PubMed Health⌕ Search

Biomedical subjects

H K Kleinman

Publications and source records attributed to H K Kleinman.

At least 55 records · Page 3Linked to original sources
PubMed1999

Enhanced cleavage of diaminopimelate-containing isopeptides by leucine aminopeptidase and matrix metalloproteinases in tumors: application to bioadhesive peptides.

We prepared (2S,6S)-Z-Dpm(Z)(OMe) (4) by protease-mediated hydrolysis of (R,R/S,S)-Z-Dpm(Z)(OMe)-OMe (3), converted it to (2S,6S)-Dpm(Z)(OMe) (6) via PCI5 to an NCA intermediate and hydrolysis, protected the amino group with Boc to give (2S,6S)-Boc-Dpm(Z)(OMe) (7), which upon ammonolysis of the Me ester afforded (2S,6S)-Boc-Dpm(Z)(NH2) (8). Hydrogenolysis of 8 and protection with Fmoc gave (2S,6S)-Boc-Dpm(Fmoc)(NH2)(10). Using 10 and SPPS, we prepared three Dpm-containing peptides and their corresponding Lys peptides. Enzymatic studies with mLAP and cLAP showed that the Leu moiety in Ac-Gly-(2S,6S)-Dpm(Leu)(NH2)-Ala (14) was hydrolyzed 68-fold and >1000-fold more rapidly, respectively, than that in Ac-Gly-Lys(Leu)-Ala (12). The enhanced rate of Leu formation from 14 compared to 12 was also observed with homogenates of mouse C3 sarcomas. This homogenate also hydrolyzed Ac-Gly-(2S,6S)-Dpm(Ac-Gly-Pro-Gln-Gly-Leu)(NH2)-Ala (16) to Ac-Gly-(2S,6S)-Dpm(NH2)-Ala (13), Leu and Ac-Gly-Pro-Gln-Gly (17). This implies the side chain is cleaved first by endopeptidases, such as matrix metalloproteinases (MMPs), and then the remaining Leu is cleaved by LAP-like exopeptidases. The rate of liberation of 17 from 16 and the corresponding Lys isopeptide, Ac-Gly-Lys(Ac-Gly-Pro-Gln-Gly-Leu)-Ala (15), was not significantly different. The rate of formation of 13 was faster from 16 than Ac-Gly-Lys-Ala (11) was from 15. Thus, the entire isopeptide side chain can be removed by the cooperative action of LAP-like and MMP-like peptidases present in tumor tissue, which occurs faster in the Dpm peptide 16 than in the Lys peptide 15. The rate of formation of 13 from 16 by lung, liver, and intestine homogenates (from the same C3 tumor-bearing mice) was comparable to or higher than from the tumor homogenates, but the rate by blood was only 4% the value of the tumor homogenates. Analogs of a bioadhesive fragment from the laminin alpha1 chain were prepared by replacing the essential Lys with Dpm(NH2) (20) and Dpm(Leu)(NH2) (21). Both Dpm-containing peptides were active, although considerably weaker than the corresponding Lys peptides 18 and 19, in a cell attachment assay with human fibrosarcoma HT-1080 cells.

Amino Acid Sequence↗
PubMed1999

Thymosin beta4 accelerates wound healing.

Angiogenesis is an essential step in the repair process that occurs after injury. In this study, we investigated whether the angiogenic thymic peptide thymosin beta4 (Tbeta4) enhanced wound healing in a rat full thickness wound model. Addition of Tbeta4 topically or intraperitoneally increased reepithelialization by 42% over saline controls at 4 d and by as much as 61% at 7 d post-wounding. Treated wounds also contracted at least 11% more than controls by day 7. Increased collagen deposition and angiogenesis were observed in the treated wounds. We also found that Tbeta4 stimulated keratinocyte migration in the Boyden chamber assay. After 4-5 h, migration was stimulated 2-3-fold over migration with medium alone when as little as 10 pg of Tbeta4 was added to the assay. These results suggest that Tbeta4 is a potent wound healing factor with multiple activities that may be useful in the clinic.

Animals↗
PubMed1999

Reconstituted basement membrane reduces proliferation and increases prolactin expression of GH3 cells.

