Human skin carcinoma arising from kidney transplant–derived tumor cells

Tumor cells with donor genotype have been identified in human skin cancer after allogeneic transplantation; however, the donor contribution to the malignant epithelium has not been established. Kidney transplant recipients have an increased risk of invasive skin squamous cell carcinoma (SCC), which is associated with accumulation of the tumor suppressor p53 and TP53 mutations. In 21 skin SCCs from kidney transplant recipients, we systematically assessed p53 expression and donor/recipient origin in laser-microdissected p53⁺ tumor cells. In one patient, molecular analyses demonstrated that skin tumor cells had the donor genotype and harbored a TP53 mutation in codon 175. In a kidney graft biopsy performed 7 years before the skin SCC diagnosis, we found p53⁺ cells in the renal tubules. We identified the same TP53 mutation in these p53⁺ epithelial cells from the kidney transplant. These findings provide evidence for a donor epithelial cell contribution to the malignant skin epithelium in the recipient in the setting of allogeneic kidney transplantation. This finding has theoretical implications for cancer initiation and progression and clinical implications in the context of prolonged immunosuppression and longer survival of kidney transplant patients.     

C-MYC–induced Apoptosis in Polycystic Kidney Disease Is Bcl-2 and p53 Independent

The SBM mouse is a unique transgenic model of polycystic kidney disease (PKD) induced by the dysregulated expression of c-myc in renal tissue. In situ hybridization analysis demonstrated intense signal for the c-myc transgene overlying tubular cystic epithelium in SBM mice. Renal proliferation index in SBM kidneys was 10-fold increased over nontransgenic controls correlating with the presence of epithelial hyperplasia. The specificity of c-myc for the proliferative potential of epithelial cells was demonstrated by substitution of c-myc with the proto-oncogene c-fos or the transforming growth factor (TGF)-α within the same construct. No renal abnormalities were detected in 13 transgenic lines established, indicating that the PKD phenotype is dependent on functions specific to c-myc. We also investigated another well characterized function of c-myc, the regulation of apoptosis through pathways involving p53 and members of the bcl-2 family, which induce and inhibit apoptosis, respectively. The SBM kidney tissues, which overexpress c-myc, displayed a markedly elevated (10–100-fold) apoptotic index. However, no significant difference in bcl-2, bax, or p53 expression was observed in SBM kidney compared with controls. Direct proof that the heightened renal cellular apoptosis in PKD is not occurring through p53 was obtained by successive matings between SBM and p53^−/− mice. All SBM offspring, irrespective of their p53 genotype, developed PKD with increased renal epithelial apoptotic index. In addition, overexpression of both bcl-2 and c-myc in double transgenic mice (SBB⁺/SBM⁺) also produced a similar PKD phenotype with a high apoptotic rate, showing that c-myc can bypass bcl-2 in vivo. Thus, the in vivo c-myc apoptotic pathway in SBM mice occurs through a p53- and bcl-2–independent mechanism. We conclude that the pathogenesis of PKD is c-myc specific and involves a critical imbalance between the opposing processes of cell proliferation and apoptosis.     

尿CD54~+淋巴细胞在肾移植急性排斥反应中的变化

背景:正常肾脏、肾小管上皮和血管内皮细胞仅有少量CD54表达,当发生急性排斥反应时,肾小管上皮细胞和血管内皮细胞CD54表达明显增加,同时大量白细胞浸润;间质浸润细胞和肾小管上皮细胞CD54表达增加。目的:探讨流式细胞仪检测尿CD54+淋巴细胞对移植肾急性排斥反应的诊断价值。方法:来自解放军成都军区总医院的肾移植后恢复正常者(n=18)、出现急性排斥反应者(n=8)、移植肾功不全者(n=9)以及健康志愿者(n=10)。流式细胞仪比较各组移植前后尿液中CD54+淋巴细胞比率变化。结果与结论:尿CD54+淋巴细胞在肾移植患者出现排斥反应时明显增加(P<0.01),抗排斥治疗后逐渐下降。移植肾功能正常者和移植肾功不全者CD54轻度升高。提示尿液中CD54+淋巴细胞水平能准确反映肾移植物移植后患者的免疫状态,可作为肾移植后急性排斥反应的特异标志。     

