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Microdissection specimens of connective, chondrous, or Bone Tissue of human osteosarcomas and chondrosarcomas transplanted to athymic nude mice.

Five osteosarcomas and two chondrosarcomas were microdissected to separate tumor compartments of calcified, chondrous, and connective tissue. The compartments were lyophilized separately and transplanted subcutaneously or intramuscularly into nude mice for three, four, and five weeks, respectively. In three of the osteosarcomas and in one of the chrondrosarcomas, calcified tissue induced ectopic bone formation by the host, while cartilaginous tissue induced ectopic bone formation in one of the osteosarcomas and in one of the chondrosarcomas. The tumor-derived connective tissue did not induce osteogenic response in the host tissue. Thus, the ability to develop an osteoinductive response and to produce bone morphogenetic protein seems to be restricted to the population of cells that eventually will, or have, differentiated into bone or cartilage.

Adolescent↗

Laser-capture microdissection: opening the microscopic frontier to molecular analysis.

As the list of expressed human genes expands, a major scientific challenge is to understand the molecular events that drive normal tissue morphogenesis and the evolution of pathological lesions in actual tissue. Laser capture microdissection (LCM) has been developed to provide a reliable method to procure pure populations of cells from specific microscopic regions of tissue sections, in one step, under direct visualization. The cells of interest are transferred to a polymer film that is activated by laser pulses. The exact morphology of the procured cells (with intact DNA, RNA and proteins) is retained and held on the transfer film. With the advent of LCM, cDNA libraries can be developed from pure cells obtained directly from stained tissue, and microhybridization arrays of thousands of genes can now be used to examine gene expression in microdissected human tissue biopsies. The fluctuation of expressed genes or alterations in the cellular DNA that correlate with a particular disease stage can ultimately be compared within or between individual patients. Such a fingerprint of gene-expression patterns can provide crucial clues for etiology and might, ultimately, contribute to diagnostic decisions and therapies tailored to the individual patient. Molecules found to be associated with a defined pathological lesion might serve as imaging ot therapeutic targets.

DNA↗

Polyclonal nature of diffuse proliferation of interstitial cells of Cajal in patients with familial and multiple gastrointestinal stromal tumours.

BACKGROUND: Diffuse proliferation of interstitial cells of Cajal (ICCs) in the myenteric plexus layer of the intestine has been described in patients with familial and multiple gastrointestinal stromal tumours (GISTs). However, it is not fully understood whether proliferation is polyclonal or monoclonal. AIMS: To evaluate the clonal nature of diffuse ICC proliferation in familial and multiple GIST cases, we carried out clonal analysis using inactivation at the human androgen receptor (HUMARA) locus. MATERIALS AND METHODS: Diffuse ICC proliferation tissues from three female patients were microdissected using a laser capture microdissection (LCM) system. Normal intestinal mucosal tissues were also microdissected for polyclonal controls and GIST tissues for monoclonal controls from the same patients, and genomic DNA was extracted. After digestion by restriction enzyme HhaI, the HUMARA locus was amplified by a fluorescent polymerase chain reaction (PCR) procedure and the PCR products were analysed. RESULTS: One case was uninformative because it was homozygous at the HUMARA locus. In the two other cases, PCR products from the diffuse ICC proliferation showed two alleles as well as those from normal intestinal mucosal tissues, indicating that ICC proliferation was polyclonal. In contrast, PCR products from associated GIST tissues showed only one allele, indicating that GISTs were monoclonal. CONCLUSION: The results suggested that diffuse ICC proliferation in familial and multiple GIST cases was non-neoplastic hyperplasia.

Cell Division↗

Detection of multiple gene hypermethylation in the development of esophageal squamous cell carcinoma.

