Relationship between intratumor histological heterogeneity and genetic abnormalities in gastric carcinoma with microsatellite instability.

Microsatellite instability (MSI)-mutator phenotype variably targets microsatellite-like sequences in coding regions of cancer-related genes. Intratumor histological heterogeneity of gastric carcinoma with MSI was evaluated and found to be linked with the topographical distribution of MSI-associated mutations. One hundred fifty tumor sites derived from 51 gastric cancer patients were microdissected with respect to histological and topographical clonality. We found 11 gastric carcinomas with a high frequency of MSI, which were characterized by marked intratumor genetic heterogeneity arising from the progressive MSI-phenotype that was associated with frameshift mutations on multiple cancer-related genes. The 11 MSI-tumor cases manifested the MSI-phenotype in 34 of 36 tumor sites tested, but not in the remaining 2 sites. Most (88.2%, 30 of 34) MSI-positive sites and most (96.2%, 25 of 26) tumor sites harboring the frameshift mutations in transforming growth factor-beta receptor type II gene exhibited intestinal-type histology, whereas the 2 MSI-negative sites were found to be of diffuse-type histology without accompanying frameshift mutations. In 2 of 5 cases harboring E2F-4 frameshift mutations, glandular structures of intestinal-type tumor were likely to be variably differentiated in relation to the extent of the mutation, i.e., the number of mutated alleles and the size of deleted or inserted base pairs. Overall, the intratumor histological heterogeneity of gastric carcinoma with MSI was associated with the progressive frameshift mutations in transforming growth factor-beta receptor type II and E2F-4 genes.     

Changes in intratumor pH by two heatings

It is a known fact that pH in rodent tumors decline significantly upon heating most likely due to breakdown of the tumor blood circulation. We recently observed that tumor blood vessels become thermotolerant after being heated with a sublethal thermal dose. The purpose of the present study was to reveal whether heating can reduce intratumor pH when the tumor vessels are thermotolerant. When the SCK tumors of A/J mice were heated at 42.5 degrees C for 1 h, the tumor vessels became most thermotolerant at 18 h postheating, as measured with the 86Rb uptake method. The intratumor pH in the control SCK tumors was 7.05 +/- 0.14 (SD), and it significantly decreased to 6.70 +/- 0.08 (P less than 0.001) after heating at 44.5 degrees C for 1 h. However, when the tumor vessels were thermotolerant, i.e., 18 h after heating at 42.5 degrees C for 1 h, reheating at 44.5 degrees C for 1 h could not reduce the intratumor pH. We concluded that such a failure to increase tumor acidity by a second heating at temperatures as high as 44.5 degrees C was due to vascular thermotolerance developed by the first heating.     

Modification of intracellular pH and thermotolerance development by amiloride

The intracellular pH (pH_i) of cells heated at 45·0°C in the presence or absence of amiloride and in choline chloride substituted sodium-free medium was measured with flow cytometry using the pH sensitive dye, carboxy-seminaphthorhodafluor (SNARF-1). Chinese hamster ovary (CHO) cells at pH 7·3 and low-pH-resistant (PHV2) cells at pH 6·6 were studied. Bimodal population distributions of pH_i were obtained for both CHO and PHV2 cells following a treatment in which cells were heated 10 min at 45·0°C, incubated 4 to 10 h at 37°C, then reheated 45 min at 45·0°C. Amiloride or sodium-free medium modified the changes in pH_i, but did not eliminate them entirely. Cells were sorted from the higher pH_i and lower pH_i subpopulations and plated for cell survival. The survival after both heat treatments was three to five-fold higher for cells sorted from the higher pH_i subpopulation than cells sorted from the low pH_i subpopulation. The development of thermotolerance was delayed in CHO cells but not in PHV2 cells when amiloride was present throughout the treatment regimen. Combining low pH with amiloride caused an even greater delay in thermotolerance development in CHO cells. However, the final fraction of thermotolerant cells after 14 h incubation was nearly identical, regardless of medium pH or the presence of amiloride.     

