Akt/mTOR活化抗UVB诱导HaCaT细胞凋亡的研究

目的 探讨Akt/mTOR信号通路活化抗中波紫外线（UVB）诱导的HaCaT细胞凋亡。方法 UVB照射角质形成细胞,Western印迹检测Akt/mTOR通路中相关信号分子的动态水平变化。免疫荧光 Hoechst 33342染色观察HaCaT细胞凋亡率。结果 UVB能活化Akt/mTOR信号通路,并在一定范围内（5 ～ 30 mJ/cm2）成剂量依赖性,在一定范围内（5 ～ 30 min）成时间依赖性。EGFR抑制剂PD 153035、PI3K抑制剂LY 294002和mTOR抑制剂雷帕霉素能显著抑制UVB对Akt/mTOR信号通路的活化作用。UVB照射前加入雷帕霉素、LY 294002预处理,HaCaT细胞凋亡率增加。结论 Akt/mTOR活化抗UVB诱导的HaCaT细胞凋亡。     

PI3K/Akt/mTOR信号通路在皮肤鳞状细胞癌中的研究进展

【摘要】 皮肤鳞状细胞癌的发病机制复杂，晚期治疗手段缺乏。本文综述磷脂酰肌醇3-激酶/蛋白激酶B/哺乳类动物雷帕霉素靶蛋白（PI3K/Akt/mTOR）信号通路在皮肤鳞状细胞癌发病机制中的作用及针对其的治疗进展，为皮肤鳞状细胞癌的靶向治疗提供新思路。     

PI3K/AKT信号通路及其与SLE的关系

PI3K/AKT信号通路是细胞内重要的信号传导通路之一,通过影响下游多种效应分子的活化调节细胞的基本功能,包括生存、生长、增殖和代谢.近年研究发现,T、B淋巴细胞PI3K/AKT信号通路的异常活化与SLE自身免疫的发生发展密切相关.概述PI3K/AKT信号通路的组成与功能,其与SLE发病机制的关系及其抑制剂在SLE治疗中的研究进展.     

麦冬皂苷B通过抑制PI3K/Akt/mTOR通路诱导人黑色素瘤A375细胞凋亡

目的探讨麦冬皂苷B对人黑色素瘤(Melanoma)A375细胞增殖,凋亡和细胞周期的影响以及相关机制。方法麦冬皂苷B处理A375细胞后,采用CCK-8法检测细胞活力;流式细胞仪检测A375细胞周期变化及细胞凋亡水平;Hoechst33258荧光染色法观察细胞凋亡形态;免疫印迹法检测麦冬皂苷B对A375细胞PI3K,p-PI3K,AKT,p-AKT蛋白以及通路下游凋亡相关蛋白Bcl-2,Bax,Cleaved-caspase3表达的影响。结果麦冬皂苷B能抑制A375细胞增殖活力及PI3K/Akt/mTOR通路的活化;麦冬皂苷B促进了A375细胞内Bax和Cleaved-caspase 3的表达,抑制Bcl-2表达,诱导人黑色素瘤细胞发生凋亡;麦冬皂苷B阻滞了A375细胞细胞周期,G0/G1期细胞比例明显升高;PI3K/Akt/mTOR通路活化剂IGF-1处理A375细胞后抑制了麦冬皂苷B的上述作用。结论麦冬皂苷B能抑制A375细胞的增殖,诱导细胞发生凋亡,阻滞细胞周期于G0/G1期。     

