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Biomedical subjects

R Fridman

Publications and source records attributed to R Fridman.

At least 55 records · Page 3Linked to original sources
PubMed1994

Enhanced expression of tissue inhibitor of metalloproteinase-2 (TIMP-2) in the stroma of breast carcinomas correlates with tumor recurrence.

The 72-kDa (MMP-2, gelatinase A) and the 92-kDa (MMP-9, gelatinase B) matrix metalloproteinases have been associated with tumor cell invasion and metastasis. Immunohistological staining of MMP-2 and MMP-9, basal lamina collagen IV and TIMP-2 were performed on frozen sections of 83 invasive breast carcinomas. MMP-2 and MMP-9 were associated with neoplastic cell plasma membrane in 72% of cases and exhibited inter-tumoral variability of staining intensity. MMP-2 and MMP-9 staining was not correlated with presence of metastases at time of diagnosis or with disease outcome. TIMP-2 was detected in the peri-tumoral stroma and was present in 87% of cases. Residual benign breast tissue was negative for TIMP-2 staining. Neoplasms with diffuse TIMP-2 staining (24%) recurred significantly more frequently (75% recurred) than cases with focal (42% recurred) or absent (27% recurred) TIMP-2. Presence of collagen IV was negatively correlated with gelatinase staining. We conclude that up-regulation of MMP-2 and MMP-9 expression in breast tumor cells is reciprocally correlated to collagen IV staining. Clinical outcome, however, is more closely related to the presence of TIMP-2 than the corresponding MMPs. Enhanced TIMP-2 expression, therefore, may denote a stromal response to tumor invasion, indicative of aggressive behavior in a subset of breast carcinomas.

Antibodies, Monoclonal↗
PubMed1994

Immunohistochemical localization of matrix metalloproteinase 2 and its specific inhibitor TIMP-2 in neoplastic tissues with monoclonal antibodies.

Matrix metalloproteinase-2 (MMP-2), synthesized as a 631 amino-acid proenzyme, is activated by cleavage of the first 80 amino acids and naturally inhibited by tissue inhibitor of metalloproteinase-2 (TIMP-2). We report here the production of MAbs against MMP-2 and TIMP-2 and their use in localizing the respective antigens on tumor tissues. The anti-MMP-2 MAb recognized the latent and activated MMP-2 mutant protein (mutein) with C-terminal deletion at amino acid 425, indicating that both N- and C-terminal amino acids of MMP-2 are not important for its binding. The binding study of anti-TIMP-2 MAb, using several C-terminally truncated TIMP-2 muteins, showed that the amino acids 111-126 of TIMP-2 are essential for the binding of this antibody. Besides their respective antigens, both MAbs also recognized the MMP-2/TIMP-2 complex. On frozen sections of breast tumor, anti-MMP-2 MAb stained mainly tumor-cell cytoplasm with varying intensity, while anti-TIMP-2 MAb gave a stromal staining of varying intensity and a weak or absent staining of tumor-cell cytoplasm, suggesting different localization of the proteins in these tumors. In addition, in 1/3 of the breast cases both antibodies also localized on tumor-cell membranes. Similar cytoplasmic and stromal but not membrane staining patterns were observed in colon, gastric, endometrial, squamous-cell, prostatic and ovarian carcinoma as well. Since MMP-2 degrades type-IV collagen, the major component of basement membranes, the differences between MMP-2 and TIMP-2 levels and localization in individual tumors may relate to the invasiveness of the tumor and thus provide predictive information. However, this aspect could not be discussed in this study because no biological and clinical parameters such as lymph-node involvement or Dukes' stage of the tumors were available.

Animals↗
PubMed1993

Altered expression of basement-membrane components and collagenases in ascitic xenografts of OVCAR-3 ovarian cancer cells.

