PTEN基因与肿瘤浸润转移

PTEN是最近克隆的肿瘤抑制基因，能多途径调控肿瘤浸润转移过程，抑制肿瘤浸润和转移。PTEN能稳定和增强肿瘤细胞间粘附，抑制肿瘤细胞迁移扩散和非锚定依赖性生长，以及诱导失巢凋亡，并可抑制细胞外基质降解和肿瘤血管生成等，从而抑制肿瘤浸润和转移。     

肿瘤抑制基因PTEN的研究现状

肿瘤抑制基因PTEN是1997年由三个研究小组发现,现统称为PTEN。PTEN包括N端、C2区域和C端区域。其主要结构功能区位于N端,编码的蛋白与张力蛋白、辅助蛋白同源,参与细胞生长及肿瘤细胞浸润、血管发生及肿瘤转移的调节;并具有磷酸酶活性,参与细胞调控。PTEN的C端可调节PTEN稳定性和酶活性。其C2区域参与正确定位PTEN的催化结构域。PTEN可通过三磷脂酰肌醇激酶途径调节细胞周期;通过FAK途径抑制细胞的浸润、转移;通过蛋白激酶途径参与细胞转化和细胞周期调控。许多原发性肿瘤中都有PTEN缺失,但早期便发生完全缺失的只有子宫内膜癌和卵巢癌,其余病例中的完全失活发生在肿瘤后期,所以PTEN基因的缺失被认为是恶变过程中的后期事件。PTEN突变中有1/3是与以常染色体为主的疾病有关。     

磷酸酶和张力素同系物与肿瘤血管生成的研究进展

磷酸酶和张力素同系物(PTEN)是众所周知的抑癌基因,能抑制肿瘤细胞的增殖、迁移、能量代谢、血管生成等多个恶性生物学行为。血管无序快速生成是肿瘤的特征之一,通过抗血管生成能抑制肿瘤生长转移。本综述回顾了PTEN和肿瘤血管生成的最新研究,并结合近年来所发现的非编码RNA和肿瘤微环境,阐述PTEN在肿瘤血管生成网络中的关键作用,展望肿瘤治疗的新方向。     

胃腺癌nm23、Bcl-2、PCNA表达与癌浸润转移关系的研究

 目的　探讨胃腺癌浸润转移与肿瘤转移抑制基因、肿瘤细胞增殖、凋亡的关系及癌浸润转移的可能机制。方法　采用免疫组化S-P法检测65例胃腺癌中nm23、Bcl-2、PCNA的表达。结果　(1) nm23与分化程度、Bcl-2与浸润深度、PCNA与分化程度和浸润深度有关,三者均与淋巴结转移相关;(2) PCNA 表达与nm23表达呈负相关,与Bcl-2表达呈正相关。结论　(1) nm23能抑制胃腺癌的转移且与肿瘤细胞增殖活性有关;(2) 胃腺癌的发展是肿瘤细胞不断增殖和凋亡抑制的结果。     

Endoglin与肿瘤血管生成、浸润及转移之问的关系

恶性肿瘤的浸润和转移是导致患者死亡的主要原因,而肿瘤新生血管对肿瘤的生长和转移具有重要的营养支持作用。Endoglin是参与调节TGF-β信号传导的跨膜蛋白,作为TGF-β家族的辅助受体发挥生物学效应。Endoglin作为新生血管内皮细胞的标志物之一,在肿瘤血管内皮细胞中呈异常高表达,并且促进肿瘤血管的形成。目前以endoglin为靶点抑制肿瘤血管生成的抗肿瘤策略已被证实具有一定成效,但肿瘤细胞依然存在对药物的抵抗、复发及转移等现象。为寻求这一现象的原因,近年来研究发现在某些原发肿瘤细胞中表达的endoglin可以抑制肿瘤细胞的浸润及转移。本文结合国内外最新报道,就endoglin与肿瘤血管生成、肿瘤浸润及转移之间的关系作以一简要综述,为今后如何抑制其促血管生成作用及发挥其抑制肿瘤细胞的浸润及转移作用提供思路。     

Endoglin与肿瘤血管生成、浸润及转移之间的关系

恶性肿瘤的浸润和转移是导致患者死亡的主要原因,而肿瘤新生血管对肿瘤的生长和转移具有重要的营养支持作用。Endoglin是参与调节TGF-β信号传导的跨膜蛋白,作为TGF-β家族的辅助受体发挥生物学效应。Endoglin作为新生血管内皮细胞的标志物之一,在肿瘤血管内皮细胞中呈异常高表达,并且促进肿瘤血管的形成。目前以endoglin为靶点抑制肿瘤血管生成的抗肿瘤策略已被证实具有一定成效,但肿瘤细胞依然存在对药物的抵抗、复发及转移等现象。为寻求这一现象的原因,近年来研究发现在某些原发肿瘤细胞中表达的endoglin可以抑制肿瘤细胞的浸润及转移。本文结合国内外最新报道,就endoglin与肿瘤血管生成、肿瘤浸润及转移之间的关系作以一简要综述,为今后如何抑制其促血管生成作用及发挥其抑制肿瘤细胞的浸润及转移作用提供思路。     

