人着色性干皮病D组基因对白细胞介素-6促进人血管平滑肌细胞增殖作用的影响

目的: 探讨人着色性干皮病D组基因(XPD)对白细胞介素-6(IL-6)促进人血管平滑肌细胞(VSMCs)增殖作用的影响。方法: 用脂质体转染法将重组质粒pEGFP-N2/XPD和空质粒pEGFP-N2稳定转染VSMCs,然后给予1×10⁵ U/L IL-6孵育48 h。实验分为6组:(1)空白对照组;(2)pEGFP-N2组;(3)pEGFP-N2/XPD组;(4)IL-6组;(5)IL-6 + pEGFP-N2组;(6)IL-6 + pEGFP-N2/XPD组。用荧光显微镜观察绿色荧光蛋白报告基因表达情况;用MTT法观察细胞增殖活力;用流式细胞仪检测细胞周期和凋亡率;用RT-PCR和Western blotting检测XPD、Bcl-2、Bax和野生型P53(wt-P53)表达量的变化。结果: 在荧光显微镜下,可在转染了重组质粒pEGFP-N2/XPD或空质粒pEGFP-N2的细胞中观察到绿色荧光,即转染成功;MTT结果显示,重组质粒pEGFP-N2/XPD的转染抑制了细胞增殖活力(P<0.05),并能抑制IL-6促进VSMCs增殖的作用(P<0.05);流式细胞仪结果显示,重组质粒pEGFP-N2/XPD的转染引起了细胞G₀/G₁期增加(P<0.05)、S期减少(P<0.05)、凋亡率增加(P<0.01),并能抑制IL-6促进VSMCs G₀/G₁期减少、S期增加、凋亡率降低的作用(P<0.01);RT-PCR和Western blotting检测发现,重组质粒pEGFP-N2/XPD的转染使得XPD表达增高(P<0.05或P<0.01),同时Bcl-2表达降低,Bax和wt-P53表达增高(P<0.05或P<0.01),并能抑制IL-6促进VSMCs的Bcl-2表达增高、Bax和wt-P53表达降低的作用(P<0.05或P<0.01)。结论: XPD能抑制VSMCs增殖并促进其凋亡,并能抑制IL-6促进VSMCs增殖和降低其凋亡的作用,有望成为治疗动脉粥样硬化的靶点。     

紫外线诱发的细胞染色体畸变与皮肤肿瘤的关系

本文研究两种对日光异常敏感的皮肤病患者的淋巴细胞经紫外线照射后染色体畸变与日光诱发皮肤肿瘤之间的关系。一是着色性干皮病(XP),另一是Cockayne综合征(CS)。两者均系常染色体隐性遗传并伴有DNA修复过程的缺陷,但XP会发展有紫外线诱发的皮肤肿瘤而CS则不会。结果看到两者均有比正常人显著高的紫外线诱发的染色体畸变发生率,各型畸变发生情况也相似,可见紫外线诱发的异常高的染色体畸变不是(至少在CS患者中)紫外线诱发皮肤肿瘤的一个足够的原因。     

着色性干皮病C组基因蛋白缺失对膀胱癌细胞自噬的影响

目的 探讨膀胱癌细胞中着色性干皮病C组基因(xeroderma pigmentosum group C,XPC)蛋白缺失对自噬的影响.方法 利用shRNA策略,建立稳定干扰XPC的膀胱癌T24细胞模型,蛋白印迹技术检测干扰XPC后自噬表征蛋白LC3Ⅱ的表达,瞬时转染GFP-LC3,荧光显微镜观察细胞荧光聚集情况,CCK-8法检测细胞的增殖状况,免疫印迹技术检测自噬及凋亡相关蛋白的表达.结果 成功建立干扰XPC的膀胱癌T24细胞模型;干扰XPC后,膀胱癌T24细胞自噬小体的形成[(1.53±0.81)％ vs(3.30 ±0.70)％,P＜0.05]明显减少,顺铂作用下膀胱癌T24细胞自噬小体的形成[(2.19±0.37)％ vs(3.20 ±0.29)％,P＜0.05]明显减少;顺铂促进XPC缺失后的膀胱癌T24细胞自噬;XPC缺失后的自噬为非保护性自噬.结论 XPC蛋白参与调控膀胱癌T24细胞的自噬.     

Non‐invasive management of non‐melanoma skin cancer in patients with cancer predisposition genodermatosis: a role for confocal microscopy and photodynamic therapy

Background Patients with genodermatosis such as Gorlin syndrome (GS) and Xeroderma pigmentosum (XP) require a close follow‐up for early diagnosis and treatment of skin cancer. We aimed to evaluate the efficacy of methyl‐aminolevulinate (MAL) photodynamic therapy (PDT) in basal cell carcinomas (BCCs) from patients with GS and XP, and to determine the utility of reflectance confocal microscopy (RCM) in the diagnosis and the evaluation of therapeutic response. Patients and methods We included four patients with GS and two siblings with XP. Single or multiple lesions in localized areas were treated with 1–3 cycles of MAL PDT. RCM was performed before and 3 months after the treatment in target lesions in all the patients. Patients were followed up for 3 years. Results In XP patients, we treated 13 pigmented BCCs on the face. All the lesions responded to the treatment and six lesions showed a complete clinical clearing. In GS patients, facial or trunk areas with multiple BCCs were treated (up to 200). Complete clinical remission was obtained in 25–67% of the lesions. Some nodular and pigmented lesions failed to achieve a complete remission. RCM could identify already described confocal features for BCC. Tumour remissions could be assessed by this technique. Conclusions Methyl‐aminolevulinate PDT may be useful for the treatment of superficial BCC in GS and XP. In some nodular lesions, PDT may complement surgery reducing tumour size. RCM may be regarded in the future as a complementary technique in BCC for the diagnosis and post‐treatment assessment to non‐invasive therapeutic modalities.     