This study investigated the effects of reconstituted basement membrane Matrigel on the proliferation and prolactin expression of GH3 cells in culture for 6 days. When cells were cultured on Matrigel, the initial attachment was increased but the cell number was not changed with time whereas rapid increase in cell number was observed in cultures on plastic. Bromodeoxyuridine (BrdU)-labeling showed that BrdU incorporation ratio of GH3 cells cultured on Matrigel was about one half of that observed with cells cultured on plastic (9.7+/-0.7% vs. 18.7+/-1.2%). Immunocytochemistry revealed that the ratio of the prolactin-immunoreactive GH3 cells was about 3.6 times (58.4+/-2.9% on Matrigel vs. 16.2+/-1.4% on plastic), which was compatible with the results of Western blot analysis. In situ hybridization demonstrated that prolactin mRNA-positive cells were identified more frequently when cells were cultured on Matrigel compared to cultures on plastic. These findings indicate that Matrigel is a proper culture substrate for the long-term culture of GH3 pituitary cells due to the inhibition of overgrowth and promotion of prolactin expression.

Animals↗
PubMed1999

Impaired wound repair and delayed angiogenesis in aged mice.

Wound repair is a multistep process consisting of hemostasis, inflammatory cell infiltration, tissue regrowth, and remodeling. In aged individuals, this progression of events is altered, resulting in wounds that heal more slowly than wounds in the young. These studies were designed to examine the proliferative phase of repair in young and aged mice, with attention to the angiogenic process. Using a standardized excisional injury model, wound re-epithelialization, collagen accumulation, and angiogenesis were examined. Re-epithelialization and collagen synthesis were substantially delayed in aged mice as compared with young mice. Angiogenesis in wounds from aged mice was also delayed, with significantly more capillary growth in wounds from young mice than aged mice. In addition, wounds from aged mice contained significantly less of the angiogenic mediators fibroblast growth factor-2 (FGF-2) and vascular endothelial growth factor (VEGF) than wounds from young animals (p < 0.05). Because macrophages are a rich source of angiogenic factors in wounds, macrophage production of VEGF was examined. Macrophages from aged mice produced significantly less VEGF than cells from young mice. To examine the in vivo endothelial cell responsiveness, a defined amount of rFGF-2 was suspended in Matrigel and placed subcutaneously in either young or aged mice. In response to FGF-2, capillary growth into Matrigel was significantly less in aged than young mice. The results suggest that a decline in angiogenic growth factor production, as well as a decline in endothelial responsiveness to specific factors, may account for the delayed wound angiogenesis in aged mice. These results also indicate that age-related alterations in macrophage function might partially account for the overall delay in the wound repair process.

Aging↗
PubMed1999

Development of intracytoplasmic lumens in a colon cancer cell line cultured on a non-adhesive surface.

Cell-matrix interactions have important effects on phenotypic features, such as morphology, differentiation and cell growth. Several papers have suggested that when cell-matrix interactions are interrupted, cells grow as multicellular spheroids and eventually undergo apoptosis. We found that when ET(-), a laminin non-adherent colon cancer cell line, was cultured on poly-2-hydroxyethyl methacrylate (HEMA) coated plastic, the cells floated as cellular aggregates of spheroids or as single cells. Some of the single cells contained a very large intracytoplasmic lumen (ICL) and appeared similar to signet ring cells. These ICL were lined by a layer of short microvilli. The number of the cell did not increased cells when cultured on poly-HEMA. Another type of single cells, usually without ICL, demonstrated the characteristics of apoptotic cells by histologic examination. Acridine orange staining, flow cytometry and electron microscopy confirmed the apoptotic nature of those cells. In immunohistochemical staining for proliferating cell nuclear antigen, spheroids of cells and single cells with ICL were immunoreactive, while most of the single cells without ICL were negative. These results suggest that multicellular aggregation and formation of ICL were induced by the adaptation of ET(-) colon cancer cells in a harmful environment caused by reduced adhesiveness, and these changes might be related to cell survival.

Acridine Orange↗
PubMed1999

Identification of laminin alpha1 and beta1 chain peptides active for endothelial cell adhesion, tube formation, and aortic sprouting.

Laminin-1 is a basement membrane glycoprotein that promotes several biological activities including cell attachment, tumor metastasis, and angiogenesis. Angiogenesis plays an important role in tissue formation, reproduction, wound healing, and several pathological conditions. In this study, we screened 405 synthetic peptides from the alpha1 and beta1 chains to identify potential sites on laminin-1 active with endothelial cells. Peptides were initially screened by testing both endothelial cell adhesion to peptide-coated wells and tube formation on Matrigel in the presence of soluble peptide. Twenty active peptides were identified in these screens. A secondary screen using the rat aortic ring sprouting assay identified 13 of the 20 peptides that stimulated endothelial sprouting. Several of these active peptides were also found to stimulate human umbilical vein endothelial cell migration in Boyden chamber assays. Differences in the amount of peptide needed for the response and in the resultant morphologies/responses were observed between the peptides in all of the assays. Our results suggest that several active domains on laminin-1 may play important roles in stimulating different steps in angiogenesis.