血管内皮生长因子-C与肿瘤转移的研究进展

血管内皮生长因子-C(VEGF-C)是特异性淋巴内皮细胞刺激因子,通过与血管内皮生长因子受体-3(VEGFR-3)结合诱导淋巴管形成.临床及基础研究表明VEGF-C能促进多种恶性肿瘤细胞的侵袭和转移,是影响肿瘤预后的重要因素.检测肿瘤细胞中有无VEGF-C表达有助于判断肿瘤的进展程度,为临床手术方式的选择及术后治疗提供参考.阻断VEGF-C与VEGFR-3之间的信号传导可能成为肿瘤治疗的新途径.     

血管弹性与肝癌自发性破裂的关系

目的 肝癌自发性破裂在亚洲的发病率较高，且发病机理不详。在我们既往的研究中，首次发现抗原抗体复合物血管壁沉积及血管受损与其破裂有关。该研究中，对小动脉周围的弹性硬蛋白进行了深入的探讨，以进一步核实我们的前期发现。方法 用免疫组化及投射电子显微镜的方法，对23例肝癌破裂及30例肝癌非破裂的手术标本进行检测。结果 在肝癌破裂组，患者小动脉的周围弹性硬蛋白厚度明显增厚，弹性硬蛋白增生、弹性蛋白酶异常分别及胶原纤维降解现象广泛存在；同时亦可发现弹性硬蛋白中的电子密度沉积物及中性粒细胞由血液浸入血管壁的现象；弹性硬蛋白中的电子密度沉积物代表了抗原抗体复合物的沉积，而中性粒细胞的浸润则将导致血管受损。由于受损后的血管将变得脆弱并易于破裂及腹腔内出血，因此推测预先存在于血管壁的抗原抗体复合物沉积及血管受损将与肝癌破裂有关。结论 抗原抗体复合物的血管壁沉积及其导致的血管受损与肝癌破裂有关。     

血管内皮生长因子与小细胞肺癌

  回顾了近年来血管内皮生长因子在小细胞肺癌中的研究现状及其进展，从血管内皮生长因子的结构、功能及影响其表达的因素、血管内皮生长因子与小细胞肺癌的关系、血管内皮生长因子与小细胞肺癌治疗的关系研究情况等方面作一综述。     

Hyperthermia, thermotolerance and topoisomerase II inhibitors.

The cytoxicity of both intercalating (m-AMSA) and non-intercalating (VP16, VM26) topoisomerase II-targeting drugs is thought to occur via trapping DNA topoisomerase II on DNA in the form of cleavable complexes. First, analysis of cleavable complexes (detected as DNA double-strand breaks) by pulsed-field gel electrophoresis confirmed the correlation between cleavable complex formation and cytotoxicity of three topoisomerase-targeting drugs in HeLa S3 cells (the order of effects being VM26 > m-AMSA > VP16). In contrast to many antineoplastic agents, hyperthermic treatments were found to protect cells against the toxicity of all three topoisomerase II drugs. Hyperthermia treatment does not alter drug accumulation but reduces the ability of the drug-topoisomerase II complex to form the cleavable complexes. Nuclear protein aggregation induced by heat at the sites of topoisomerase II-DNA interaction may explain such an effect. In thermotolerant cells, the toxic effects of VP16 but not m-AMSA were reduced. For both drugs, however, the status of thermotolerance did not affect cleavable complex formation by the drugs. Thus, protection against VP-16 toxicity seems not to be associated with heat-induced activation of the P-gp 170 pump or altered topoisomerase II-DNA interactions. Rather, a protective (heat shock protein mediated?) mechanism against non-intercalating topoisomerase II drugs seems to occur at a stage after DNA-drug interaction. Finally, heat treatment before topoisomerase II drug treatment reduced toxicity and cleavable complex formation in thermotolerant cells to about the same extent as in non-tolerant cells, consistent with the presumption of nuclear protein aggregation being responsible for this effect.     