白藜芦醇对病理性瘢痕成纤维细胞mTOR信号通路相关分子表达的影响

目的观察白藜芦醇对病理性瘢痕成纤维细胞mTOR信号通路关键分子PI3K、Akt、mTOR表达的影响。方法应用免疫荧光检测PI3K、Akt、mTOR在病理性瘢痕及正常皮肤组织成纤维细胞中的表达;病理性瘢痕成纤维细胞经不同浓度白藜芦醇处理后,分别应用RT-PCR、Western Blot检测PI3K、Akt、mTOR mRNA和蛋白的表达。结果免疫荧光检测结果显示,PI3K、Akt、mTOR在病理性瘢痕成纤维细胞中表达明显增强,且主要表达于细胞核,而在正常皮肤组织成纤维细胞中未见明显表达;RT-PCR及Western Blot检测结果显示,病理性瘢痕成纤维细胞经不同浓度的Res干预后,Akt和mTOR mRNA和蛋白表达量降低,并且呈剂量依赖关系,与对照组相比,差异具有统计学意义(P0.05),而PI3K mRNA和蛋白表达量降低不明显,与对照组相比差异无统计学意义(P0.05)。结论白藜芦醇抑制病理性瘢痕成纤维细胞增殖的机制可能与其下调mTOR信号通路关键分子Akt、mTOR表达有关。     

PI3K/Akt/mTOR信号通路与皮肤肿瘤靶向治疗

P13K/AkdmTOR信号转导通路是促存活通路,在很多肿瘤中组成性激活.该通路激活的机制是肿瘤抑制基PTEN功能缺失、P13K扩增或突变、Akt扩增或突变.近年研究发现,该通路失常可促进肿瘤细胞的存活和生长,持续活化在皮肤肿瘤发病中起着重要的作用,已经发现抑制该通路中的信号分子可以治疗多种肿瘤,目前,针对该通路的抑制药物也在研究中,主要集中于mTOR抑制剂.     

五倍子瘢痕膏对瘢痕疙瘩miR-21/mTOR信号通路相关分子表达的影响

目的观察五倍子瘢痕膏对瘢痕疙瘩miR-21/mTOR信号通路关键分子miR-21、磷脂酰肌醇3-激酶(PI3K)、10号染色体张力缺失蛋白磷酸酶(PTEN)、蛋白激酶B(Akt)、哺乳动物雷帕霉素靶蛋白(mTOR)表达的影响。方法将36只裸鼠瘢痕疙瘩模型随机分成治疗组和对照组,每组18只。治疗组涂抹五倍子瘢痕膏,对照组仅涂抹制作五倍子瘢痕膏的基质,3次/d,连续30 d。然后分别应用逆转录聚合酶链反应(RT-PCR)和免疫组化技术检测治疗组、对照组及正常皮肤组中miR-21和PI3K、PTEN、Akt、mTOR的表达。结果RT-PCR检测结果显示,治疗组和正常皮肤组miR-21相对表达量差异无统计学意义(P>0.05,t=1.24),但二者与对照组相比均明显降低,差异有统计学意义(P<0.05,t=2.76、2.81);免疫组化检测结果显示,PI3K、Akt、mTOR在对照组中高表达,而在治疗组和正常皮肤组中低表达;PTEN在对照组中低表达,而在治疗组和正常皮肤组中高表达。结论五倍子瘢痕膏抑制瘢痕疙瘩成纤维细胞增殖的机制可能与其通过抑制miR-21表达而上调PTEN表达,进而下调mTOR信号通路中PI3K、Akt、mTOR表达有关。其中PTEN是负反馈调节因子;下游的核糖体蛋白S6激酶(S6K)、真核细胞翻译起始因子4E结合蛋白(4EBP),二者均是蛋白翻译的关键调节因子。     

PI3K和磷酸化Akt在尖锐湿疣皮损中的表达

目的:检测PI3K/Akt信号转导通路中PI3K和磷酸化Akt在尖锐湿疣皮损中的表达.方法:采用免疫组化和蛋白印迹法检测30例尖锐湿疣皮损及15例正常对照者皮肤活检组织中PI3K和磷酸化Akt的表达,并利用计算机图像采集与分析系统对免疫组化结果进行平均吸光度(A值)测定和对免疫印迹测定结果进行灰度扫描.结果:尖锐湿疣皮损中PI3K和磷酸化Akt的表达明显高于正常皮肤.蛋白印迹结果与免疫组化检测一致(两组比较,均P＜ 0.01).结论:PI3K/Akt信号通路异常激活可能参与了尖锐湿疣的发病.     

