Gefitinib enhances the radiosensitivity of nasopharyngeal carcinoma cell line CNE2 in vitro / 南方医科大学学报

<p><b>OBJECTIVE</b>To study the radiosensitizing effect of gefitinib on nasopharyngeal carcinoma cell line CNE2 in vitro.</p><p><b>METHODS</b>Nasopharyngeal carcinoma cell line CNE2 was cultured in RP2MI 1640. MTT assay was performed to evaluate the cell proliferation changes in response to gefitinib treatment and the radiosensitizing effect of gefitinib. The cell survival curves and sensitive enhancement ratio (SERs) were obtained with a clonogenic assay. Flow cytometry analysis was applied to detect the cell cycle changes and cell apoptosis.</p><p><b>RESULTS</b>MTT assay showed that cells exposed to gefitinib and radiation had a significantly lower survival ratio compared to the cells with radiation exposure only (0.582∓0.012 vs 0.398∓0.016, P=0.002), with a SER of 1.535∓0.134. The S phase cell percentage was significantly decreased and G(2)-M phase cells increased in gefitinib plus radiation group (P=0.000), suggesting a synergistic effect of gefitinib and radiation.</p><p><b>CONCLUSION</b>Gefitinib can enhance the radiosensitivity of nasopharyngeal carcinoma CNE2 cells in vitro possibly by inhibiting cell proliferation, inducing cell apoptosis, and causing changes in the cell cycle distribution.</p>

Association between single nucleotide polymorphism locus rs189037 in the promoter of ATM gene and nasopharyngeal carcinoma susceptibility in Cantonese / 南方医科大学学报

<p><b>OBJECTIVE</b>To evaluate the correlation between single nucleotide polymorphisms (SNP) in the promoter of ataxia-telangiectasia mutated (ATM) gene and the susceptibility of nasopharyngeal carcinoma in Cantonese.</p><p><b>METHODS</b>A total of 176 NPC Cantonese NPC patients and 202 age-matched healthy controls were enrolled in this study. G/A genotyping of the SNP locus rs189037 in the promoter of ATM gene was performed by PCR and direct sequencing of the PCR products.</p><p><b>RESULTS</b>The genotype frequency of heterozygote G/A was 50% (88/176) and 47.5% (96/202), and that of the homozygote variant A/A was 15.3% (27/176) and 18.3% (37/202) in NPC patients and healthy individuals, respectively. Statistics analysis revealed no evident correlations of the G/A and A/A genotypes to the clinical phenotypes of NPC in either NPC group or healthy control group (OR7equals;1.022, 95%CIequals;0.668-1.564 for G/A+A/A). Analysis after stratification by age and gender found no such correlations either.</p><p><b>CONCLUSION</b>The genotype frequencies of SNP locus rs189037 in the promoter of ATM gene are similar between NPC patients and healthy subjects, suggesting that rs189037 is not related to the genetic susceptibility of NPC in Cantonese.</p>

Determination of the repair half-time of human nasopharyngeal carcinoma cell lines CNE1, CNE2, HONE1 and C666-1 / 南方医科大学学报

<p><b>OBJECTIVE</b>To determine the repair half-time (T1/2), a speed parameter of sub-lethal damage repair (SLDR), of human nasopharyngeal carcinoma (NPC) cell lines CNE1, HONE1, C666-1 and CNE2.</p><p><b>METHODS</b>A total radiation dose of 8 Gy divided into 4+4 Gy was delivered to the cell lines at the interval of 0 s, 15 s, 30 s, 1 h, 2 h, 4 h or 6 h. The cell survival fractions were determined using the standard cell clonogenic assay. The curves of the changes in the surviving cell fraction after a total dose of 8 Gy, as a function of the interval between the two doses of 4 Gy, were fitted manually, and the T1/2 of each cell line was calculated according to the curves.</p><p><b>RESULTS</b>The T1/2 of CNE1, HONE1, C666-1 and CNE2 were 18 s, 22 s, 29 s and 27 s, respectively.</p><p><b>CONCLUSION</b>The speed of SLDR of NPC cells is quite rapid, indicating that the fraction delivery time longer than 20 s might decrease the effect of radiotherapy.</p>

Three-dimensional conformal radiotherapy combined with transcatheter arterial chemoembolization for massive primary liver cancer / 南方医科大学学报

<p><b>OBJECTIVE</b>To evaluate the outcomes of patients with unresectable massive primary liver cancer (PLC) receiving three-dimensional conformal radiotherapy (3-DCRT) combined with transcatheter arterial chemoembolization (TACE).</p><p><b>METHODS</b>From January 2001 to December 2004, 84 patients with unresectable massive PLC (tumor size> or =10 cm) received 3-DCRT combined with TACE, including 49 cases in UICC/AJCC T(3) stage and 35 cases in T(4) stages. Lymph node metastasis was found in none of the patients, and portal vein tumor thrombosis (PVTT) was detected in 30 cases. Child-Pugh grade A of liver cirrhosis was present in 64 cases and grade B in 20 cases. The mean value of GTV was 705-/+430 cm(3) (170-2099 cm(3)). Following injections of fluorouracil and hydroxycamptothecine into the target artery of the tumor, the mixture of carboplatin, mitomycin (or pirarubicin) and super-liquefactive iodized oil was injected into the target artery. Gelatin sponge was used to embolize the artery. The procedure was repeated every 1.5-2 months according to the condition of the patients, and each patient received 1-3 such procedures. 3-DCRT was performed in all the patients, who received a total dose of 53.6-/+6.6 Gy (4-6 Gy per fraction at the interval of 48 h), and 3 fractions were given every week.</p><p><b>RESULTS</b>Eight patients died in 3 months after 3-DCRT and were not evaluated. The total response rate (CR+PR) in these patients was 68.9% (51/74). The overall survival rates at 1, 2 and 3 years were 55.4%, 24.7% and 15.4%, respectively. T stage, GTV, PVTT and fraction size had no significant impact on the overall survival. Child-Pugh grade was found to have significant impact on the patients' survival (P=0.035, RR=2.440).</p><p><b>CONCLUSION</b>3-DCRT combined with TACE has definite therapeutic effect on advanced massive PLC, and Child-Pugh grade is an independent prognostic factor in such cases.</p>