Amino Acid Sequence↗
PubMed1998

Cell binding sequences in mouse laminin alpha1 chain.

Laminin-1, a multifunctional glycoprotein of the basement membrane, consists of three different subunits, alpha1, beta1, and gamma1 chains. Previously, we used synthetic peptides to screen for biologically active sequences in the laminin alpha1 chain C-terminal globular domain (G domain) and identified several cell binding sequences (Nomizu, M., Kim, W. H., Yamamura, K., Utani, A., Song, S. Y., Otaka, A., Roller, P. P., Kleinman, H. K., and Yamada, Y. (1995) J. Biol. Chem. 270, 20583-20590). Here, we identify new cell binding sequences on the remainder of the laminin alpha1 chain by systematic peptide screening, using 208 overlapping synthetic peptides encompassing the central and N-terminal portions of the alpha1 chain. HT-1080 cell attachment activity to the peptides was evaluated using peptide-coated plastic substrates and peptide-conjugated Sepharose beads. Twenty five peptides showed cell attachment activities on either the peptide-coated plastic substrates and/or the peptide-conjugated Sepharose beads. A-13 (RQVFQVAYIIIKA) showed strongest cell attachment activity in both the assays. Cell attachment to 14 of the peptides was inhibited by heparin. EDTA and integrin antibodies inhibited cell adhesion to two of the peptides, A-13 and A-25, suggesting that these sites likely bind to integrins. These peptides inhibited cell attachment to laminin-1 but not to collagen I, suggesting these active sites are available on the intact molecule. Most of active sequences were localized on globular domains suggesting that these structures play a critical role in binding to cell-surface receptors.

Amino Acid Sequence↗
PubMed1998

Laminin-1 and laminin-2 G-domain synthetic peptides bind syndecan-1 and are involved in acinar formation of a human submandibular gland cell line.

The culture of human submandibular gland (HSG) cells on laminin-1 induces acinar differentiation. We identified a site on laminin involved in acinar differentiation using synthetic peptides derived from the C-terminal G-domain of the laminin alpha1 and alpha2 chains. The alpha1 chain peptide AG73 (RKRLQVQLSIRT) decreases the size of acini formed on laminin-1. Cells cultured with either AG73 or the homologous alpha2 chain peptide MG73 (KNRLTIELEVRT) form structures that appear acinar-like, but the cell nuclei are not polarized to the basal surface and no lumen formation occurs, indicating that additional sites on laminin are required for complete differentiation. The G-domain of laminin-1 contains both integrin and heparin binding sites, and anti-beta1-integrin antibodies disrupt acinar formation. Cell adhesion to the peptides and to E3, an elastase digest fragment of laminin-1 containing AG73, is specific, since other laminin peptides or EDTA do not compete the binding. Heparin and heparan sulfate decrease cell adhesion to AG73 and MG73 but anti-beta1-integrin antibodies have no effect. Treating the cell surface with heparitinase inhibits adhesion to both AG73 and MG73. We isolated cell surface ligands using both peptide affinity chromatography and laminin-1 affinity chromatography. Treating the material bound to the affinity columns with heparitinase and chondroitinase enriches for a core protein identified as syndecan-1 by Western blot analysis, thus identifying a syndecan-1 binding site in the globular domain of laminin-1 and laminin-2. In summary, multiple interactions between laminin and HSG cells contribute to acinar differentiation, involving both beta1-integrins and syndecan-1.

Amino Acid Sequence↗
PubMed1998

Laminin-like proteins are differentially regulated during cerebellar development and stimulate granule cell neurite outgrowth in vitro.