Pkd1 regulates immortalized proliferation of renal tubular epithelial cells through p53 induction and JNK activation

Autosomal dominant polycystic kidney disease (ADPKD) is the most common human monogenic genetic disorder and is characterized by progressive bilateral renal cysts and the development of renal insufficiency. The cystogenesis of ADPKD is believed to be a monoclonal proliferation of PKD-deficient (PKD(-/-)) renal tubular epithelial cells. To define the function of Pkd1, we generated chimeric mice by aggregation of Pkd1(-/-) ES cells and Pkd1(+/+) morulae from ROSA26 mice. As occurs in humans with ADPKD, these mice developed cysts in the kidney, liver, and pancreas. Surprisingly, the cyst epithelia of the kidney were composed of both Pkd1(-/-) and Pkd1(+/+) renal tubular epithelial cells in the early stages of cystogenesis. Pkd1(-/-) cyst epithelial cells changed in shape from cuboidal to flat and replaced Pkd1(+/+) cyst epithelial cells lost by JNK-mediated apoptosis in intermediate stages. In late-stage cysts, Pkd1(-/-) cells continued immortalized proliferation with downregulation of p53. These results provide a novel understanding of the cystogenesis of ADPKD patients. Furthermore, immortalized proliferation without induction of p53 was frequently observed in 3T3-type culture of mouse embryonic fibroblasts from Pkd1(-/-) mice. Thus, Pkd1 plays a role in preventing immortalized proliferation of renal tubular epithelial cells through the induction of p53 and activation of JNK.     

Enhanced propagation of adult human renal epithelial progenitor cells to improve cell sourcing for tissue-engineered therapeutic devices for renal diseases

Renal cell therapy employing cells derived from adult renal epithelial cell (REC) progenitors promises to reduce the morbidity of patients with renal insufficiency due to acute renal failure and end stage renal disease. To this end, tissue engineered devices addressing the neglected biologic component of renal replacement therapy are being developed. Because human donor tissue is limited, novel enhanced progenitor cell propagation (EP) techniques have been developed and applied to adult human kidney transplant discards from six donors. Changes include more efficient digestion and the amplification of progenitors prior to terminal epithelial differentiation promoted by contact inhibition and the addition of retinoic acid. Differentiated morphology in EP populations was demonstrated by the ability to form polarized epithelium with tight junctions, apical central cilia and expression of brush border membrane enzymes. Evaluation of lipopolysaccharide stimulated interleukin-8 secretion and γ-glutamyl transpeptisade activity in EP derived cells was used to confirm therapeutic equivalence to REC obtained using published techniques, which have previously shown efficacy in large animal models and clinical trials. Yield exceeded 10(16) cells/gram cortex from the only kidney obtained due to an anatomical defect, while the average yield from diseased kidneys ranged from 1.1 × 10(9) to 8.8 × 10(11) cells/gram cortex, representing an increase of more than 10 doublings over standard methods. Application of the EP protocol to REC expansion has solved the problem of cell sourcing as the limiting factor to the manufacture of cell based therapies targeting renal diseases and may provide a method for autologous device fabrication from core kidney biopsies.     