p62通过调控PI3K/AKT通路促进黑素瘤增殖

目的探讨p62促进黑素瘤A375细胞生长增殖的作用及具体机制。方法取生长状态良好的黑素瘤A375细胞,采用干扰p62表达的siRNA片段转染A375细胞;EDU着色法检测干扰组和对照组的细胞分裂情况;采用Western blot检测干扰组和对照组PI3K/AKT/mTOR及下游因子的表达情况。结果干扰组的EDU着色数目较对照组明显减少;p62干扰后PI3K/AKT/mTOR及下游因子的表达明显受抑制。结论p62可能通过调控PI3K/AKT通路发挥促进黑素瘤增殖的作用。     

mTORC1信号通路在狼疮鼠体内的表达及意义

目的：检测mTORC1信号通路在系统性红斑狼疮鼠体内的表达,探讨其在系统性红斑狼疮发病中的作用。方法： 研究对象为6只B6.MRL/lpr狼疮小鼠和6只C57正常小鼠。RT-PCR和Western blot检测肾脏组织Akt、mTOR、p70S6K、IL-17 mRNA和蛋白的表达。细胞内染色流式细胞术检测脾脏Th17淋巴细胞亚群比例。结果： 狼疮鼠组Akt、mTOR、p70S6K、IL-17 mRNA、磷酸化蛋白表达水平高于对照组（P<0.05）;狼疮鼠组的Th17细胞占CD4+T细胞的比例高于正常对照组（P<0.05）。结论： mTORC1（Akt-mTOR-p70S6K）信号通路在SLE的发病中起着重要作用。     

Leukoderma in the nude C57BL/6 mouse

The nu gene bred into mice causes the animals to be athymic and nude, that is their hairs do not project past the follicular orifice making them appear to be hairless. The gene has been bred into C57BL/6 mice. C57BL/6 mice which are homozygous for the gene are runted and nude and develop leukoderma around 6 weeks of age. The leukoderma is caused by shedding of short stubby, barely visible black hairs, probably a normal hair cycle. This type of leukoderma is not vitiligo, a disease which causes the skin to turn white because of destruction of the melanocytes in the epidermis or hair bulbs.     

CH50 and C3 Component of Complement in Hansen''s Disease

Although a variety of complement values have been reported in leprosy, we found no difference in the CH50 and C3 in the sera of 30 normal persons and 233 lepromatous patients. No statistically significant difference was observed in CH50 and C3 values between healthy controls and lepromatous patients taken as a whole or separated into the different types of the disease spectrum (P greater than 0.1). A statistical difference in C3 titers was found between health controls and borderline patients (P less than 0.05 greater than 0.01) but the sample number is too small to be valid. An important number of sera tested had low and an equally important number had high complement values. Sera with high and low values are important because high values are found in acute inflammatory reactions and low values demonstrate complement activation. Discrepancies in reported results are probably due not only to differences in the methods used, storage and limited number of sera tested, but mainly to the stage of the disease and the drug's administration.     

T4/T8 ratio and absolute T4 cell numbers in different clinical stages of Kaposi''s sarcoma in AIDS

Thirty-seven men (36 homosexual or bisexual and one heterosexual) with epidemic Kaposi's sarcoma and underlying HIV infection were followed up over a period of up to 32 months. Fourteen patients (38%) died, with a median survival time of 7.2 months after the diagnosis of AIDS. Seventeen patients (46%) presented with one or more opportunistic infections, mostly Pneumocystis carinii pneumonia. Eighteen patients (49%) had lymphadenopathy syndrome according to the definition of the CDC. Using the Laubenstein-classification of Kaposi's sarcoma, all patients either remained stable or deteriorated, improvement was never observed. Absolute T4 lymphocyte counts and the T4/T8 ratio were not related to the disease stage. With the onset of B symptoms (systemic symptoms), however, the absolute T4 numbers and the T4/T8 ratio markedly decreased. Delayed type hypersensitivity also showed no relationship to the clinical stages of Kaposi's sarcoma. Thus, the clinical progression of Kaposi's sarcoma lesions seems to be largely independent of the immunological parameters investigated. However, the onset of B symptoms was observed to be related to changes in immune status.     