The dominant diseases of modernized societies as omega-3 essential fatty acid deficiency syndrome: Substrate beriberi

About 1900, modern food selection and processing caused widespread $\text{epidemics}$ of the B vitamin deficiency diseases of beriberi and pellagra which, for genetic reasons, often expressed as different diseases ranging from bowel and heart disease to dermatoses and psychoses. But the B vitamins merely help convert essential fatty acids (EFA) into the prostaglandin (PG) tissue regulators and it now turns out that, through hydrogenation, milling and selection of w3-poor southern foods, we have also been systematically depleting, by as much as 90%, a newly discovered trace Nordic EFA (w3) of special importance to primates and sole precursor of the PG3(4) series, even as a concurrent fiber deficiency increases body demand for EFA. Since substrate EFA is processed by many B vitamin catalysts, an EFA deficiency will mimic a $\text{panh}$ypovitaminosis B, i.e., a mixture of $\text{substrate}$ beriberi and $\text{substrate}$ pellagra resembling vitamin beriberi and pellagra but exhibiting as even more diverse $\text{endemic}$ disease. This would consitute a second stage of the Modern Malnutrition and explain why some workers now hold the dominant diseases of modermized societies to be new, nutritionally based, pellagraform yet lipid-related and to range, once again, from heart disease to psychosis. It is an assumption that our dominant diseases are unrelated to each other or are merely revealed by our diagnostic acumen and therapeutic success; and that hydrogenating millions of tons of food oils annually, to destroy the rancidity producing w3-EFA, is safe for $\text{primates}$. Extensive beriberiform disease is reported here in 32 typical cases taken from medical practice which responds strikingly to linseed oil supplements (60% w3-EFA) in confirmation of identical results in Capuchins.     

Lack of involvement of nucleotide excision repair gene polymorphisms in colorectal cancer

DNA repair has an essential role in protecting the genome from damage by endogenous and environmental agents. Polymorphisms in DNA repair genes and differences in repair capacity between individuals have been widely documented. For colorectal cancer, the loss of mismatch repair gene activity is a key genetic determinant. Nucleotide excision repair (NER), recombination repair (RR) and base excision repair (BER) pathways have critical roles in protection against other cancers, and we wished to investigate their role in colorectal cancer. We have compared the frequency of polymorphisms in the NER genes, XPD, XPF, XPG, ERCC1; in the BER gene, XRCC1; and in the RR gene, XRCC3; in colorectal cancer patients and in a control group. No significant associations were found for any of the NER gene polymorphisms or for the XRCC1 polymorphism. The C allele (position 18067) of the XRCC3 gene was weakly but significantly associated with colorectal cancer (odds ratio 1.52, 95% confidence interval 1.04-2.22, P=0.03). For all patients who were heterozygous for any of the repair genes studied, tumour tissue was investigated for loss of heterozygosity (LOH). Only one example of LOH was found for all the genes examined. From the association and LOH data, we conclude that these genes do not have an important role in protection against colorectal carcinogenesis.     

Non-radioisotope method for diagnosing photosensitive genodermatoses and a new marker for xeroderma pigmentosum variant

Xeroderma pigmentosum (XP) is an autosomal recessive disorder characterized by photo-induced deterioration of the skin, which often leads to the early development of skin cancers. To diagnose patients with XP and the related disorder Cockayne syndrome (CS), our laboratory has established a simple autoradiographic method that examines three cellular markers of DNA repair: unscheduled DNA synthesis (UDS), recovery of RNA synthesis (RRS) and recovery of replicative DNA synthesis (RDS). However, it is very laborious to measure the three markers using tritiated thymidine or uridine; therefore, we developed a non-isotope method for diagnosing XP and CS. Fibroblasts from the patient were labeled with bromodeoxyuridine (BrdU) instead of tritiated thymidine to measure UDS and RDS, or were labeled with bromouridine (BrU) instead of tritiated uridine to measure RRS. Incorporated BrdU or BrU could be detected using the immunofluorescence method. Moreover, we discovered a new useful marker for XP variant based on checkpoint activity. The non-radioisotope method and the new marker described here comprise an easy way to diagnose XP and CS.     

Xeroderma pigmentosum variant associated with multiple cancers

A 62-year-old Japanese man with xeroderma pigmentosum (XP) variant is reported. The patient had developed at least 6 basal cell carcinomas, a squamous cell carcinoma, and a malignant melanoma on sun-exposed areas, and an atypical carcinoid on the right lung. In vivo phototesting showed a normal response. The minimal erythema dose of ultraviolet B (UVB) was not lowered and no delayed peaking of the erythema reaction was observed. His skin fibroblasts exhibited higher sensitivity to UV irradiation, but a normal level of unscheduled DNA and RNA synthesis. Cell fusions with XP group A, C, D, E, F, and G cells after UV irradiation were all complemented. Previous reports together with this case suggest that older XP variant patients have a high frequency of not only skin cancers, but also internal malignancies.