甘氨双唑钠在Ⅲ期非小细胞肺癌三维适形放疗中的应用

目的观察甘氨双唑钠(CMNa)对Ⅲ期非小细胞肺癌(NSCLC)三维适形放疗(3-DCRT)的放射增敏作用及其安全性。方法经病理和细胞学证实的Ⅲ期NSCLC病人42例,随机分为试验组(A组)22例和对照组(B组)20例,B组采用全身伽玛刀放疗,每周5次,每次3.5Gy,总剂量为70Gy。A组采用全身伽玛刀放疗,同时使用CMNa800mgm2,每周5次。结果A组CR率和总有效率(CR PR)均明显高于B组;A组病人治疗达到PR和CR时的中位照射剂量均低于B组;两组病人不良反应发生率比较无统计学意义。结论CMNa对Ⅲ期非小细胞肺癌三维适形放疗有较肯定的放射增敏作用,明显提高了NSCLC的近期疗效,不增加不良反应。     

Inhibition of matrix metalloproteinase‐2 enhances radiosensitivity by abrogating radiation‐induced FoxM1‐mediated G2/M arrest in A549 lung cancer cells

Matrix metalloproteinase‐2 (MMP‐2), is known to degrade the collagen IV, plays a role in radiation‐induced lung injury. We therefore investigated the antitumor effects of combining MMP‐2 inhibition using an adenovirus expressing siRNA against MMP‐2 (Ad‐MMP‐2‐Si) with radiation therapy (IR) on A549 lung cancer cells in vitro and in vivo. IR increased MMP‐2 mRNA, protein and activity in lung cancer cells. MMP‐2 inhibition along with IR enhanced radiosensitivity as determined by clonogenic assay, flow cytometry and TUNEL assay. We show that MMP‐2 inhibition prior to irradiation reduced p53 phosphorylation, with a corresponding reduction in the expression of the p53 downstream target gene p21^Cip1/Waf1. Irradiated tumor cells induced the FoxM1‐mediated DNA repair gene, XRCC1 and Checkpoint kinases 2/1, which were abrogated with combined treatment of Ad‐MMP‐2‐Si and IR. Further, the combination of Ad‐MMP‐2‐Si with radiotherapy significantly increased antitumor efficacy in vivo compared to either agent alone. Indeed, histological analysis of tumor sections collected from the combination group revealed more apoptotic cells. These studies suggest that MMP‐2 inhibition in combination with radiotherapy abrogates G2 cell cycle arrest leading to apoptosis and provide evidence of the antitumor efficacy of combining MMP‐2 inhibition with irradiation as a new therapeutic strategy for the effective treatment of NSCLC patients. © 2008 Wiley‐Liss, Inc.     

WEE1 kinase inhibitor MK-1775 sensitizes oral tongue squamous cell carcinoma cells to radiation irrespective of TP53 status

Objective

Oral tongue squamous cell carcinoma (OTSCC) frequently harbors non-functional p53 and depends on G2/M checkpoint mediated by WEE1. WEE1 suppression has been identified as a promising anti-tumor strategy. This study investigated the capacity of WEE1 kinase inhibitor (MK-1775) and its underlying mechanisms in enhancing radiation responses of OTSCC cells in vitro.

Materials and methods

WEE1 kinase expression and its downstream target (CDK1) were investigated in OTSCC versus normal oral tissue. A synergistic combination of MK-1775 with radiation on OTSCC cell lines with different p53 statuses was assessed by viability assay. The radio-sensitizing effects of MK-1775 on apoptosis, cell cycle, DNA damage, and mitotic entry were also determined.

Results

Irradiation enhanced CDK1 expression in all tested cell lines, though the effect was far more pronounced in p53 mutated cell lines. MK-1775 exhibited inhibitory effects against the survival of all cell lines and enhanced their response to the radiation. These effects were strongly elicited by induction of apoptosis and lethal mitosis, but less likely by abrogation of radiation-induced G2 arrest.

Conclusion

These results demonstrate the efficacy of MK-1775 in enhancing the radiation effect on OTSCC in vitro associated with a significant apoptotic death rate, identifying WEE1 inhibitor as a potent radiosensitizer in OTSCC irrespective of p53 mutational status.     