Abnormal hypermethylation of CpG islands associated with tumor suppressor genes can lead to repression of gene expression and contribute significantly to tumorigenesis. Esophageal squamous cell carcinoma (ESCC) is thought to be developed through a multi-stage process, which involves basal cell hyperplasia (BCH), dysplasia (DYS), carcinoma in situ (CIS) and carcinoma. In the present study, we studied the hypermethylation of 10 selected genes in biopsies from normal individuals and resected tissues from ESCC patients. Tumor and neighboring normal and precancerous tissues including BCH, DYS and CIS were microdissected from the resected tissues by laser capture microdissection. Hypermethylation of CpG islands was examined in these samples for 10 genes: p16(INK4a), p15(INK4b), p14(ARF), human leukocyte antigen (HLA)-A, -B, -C, hMLH1, E-cadherin (E-cad), fragile histidine triad and von Hippel-Lindau (VHL). Methylation of two Alu sequences, which neighbor E-cad and VHL, respectively, was used as control to verify the procedure of DNA extraction and chemical modification. In 48 biopsy samples with BCH or DYS, the most frequent hypermethylated genes were p16(INK4a) (18.8%) and p14(ARF) (14.6%). Seventeen out of these 48 samples (35.4%) contained hypermethylation of at least one gene. In the resected tissues, 52% of the BCH and 81% of the tumors showed hypermethylation of at least one gene. Genes hypermethylated in earlier stage lesions were always found hypermethylated at the later stage lesions in the same patient. All of the genes were methylated at some stages and they were clustered into four groups according to their frequencies. The first group of genes, which consisted of p16(INK4a) and p14(ARF), was most frequently hypermethylated in all stages, and the frequencies increased from normal epithelial (0%) to BCH, to displasia/carcinoma in situ and ESCC. Other genes were hypermethylated less frequently. Our results suggest that hypermethylation of key genes, such as p16(INK4a), p14(ARF) and hMLH1, may be used in combination with other molecular changes, such as p53 mutation, in the development of biomarkers for predicting the risk for ESCC.

Base Sequence↗

LOH at the sites of the DCC, APC, and TP53 tumor suppressor genes occurs in Barrett's metaplasia and dysplasia adjacent to adenocarcinoma of the esophagus.

Barrett's esophagus carries a 30- to 100-fold increased risk of adenocarcinoma, which is thought to develop via a metaplasia-dysplasia-carcinoma progression. A common genetic abnormality detected in Barrett's adenocarcinoma is loss of heterozygosity (LOH) at the sites of known or putative tumor suppressor genes, of which there are at least 9 associated with esophageal adenocarcinoma. The aim of this study was to identify at which histological stage of carcinogenesis LOH at these sites occur. Microdissection of multiple paraffin-embedded tissue blocks from 17 esophagogastrectomy specimens of adenocarcinoma arising in Barrett's esophagus yielded areas of metaplasia, low-, intermediate- and high-grade dysplasia, and carcinoma. LOH analysis of microdissected tissues was performed using a double polymerase chain reaction technique with 11 microsatellite primers shown previously to have LOH in at least 30% of esophageal adenocarcinomas. Identical LOH was detected in premalignant and malignant tissues in 4 of 17 patients, and was located at 5q21-q22 (D5S346 primer), 17p11.1-p12 (TCF2 primer), 17p13.1 (TP53 primer), 18q21.1 (detected in colon cancer tumor suppressor gene [DCC] primer), and 18q23-qter (D18S70 primer). These results suggest that LOH at the sites of the DCC, adenomatous polyposis coli (APC), and TP53 tumor suppressor genes occur before the development of adenocarcinoma in Barrett's esophagus, and so merit further study as potential biomarkers of neoplastic progression in patients with Barrett's esophagus undergoing endoscopic and histological surveillance.

Adenocarcinoma↗

PCR artifacts in LOH and MSI analysis of microdissected tumor cells.

Polymerase chain reaction (PCR) analysis to study loss of heterozygosity (LOH) and microsatellite instability (MSI) in tumors is widely used. Microdissection techniques are applied to obtain tumor-specific tissue cells. By microdissection, however, the amount of template DNA extracted may vary considerably and interfere with optimal PCR amplification. To circumvent LOH and MSI misinterpretations due to low DNA input, we have assessed the critical level of DNA input for reliable PCR analysis. PCR analysis was performed by using 18 polymorphic markers (mono-, di-, tri-, and tetranucleotide) on DNA derived from both paraffin-embedded, formalin-fixed, and fresh frozen tumor specimens at template input levels ranging from 0.05 to 25.0 ng. We show a highly significant relation between DNA input and the occurrence of LOH and MSI artifacts. Furthermore, for DNA extracted from paraffin-embedded material, the percentage of LOH artifacts is significantly higher compared with DNA extracted from frozen tissue. For reliable PCR analyses using a mono-, di-, tri-, or tetranucleotide marker, a minimum of 10.0 ng DNA is required when DNA is isolated from formalin-fixed, paraffin-embedded tissue and 5.0 ng when isolated from fresh frozen tissue. HUM PATHOL 31:1414-1419.

Alleles↗

New approaches to fluorescence in situ hybridization.