The basement membrane glycoprotein laminin-1 is a potent stimulator of neurite outgrowth. Although a variety of laminin isoforms have been described in recent years, the role of alternative laminin isoforms in neural development remains largely uncharacterized. We found that a polyclonal antibody raised against the alpha1, beta1, and gamma1 chains of laminin-1 and a monoclonal antibody raised against the alpha2 chain of laminin-2 detect immunoreactive material in neuronal cell bodies in the developing mouse cerebellum. In addition, laminin-1-like immunoreactivity was found in cell types throughout the cerebellum, but laminin-alpha2-like immunoreactivity was restricted to the Purkinje cells. Purified laminin-1 and laminin-2 stimulated neurite outgrowth in primary cultures of mouse cerebellar granule neurons to a similar extent, whereas the synthetic peptides tested appeared to be active only for cell adhesion and not for stimulation of neurite outgrowth. The E8 proteolytic fragment of laminin-1 contained full neurite outgrowth activity. The identity of laminins expressed in granule neurons was also examined by Western blotting; laminin-like complexes were associated with the cell and appeared to have novel compositions. These results suggest that laminin-like complexes play important roles in cerebellar development.

Animals↗
PubMed1998

Laminin-1 and the RKRLQVQLSIRT laminin-1 alpha1 globular domain peptide stimulate matrix metalloproteinase secretion by PC12 cells.

Here we have investigated the ability of laminin-1 and specific laminin-1-derived synthetic peptides to stimulate neuronal cell matrix metalloproteinase secretion. Zymographic analysis of conditioned media from laminin-1-treated PC12 and NG108-15 cells revealed a 72-kDa matrix metalloproteinase which was not secreted by untreated cells. Laminin-1 alpha1 chain-derived synthetic peptides, AASIKVAVSADR (LAM-L) and RKRLQVQLSIRT (AG-73), also stimulated PC12 cell secretion of a 72-kDa matrix metalloproteinase. We further investigated the structural requirements of AG-73 for cell attachment, neurite outgrowth, and matrix metalloproteinase secretion using a series of AG-73 analogs that had single amino acids substituted with alanine. At the substrate levels tested, the AG-73 peptide promoted the adhesion of 67% of the PC12 cells and neurite outgrowth in 71% of the PC12 cells. Substitutions in any one of the amino acids within the central LQVQ sequence resulted in a large reduction in cell attachment whereas substitution in the carboxyl terminal proximal amino acids L, S, and R had little effect on attachment. Alanine substitution of any of the amino terminal proximal LQV amino acids and the carboxyl terminal L, I, and R residues resulted in a 65-91% reduction in neurite outgrowth. These data demonstrate that the sequence requirements for cell attachment and neurite outgrowth were not necessarily coupled but that the sequence requirements for neurite outgrowth and matrix metalloproteinase secretion were identical. We conclude that laminin-1 is able to stimulate neuronal cells to secrete a matrix metalloproteinase. Further, this study identifies the LQVXLXIR laminin-1 alpha1 globular domain peptide to be capable of stimulating both neurite outgrowth and matrix metalloproteinase secretion.

Animals↗
PubMed1998

Laminin-alpha1-chain sequence Leu-Gln-Val-Gln-Leu-Ser-Ile-Arg (LQVQLSIR) enhances murine melanoma cell metastases.

We earlier screened overlapping synthetic peptides from the globular domain of the laminin alpha1 chain to identify active sites for cell attachment. We report here that one of the active cell-adhesion peptides, AG-73 (Arg-Lys-Arg-Leu-Gln-Val-Gln-Leu-Ser-Ile-Arg-Thr; RKRLQVQLSIRT) causes B16F10 murine melanoma cells to metastasize to the liver, a site not normally colonized by these cells. Increases in liver metastases and in lung colonization are observed in immune-deficient beige/nude/xid and in C57Bl/6 mice with this peptide. This metastatic activity was observed with i.v. and with i.p. peptide injections, regardless of tumor cell or of peptide-injection times. In vitro, the AG-73 peptide enhances tumor cell adhesion, migration, invasion, and gelatinase production, and blocks laminin-1-mediated cell migration. AG-73 was found to significantly inhibit cell adhesion to a proteolytic laminin-1 fragment, E3, containing the AG-73 sequence. Cell attachment to AG-73, the E3 fragment, and laminin-1 involved cation-dependent receptors. We report that a laminin peptide has the novel and unexpected activity of causing B16F10 melanoma cells, a lung selected cell line, to metastasize to the liver. The minimal active sequence of AG-73, LQVQLSIR, could be one of the most important biologically active sites of laminin-1, especially in promotion of the malignant phenotype. Activation of the malignant phenotype by this peptide provides a significant new model for understanding metastatic mechanisms.

Animals↗
PubMed1998

Neuropeptide Y: a novel angiogenic factor from the sympathetic nerves and endothelium.