胃癌组织中 PTEN、VEGF 和 MMP2 表达及其临床意义

目的：探讨PTEN、VEGF和MMP2在胃癌组织中的表达及其临床意义。方法：采用免疫组化sP技术检测80例胃癌组织中PTEN、VEGF和MMP2表达。结果：胃癌组织中PTEN高表达率43．8％，与肿瘤分化程度、浸润深度、淋巴结转移和肿瘤分期显著相关。VEGF、MMP2阳性表达率分别为60．O％和51．3％，与肿瘤大小、浸润深度、淋巴结转移和肿瘤分期显著相关。胃癌组织中PTEN与VEGF和MMP2表达显著负相关，与病人预后相关，Kaplan—Meier生存曲线显示PTEN高表达者术后累计生存率显著高于低表达者；VEGF和MMP2阳性表达者术后累计生存率显著低于阴性表达者。结论：PTEN通过调控胃癌组织VEGF和MMP2表达，抑制胃癌的浸润和转移，改善病人预后。     

胃癌组织中PTEN、VEGF和MMP2表达及其临床意义

目的：探讨PTEN、VEGF和MMP2在胃癌组织中的表达及其临床意义。方法：采用免疫组化sP技术检测80例胃癌组织中PTEN、VEGF和MMP2表达。结果：胃癌组织中PTEN高表达率43．8％，与肿瘤分化程度、浸润深度、淋巴结转移和肿瘤分期显著相关。VEGF、MMP2阳性表达率分别为60．O％和51．3％，与肿瘤大小、浸润深度、淋巴结转移和肿瘤分期显著相关。胃癌组织中PTEN与VEGF和MMP2表达显著负相关，与病人预后相关，Kaplan—Meier生存曲线显示PTEN高表达者术后累计生存率显著高于低表达者；VEGF和MMP2阳性表达者术后累计生存率显著低于阴性表达者。结论：PTEN通过调控胃癌组织VEGF和MMP2表达，抑制胃癌的浸润和转移，改善病人预后。     

MLN4924抗肿瘤作用机制

MLN4924可通过诱导肿瘤细胞凋亡、衰老、细胞自噬抑制肿瘤细胞的增殖、浸润、转移,其可抑制肿瘤血管生成并能增强肿瘤对放疗、化疗的敏感性,发挥良好的抗肿瘤效应.     

PTEN下调FAK磷酸化来抑制EGFR受体突变体引起的胶质瘤细胞侵袭

背景与目的:抑癌基因PTEN在胶质瘤中突变率达20%～40%,且PTEN缺失和表皮生长因子受体突变体EGFRvⅢ同时存在EGFR表达的胶质瘤组织中.PTEN通过直接与FAK作用从而降低其酪氨酸磷酸化来抑制肿瘤细胞侵袭.EGFRvⅢ表达,PTEN缺失都是肿瘤细胞侵袭性增加的原因之一.PTEN功能的丧失可能是EGFRvⅢ表达的肿瘤进一步发展成恶性侵袭性肿瘤的原因之一.本文将探讨在EGFRvⅢ表达和PTEN缺失的肿瘤细胞中转入PTEN以观察其是否能抑制EGFRvⅢ所引起的肿瘤细胞的侵袭.方法:将野生型PTEN及其突变体分别导入人胶质瘤细胞U87ΔEGFR中,利用Transwell-细胞侵袭实验观察细胞侵袭运动变化;免疫印迹实验检查FAK磷酸化变化;FAK表达载体来转染FAK磷酸化程度低的U87ΔEGFR-wtPTEN细胞,观察细胞侵袭运动变化.结果:PTEN和PTEN(G129E)能够抑制U87ΔEGFR细胞侵袭,并且下调FAK 397位点磷酸化水平.U87ΔEGFR-wtPTEN细胞中FAK 397位点磷酸化水平增加伴随着细胞侵袭能力的提高.结论:PTEN 可能通过下调FAK 397位点磷酸化水平来抑制EGFRvⅢ引起的胶质瘤细胞侵袭.     

Bacteria and cancer--antagonisms and benefits

There is considerable historical and recent evidence concerning the antagonisms between acute bacterial infections or their toxins and cancer and allied diseases. These data provide renewed incentives to undertake clinical programmes with mixed bacterial vaccines in many countries at the present time.     