Fluorescence in situ hybridization (FISH) is a nonisotopic labeling and detection method that provides a direct way to determine the relative location or copy number of specific DNA sequences in nuclei or chromosomes. With recent advancements, this technique has found increased application in a number of research areas, including cytogenetics, prenatal diagnosis, cancer research and diagnosis, nuclear organization, gene loss and/or amplification, and gene mapping. The availability of different types of probe and the increasing number of FISH techniques has made it a widespread and diversely applied technology. Multicolor karyotyping by multicolor FISH and spectral karyotyping interphase FISH and comparative genomic hybridization allow genetic analysis of previously intractable targets. We present a brief overview of FISH technology and describe in detail methods of probe labeling and detection for different types of tissue sample, including microdissected nuclei from formalin-fixed paraffin-embedded tissue sections.

Cell Cycle↗

Reconstitution of paired T cell receptor alpha- and beta-chains from microdissected single cells of human inflammatory tissues.

We describe a strategy to "revive" putatively pathogenic T cells from frozen specimens of human inflammatory target organs. To distinguish pathogenic from irrelevant bystander T cells, we focused on cells that were (i) clonally expanded and (ii) in direct morphological contact with a target cell. Using CDR3 spectratyping, we identified clonally expanded T cell receptor (TCR) beta-chains in muscle sections of patients with inflammatory muscle diseases. By immunohistochemistry, we identified those Vbeta-positive T cells that fulfilled the morphological criteria of myocytotoxicity and isolated them by laser microdissection. Next, we identified coexpressed pairs of TCR alpha- and beta-chains by a multiplex PCR protocol, which allows the concomitant amplification of both chains from single cells. This concomitant amplification had not been achieved previously in histological sections, mainly because of the paucity of available anti-alpha-chain antibodies and the great heterogeneity of the alpha-chain genes. From muscle tissue of a patient with polymyositis, we isolated 64 T cells that expressed an expanded Vbeta1 chain. In 23 of these cells, we identified the corresponding alpha-chain. Twenty of these 23 alpha-chains were identical, suggesting antigen-driven selection. After functional reconstitution of the alphabeta-pairs, their antigen-recognition properties could be studied. Our results open avenues for combined analysis of the full TCR alpha- and beta-chain repertoire in human inflammatory tissues.

Autoimmunity↗

Processing renal biopsies for diagnostic mRNA quantification: improvement of RNA extraction and storage conditions.

The goal of this study was to improve a procedure for the extraction and storage of RNA from minute quantities of human renal tissue in clinical practice, using kidney biopsies and cadaveric donor kidneys unsuitable for transplantation. Collagen alpha1(IV) mRNA was analyzed as a measure for RNA integrity. The results show that at least 3 h may pass between microdissecting the renal tissue and the onset of cDNA synthesis without degradation of the glomerular mRNA. To extract the glomerular mRNA, microdissected glomeruli were incubated in a permeabilization solution. Treating glomeruli with collagenase IV before permeabilization had a deteriorating effect on the mRNA yield. The addition of reverse transcription mixture to the permeabilization solution in the presence of the glomeruli resulted in the highest cDNA yields. Storage of glomerular tissue in the presence of Nonidet P-40-based buffer for 1 wk at -70 degrees C did not significantly affect the mRNA, but storage for 2 or 4 wk resulted in deterioration of the mRNA by approximately 40 and 95%, respectively. Furthermore, three methods for total RNA isolation from microdissected interstitial tissue were compared. An approximately 2.5 times higher yield of collagen alpha1(IV) mRNA was obtained with silica gel-based membrane spin technology than with a guanidine isothiocyanate/phenol chloroform or a lithium chloride/phenol chloroform method. Finally, this study shows for the first time reliable detection of collagen alpha1(IV) mRNA in biopsies that had been frozen for at least 10 yr at -70 degrees C. These experiments have helped to improve a procedure for the processing of glomerular and interstitial tissue acquired from human kidney biopsies for mRNA analysis. This method is suitable for implementation in routine clinical practice.

Biopsy↗

Microdissection genotyping of archival fixative treated tissue for Gaucher disease.