Heat fractionation and thermotolerance: a review.

A rational approach to the design of clinical protocols combining fractionated hyperthermia plus X-irradiation or hyperthermia plus chemotherapy requires an understanding of the biology of fractionated heat alone. Mammalian cells growing in vitro can dramatically increase their tolerance to thermal damage (i.e., reduce the cellular inactivation rate) after prior heat conditioning. Although the mechanism(s) for this cellular thermotolerance is still unknown, it is apparent that the thermal history, the heat fractionation interval, and the recovery conditions all modify significantly the degree of thermotolerance subsequently exhibited. At the tissue level, the role of cellular thermotolerance is further complicated by host physiological mechanisms. Few data are available on heat fractionation in vivo, and the relative importance of physiological versus cellular effects remains to be defined.     

The kinetics of vascular thermotolerance in SCK tumors of A/J mice

Development of thermotolerance has been observed in diverse biological systems. Despite the important role of blood circulation in heat-induced tissue damage, little is known about vascular thermotolerance. The kinetics of vascular thermotolerance in SCK tumors of A/J mice was investigated in this study. A single heating at 43.5 degrees C or 44.5 degrees C for 1 hr caused marked damage in tumor vasculature, as demonstrated by a marked decrease in Rb-86 uptake (% of injected dose/g of dried tissue). The tumor vasculature became resistant or tolerant to subsequent heatings at those temperatures when the tumors were preheated at 42.5 degrees C for 1 hr. Vascular thermotolerance became significant at 5 hr and reached its maximum at 18 hr after preheating at 42.5 degrees C. When the vascular thermotolerance was at its peak, heating at temperatures as high as 44.5 degrees C for 1 hr could not reduce the tumor blood flow. The vascular thermotolerance decayed considerably but not completely at 72 hr after the preheating. The vascular thermotolerance may exert a profound implication on the response of tissues, including tumors, to multiple heatings.     

Development of thermotolerance requires interaction between polymerase-beta and heat shock proteins

Although heat shock proteins (HSP) are well known to contribute to thermotolerance, they only play a supporting role in the phenomenon. Recently, it has been reported that heat sensitivity depends on heat-induced DNA double-strand breaks (DSB), and that thermotolerance also depends on the suppression of DSB formation. However the critical elements involved in thermotolerance have not yet been fully identified. Heat produces DSB and leads to cell death through denaturation and dysfunction of heat-labile repair proteins such as DNA polymerase-β (Polβ). Here the authors show that thermotolerance was partially suppressed in Polβ^−/– mouse embryonic fibroblasts (MEF) when compared to the wild-type MEF, and was also suppressed in the presence of the HSP inhibitor, KNK437, in both cell lines. Moreover, the authors found that heat-induced γH2AX was suppressed in the thermotolerant cells. These results suggest that Polβ at least contributes to thermotolerance through its reactivation and stimulation by Hsp27 and Hsp70. In addition, it appears possible that fewer DSB were formed after a challenging heat exposure because preheat-induced Hsp27 and Hsp70 can rescue or restore other, as yet unidentified, heat-labile proteins besides Polβ. The present novel findings provide strong evidence that Polβ functions as a critical element involved in thermotolerance and exerts an important role in heat-induced DSB. ( Cancer Sci 2008; 99: 973–978)     

Mild temperature hyperthermia and radiation therapy: Role of tumour vascular thermotolerance and relevant physiological factors

Here we review the significance of changes in vascular thermotolerance on tumour physiology and the effects of multiple clinically relevant mild temperature hyperthermia (MTH) treatments on tumour oxygenation and corresponding radiation response. Thus far vascular thermotolerance referred to the observation of significantly greater blood flow response by the tumour to a second hyperthermia exposure than in response to a single thermal dose, even at temperatures that would normally cause vascular damage. New information suggests that although hyperthermia is a powerful modifier of tumour blood flow and oxygenation, sequencing and frequency are central parameters in the success of MTH enhancement of radiation therapy. We hypothesise that heat treatments every 2 to 3 days combined with traditional or accelerated radiation fractionation may be maximally effective in exploiting the improved perfusion and oxygenation induced by typical thermal doses given in the clinic.     

