Caffeine enhances radiosensitization to orthotopic transplant LM3 hepatocellular carcinoma in vivo.
ABSTRACT The aim of this study was to determine whether caffeine enhanced radiosensitization in an orthotopic transplant of LM3 human hepatocellular cancer in nude mice. LM3 hepatocellular carcinoma cells were infected with red fluorescent protein and irradiated, and cell cycle distribution and survival fraction were detected. A nude mouse model of orthotopic transplant of red fluorescent protein-expressing LM3 hepatocellular cancer was established. Nude mice were divided into four groups: control (NS); caffeine (Caff) alone; irradiation (IR) alone; and caffeine + IR (Caff + IR). Tumor growth curves were described. Expression of cyclin and apoptosis were evaluated by analysis of phosphorylated cyclin dependent kinase 1 (CDC2) Tyr15 (CDC2-Tyr15-P), cyclinB1, TUNEL staining, and caspase-3. Caffeine abrogated IR-induced G(2) phase arrest and decreased survival of irradiated LM3 cells. Caffeine enhanced radiosensitivity of LM3 hepatocellular cancer in vivo. Tumor growth delay time in the Caff + IR group was 14.3 days compared with the NS group, 14.1 days compared with the Caff alone group, and 7.2 days compared with the IR alone group. At 15 Gy, expression of CDC2-Tyr15-P in the Caff + IR group (26.0 +/- 8.9%) was significantly lower than in the IR alone group (68.4 +/- 10.6%), expression of cyclinB1 and proportion of TUNEL-positive cells in the Caff + IR group (30.4 +/- 8.7% and 59.2 +/- 9.5%, respectively) was significantly higher than in the IR alone group (7.0 +/- 3.7% and 24.2 +/- 7.2%, respectively), expression of caspase-3 was consistent with the TUNEL staining results. This study suggested that caffeine might enhance the radiosensitivity of LM3 hepatocellular cancer in vivo, and may be feasible for further clinical applications.
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ABSTRACT: Damage induced in the DNA after exposure of cells to ionizing radiation activates checkpoint pathways that inhibit progression of cells through the G1 and G2 phases and induce a transient delay in the progression through S phase. Checkpoints together with repair and apoptosis are integrated in a circuitry that determines the ultimate response of a cell to DNA damage. Checkpoint activation typically requires sensors and mediators of DNA damage, signal transducers and effectors. Here, we review the current state of knowledge regarding mechanisms of checkpoint activation and proteins involved in the different steps of the process. Emphasis is placed on the role of ATM and ATR, as well on CHK1 and CHK2 kinases in checkpoint response. The roles of downstream effectors, such as P53 and the CDC25 family of proteins, are also described, and connections between repair and checkpoint activation are attempted. The role of checkpoints in genomic stability and the potential of improving the treatment of cancer by DNA damage inducing agents through checkpoint abrogation are also briefly outlined.Oncogene 10/2003; 22(37):5834-47. · 7.36 Impact Factor
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ABSTRACT: To study biological characteristics of stable red fluorescent protein (RFP)-expressing or green fluorescent protein (GFP)-expressing HCCLM3 cell lines and those of their relevant xenograft models in nude mice. HCCLM3, a human hepatocellular carcinoma cell line with high metastatic potential was infected with RFP or GFP full-length cDNA via lentivirus. Stable RFP-expressing or GFP-expressing HCCLM3 cells, namely HCCLM3-R and HCCLM3-G, were subcutaneously injected and two patient-like metastatic models of HCCLM3-R and HCCLM3-G in nude mice were established using surgical orthotopic implantation from subcutaneous tumor tissues. Cell proliferation, karyotype, biomarker expression, tumor growth, and metastasis of HCCLM3-R and HCCLM3-G were analyzed in vitro and in vivo. RFP and GFP genes were integrated in genomic DNA of HCCLM3. HCCLM3-R and HCCLM3-G expressed red and green fluorescence, stable and intense, 300 days after 60 consecutive passages, and also positively expressed CK8+, P16+, AFP+ and negatively expressed HBsAg-. Their biomarker expression and karyotype were found to be similar to those of the parental HCCLM3, and their tumorigenesis occurred in 10 nude mice without exception after a subcutaneous injection and did the same in 20 nude mice after an orthotopic implantation. The results showed that the rate of spontaneous metastasis to the liver and lung and peritoneal seeding was 100, 100, and 90%, respectively. Stable fluorescent protein-expressing HCCLM3-R and HCCLM3-G xenografts in nude mice could be of two useful models for studying mechanisms of hepatocellular carcinoma growth and metastasis in real time.European journal of gastroenterology & hepatology 12/2008; 20(11):1077-84. · 1.66 Impact Factor
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ABSTRACT: This study evaluated the effect of transcatheter arterial chem-oembolization combined with external beam radiotherapy on the response rates and sur vival of patients with unresectable hepato-cellular carcinoma. Transcatheter arterial chemoembolization is frequently used for the treatment of this cancer, but complete or massive necrosis is seldom observed. Historically, radiotherapy for hepatocellular carcinoma has yielded poor long-term survival. Multimodality therapy has been initiated in an effort to improve survival statistics. We retrospectively studied 203 patients with unresectable hepa-tocellular carcinoma, who were free of tumor thrombus, lymph node involvement, or extrahepatic metastasis based on computed tomography scans of the chest and abdomen. Among the 203 patients who received transcatheter ar terial chemoembolization as initial therapy, 54 also received combination therapy with external beam radiotherapy. Tumor response rate, survival, and failure patterns were analyzed and compared between the two groups. Objective responses (complete and partial responses) on computed tomography study were obser ved in 31% and 76% of patients in the non-radiotherapy and radiotherapy groups, respectively. Overall survival rates in the patients in the radiotherapy group were 71.5%, 42.3%, and 24.0% at 1, 2, and 3 years, respectively, improved over the non-radiotherapy group rates of 59.6%, 26.5%, and 11.1% at 1, 2, and 3 years, respectively. Intrahepatic failure was lower in the radiotherapy group than in the non-radiotherapy group, but the difference was not significant. Side effects from radiotherapy were common, but rarely severe. This retrospective study suggests that the outcome of unresectable hepatocellular carcinoma can be influenced by radiation therapy, but a prospective randomized trial would be necessary to draw definitive conclusions.The Cancer Journal 08/2004; 10(5):307-16. · 3.66 Impact Factor