The genetic diagnosis of Gaucher disease by molecular methods is complicated by the existence of a highly homologous transcribed pseudogene (96% identity) that is found in close proximity to the true gene on chromosome 1q21. In addition, the pseudogene sequence can mimic disease-causing mutations in the true gene. Selective polymerase chain reaction (PCR) amplification of the true gene can be accomplished in extracted DNA from fresh-frozen samples by designing oligonucleotide primers to hybridize to defined regions that are not present in the pseudogene. This standard molecular approach, which entails amplification of relatively long segments of intact DNA, is not feasible in archival, paraffin-embedded, solid-tissue specimens in which the negative effects of chemical fixation result in DNA strand scission and breakdown of nucleic acid. A novel approach, specifically created for use with archival, fixative-treated tissue specimens, was developed for detection and characterization of common mutations of Gaucher disease. Three separate robust PCR reactions were formulated, 2 for selective amplification of portions of only the true gene exons 2 and 9, with a third reaction targeting exon 10, wherein both the true and pseudogene were coamplified. In the latter, DNA sequencing was used to determine the presence of true and pseudogene allele content in addition to identification of base sequence alterations. This method, requiring a single, 4-microm-thick histologic section, was successfully applied to archival paraffin block tissue specimens that had been in storage for up to 75 years. It was capable of accurately genotyping common Gaucher disease mutations as well as discovering a novel mutation and genetic polymorphism. We recommend our approach when only fixative-treated tis sue is available for molecular genotyping.

DNA Primers↗

Microsatellite instability and mutations in DNA mismatch repair genes in sporadic colorectal cancers.

PURPOSE: This study was designed to investigate the frequency of mutations in DNA mismatch repair genes in sporadic colorectal cancers. METHODS: Genomic DNAs procured from paraffin blocks of the pathologic specimens from 230 consecutive patients with colorectal cancer were examined for their microsatellite instability status using a mononucleotide microsatellite marker, BAT-26, and also evaluated expressions of hMLH1, hMSH2, and hMSH6 proteins by immunohistochemical staining. Any of these 230 patients did not have family histories of hereditary nonpolyposis colorectal cancer, familial adenomatous polyposis, colorectal cancer, or hereditary nonpolyposis colorectal-related cancers, such as endometrial, small bowel, and ureteral and renal pelvic cancers. When microsatellite instability was positive, mutations in the simple repeated sequences of TGF-betaRII, BAX, IGF IIR, hMSH3, and hMSH6 genes were examined. In microsatellite instability-positive or staining-negative cases, polymerase chain reaction-single-strand conformation polymorphism and DNA sequencing detected mutations of hMLH1, hMSH2, and hMSH6 genes. If mutations were found in tumor tissue samples, we tested for a germline mutation with a microdissected corresponding normal tissue. RESULTS: Among 230 cases of sporadic colorectal cancer, 21 (9.1 percent) manifested microsatellite instability. In the immunohistochemical staining, 20 (8.6 percent) showed loss of expressions. All 20 staining-negative cases were microsatellite instability-positive. Only 1 of 21 (4.8 percent) microsatellite instability-positive cases showed intact staining for three proteins. The frame-shift mutations of the simple repetitive sequences were found in 17 cases (81.0 percent) in TGF-betaRII, 11 (52.4 percent) in BAX, 5 (23.8 percent) in IGF IIR, 7 (33.3 percent) in hMSH3, and 8 (38.1 percent) in hMSH6 genes. Germline mutation was observed in only one case, which accounts for 4.8 percent among positive microsatellite instability and 0.4 percent of total patients, and was found in hMSH2. Five somatic mutations (2 in hMLH1, 2 in hMSH2, and 1 in hMSH6) also were found. CONCLUSION: The results indicated that a germline mutation of DNA mismatch repair gene was a rare event in sporadic colorectal cancers.

Base Pair Mismatch↗

Reverse transcription-PCR analysis of laser-captured cells points to potential paracrine and autocrine actions of neurotrophins in pancreatic cancer.

