Increased cathepsin D protein expression is a biomarker for osteosarcomas,pulmonary metastases and other bone malignancies

Cancer proteomics provide a powerful approach to identify biomarkers for personalized medicine. Particularly, biomarkers for early detection, prognosis and therapeutic intervention of bone cancers, especially osteosarcomas, are missing. Initially, we compared two-dimensional gel electrophoresis (2-DE)-based protein expression pattern between cell lines of fetal osteoblasts, osteosarcoma and pulmonary metastasis derived from osteosarcoma. Two independent statistical analyses by means of PDQuest^® and SameSpot^® software revealed a common set of 34 differentially expressed protein spots (p < 0.05). 17 Proteins were identified by mass spectrometry and subjected to Ingenuity Pathway Analysis resulting in one high-ranked network associated with Gene Expression, Cell Death and Cell-To-Cell Signaling and Interaction. Ran/TC4-binding protein (RANBP1) and Cathepsin D (CTSD) were further validated by Western Blot in cell lines while the latter one showed higher expression differences also in cytospins and in clinical samples using tissue microarrays comprising osteosarcomas, metastases, other bone malignancies, and control tissues. The results show that protein expression patterns distinguish fetal osteoblasts from osteosarcomas, pulmonary metastases, and other bone diseases with relevant sensitivities between 55.56% and 100% at ≥87.50% specificity. Particularly, CTSD was validated in clinical material and could thus serve as a new biomarker for bone malignancies and potentially guide individualized treatment regimes.     

The cathepsin D rs17571 polymorphism: effects on CSF tau concentrations in Alzheimer disease

The lysosomal protease cathepsin D (CtsD, EC 3.4.23.5; gene, CTSD) has been associated with Alzheimer disease (AD) due to its cerebral expression being increased early in the course of AD; additionally, a CTSD exon 2 polymorphism (rs17571; NT_009237.17:g.569834T>C) may confer risk to AD. Functionally, it may be implicated in amyloid precursor protein (APP) processing and tau protein degradation. The objective of this study was to determine whether the CTSD exon 2 polymorphism affects cerebrospinal fluid (CSF), concentrations of beta-amyloid (Abeta42) and tau in two independent samples from Germany (n=73) and Sweden (n=66). Patients carrying the CTSD rs17571-T allele had significantly decreased CSF levels of tau (Munich, p=0.003; Swedish, p=0.029; combined sample, p<0.001), whereas no significant effect was observed on Abeta42 concentrations. Likewise, no significant impact was observed on Mini Mental State Examination (MMSE) scores. The data of both independent samples suggest that the CTSD rs17571 polymorphism does not affect APP processing but shows significant effects on tau processing. The result may corroborate the implication of the lysosomal system in the pathogenesis of AD and is of particular importance if CSF tau is used as a diagnostic biomarker.     

NTM and NR3C2 polymorphisms influencing intelligence: family-based association studies

Family, twin, and adoption studies have indicated that human intelligence quotient (IQ) has significant genetic components. We performed a low-density genome-wide association analysis with a family-based association test to identify genetic variants influencing IQ, as measured by Wechsler Adult Intelligence Scale full-score IQ (FSIQ). We examined 11,120 single-nucleotide polymorphisms (SNPs) from the Affymetrix GeneChips 10K mapping array genotyped in 292 nuclear families from Genetic Analysis Workshop 14, a subset from the Collaborative Study on the Genetics of Alcoholism (COGA). A replication analysis was performed using part of International Multi-Center ADHD Genetics Project (IMAGE) dataset. Twenty-two SNPs were identified as having suggestive associations with IQ (p < 10^− 3) in the COGA sample and eleven of the SNPs were located within known genes. In particular, NTM at 11q25 (rs411280, p = 0.000764) and NR3C2 at 4q31.1 (rs3846329, p = 0.000675) were two novel genes which have not been associated with IQ in other studies. It has been reported that NTM might play a role in late-onset Alzheimer disease while NR3C2 may be associated with cognitive function and major depression. The associations of these two genes were well-replicated by single-marker and haplotype analyses in the IMAGE sample. In conclusion, our findings provide evidence that chromosome regions of 11q25 and 4q31.1 contain genes affecting IQ. This study will serve as a resource for replication in other populations.     