Sympathetic nerves have long been suspected of trophic activity, but the nature of their angiogenic factor has not been determined. Neuropeptide Y (NPY), a sympathetic cotransmitter, is the most abundant peptide in the heart and the brain. It is released during nerve activation and ischemia and causes vasoconstriction and smooth muscle cell proliferation. Here we report the first evidence that NPY is angiogenic. At low physiological concentrations, in vitro, it promotes vessel sprouting and adhesion, migration, proliferation, and capillary tube formation by human endothelial cells. In vivo, in a murine angiogenic assay, NPY is angiogenic and is as potent as a basic fibroblast growth factor. The NPY action is specific and is mediated by Y1 and Y2 receptors. The expression of both receptors is upregulated during cell growth; however, Y2 appears to be the main NPY angiogenic receptor. Its upregulation parallels the NPY-induced capillary tube formation on reconstituted basement membrane (Matrigel); the Y2 agonist mimics the tube-forming activity of NPY, whereas the Y2 antagonist blocks it. Endothelium contains not only NPY receptors but also peptide itself, its mRNA, and the "NPY-converting enzyme" dipeptidyl peptidase IV (both protein and mRNA), which terminates the Y1 activity of NPY and cleaves the Tyr1-Pro2 from NPY to form an angiogenic Y2 agonist, NPY3-36. Endothelium is thus not only the site of action of NPY but also the origin of the autocrine NPY system, which, together with the sympathetic nerves, may be important in angiogenesis during tissue development and repair.

Animals↗
PubMed1998

Thymosin alpha 1 stimulates endothelial cell migration, angiogenesis, and wound healing.

In wound healing, lymphoid cells release soluble factors that attract fibroblasts and macrophages, initiating repair, endothelial cell migration, angiogenesis, and matrix production. We analyzed the effect of thymosin alpha1 (Talpha1) on endothelial cell migration, angiogenesis, and wound healing. Talpha1, a 28 amino acid peptide initially isolated from the thymus, enhanced the morphologic differentiation of endothelial cells and was a potent chemoattractant for endothelial cells and monocytes in vitro. In vivo, Talpha1 stimulated angiogenesis in a subcutaneous model. When given either topically or i.p., it accelerated wound healing in a punch model, demonstrating that Talpha1 promotes angiogenesis and wound healing.

Adjuvants, Immunologic↗
PubMed1998

Growth factor regulation of the amylase promoter in a differentiating salivary acinar cell line.

Salivary glands contain two major epithelial cell types: acinar cells which produce the primary salivary secretion, including amylase, and ductal cells which reabsorb electrolytes but also secrete kallikrein. Here we investigated salivary acinar cell differentiation in vitro using the activity of the salivary amylase and tissue kallikrein promoters as markers of acinar cell and ductal cell differentiation, respectively. Each of the promoter sequences was cloned into a replication-deficient adenoviral vector containing the luciferase reporter gene. Previous studies showed that a human submandibular gland cell line (HSG) differentiated into acinar cells when cultured on a reconstituted basement membrane matrix (Matrigel). The luciferase activity of the amylase promoter vector (AdAMY-luc) was low in HSG cells cultured on plastic, where they grow as an epithelial monolayer. The promoter activity increased approximately tenfold when HSG cells were cultured on Matrigel and developed an acinar phenotype. Under the same conditions, the luciferase activity of the kallikrein promoter (AdKALL-luc) was not induced. Because HSG cells demonstrate acinar cell morphology, but not amylase gene expression, when cultured on laminin-1, certain soluble components of Matrigel were tested for their ability to induce the amylase promoter during in vitro differentiation of acinar cells. We find that epidermal growth factor (EGF) and transforming growth factor-alpha (TGF-alpha), which are present in the basement membrane, and hepatocyte growth factor (HGF) increase activity of the amylase promoter. Other basement membrane-derived growth factors such as TGF-beta, basic fibroblast growth factor (bFGF), and platelet-derived growth factor (PGDF), as well as tumor necrosis factor (TNF-alpha), keratinocyte growth factor (KGH), nerve growth factor (NGF) and interferon gamma (IFN-gamma) were inactive. This system will be further exploited to study the mechanisms by which extracellular matrix molecules and growth factors regulate salivary acinar cell differentiation.

Amylases↗
PubMed1998

Tissue transglutaminase is not increased during apoptosis of HT-1080 human fibrosarcoma cells.