Religiosity and physical and emotional functioning among African American and White colorectal and lung cancer patients

The literature suggests that religiosity helps cope with illness. The present study examined the role of religiosity in functioning among African Americans and Whites with a cancer diagnosis. Patients were recruited from an existing study and mailed a religiosity survey. Participants (N = 269; 36% African American, 56% women) completed the mail survey, and interview data from the larger cohort was utilized in the analysis. Multivariate analyses indicated that in the overall sample religious behaviors were marginally and positively associated with mental health and negatively with depressive symptoms. Among women, religious behaviors were positively associated with mental health and negatively with depressive symptoms. Religiosity was not a predictor of study outcomes for men. Among African Americans, religious behaviors were positively associated with mental health and vitality. Among Whites, religious behaviors were negatively associated with depressive symptoms. These findings suggest a mixed role of religious involvement in cancer outcomes. The current findings may have applied potential in the areas of emotional functioning and depression.     

Renal irradiation and the pharmacology and toxicity of methotrexate and cisplatinum

We used a rat model to study the effects of renal irradiation on the pharmacology of methotrexate (MTX) and cisplatinum (cis-Pt). Unanesthetized rats were given bilateral kidney irradiation (20 Gy in 9 fractions). At 9 months after irradiation, 3% of the animals had died and survivors showed moderately impaired renal function. At 15 months, 30% of the animals had died and survivors showed severely impaired renal function. Some animals were given i.v. MTX 1 week to 15 months after irradiation. In irradiated rats, the area under the MTX plasma clearance curve equaled that of controls through 6 months, and was significantly above controls from 9 months on. Other animals were given i.p. cis-Pt 1 week to 9 months after irradiation. The acute toxicity of cis-Pt was the same in control and irradiated rats when cis-Pt was given immediately before or after irradiation. Beginning 3 months after irradiation there was a progressive increase in cis-Pt toxicity and a simultaneous decrease in urinary platinum excretion. Irradiated animals that survived cis-Pt treatment showed increased radiation nephritis; the greatest effect occurred when cis-Pt was given 3 months or more after irradiation. MTX and cis-Pt clearance decreased when renal dysfunction was first observed and changes in renal function preceded changes in drug clearance and toxicity.     

VEGF及KDR在大肠腺瘤和腺癌中的表达及意义

目的：探讨VEGF和KDR在大肠腺瘤和大肠腺癌中的表达及临床病理特征的关系。方法：大肠腺瘤和大肠腺癌组织标本各100例,采用免疫组织化学染色法检测VEGF和KDR在标本中的表达情况。结果：VEGF和KDR在大肠腺癌组中的阳性表达明显高于大肠腺瘤组（P〈0.05）;在正常大肠黏膜均未见VEGF和KDR表达的阳性染色;VEGF阳性表达组中KDR的阳性表达率为70%,显著高于VEGF阴性表达组中KDR的阳性表达率16%,两组比较有统计学意义（P〈0.01）。结论：大肠腺癌组织中KDR的表达与肿瘤大小、转移情况、浸润深度密切相关;VEGF和KDR在大肠腺瘤中的表达与患者的年龄、性别及分型均无相关性,而与增生程度相关（P〈0.05）。在大肠腺癌患者中VEGF及KDR表达更高,二者具有协同效应。     

Morphine and tumor growth and metastasis

Morphine is an analgesic widely used to alleviate cancer pain. In addition, the perioperative management of pain in cancer surgery patients most often includes opioids. However, there are reports that these drugs may alter cancer recurrence or metastasis. Several mechanisms have been proposed, such as the modulation of the immune response or cellular pathways that control the survival and migratory behavior of cancer cells. The published literature, however, presents some discrepancies, with reports suggesting that opioids may either promote or prevent the spread of cancer. It is of great importance to determine whether opioids, in particular the most widely used, morphine, may increase the risk of metastasis when used in cancer surgery. This review examines the available data on the effects of morphine which influence cancer metastasis or recurrence, including immunomodulation, tumor cell aggressiveness, and angiogenesis, with special emphasis on recently published clinical and laboratory based studies. We further discuss the parameters that may explain the difference between reports on the effects of morphine on cancer.     

肾上腺素能β受体与肿瘤生长及转移

大量研究表明肿瘤细胞可表达β受体，而一些神经递质、药物和社会心理因素可能通过β受体影响肿瘤的生长和转移，β受体激动剂、β受体阻滞剂以及抑郁等社会心理因素可加强或削弱这种作用。这为表达β受体肿瘤的治疗开辟了新的道路，提供了新的治疗靶点。