5-Fluorouracil radiation sensitization — A brief review

Summary 5-Fluorouracil (FUra) has emerged as the most promising clinical radiosensitizer now available. FUra's capacity to render human cells more sensitive to x-rays was established soon after its synthesis. However, the recognition that the drug's unusual pharmacology dictated explicit scheduling requirements in man was not realized until recently when work in the author's laboratory identified the extra-cellular drug concentration X time factors necessary to create the intra-cellular radiosensitive state. Subsequent clinico-pharmacologic investigations led to the realization that only prolonged continuous infusions combined with appropriately fractionated, cyclical radiation therapy would maximize the clinical utility of this approach. Infused FUra radiation-sensitization therapy reaches its maximum efficacy against the squamous-transitional cancers. This group of human malignancies comprises about 15% of all human cancers. Preliminary data also suggests substantial promise in the local/regional control of rectal and breast cancers. Infused FUra used as a radiosensitizer has the potential to eliminate the need for about 90% of all radical cancer surgery.     

柠檬酸转运体SLC25A1对食管鳞癌细胞体外放射敏感性的影响及其分子机制

目的： 探讨线粒体柠檬酸转运体SLC25A1对食管癌细胞体外放射敏感性的影响及其分子机制。方法： 采用癌症基因组图谱（TCGA）数据库及UALCAN交互式网络工具比较分析184例食管癌组织与11例正常组织的SLC25A1 mRNA表达水平的差异；采用亚致死剂量X射线多次暴露法建立放射抵抗及对照组食管癌细胞系，放射克隆存活法线性二次靶模型分析两株食管癌细胞株放疗反应性的差异；多次X射线照射（总剂量6.0 Gy）上述两株食管癌细胞后，Hoechst33258染色荧光显微镜观察细胞凋亡形态学变化，流式细胞术检测细胞活性氧水平；免疫印迹法分析慢病毒小发夹RNA稳定转染敲低SLC25A1表达对DNA损伤修复关键信号分子H2AX和DNA-PKcs磷酸化水平的影响。结果： TCGA肿瘤组织数据库比较分析证实，与正常食管组织比较，食管癌组织SLC25A1 mRNA表达水平升高1.65倍（P=1.64×10^-4）；多轮亚致死剂量暴露法构建的放射抵抗食管鳞癌细胞株SLC25A1蛋白表达水平较对照组升高2.36倍（P < 0.05）；与对照组比较，稳定敲低SLC25A1表达的放射抵抗食管癌细胞株凋亡率增加1.58倍（P < 0.05）；活性氧水平下调（65.3±14.3）%（P=0.007）；并下调磷酸化H2AX（Ser139）和磷酸化DNA-PKcs（Ser2056）水平（P均 < 0.05）。结论： SLC25A1可能是一种参与食管鳞癌发病和放射抵抗的癌基因，通过下调活性氧水平，抑制DNA损伤修复，诱导细胞凋亡并可作为食管鳞癌放射增敏的潜在分子靶标。     

Implantable biodegradable polymers for IUdR radiosensitization of experimental human malignant glioma