PUMA对高脂饮食小鼠LPS诱导的急性肾损伤和凋亡的影响

目的 探讨p53上调凋亡调控因子（PUMA）是否参与调节高脂饮食（HFD）所致糖尿病小鼠脂多糖（LPS）诱导的急性肾损伤。方法 将24只小鼠随机均分为普食（Chow）组与HFD组,分别以普通饲料或者高脂饮食喂养12周,饮食干预结束后分别再分为LPS组与Con组,LPS组小鼠腹腔注射LPS 10 mg/kg制备脓毒症急性肾损伤模型,Con组给予等体积磷酸盐缓冲液腹腔注射,24 h后检测小鼠肾病理损伤、血清肌酐、血尿素氮、PUMA蛋白和Caspase-3蛋白表达水平以及肾脏凋亡情况。结果 与Chow组相比,HFD组小鼠体质量增加、随机血糖升高（P均< 0.05）,产生胰岛素抵抗。与Con组相比,LPS组血清肌酐和血尿素氮升高（P均< 0.05）,出现肾上皮细胞形态异常、上皮细胞坏死和炎症浸润等病理损伤,原位末端转移酶标记技术染色显示肾组织出现大量凋亡细胞,PUMA蛋白水平及Caspase-3蛋白表达增高（P均< 0.05）。与Chow+LPS组相比,HFD+LPS组上述表现更为明显（P均< 0.05）。结论 HFD通过上调PUMA表达,促进了LPS诱导的小鼠急性肾损伤以及凋亡。     

Restoration of tubular epithelial cells during repair of the postischemic kidney occurs independently of bone marrow-derived stem cells

Ischemia causes kidney tubular cell damage and abnormal renal function. The kidney is capable of morphological restoration of tubules and recovery of function. Recently, it has been suggested that cells repopulating the ischemically injured tubule derive from bone marrow stem cells. We studied kidney repair in chimeric mice expressing GFP or bacterial beta-gal or harboring the male Y chromosome exclusively in bone marrow-derived cells. In GFP chimeras, some interstitial cells but not tubular cells expressed GFP after ischemic injury. More than 99% of those GFP interstitial cells were leukocytes. In female mice with male bone marrow, occasional tubular cells (0.06%) appeared to be positive for the Y chromosome, but deconvolution microscopy revealed these to be artifactual. In beta-gal chimeras, some tubular cells also appeared to express beta-gal as assessed by X-gal staining, but following suppression of endogenous (mammalian) beta-gal, no tubular cells could be found that stained with X-gal after ischemic injury. Whereas there was an absence of bone marrow-derived tubular cells, many tubular cells expressed proliferating cell nuclear antigen, which is reflective of a high proliferative rate of endogenous surviving tubular cells. Upon i.v. injection of bone marrow mesenchymal stromal cells, postischemic functional renal impairment was reduced, but there was no evidence of differentiation of these cells into tubular cells of the kidney. Thus, our data indicate that bone marrow-derived cells do not make a significant contribution to the restoration of epithelial integrity after an ischemic insult. It is likely that intrinsic tubular cell proliferation accounts for functionally significant replenishment of the tubular epithelium after ischemia.     

Cystin, a novel cilia-associated protein, is disrupted in the cpk mouse model of polycystic kidney disease

The congenital polycystic kidney (cpk) mutation is the most extensively characterized mouse model of polycystic kidney disease (PKD). The renal cystic disease is fully expressed in homozygotes and is strikingly similar to human autosomal recessive PKD (ARPKD), whereas genetic background modulates the penetrance of the corresponding defect in the developing biliary tree. We now describe the positional cloning, mutation analysis, and expression of a novel gene that is disrupted in cpk mice. The cpk gene is expressed primarily in the kidney and liver and encodes a hydrophilic, 145-amino acid protein, which we term cystin. When expressed exogenously in polarized renal epithelial cells, cystin is detected in cilia, and its expression overlaps with polaris, another PKD-related protein. We therefore propose that the single epithelial cilium is important in the functional differentiation of polarized epithelia and that ciliary dysfunction underlies the PKD phenotype in cpk mice.     

Green tea polyphenol-induced epidermal keratinocyte differentiation is associated with coordinated expression of p57/KIP2 and caspase 14

