Increased calcium oxalate monohydrate crystal binding to injured renal tubular epithelial cells in culture

The retention of crystals in the kidney is considered to be a crucial step in the development of a renal stone. This study demonstrates the time-dependent alterations in the extent of calcium oxalate (CaOx) monohydrate (COM) crystal binding to Madin-Darby canine kidney (MDCK) cells during their growth to confluence and during the healing of wounds made in confluent monolayers. As determined by radiolabeled COM crystal binding studies and confirmed by confocal-scanning laser microscopy, relatively large amounts of crystals (10.4 +/- 0.4 micrograms/cm2) bound to subconfluent cultures that still exhibited a low transepithelial electrical resistance (TER < 400 omega.cm2). The development of junctional integrity, indicated by a high resistance (TER > 1,500 omega.cm2), was followed by a decrease of the crystal binding capacity to almost undetectable low levels (0.13 +/- 0.03 microgram/cm2). Epithelial injury resulted in increased crystal adherence. The highest level of crystal binding was observed 2 days postinjury when the wounds were already morphologically closed but TER was still low. Confocal images showed that during the repair process, crystals selectively adhered to migrating cells at the wound border and to stacked cells at sites were the wounds were closed. After the barrier integrity was restored, crystal binding decreased again to the same low levels as in undamaged controls. These results indicate that, whereas functional MDCK monolayers are largely protected against COM crystal adherence, epithelial injury and the subsequent process of wound healing lead to increased crystal binding

Metastatic potential of human renal cell carcinoma: experimental model using subrenal capsule implantation in athymic nude mice

The aim of this study was to determine whether subrenal capsule (SRC) implantation is a suitable model for the study of the metastatic potential of our human renal cell carcinoma (HRCC) lines and to establish new sublines with enhanced metastatic ability. NMRI athymic nude mice 7-11 weeks old received SRC implantation of our HRCC lines RC43 and RC21. These lines were not metastatic when implanted s.c. Mice were killed after 4 or 8 weeks, or when moribund. With the RC43 cell line the success rate for implantation was 69%, with 89% of these showing metastases. The average volume of the implanted tumour fragments was 0.5 mm3 (range 0.28-0.7), the average volume at the primary site at the time of death was 9087 (9-32000) mm3. Metastases were found in lymph nodes, liver, spleen, peritoneum, psoas muscle, pancreas, diaphragm and skin. The average volume of the metastases was 4139 (0.5-9000) mm3. Growing cell lines were established in vivo and in vitro from one splenic, one peritoneal, one diaphragmatic, and one hepatic metastasis. These sublines have faster in vivo and slower in vitro growth rates than the parental lines. With the RC21 cell line the success rate for implantation was 56% and the metastatic rate 78%. The average volume of the implanted tumour was 0.8 mm3 (0.28-1.2), the average volume at the primary site at the time of death was 2685 mm3 (1.4-6534) and the average volume of metastases was 7.1 mm3 (0.5-37.5). Metastases were found in lymph nodes, lung and skin. No establishment was attempted for RC21 because of the small dimensions of these metastases. SRC implantation is thus considered a useful tool for the study of the metastatic ability of our cell lines RC43 and RC21. The establishment of new sublines with a faster growth rate and an enhanced metastatic ability will be useful for further studies on the metastatic process

Glycosaminoglycans and other sulphated polysaccharides in calculogenesis of urinary stones

Naturally occurring glycosaminoglycans (GAGs) and other, semisynthetic, sulphated polysaccharides are thought to play an important role in urolithiasis. Processes involved in urinary stone formation are crystallization and crystal retention. Oxalate transport and renal tubular cell injury are determining factors in these processes. In this article experimental results concerning the possible mechanisms of action of GAGs and other sulphated polysaccharides are reviewed. GAGs are inhibitors of crystal growth and agglomeration and possibly also of nucleation. They can prevent crystal adherence, correct an abnormal oxalate flux and prevent renal tubular cell damage

Tissue specific and androgen-regulated expression of human prostate-specific transglutaminase