Ascitic ovarian cancer cells, which derive from solid tumors, complicate the treatment of ovarian cancer by spreading throughout the peritoneal cavity. Because basement-membrane components may influence tumor-cell proliferation and dissemination, the present studies examined the production of (a) basement-membrane attachment and migration factors (laminin, fibronectin and type IV collagen); (b) a laminin receptor, the 32/67-kDa laminin-binding protein, the presence of which correlates with malignancy; and (c) metalloproteinases (types I and IV collagenase and stromelysin), by ascitic and cultured OVCAR-3 cells and solid OVCAR-3 tumors. The cultured cells and solid tumors produced high levels of mRNA encoding attachment factors and metalloproteinases, and low levels of mRNA for the 32/67-kDa laminin receptor. In contrast, the ascitic ovarian cells had low or undetectable levels of mRNA encoding laminin, type IV collagen and metalloproteinases, but higher levels of transcripts for the laminin receptor. Our results suggest that the apparent inability of ascitic OVCAR-3 cells to attach to host-tissue surfaces may be a consequence, in part, of low levels of expression of laminin, type IV collagen and/or type IV collagenase.

Animals↗
PubMed1993

Expression of human recombinant 72 kDa gelatinase and tissue inhibitor of metalloproteinase-2 (TIMP-2): characterization of complex and free enzyme.

The human 72 kDa gelatinase/type IV collagenase is a metalloproteinase that is thought to play a role in metastasis and angiogenesis. The 72 kDa progelatinase can be isolated from conditioned media as a complex with the tissue inhibitor of metalloproteinase-2 (TIMP-2). To investigate 72 kDa gelatinase-TIMP-2 interactions and to compare the activity of the complex versus that of the free enzyme, we have expressed and purified human 72 kDa progelatinase and TIMP-2 as single proteins in a recombinant vaccinia virus mammalian cell expression system. The recombinant 72 kDa progelatinase was able to bind TIMP-2, and it digested gelatin and collagen type IV after activation by p-aminophenylmercuric acid (APMA). The specific activity of the recombinant free enzyme was 20-fold higher than the activity of an APMA-treated stoichiometric complex of recombinant 72 kDa progelatinase and TIMP-2. Also, TIMP-2 caused an 86% inhibition of activity when added to the activated enzyme at a 1:1 molar ratio. Activation of the free recombinant 72 kDa progelatinase yielded the 62 kDa species and two fragments of 46 and 35 kDa that cross-reacted with monoclonal antibodies to the 72 kDa proenzyme. TIMP-2 inhibited the conversion of the recombinant proenzyme to the 62 kDa species and the appearance of the 45 and 35 kDa bands. These results suggest that TIMP-2 is not only a potent inhibitor of the activated enzyme but also prevents the generation of low-molecular-mass species and full enzymic activity from the zymogen.

Blotting, Western↗
PubMed1993

Type IV collagenase(s) and TIMPs modulate endothelial cell morphogenesis in vitro.

It has been proposed that proteases are important in endothelial cell behavior. We examined the contribution of the gelatinase/type IV collagenase system in an in vitro model of endothelial differentiation. Human umbilical vein endothelial cells rapidly align and form networks of tubes when cultured on a basement membrane preparation, Matrigel. Zymograms of culture supernates demonstrate a 72-kD and a 92-kD gelatinase activity; the cells produce most of the 72-kD gelatinase, whereas the 92-kD activity is derived entirely from the Matrigel. Addition of antibodies against type IV gelatinase/collagenase decreases the area of the tube network. Both tissue inhibitors of metalloproteinases, TIMP-1 and TIMP-2, similarly decrease tube formation when added to cultures. Conversely, exogenous recombinant 72-kD gelatinase increases tube-forming activity. The effects of the anti-gelatinase antibodies and the TIMPs are not additive. Inhibition by either antibodies or TIMPs is greatest when they are added at culture initiation, suggesting that the protease activity is important in the early steps of morphogenesis. However, culture of the cells on Matrigel does not increase early expression of mRNA for the 72-kD gelatinase. Expression of message for the enzyme actually decreases during the course of the assay, while transcription of mRNAs for TIMPs increases, further supporting the concept that collagenases facilitate an early event in tube formation. These data demonstrate that gelatinase/type IV collagenase activity is important in endothelial cell morphogenesis on Matrigel, and suggest a role for collagenases in formation of new capillaries in vivo.