PURPOSE: Neurotrophins (NTs) can stimulate cell proliferation and differentiation in various cell types, and play a role in certain human cancers. In this study we analyzed the expression and localization of NTs and their receptors in microdissected pancreatic cancer tissue samples, and studied their ability to stimulate cell growth. EXPERIMENTAL DESIGN: The expression of nerve growth factor, brain-derived neurotrophic factor, NT-3, and NT-4/5, and the receptors tropomyosin receptor kinase A, B, and C, and P75 was studied in pancreatic cancer cell lines, and normal and pancreatic ductal adenocarcinoma (PDAC) tissue samples by quantitative reverse transcription-PCR. Laser capture microdissection was performed in 21 PDAC samples, and mRNA levels were determined in cancer cells, acinar cells, desmoplastic stroma areas, and nerve fibers. Cell growth assays with NTs and in coculture with dorsal root ganglia were performed. RESULTS: NT receptors were differentially expressed in the cancer cell lines, whereas tropomyosin receptor kinase C was not detectable. NTs modulated pancreatic cancer cell growth. Analysis of nonmicrodissected samples revealed that all of the receptors and tested ligands were overexpressed in PDAC when compared with normal pancreas. Analysis of laser captured samples revealed that NTs and their receptors were expressed in the cancer cells but were especially abundant in the intratumoral nerves. Coculture of dorsal root ganglia with T3M4 cells significantly enhanced the proliferation of this cell line. CONCLUSION: The abundance of NTs in the intratumoral nerves in PDAC and the presence of NT receptors in the cancer cells, in conjunction with the ability of NTs to modulate pancreatic cancer cell growth, point to potential paracrine and autocrine effects of NTs in PDAC. Thus, our findings provide additional evidence that blocking NT actions may have a therapeutic potential in PDAC.

Adenocarcinoma↗

Discovery and identification of alpha-defensins as low abundant, tumor-derived serum markers in colorectal cancer.

BACKGROUND & AIMS: Although colorectal cancer is one of the best characterized tumors with regard to the multistep genetic progression, it remains one of the most frequent and deadly neoplasms in Western countries. This is mainly due to the fact that, up to now, no clinically relevant serum markers could be established in an early routine diagnostic procedure. METHODS: We comparatively analyzed microdissected normal and tumorous colonic epithelium by ProteinChip technology to detect proteins specific for the tumor directly in the tissue. Immunohistochemistry (IHC) was used for the in situ localization of the discovered proteins, and an ELISA was performed to quantify these proteins in serum. RESULTS: By this approach, we found and identified alpha-defensins 1-3 (HNP1-3) to be more highly expressed in the tumor than in normal epithelium. These findings could be confirmed by IHC. Detection of these peptides in the corresponding serum samples was subsequently performed with ELISA, resulting in an average sensitivity of 69% and specificity of 100% for the recognition of colorectal cancer when using the HNP1-3 level in the serum of the patients. CONCLUSIONS: The direct analysis of microdissected tissue for the discovery of tumor-specific markers followed by the specific detection of these markers in serum by antibody-based methods proved to be a successful strategy in this study. Therefore, we can conclude that these promising markers would not have been found in serum without the information gained through the analysis of microdissected tissue by ProteinChip technology.

Adenoma↗

Quantitation of N-acetyl-aspartyl-glutamate in microdissected rat brain nuclei and peripheral tissues: findings with a novel liquid phase radioimmunoassay.

Antibodies were raised in rabbits against the neuropeptide N-acetyl-L-aspartyl-L-glutamate (NAAG) coupled to bovine serum albumin via a carbodiimide linkage. One of these rabbit antisera, which preferentially recognizes coupled NAAG-like immunoreactivity (LIR), has been previously used to immunocytochemically localize NAAG-LIR. We have now employed a second of these antisera, which preferentially recognizes free NAAG, to develop a competitive liquid phase radioimmunoassay (RIA). Using this assay, we were able to detect picomole amounts of NAAG in rat tissue extracts. The specificity of the assay revealed a 60-fold greater affinity of the antibody for NAAG over N-acetyl-aspartate (NAA) and greater than one million-fold specificity for NAAG over both aspartate and glutamate. High-pressure liquid chromatographic (HPLC) separation of tissue extracts yielded only two detectable peaks of NAAG-LIR in collected fractions and these co-chromatographed with NAAG and NAA. NAAG levels determined by this liquid phase RIA and by HPLC were essentially identical after correction for the presence of NAA crossreactivity. The antibody that preferentially recognizes coupled NAAG was used to immunocytochemically localize NAAG-LIR to the red nucleus, the facial nucleus, the dorsal raphe, and the locus coeruleus. To further confirm this localization of NAAG, these and other nuclei were microdissected and levels of NAAG were determined by liquid phase RIA. Nuclei which stained intensely were found to contain high levels of NAAG by RIA and between 60 and 100% of this NAAG-LIR co-chromatographed with NAAG. These results support our previous conclusion that NAAG is co-localized in noradrenergic, serotonergic and cholinergic neurons.(ABSTRACT TRUNCATED AT 250 WORDS)

Animals↗

Laser capture microdissection.