Transglutaminases (TGases) are calcium-dependent enzymes catalysing the post-translational cross-linking of proteins. In the prostate at least two TGases are present, the ubiquitously expressed tissue-type TGase (TGC), and a prostate-restricted TGase (TGP). This paper deals with the molecular cloning and characterization of the cDNA encoding the human prostate TGase (hTGP). For this purpose we have screened a human prostate cDNA library with a probe from the active-site region of TGC. The largest isolated cDNA contained an open reading frame encoding a protein of 684 amino acids with a predicted molecular mass of 77 kDa as confirmed by in vitro transcription-translation and subsequent SDS/PAGE. The hTGP gene was tissue-specifically expressed in the prostate, yielding an mRNA of approx. 3.5 kb. Furthermore, a 3-fold androgen-induced upregulation of hTGP mRNA expression has been demonstrated in the recently developed human prostate cancer cell line, PC346C. Other well established human prostate cancer cell lines, LNCaP and PC-3, showed no detectable hTGP mRNA expression on a Northern bolt. The gene coding for prostate TGase was assigned to chromosome 3

Loss and gain of chromosomes 1, 18, and Y in prostate cancer

Nuclear suspensions of 42 prostate carcinoma specimens obtained at surgery were used to investigate loss and gain of chromosomes 1, 18, and Y by fluorescence in situ hybridization (FISH) with centromere-specific probes. The outcome of FISH analysis was correlated with clinical parameters and the relationship between DNA-FCM (ploidy at cellular level) and FISH (ploidy of individual chromosomes) was assessed. Significant loss of chromosomes 1 and 18 was infrequent (respectively, three and five cases), but 53% of the tested specimens showed loss of Y. Loss was not correlated with DNA ploidy. Significant gain occurred in 36% (chromosome 1), 63% (chromosome 18), and 28% (Y) of the specimens. Gain of chromosome 18 was shown in DNA diploid (7/14) and aneuploid tumors (18/26), while gain of chromosomes 1 and Y was nearly restricted to DNA aneuploid specimens. Significant unbalance between these chromosomes occurred in 11 cases. Most cases which had significant gain of chromosome 1 or 18 showed trisomic as well as tetrasomic cells. Simultaneous loss of some and gain of other investigated chromosomes is suggestive of clonal heterogeneity and/or multiclonality. This was observed in eight tumors. Correlation between DNA-FCM and FISH was best for the Y chromosome. DNA-FCM showed more aberrant histograms with increasing stage and grade of tumors. The presence of numerical aberrations of the investigated chromosomes however, seemed independent of clinical grade or stage

Immunocytochemical characterization of explant cultures of human prostatic stromal cells

The study of stromal-epithelial interactions greatly depends on the ability to culture both cell types separately, in order to permit analysis of their interactions under defined conditions in reconstitution experiments. Here we report the establishment of explant cultures of human prostatic stromal cells and their immunocytochemical characterization. As determined by antibodies to keratin and prostate specific acid phosphatase, only small numbers (<5%) of epithelial cells were present in primary cultures; subsequent passaging further reduced epithelial cell contamination. Antibodies against intermediate filament proteins (keratins, vimentin, and desmin) and smooth muscle actin microfilaments demonstrated that stromal cells from benign prostatic hyperplasia and prostate carcinoma differed in regard to their differentation markers. Two contrasting phenotypes were identified in cultures derived from these two different lesions: One, exhibiting fibroblastic features, was predominant in cultures derived from benign lesions and a second, showing varying degrees of smooth muscle differentiation, was more abundant in carcinoma-derived cultures. These findings are indicative of a remarkable divergence in the stromal-epithelial relationships associated with these pathological conditions and may provide us with a potential tool for studying these processes

The androgen receptor: Functional structure and expression in transplanted human prostate tumors and prostate tumor cell lines

Abstract The growth of the majority of prostate tumors is androgen-dependent, for which the presence of a functional androgen receptor is a prerequisite. Tumor growth can be inhibited by blockade of androgen receptor action. However, this inhibition is transient. To study the role of the androgen receptor in androgen-dependent and androgen-independent prostate tumor cell growth, androgen receptor mRNA expression was monitored in six different human prostate tumor cell lines and tumors, which were grown either in vitro or by transplantation on (male) nude mice. Androgen receptor mRNA was clearly detectable in three androgen-dependent (sensitive) tumors and absent or low in three androgen-independent tumors. Growth of the LNCaP prostate tumor cell line can be stimulated both by androgens and by fetal calf serum. In the former situation androgen receptor mRNA expression is downregulated, whereas in the latter no effect on androgen receptor mRNA levels can be demonstrated. Sequence analysis showed that the androgen receptor gene from LNCaP cells contains a point mutation in the region encoding the steroid-binding domain, which confers an ACT coVon encoding a threonine residue to GCT, encoding alanine