Amino Acid Sequence↗
PubMed1992

The neurotoxin 1-methyl-4-phenylpyridinium: a selective cytostatic agent in small-cell lung cancer cell lines with neuroendocrine properties.

BACKGROUND: Small-cell lung cancer (SCLC) is a common malignancy that is usually fatal, since it metastasizes and recurs even after aggressive chemotherapy. While the cellular origin of this cancer is not well established, the cells of certain tumors exhibit neuroendocrine markers, including L-dopa decarboxylase. PURPOSE: We designed in vitro and in vivo studies to investigate whether the neuroendocrine features in classic SCLC cell lines were sufficient to make them sensitive to 1-methyl-4-phenylpyridinium (MPP+), a known neurotoxin that destroys nigrostriatal dopaminergic neurons. METHODS: Both classic SCLC cell lines (NCI-H345, NCI-H510, NCI-H187, and NCI-H146) and variant SCLC cell lines (NCI-H417, NCI-H82, NCI-H446, and NCI-H524) were exposed to MPP+ (0-512 microM) for 3 days. Inhibition of DNA synthesis was determined by [3H]thymidine incorporation assays. In a related experiment, MPP+ was removed from the classic cell line culture, and the incorporation of [3H]thymidine was determined. In the in vivo study, male athymic nude mice received subcutaneous injections of 0.5 mL tumor cells with matrigel for 10 days to enhance tumor growth, followed by MPP+ at doses of 100-400 micrograms/d given intraperitoneally for 2 days. RESULTS: All four classic SCLC cell lines showed great sensitivity to MPP+, with detachment from laminin substrates and inhibition of DNA synthesis. MPP+ interfered with [3H]thymidine incorporation and, thus, with DNA synthesis in classic SCLC cell lines at low doses (median +/- SD, 12 +/- 4 microM), whereas much higher doses (median, > 512 microM) were required to inhibit [3H]thymidine incorporation in the variant lines. Treated cells excluded trypan blue dye, showing that inhibition of DNA synthesis was not due to cytotoxicity, and the cells incorporated [3H]thymidine when MPP+ was removed from the culture medium, demonstrating that the inhibition was reversible. MPP+ inhibited the growth of the classic NCI-H187 and variant NCI-H417 cell lines implanted in nude mice. CONCLUSIONS: These results suggest that MPP+ differentially interferes with DNA synthesis in SCLC cell lines in vitro; the selective inhibitory effect on classic cell lines suggests that the neuroendocrine properties expressed by classic SCLC cells may be responsible for the differential effect. IMPLICATIONS: MPP+ exerts a cytostatic effect on these cell lines, and the differential sensitivity observed in vitro is maintained in vivo, suggesting that MPP+ or other pyridinium compounds may be of therapeutic value in SCLC.

1-Methyl-4-phenylpyridinium↗
PubMed1992

Domain structure of human 72-kDa gelatinase/type IV collagenase. Characterization of proteolytic activity and identification of the tissue inhibitor of metalloproteinase-2 (TIMP-2) binding regions.

