographic analysis revealed that the DNA-ladder was identified at 5 days after BOAI. Although Bcl-2 immuno-reactivity was faintly detected, the expression of Bax increased at 3 days (49.4 +/- 10.4%) after BOAI. CONCLUSION: The results indicated that treatment with BOAI resulted in transient increases of apoptosis in cervical cancer in association with the increased expression of Bax. (+info)