JAK2 V617F基因突变与血管栓塞性疾病的相关性研究

目的 探讨JAK2 V617F基因突变与血管栓塞性疾病的相关性,为临床诊治和预防栓塞提供依据.方法 以首都医科大学宣武医院神经内科、心脏科及血管外科收治的血红蛋白＞ 160g/L、血小板计数＞ 300×109/L的56例患者为研究对象,其中骨髓增殖性肿瘤患者47例.回顾性分析患者血管栓塞情况、JAK2 V617F突变情况及两者之间的相关性.结果 JAK2 V617F基因突变阳性率为37.50％(21/56),血管栓塞发生率为41.07％(23/56),两者之间存在关联性(P=0.014).结论 JAK2 V617F基因突变检测有助于骨髓增殖性肿瘤患者的早期诊断和治疗,减少栓塞并发症,提高患者生命质量.     

p53和VEGF蛋白表达与胆囊癌的关系

目的探讨抑癌基因p53和血管内皮生长因子(vascular endothelial growth factor,VEGF)与胆囊癌的关系。方法采用免疫组化方法分别检测50例胆囊癌、35例胆囊腺瘤和26例慢性胆囊炎组织中p53和VEGF蛋白表达。结果胆囊癌组织中p53和VEGF的阳性表达率分别为64.0%和72.0%,明显高于胆囊腺瘤的17.1%和22.9%及慢性胆囊炎的19.2%和23.1%,χ2=4.25,P=0.006,根据Nevin分期,胆囊癌S1、S2、S3期的p53阳性表达率为63.2%,明显高于S4、S5期的35.5%,χ2=7.29,P=0.009,而VEGF在胆囊癌S4、S5期的阳性表达率为87.1%,明显高于S1、S2、S3期的47.4%,χ2=4.29,P=0.007,胆囊癌中p53和VEGF的阳性表达明显相关,r=0.87,P=0.009。它们与胆囊癌病理分级均未发现明显相关性。结论p53和VEGF的过度表达可能对胆囊癌的发生、发展及预后判断有一定作用。     

p53和VEGF蛋白表达与胆囊癌的关系

目的：探讨抑癌基因p53和血管内皮生长因子（vascular endothelial growth factor,VEGF）与胆囊癌的关系.方法： 采用免疫组化方法分别检测50例胆囊癌、35例胆囊腺瘤和26例慢性胆囊炎组织中p53和VEGF蛋白表达.结果： 胆囊癌组织中p53和VEGF的阳性表达率分别为64.0%和72.0%,明显高于胆囊腺瘤的17.1%和22.9%及慢性胆囊炎的19.2%和23.1%,χ^2=4.25,P=0.006,根据Nevin分期,胆囊癌S1、S2、S3期的p53阳性表达率为63.2%,明显高于S4、S5期的35.5%,χ^2=7.29,P=0.009,而VEGF在胆囊癌S4、S5期的阳性表达率为87.1%,明显高于S1、S2、S3期的47.4%,χ^2=4.29,P=0.007,胆囊癌中p53和VEGF的阳性表达明显相关,.r=0.87,P=0.009.它们与胆囊癌病理分级均未发现明显相关性.结论： p53和VEGF的过度表达可能对胆囊癌的发生、发展及预后判断有一定作用.     