Purpose: The potential of halogenated pyrimidines for the radiosensitization of human malignant gliomas remains unrealized. To assess the role of local delivery for radiosensitization, we tested a synthetic, implantablebiodegradable polymer for the controlled release of 5-iodo-2-deoxyuridine (IUdR) both in vitro and in vivo and the resultant radiosensitizationof human malignant glioma xenografts in vivo.Materials and methods: In vitro: To measure release, increasing (10%, 30%, 50%) proportions (weight/weight) of IUdR in the polyanhydride [(poly(bis(p-carboxyphenoxy)-propane) (PCPP) :sebacic acid (SA) (PCPP : SA ratio 20 : 80)] polymer discs were incubated (1 ml phosphate-buffered saline, 37° C). The supernatant fractions were serially assayed using high performance liquid chromatography. To measure modulation of release,polymer discs were co-loaded with 20 Ci 5-125-iodo-2-deoxyuridine (125-IUdR) and increasing (10%, 30%, or 50%) proportions of D-glucose. To test radiosensitization, cells (U251 human malignant glioma) were sequentially exposed to increasing (0 or 10 M) concentrations of IUdR and increasing (0, 2.5, 5.0, or 10 Gy) doses of acute radiation. In vivo: To measure release, PCPP : SA polymerdiscs having 200 Ci 125-IUdR were surgically placed in U251 xenografts (0.1—0.2 cc) growing in the flanksof nude mice. The flanks were reproducibly positioned over a collimated scintillation detector and counted. To measure radiosensitization, PCPP : SApolymer discs having 0% (empty) or 50% IUdR wereplaced in the tumor or contralateral flank. After five days, the tumors were acutely irradiated (500 cGy × 2 daily fractions).Results: In vitro: Intact IUdR was released from the PCPP : SA polymer discs in proportion to the percentage loading. After 4 days the cumulative percentages of loaded IUdR that were released were 43.7 $plusmn; 0.1, 70.0 ± 0.2, and 90.2 ± 0.2 (p < 0.001 ANOVA) for the 10, 30, and 50% loadings. With 0, 10, 30,or 50% D-glucose co-loading, the cumulative release of 125-IUdR from PCPP : SA polymers was 21, 70, 92, or 97%(p < 0.001), respectively, measured 26 days after incubation.IUdR radiosensitized U251 cells in vitro. Cell survival (log₁₀) was – 2.02 ± 0.02 and – 3.68± 0.11 (p < 0.001) after the 10 Gy treatment and no (control) or 10 M IUdR exposures, respectively. In vivo: 125-IUdR Release: The average counts (log₁₀ cpm ± SEM) (hours after implant) were 5.2 ± 0.05 (0.5), 4.3 ± 0.07 (17), 3.9 ± 0.08 (64), and 2.8 ± 0.06 (284). Radiosensitization: Afterintratumoral implantation of empty polymer or intratumoral 50%IUdR polymer, or implantation of 50% IUdR polymers contralateral to tumors, the average growth delays of tumors to4 times the initial volumes were 15.4 ± 1.8, 20.1 + 0.1,and 20.3 + 3.6 (mean + SEM) days, respectively (p = 0.488one-way ANOVA). After empty polymer and radiation treatments,no tumors regressed and the growth delay was 31.1 + 2.1 (p = 0.046 vs. empty polymer alone) days. After implantation of50% IUdR polymers either contralateral to the tumors orinside the tumors, followed by radiation, tumors regressed; growth delays to return to the initial average volumes of 14.0+ 3.6 or 24.2 + 0.2 (p < 0.01) days, respectively.Conclusions: Synthetic, implantable biodegradable polymers hold promise for the controlled release and local delivery ofIUdR for radiosensitization of gliomas.     

血卟啉衍生物对X线增敏作用的生化研究

通过对小鼠S-180腹水瘤细胞DNA单链断裂及其重接的测定和细胞质膜对~(50)CrO_4~(2-)通透性的测定,探讨了光敏剂血卟啉衍生物(HPD)是否对X线增敏的问题。结果表明,在避光时HPD对X线的增敏作用不明显,但在自然光的照射下,HPD能增强X线的辐射效应,表现在DNA单链断裂重接的抑制和膜通透性的加强。对上述现象的原因进行了讨论。     

Concomitant administration of radiation with eribulin improves the survival of mice harboring intracerebral glioblastoma

Glioblastoma is the most common and devastating type of malignant brain tumor. We recently found that eribulin suppresses glioma growth in vitro and in vivo and that eribulin is efficiently transferred into mouse brain tumors at a high concentration. Eribulin is a non‐taxane microtubule inhibitor approved for breast cancer and liposarcoma. Cells arrested in M‐phase by chemotherapeutic agents such as microtubule inhibitors are highly sensitive to radiation‐induced DNA damage. Several recent case reports have demonstrated the clinical benefits of eribulin combined with radiation therapy for metastatic brain tumors. In this study, we investigated the efficacy of a combined eribulin and radiation treatment on human glioblastoma cells. The glioblastoma cell lines U87MG, U251MG and U118MG, and SJ28 cells, a patient‐derived sphere culture cell line, were used to determine the radiosensitizing effect of eribulin using western blotting, flow cytometry and clonogenic assay. Subcutaneous and intracerebral glioma xenografts were generated in mice to assess the efficacy of the combined treatment. The combination of eribulin and radiation enhanced DNA damage in vitro. The clonogenic assay of U87MG demonstrated the radiosensitizing effect of eribulin. The concomitant eribulin and radiation treatment significantly prolonged the survival of mice harboring intracerebral glioma xenografts compared with eribulin or radiation alone (P < .0001). In addition, maintenance administration of eribulin after the concomitant treatment further controlled brain tumor growth. Aberrant microvasculature was decreased in these tumors. Concomitant treatment with eribulin and radiation followed by maintenance administration of eribulin may serve as a novel therapeutic strategy for glioblastomas.