Tissue transglutaminase (tTGase), a cytosolic enzyme which catalyzes the covalent cross-linking of proteins, is thought to be involved in the apoptosis. Here, we tested whether tTGase is involved during HT-1080 fibrosarcoma cell apoptosis induced by the YIGSR (Tyr-Ile-Gly-Ser-Arg) peptide. This sequence is derived from the laminin alpha1 chain, and its potency is increased by the formation of a 16mer polymerization using a lysine tree structure. Cells were treated with several different concentrations of Ac-Y 16 for 16 hours, and apoptosis was increased in dose-dependent manner. When assayed by incorporation of [14C] putrescine into succinylated casein, total transglutaminase activity was decreased in parallel with the change in the number of attached cells. Western blot analysis using polyclonal antibody against tTGase showed that the tTGase protein level had not been significantly changed when equal amounts of the protein were applied. To confirm this result, we induced apoptosis of these cells by coating the tissue culture plates with non-adhesive poly-hydroxyethyl methacrylate (HEMA). Western blot analysis showed that the tTGase protein level did not change during this process of apoptosis. Although it has been suggested that tTGase is involved in the process of apoptosis of various cells in vitro and in vivo, our data demonstrate that tTGase is not involved in the process of apoptosis of HT-1080 human fibrosarcoma cell induced by either Ac-Y 16 or a non-adhesive culture surface.

Apoptosis↗
PubMed1998

Expression of 32/67-kDa laminin receptor in laminin adhesion-selected human colon cancer cell lines.

Laminin promotes the malignant phenotype, and the expression of certain laminin receptors is increased in malignancy. Previously, we demonstrated that a laminin-adhesive subclone of a human colon cancer cell line showed increased tumorigenicity in nude mice and increased affinity of the beta1 integrin for laminin relative to the laminin-non-adhesive subclone. The total amount of either beta1 integrin protein or mRNA did not increase. As levels of the 32/67-kDa laminin receptor (67LR) correlate with malignancy, we examined 67LR expression in the laminin adhesion-selected human colon cancer cells. The laminin-adhesive subclone, which was more tumorigenic in both heterotopic and orthotopic locations than in a laminin-non-adhesive subclone, showed cell-surface membrane staining of 67LR, whereas the laminin-non-adhesive subclone showed cytoplasmic staining of 67LR. No difference in either the amount of 67LR mRNA or the amount of protein was observed in the parental cells than in the laminin-adhesive and non-adhesive subclones. When assayed on a laminin affinity column, more 67LR molecules bound to the column with cell extracts from the laminin-adhesive subclone than was observed with the non-adhesive subclone. These findings suggest that the increased tumorigenicity of laminin adhesion-selected tumour cells might be due to an alteration in the distribution and/or adhesiveness of multiple receptors including 67LR and beta1 integrin.

Animals↗
PubMed1998

Differentiation of a colon cancer cell line on a reconstituted basement membrane in vitro.

Basement membrane, a thin extracellular matrix, functions as a tissue stabilizer that promotes tissue integrity and differentiated phenotype. We studied a human colon cancer cell line, SNU 61, to evaluate its ability to differentiate on basement membrane. Cells were cultured on plastic, reconstituted basement membrane (Matrigel) or polyhydroxyethyl methacrylate (poly HEMA) for 72 h and evaluated by light and electron microscopy. On Matrigel, the cells showed gland formation with highly polarized cells containing basal nuclei and well developed brush border microvilli on the luminal surface. Apoptosis was noted mainly at the luminal side. On electron microscopic examination, numerous long microvilli, abundant cytoplasmic organelles and intercellular junctions were noted in the Matrigel-cultured cells. Intermediate cytoskeletons were scattered in the cytoplasm and existed on the axes of microvilli. Junctional complexes and desmosomes were frequently formed along intercellular spaces. The cells cultured on poly HEMA, on the other hand, were poorly differentiated and contained a few glandular structures with small lumens. Brush border microvilli, characteristic of enterocytic differentiation, were few in number and were developed on the basal surface. Intermediate filaments and microtubules were fewer than in the Matrigel-cultured cells. Carcinoembryonic antigen was expressed on the luminal surface of the Matrigel-cultured cells and in the cytoplasm of the poly HEMA cultured cells. CD44 stained the basolateral surface in the Matrigel-cultured cells, but the basal side was not stained in the poly HEMA cultured cells. These results are consistent with the different localization of microvilli in the Matrigel and in the poly HEMA cultured cells. Our observations suggest that human colon cancer cells on basement membrane can undergo glandular differentiation and that extracellular matrix is an important factor in morphogenesis.

Basement Membrane↗