Epigallocatechin-3-gallate (EGCG), the most abundant polyphenol in green tea, exerts chemopreventive effects by selectively inducing apoptosis in tumor cells. In contrast, EGCG accelerates terminal differentiation in normal human epidermal keratinocytes (NHEK) mediated partially by up-regulation of p57/KIP2, a cyclin-dependent kinase inhibitor that confers growth arrest and differentiation. However, it is unclear if EGCG modulates caspase 14, a unique regulator of epithelial cell terminal differentiation associated with cornification. Here, we examined the effect of EGCG on caspase 14 expression in NHEK and correlated the protein and mRNA expression of p57/KIP2 with those of caspase 14 in either normal keratinocytes or p57/KIP2-expressing tumor cells (OSC2, an oral squamous cell carcinoma cell line). Additionally, paraffin-embedded normal and untreated psoriatic (aberrant keratinization) skin sections from humans were assessed for caspase 14 by immunohistochemistry. In NHEK, EGCG induced the expression of caspase 14 mRNA and protein levels within a 24-h period. The expression of p57/KIP2 in OSC2 cells was adequate to induce caspase 14 in the absence of EGCG; this induction of caspase 14 was down-regulated by transforming growth factor-beta1. In human psoriatic skin samples, caspase 14 staining in the upper epidermis was reduced, especially in nuclear areas. These results suggest that, in addition to p57/KIP2, EGCG-induced terminal differentiation of epidermal keratinocytes involves up-regulation of caspase 14. Further understanding of how EGCG modulates cellular differentiation may be useful in developing green tea preparations for selected clinical applications.     

骨髓间充质干细胞修复损伤肾小管上皮细胞：可能与可行？

背景：研究表明骨髓间充质干细胞在急性肾损伤后能够通过直接分化为肾小管上皮细胞而促进肾功能的恢复,其修复肾脏的作用机制尚不清楚,能否直接分化为肾小管上皮细胞,目前仍有争议。目的：观察骨髓间充质干细胞输注后急性肾衰竭小鼠肾功能改变,外源性骨髓间充质干细胞在肾组织的分布以及是否向肾小管上皮细胞分化。方法：骨髓间充质干细胞来源于绿色荧光蛋白转基因小鼠。8～10周龄的健康雌性昆白小鼠90只随机随机分为3组。急性肾衰竭组和骨髓间充质干细胞组注射顺铂建立急性肾衰竭模型,骨髓间充质干细胞组在建模后24h经尾静脉输注绿色荧光蛋白转基因小鼠的骨髓间充质干细胞悬液。正常对照组不进行任何干预。建模后第1,4,7,14,28天测定血尿素氮和血肌酐,观察肾组织病理变化,荧光显微镜下观察绿色荧光蛋白阳性的骨髓间充质干细胞在肾组织的分布,共聚焦显微镜下观察骨髓间充质干细胞向肾小管上皮细胞的分化情况。结果与结论：骨髓间充质干细胞组顺铂注射4～14d后,尿素氮、肌酐值比急性肾衰竭组明显降低（P〈0.01或P〈0.05）。骨髓间充质干细胞组第4天肾组织中可见绿色荧光的绿色荧光蛋白细胞,分布在外髓质区肾小管,第7天仍可见少量荧光细胞,同时表达肾小管上皮特异性的功能蛋白megalin。结果提示骨髓间充质干细胞在损伤肾脏可直接分化为肾小管上皮细胞,并改善急性肾衰竭小鼠的肾功能。     

Macrophage migration inhibitory factor promotes cyst growth in polycystic kidney disease

Autosomal dominant polycystic kidney disease (ADPKD) is characterized by renal cyst formation, inflammation, and fibrosis. Macrophages infiltrate cystic kidneys, but the role of these and other inflammatory factors in disease progression are poorly understood. Here, we identified macrophage migration inhibitory factor (MIF) as an important regulator of cyst growth in ADPKD. MIF was upregulated in cyst-lining epithelial cells in polycystin-1–deficient murine kidneys and accumulated in cyst fluid of human ADPKD kidneys. MIF promoted cystic epithelial cell proliferation by activating ERK, mTOR, and Rb/E2F pathways and by increasing glucose uptake and ATP production, which inhibited AMP-activated protein kinase signaling. MIF also regulated cystic renal epithelial cell apoptosis through p53-dependent signaling. In polycystin-1–deficient mice, MIF was required for recruitment and retention of renal macrophages, which promoted cyst expansion, and Mif deletion or pharmacologic inhibition delayed cyst growth in multiple murine ADPKD models. MIF-dependent macrophage recruitment was associated with upregulation of monocyte chemotactic protein 1 (MCP-1) and inflammatory cytokine TNF-α. TNF-α induced MIF expression, and MIF subsequently exacerbated TNF-α expression in renal epithelial cells, suggesting a positive feedback loop between TNF-α and MIF during cyst development. Our study indicates MIF is a central and upstream regulator of ADPKD pathogenesis and provides a rationale for further exploration of MIF as a therapeutic target for ADPKD.     