Laser capture microdissection (LCM) is a technique for isolating pure cell populations from a heterogeneous tissue section or cytological preparation via direct visualization of the cells. This technique is applicable to molecular profiling of diseased and disease-free tissue, permitting correlation of cellular molecular signatures with specific cell populations. DNA, RNA, or protein analysis can be performed with the microdissected tissue by any method with adequate sensitivity. The principle components of LCM technology are (1) visualization of the cells of interest via microscopy, (2) transfer of laser energy to a thermolabile polymer with formation of a polymer-cell composite, and (3) removal of the cells of interest from the heterogeneous tissue section. LCM is compatible with a variety of tissue types, cellular staining methods, and tissue-preservation protocols that allow microdissection of fresh or archival specimens. LCM platforms are available as a manual system (PixCell; Arcturus Bioscience) or as an automated system (AutoPix).

Cell Separation↗

WNT11 promotes cardiac tissue formation of early mesoderm.

Cardiac tissue in the bird is derived from paired regions of lateral mesoderm within the anterior half of the embryo (Rawles [1943] Physiol. Zool. 16:22-42; Stalsberg and DeHaan [1969] Dev. Biol. 19:128-159). Previously, we reported that WNT11 is expressed in early avian mesoderm in a pattern that overlaps with the precardiac regions. To examine whether this molecule may play a role in promoting cardiogenesis, we cultured tissue explants from microdissected HH stage 4, 5, and 6 quail embryos. The isolated tissue consisted of both the mesoderm and endoderm layers from either anterior precardiac or posterior noncardiogenic regions of the embryo. As a necessary control for examining the ability of WNT11 to convert noncardiogenic mesoderm to cardiac tissue, we compared the cardiogenic potential of anterior and posterior regions. For stages 5 and 6, our results were consistent with what has been previously reported (Rawles [1943] Physiol. Zool. 16:22-42; Sugi and Lough [1994] Dev. Dyn. 200:155-162); as anterior mesoderm becomes contractile, while posterior mesoderm does not produce cardiac tissue. Surprisingly, when we examined stage 4 embryos both anterior and posterior regions gave rise to cardiac tissue in culture. To determine whether WNT11 could promote cardiac differentiation in tissue that was noncardiogenic, this molecule was ectopically expressed or added to mesoderm/endoderm explants obtained from stage 5 or 6 posterior tissue. Transfection of stage 5 posterior tissue with a WNT11 expression plasmid provoked the appearance of cardiomyocytes in 33% of the explants; half of which were contractile. Similarly transfected stage 6 posterior explants did not demonstrate cardiac differentiation. More dramatic results were obtained when noncardiogenic tissue was exposed to conditioned media containing soluble WNT11; as 63% and 33% of posterior stage 5- or stage 6-derived explants underwent cardiac differentiation. Together, these results indicate that WNT11 can promote cardiac development within noncardiac tissue. The expression of WNT11 in anterior mesoderm of early gastrula stage embryos suggests it may play a role in the formation of the vertebrate heart. Dev Dyn 1999;216:45-58.

Animals↗

Demonstration of adiponectin receptors 1 and 2 mRNA expression in human breast cancer cells.

Recently, we have shown that low adiponectin levels are significantly associated with an increased breast cancer risk. It seems to be very important to study the expression of adiponectin receptor 1 (AdipoR1) and receptor 2 (AdipoR2) in the human breast epithelial cells and breast cancer cells in order to clarify whether or not adiponectin exerts its effects directly on these cells. Expression of adiponectin, AdipoR1, and AdipoR2 mRNA was determined by RT-PCR assay using the RNA samples obtained from human breast cancer cell lines (MCF-7, T47D, SKBR3, and MDA-MB231), HMEC (primary culture of normal human mammary epithelial cells), adipose tissues (axilla) as well as breast cancer cells and normal breast epithelial cells selectively collected from breast cancer tissues by laser microdissection (LMD). Adiponectin mRNA expression was observed only in the adipose tissues. On the other hand, AdipoR1 and AdipoR2 mRNA expression was observed in all four breast cancer cell lines, HMEC, adipose tissues as well as breast cancer cells and normal breast epithelial cells selectively collected by LMD. In addition, AdipoR1 and AdipoR2 expression in both normal breast epithelial cells and breast cancer cells was confirmed by immunohistochemistry. These results suggest a possibility that adiponectin might modulate the growth of normal breast epithelial cells and breast cancer cells directly through AdipoR1 and AdipoR2 receptors, and that the association of low serum adiponectin levels with a high breast cancer risk might be explained, at least in part, by the direct effect of adiponectin on the breast epithelial cells.

Adiponectin↗