Influence of low pH on the development and decay of 42°C thermotolerance in cho cells

The development, magnitude and decay of thermotolerance in Chinese hamster ovary cells heated to 42°C at pH 6.7 was examined. The cells were exposed to single or fractionated heat treatments with 0 to 168 hours elapsing between the treatments. Administration of a specified heat treatment in two fractions at low pH substantially reduced the lethal effect of heat. The rate of hyperthermic cell killing was reduced by a factor of approximately 2.5 in preheated cells compared to cells not receiving prior heat treatment. Tolerance to second heat treatments was apparent when 3 hours at 37°C separated the treatments, and was near maximum when 6 hours separated the treatments. Beginning about 96 hours after the initial heat treatment, resistance to second heat treatments began to decline, and was not evident when 168 hours at 37°C separated the treatments. In contrast to these results, a sparing effect as a result of dose fraction was not observed at pH 7.4. At pH 7.4, cells developed thermotolerance during the initial heat treatment and additional culturing at 37°C was without additional effect. Nevertheless, the sensitivity of cells to hyperthermia was greater at pH 6.7 than at pH 7.4. This pH sensitizing effect was more pronounced in cells exposed to single heat treatments than in cells exposed to fractionated treatments at 42°C.     

The origins and implications of intratumor heterogeneity

Human tumors often display startling intratumor heterogeneity in various features including histology, gene expression, genotype, and metastatic and proliferative potential. This phenotypic and genetic heterogeneity plays an important role in neoplasia, cancer progression, and therapeutic resistance. In this issue of the journal (beginning on page 1388), Merlo et al. report their use of molecular data from 239 patients with Barrett's esophagus to evaluate the propensity of major diversity indices for predicting progression to esophageal adenocarcinoma. This work helps elucidate the implications of molecular heterogeneity for the evolution of neoplasia.     

非小细胞肺癌中血管内皮生长因子与树突细胞的关系

血管内皮生长因子(VEGF)是重要的肿瘤细胞生长因子之一,其可以抑制树突细胞(DC)的分化成熟,诱导成熟DC功能障碍,而DC亦可通过自分泌VEGF加重自身的功能障碍,从而介导肿瘤细胞逃逸免疫监视.因此VEGF和DC的相互关系与非小细胞肺癌(NSCLC)的分化程度、淋巴结转移、临床分期密切相关.二者关系可为临床NSCLC的治疗提供相应理论依据.     

Relationship between human tumour angiogenic profile and combretastatin-induced vascular shutdown: an exploratory study

Combretastatin-A4-phosphate (CA4P) acts most effectively against immature tumour vasculature. We investigated whether histological angiogenic profile can explain the differential sensitivity of human tumours to CA4P, by correlating the kinetic changes demonstrated by dynamic MRI (DCE-MRI) in response to CA4P, with tumour immunohistochemical angiogenic markers. Tissue was received from 24 patients (mean age 59, range 32-73, 18 women, 6 men). An angiogenic profile was performed using standard immunohistochemical techniques. Dynamic MRI data were obtained for the same patients before and 4 h after CA4P. Three patients showed a statistically significant fall in K(trans) following CA4P, and one a statistically significant fall in IAUGC(60). No statistically significant correlations were seen between the continuous or categorical variables and the DCE-MRI kinetic parameters other than between ang-2 and K(trans) (P=0.044). In conclusion, we found no strong relationships between changes in DCE-MRI kinetic variables following CA4P and the immunohistochemical angiogenic profile.     

血管内皮生长因子表达及微血管密度与放射敏感性

血管内皮生长因子(VEGF)是一种具有肝素结合活性的生长因子,能特异作用于血管内皮细胞,对血管生长有极强R诱导作用.VEGF的表达与肿瘤内微血管密度(MVD)呈明显正相关.缺氧是VEGF表达最主要的调节因素.恶性肿瘤在生长过程中,由于组织增生过快必然会造成局部组织缺氧,从而诱导VEGF表达;而乏氧细胞对射线抗拒.所以,有希望以VEGF的表达及MVD来预测放射敏感性.