Transforming growth factor beta 2 in epithelial differentiation of developing teeth and odontogenic tumors.

Dysregulation of TGF beta 2, a modulator of cell growth and differentiation, can result in uncontrolled growth and tumor formation. Our comparative studies on the expression of TGF beta 2 mRNA and protein indicate that TGF beta 2 may primarily be a regulator of epithelial differentiation during tooth development (between 13 and 20 gestational wk) and tumorigenesis of odontogenic neoplasms. A paracrine mode of action for TGF beta 2 in early human tooth germ (cap/early bell stage) is suggested by location of mRNA in the mesenchyme surrounding the tooth germ, whereas protein is found in the epithelial dental lamina and enamel organ. During the late bell stage, TGF beta 2 gene expression shifted from the mesenchyme to the odontogenic epithelium and was colocalized with protein, suggesting an autocrine role for the terminal differentiation of ameloblasts. In odontogenic tumors of epithelial origin (ameloblastomas) and epithelial-ectomesencymal origin (ameloblastic fibromas), TGF beta 2 mRNA was mostly located in the mesenchymal tumor component and protein in the epithelial tumor component. Odontogenic ectomesenchymal tumors (myxomas) were not associated with TGF beta 2 mRNA and protein expression. The results imply that TGF beta 2 may play an important role in epithelial-mesenchymal interactions in human tooth morphogenesis and development of odontogenic tumors.     

Sirtuin 1 inhibition delays cyst formation in autosomal-dominant polycystic kidney disease

Autosomal-dominant polycystic kidney disease (ADPKD) is caused by mutations in either PKD1 or PKD2 and is characterized by the development of multiple bilateral renal cysts that replace normal kidney tissue. Here, we used Pkd1 mutant mouse models to demonstrate that the nicotinamide adenine dinucleotide–dependent (NAD-dependent) protein deacetylase sirtuin 1 (SIRT1) is involved in the pathophysiology of ADPKD. SIRT1 was upregulated through c-MYC in embryonic and postnatal Pkd1-mutant mouse renal epithelial cells and tissues and could be induced by TNF-α, which is present in cyst fluid during cyst development. Double conditional knockouts of Pkd1 and Sirt1 demonstrated delayed renal cyst formation in postnatal mouse kidneys compared with mice with single conditional knockout of Pkd1. Furthermore, treatment with a pan-sirtuin inhibitor (nicotinamide) or a SIRT1-specific inhibitor (EX-527) delayed cyst growth in Pkd1 knockout mouse embryonic kidneys, Pkd1 conditional knockout postnatal kidneys, and Pkd1 hypomorphic kidneys. Increased SIRT1 expression in Pkd1 mutant renal epithelial cells regulated cystic epithelial cell proliferation through deacetylation and phosphorylation of Rb and regulated cystic epithelial cell death through deacetylation of p53. This newly identified role of SIRT1 signaling in cystic renal epithelial cells provides the opportunity to develop unique therapeutic strategies for ADPKD.     

Widely dispersed p53 mutation in respiratory epithelium. A novel mechanism for field carcinogenesis.