p21 WAF1/cip1expression in non-melanoma skin tumors

Abnormal control of the cell cycle is closely linked to carcino-genesis. p21^WAF1/CIP1 protein is a universal inhibitor of Gl cyclin-dependent kinase and is induced by p53-dependent and -independent pathways. In order to elucidate the role of p21^WAF1/CIP1 in human skin carcinogenesis, protein expression in squamous cell carcinoma (SCC), basal cell carcinoma (BCC), Bowen's disease (BD), actinic keratosis (AK), keratoacanthoma (KA), seborrheic keratosis (SK), and normal skin was examined using an immunohistochemical method. In normal skin, a few positive cells were seen in some cases in the upper spinous layer of the epidermis; sebaceous glands also had positive cells. In cases of SK and KA, positive cells were found in the basal and suprabasal epidermal layers (proliferation pattern), and in cases of BD and AK, positive cells were seen mainly in the upper spinous layer (differentiation pattern). Cases of SCC had more positive cells and showed two staining patterns: proliferation, or mixed. Cases of BCC had no positive cells. p21^WAF1/CIP1 has some unidentified role in keratinocyte tumorigenesis, which may not be related directly to carcinogenesis.     

H2 Blockers in Chronic Urticaria

Two hundred unselected patients with chronic idiopathic urticaria were treated with adequate doses of conventional antihistamines given at frequent intervals; 98.5% were completely freed of disease while on therapy. In three cases, the lesions subsided but did not clear completely. The addition of 800 mg of cimetidine in divided doses cleared the lesions in two cases, and in the third case the dose of H1 blocker was increased, which resulted in complete clearance of wheals and symptoms. Addition of H2 blockers play a role, but only in a very small percentage of patients with chronic idiopathic urticaria who do not completely respond to adequate doses of H1 blockers.     

Complement C3 proteins in psoriasis

A new polymorphism of the complement factor C3 in human plasma was demonstrated by isotachophoresis in agarose gels followed by immunodetection with rabbit anti-human C3c and C3d immunoglobulins. Four bands were detected in the immunoprint of freshly drawn EDTA-plasma, which were C3s1, C3s2, C3f1 and C3f2. At least four additional C3 components in Mg2+ -zymosan activated plasma were present, which were C3b1 to C3b4. The different forms of C3 in frozen and thawed heparin-plasma from 20 patients with psoriasis and 20 healthy individuals were studied from the immunoprint. The total content of C3 components was 29% greater in the patients with psoriasis than controls. The major difference was in the C3b components which were increased by 46%. In psoriatic patients, the two slow C3 components C3s1 and C3s2 were increased by 24 and 56% respectively, when compared with controls. The two fast C3 components C3f1 and C3f2 were decreased to 29 and 37%. The results suggest a direct involvement of the complement factor C3 in psoriasis.     

Leukotrienes B4, C4 and D4 stimulate DNA synthesis in cultured human epidermal keratinocytes

Leukotrienes in psoriatic skin lesions are potent mediators of inflammation. We have studied the capacity of leukotrienes to stimulate the DNA synthesis of cultured human epidermal keratinocytes. At concentrations ranging from 10(-12) to 10(-8) M, LTB4 produced a 100% increase of DNA synthesis determined both as the incorporation of [3H] thymidine and as the labelling index. In comparison, LTB4 had no effect on the DNA synthesis of dermal fibroblast cultures. 5S,12S-LTB4 and 5S,12S-all-trans-LTB4 did not change the DNA synthesis of keratinocytes, but the effect of LTB4 was abolished in the presence of 5S,12S-all-trans HLTB4. Being less potent than LTB4 the peptidoleukotrienes (LTC4, LTD4) also stimulated keratinocyte DNA synthesis. The effect of the peptidoleukotrienes, but not of LTB4, was antagonized by FPL 55712. These results show that leukotrienes B4, C4 and D4 exert potent and stereospecific mitogenic effects on cultured human keratinocytes. The presence of these arachidonic acid metabolites in psoriatic skin lesions may be pertinent to both inflammation and aberrant epidermal growth in psoriasis.