CTSD基因表遗传学修饰与乳腺癌转移的关系

目的:检测乳腺癌组织CTSD基因增强子区遗传和表遗传学改变,探讨其与乳腺癌转移的关系?方法:取152例乳腺癌标本及对应的癌旁组织,采用PCR扩增技术对CTSD基因增强子区进行扩增,产物进行基因测序?应用甲基化特异性限制性内切酶酶切联合PCR扩增技术,观察乳腺癌组织CTSD基因增强子区去甲基化状态?结果:遗传学改变研究表明,CTSD基因增强子区基因片段测序结果显示未发现有意义的突变位点?表遗传研究表明,转移乳腺癌组织中增强子区去甲基化发生率为85.3%,癌旁组织为0,两者差别有显著统计学意义(P < 0.05)?未转移乳腺癌去甲基化发生率为 51.9%,相较于癌旁组织,差别有统计学意义(P < 0.05)?转移和未转移乳腺癌去甲基化发生率相比,差别也有统计学意义(P < 0.05)?结论:CTSD基因增强子区的功能调控不受遗传学突变的影响,其去甲基化率与乳腺癌的转移有关,有望成为乳腺癌的一个预后指标?     

Prion protein: From physiology to cancer biology

Prion protein (PrPc) was originally viewed solely as being involved in prion disease, but now several intriguing lines of evidence have emerged indicating that it plays a fundamental role not only in the nervous system, but also throughout the human body. PrPc is expressed most abundantly in the brain, but has also been detected in other non-neuronal tissues as diverse as lymphoid cells, lung, heart, kidney, gastrointestinal tract, muscle, and mammary glands. Recent data indicate that PrPc may be implicated in biology of glioblastoma, breast cancer, prostate and gastric cancer. Over expression of PrPc is correlated to the acquisition by tumor cells of a phenotype for resistance to cell death induced by TNF alpha and TRAIL or antitumor drugs such as paclitaxel and anthracyclines. PrPc may promote tumorigenesis, proliferation and G1/S transition in gastric cancer cells. This review revisits the physiological functions of PrPc, and its possible implications for cancer biology.     

Inhibition of Cathepsin D (CTSD) enhances radiosensitivity of glioblastoma cells by attenuating autophagy

Postoperative radiotherapy combined with chemotherapy is a commonly used treatment for glioblastoma (GBM) but radiotherapy often fails to achieve the expected results mainly due to tumor radioresistance. In this study, we established a radioresistant subline from human glioma cell line U251 and found that Cathepsin D (CTSD), a gene closely related to the clinical malignancy and prognosis in glioma, had higher expression level in radioresistant clones than that in parental cells, and knocking down CTSD by small interfering RNA (siRNA) or its inhibitor Pepstatin-A increased the radiosensitivity. The level of autophagy was enhanced in the radioresistant GBM cells compared with its parent cells, and silencing autophagy by light chain 3 (LC3) siRNA significantly sensitized GBM cells to ionizing radiation (IR). Moreover, the protein expression level of CTSD was positively correlated with the autophagy marker LC3 II/I and negatively correlated with P62 after IR in radioresistant cells. As expected, through the combination of Western blot and immunofluorescence assays, inhibition of CTSD increased the formation of autophagosomes, while decreased the formation of autolysosomes, which indicating an attenuated autophagy level, leading to radiosensitization ultimately. Our results revealed for the first time that CTSD regulated the radiosensitivity of glioblastoma by affecting the fusion of autophagosomes and lysosomes. In significance, CTSD might be a potential molecular biomarker and a new therapeutic target in glioblastoma.     

Miscarriage and use of multivitamins or folic acid

In two recent studies from Germany, a strong association was found between the allelic variant T of the amino acid substitution encoding polymorphism 224 C/T (A38V) in exon 2 of the cathepsin D gene (CTSD) and late onset Alzheimer disease (AD). Other studies from Europe and the USA revealed ambiguous results. Therefore, we performed an independent association study on CTSD and AD in a sample of 324 Caucasian patients from Germany, Switzerland, and Italy with late onset AD, and 302 non‐demented controls. We could not confirm an association between CTSD genotype and AD, although there was a slight but not significant increase in frequency of the T allele and T carrier status in AD. Post hoc data analyses suggested that there might be a stronger effect of CTSD genotype on AD risk in males, and an interaction between CTSD and APOE genotypes in males but not females. © 2001 Wiley‐Liss, Inc.