Individuals with one aerodigestive tract malignancy have a high incidence of second primary aerodigestive tumors. The mechanism for this field effect has not been determined. We studied an individual with widespread dysplastic changes in the respiratory epithelium but no overt carcinoma. The entire tracheobronchial tree obtained at autopsy was embedded in paraffin, and bronchial epithelial cells were isolated by microdissection. DNA extracted from the microdissected cells was analyzed for point mutations in the p53 tumor suppressor gene. A single, identical point mutation consisting of a G:C to T:A transversion in codon 245 was identified in bronchial epithelium from 7 of 10 sites in both lungs. Epithelium at sites containing the p53 mutation was morphologically abnormal, exhibiting squamous metaplasia and mild to moderate atypia. No invasive tumor was found in the tracheobronchial tree or any other location. Cells from peripheral blood, kidney, liver, and lymph node exhibited no abnormality in the p53 gene. The widespread presence of a single somatic p53 point mutation in the bronchi of a smoker suggests that a single progenitor bronchial epithelial clone may expand to populate broad areas of the bronchial mucosa-a novel mechanism for field carcinogenesis in the respiratory epithelium that may be of importance in assessing individuals for risk of a second primary tumor as well as in devising effective strategies for chemoprevention of lung cancer.     

Cytokine-induced expression of a nitric oxide synthase in rat renal tubule cells.

Nitric oxide (NO.) has been implicated in the regulation of renal vascular tone and tubular sodium transport. While the endothelial cell is a well known source of NO(.), recent studies suggest that tubular epithelial cells may constitutively generate NO(.). An inducible isoform of nitric oxide synthase which produces far greater quantities of NO. exists in some cell types. We sought to determine whether kidney epithelial cells exposed to cytokines could express an inducible nitric oxide synthase. Primary cultures of rat proximal tubule and inner medullary collecting duct cells generated NO. on exposure to TNF-alpha and IFN-gamma. NO. production by both cell types was inhibited by NG-monomethyl-L-arginine; this inhibition was partially reversed by the addition of excess L-arginine. Stimulation of kidney epithelial cells with TNF-alpha and IFN-gamma dramatically increased the level of inducible nitric oxide synthase mRNA. In summary, renal proximal tubule and inner medullary collecting duct cells can produce NO. via expression of an inducible isoform of nitric oxide synthase.     

增生性瘢痕组织中p53和c-myc蛋白含量的变化及其对瘢痕内细胞凋亡发生的影响

目的 :观察 p5 3和 c myc两种蛋白在增生性瘢痕和正常皮肤组织内的表达特征及其对增生性瘢痕内细胞凋亡发生的影响。方法 :在 16份被测标本中包括创面愈合后不同时期的增生性瘢痕 8例和其对应的周围正常皮肤组织 8例 ,用免疫组织化学方法和常规病理技术确定 p5 3和 c myc两种蛋白在增生性瘢痕和正常皮肤组织中的定位和表达量及变化规律。结果 :p5 3和 c myc蛋白在正常皮肤和瘢痕组织内都有表达。正常皮肤组织中 p5 3蛋白主要分布于表皮基底层细胞的胞质和胞核中 ;而 c myc蛋白的阳性信号则存在于表皮基底细胞、血管内皮细胞、毛囊和汗腺细胞的胞浆和胞核内。增生性瘢痕组织中 p5 3和 c myc两种蛋白表达均增强 ,p5 3主要存在于角质形成细胞和部分成纤维细胞的胞质和胞核内 ;而 c m yc阳性表达颗粒则分布于表皮细胞和部分成纤维细胞内。与正常皮肤组织相比 ,增生性瘢痕的 p5 3蛋白含量虽有增高趋势 ,但差异不显著 ;而c m yc蛋白的阳性颗粒明显增多。结论 :在增生性瘢痕发生过程中 ,p5 3和 c myc蛋白不同的分布和表达变化规律显示 ,这两种蛋白可能参与调控增生性瘢痕形成过程中细胞凋亡的发生 ,以 c myc蛋白的作用更为重要。     

MDM2、p53在卵巢肿瘤组织及细胞系的表达和意义

目的　研究MDM 2 (murinedoubleminute 2 )和 p5 3在卵巢肿瘤组织、细胞系表达及与卵巢癌发生关系。 方法　①用细胞培养、蛋白质提取、Western免疫印迹法检测 17个卵巢癌细胞系MDM 2、p5 3蛋白表达。②用免疫组化SP法检测卵巢良性上皮性肿瘤、卵巢交界性上皮性肿瘤和卵巢癌中MDM 2、p5 3蛋白的表达。结果　① 17个卵巢癌细胞系MDM 2蛋白p90表达阳性率为 11 8% (2 / 17) ;p5 3的阳性表达率为 3 5 3 % (6/ 17) ,2例MDM 2表达阳性出现在野生型卵巢癌细胞株。②在卵巢良性上皮性肿瘤、卵巢交界性上皮性肿瘤和卵巢癌中MDM 2的阳性表达率分别为 :2 0 % (2 / 10 )、2 5 % (2 / 8)和 2 5 % (5 / 2 0 ) ;p5 3的阳性表达率分别为 2 0 % (2 / 10 )、3 7 5 % (3 / 8)和 60 % (12 / 2 0 )。 3组中 ,MDM 2阳性表达率无显著性差异 (P >0 0 5 ) ,而 p5 3在卵巢癌中的阳性表达率显著高于卵巢良性上皮性肿瘤和交界性上皮性肿瘤 (P <0 0 5 )。结论　p5 3的异常表达与卵巢肿瘤的恶性表型相关。在卵巢癌的发生发展过程中 ,p5 3的异常表达比MDM 2更有意义。MDM 2表达阳性可能在无 p5 3基因突变的卵巢癌细胞发生、发展过程中起一定作用     

The role of vascular endothelial growth factor in the kidney in health and disease

Vascular endothelial growth factor (VEGF) is a potent endothelial cell mitogen, angiogenic factor and enhancer of vascular permeability. Expressed in the epithelial cells of the developing glomerulus and tubular epithelium, VEGF plays an important role in the development and maintenance of the early vasculature of the kidney. Here, we review the available literature regarding the expression and function of VEGF both in the developing and healthy adult kidney. Furthermore, we highlight how VEGF expression is altered in the diseased kidney and how this modulated expression may impact on and reflect underlying functional changes occurring during the disease process. As discussed, many controversial issues remain, particularly concerning the role of VEGF in the diseased kidney. That VEGF has been proposed as a potential future therapeutic target for the management of some renal diseases requires first that the precise role of VEGF in the normal kidney and various renal pathologies be further and more clearly defined.     

Restoration of p53 function for selective Fas-mediated apoptosis in human and rat glioma cells in vitro and in vivo by a p53 COOH-terminal peptide

We have shown that a COOH-terminal peptide of p53 (amino acids 361-382, p53p), linked to the truncated homeobox domain of Antennapedia (Ant) as a carrier for transduction, induced rapid apoptosis in human premalignant and malignant cell lines. Here, we report that human and rat glioma lines containing endogenous mutant p53 or wild-type (WT) p53 were induced into apoptosis by exposure to this peptide called p53p-Ant. The peptide was comparatively nontoxic to proliferating nonmalignant human and rat glial cell lines containing WT p53 and proliferating normal human peripheral marrow blood stem cells. Degree of sensitivity to the peptide correlated directly with the level of endogenous p53 expression and mutant p53 conformation. Apoptosis induction by p53p-Ant was quantitated by terminal deoxynucleotidyl transferase-mediated dUTP nick end labeling assay and Annexin V staining in human glioma cells in vitro and in a syngeneic orthotopic 9L glioma rat model using convection-enhanced delivery in vivo. The mechanism of cell death by this peptide was solely through the Fas extrinsic apoptotic pathway. p53p-Ant induced a 3-fold increase in extracellular membrane Fas expression in glioma cells but no significant increase in nonmalignant glial cells. These data suggest that p53 function for inducing Fas-mediated apoptosis in gliomas, which express sufficient quantities of endogenous mutant or WT p53, may be restored or activated, respectively, by a cell-permeable peptide derived from the p53 COOH-terminal regulatory domain (p53p-Ant). p53p-Ant may serve as a prototypic model for the development of new anticancer agents with unique selectivity for glioma cancer cells and it can be successfully delivered in vivo into a brain tumor by a convection-enhanced delivery system, which circumvents the blood-brain barrier.