The 72-kDa gelatinase/type IV collagenase, a metalloproteinase thought to play a role in metastasis and in angiogenesis, forms a noncovalent stoichiometric complex with the tissue inhibitor of metalloproteinase-2 (TIMP-2), a potent inhibitor of enzyme activity. To define the regions of the 72-kDa gelatinase responsible for TIMP-2 binding, a series of NH2- and COOH-terminal deletions of the enzyme were constructed using the polymerase chain reaction technique. The full-length and the truncated enzymes were expressed in a recombinant vaccinia virus mammalian cell expression system (Vac/T7). Two truncated enzymes ending at residues 425 (delta 426-631) and 454 (delta 455-631) were purified. Like the full-length recombinant 72-kDa gelatinase, both COOH-terminally truncated enzymes were activated with organomercurial and digested gelatin and native collagen type IV. In contrast to the full-length enzyme, delta 426-631 and delta 455-631 enzymes were less sensitive to TIMP-2 inhibition requiring 10 mol of TIMP-2/mol of enzyme to achieve maximal inhibition of enzymatic activity. The activated but not the latent forms of the delta 426-631 and delta 455-631 proteins formed a complex with TIMP-2 only when excess molar concentrations of inhibitor were used. We also expressed the 205-amino acid COOH-terminal fragment, delta 1-426, and found that it binds TIMP-2. In addition, a truncated version of the 72-kDa gelatinase lacking the NH2-terminal 78 amino acids (delta 1-78) of the proenzyme retained the ability to bind TIMP-2. These studies demonstrate that 72-kDa gelatinases lacking the COOH-terminal domain retain full enzymatic activity but acquire a reduced sensitivity to TIMP-2 inhibition. These data suggest that both the active site and the COOH-terminal tail of the 72-kDa gelatinase independently and cooperatively participate in TIMP-2 binding.

Base Sequence↗
PubMed1992

Malignant transformation of NIH-3T3 cells after subcutaneous co-injection with a reconstituted basement membrane (matrigel).

NIH-3T3 cells are non-tumorigenic when injected into athymic mice. If these cells are mixed with an extract of basement-membrane proteins (matrigel) and injected s.c., they form locally invasive and highly vascularized tumors. Cells cultured from the NIH-3T3-matrigel-induced tumors showed a transformed phenotype and lacked contact inhibition. When cultured in a gel of matrigel, they proliferated and formed branched and invasive colonies. In contrast, the parental NIH-3T3 cells cultured on matrigel remained as cell aggregates and were not invasive. I.V. injections of the tumor-derived NIH-3T3 cells produced many colonies on the surface of the lungs, whereas the parental NIH-3T3 cells were not metastatic. Zymographic analysis of the conditioned media obtained from both the tumor-derived and parental NIH-3T3 cells demonstrated higher amounts of the 72-kDa gelatinase (type-IV collagenase) enzyme in the tumor-derived cells. Also, tumor-derived NIH-3T3 cells, but not parental NIH-3T3 cells, secreted the 92-kDa type-IV collagenase. These studies suggest that the interaction of pre-malignant NIH-3T3 cells with extracellular matrix components may contribute to the process of tumor progression.

Animals↗
PubMed1992

Interaction of endothelial cells with a laminin A chain peptide (SIKVAV) in vitro and induction of angiogenic behavior in vivo.

Endothelial cells are known to bind to laminin, and two peptides derived from the laminin A (CTFALRGDNP) and B1 (CDPGYIGSR) chains block the capillary-like tube formation on a laminin-rich basement membrane matrix, Matrigel. In the present study, we have used various in vitro and in vivo assays to investigate the angiogenic-biologic effects of a third active site in the laminin A chain, CSRARKQAASIKVAVSADR (designated PA22-2) on endothelial cells. The SIKVAV-containing peptide was as active as the YIGSR-containing peptide for endothelial cell attachment but was less active than either the RGD-containing peptide or intact laminin. Endothelial cells seeded on this peptide appeared fibroblastic with many extended processes, unlike the normal cobblestone morphology observed on tissue culture plastic. In addition, in contrast to normal tube formation on Matrigel, short irregular structures formed, some of which penetrated the matrix and sprouting was more apparent. Analysis of endothelial cell conditioned media of cells cultured in the presence of this peptide indicated degradation of the Matrigel and zymograms demonstrated active collagenase IV (gelatinase) at 68 and 62 Kd. A murine in vivo angiogenesis assay and the chick yolk sac/chorioallantoic membrane assays with the peptide demonstrated increased endothelial cell mobilization, capillary branching, and vessel formation. These data suggest that the -SIKVAV-site may play an important role in initiating branching and formation of new capillaries from the parent vessels, a behavior that is observed in vivo in response to tumor growth or in the normal vascular response to injury.

Amino Acid Sequence↗
PubMed1992

Correlation in the expression of type IV collagenase and the invasive and chemotactic abilities of myelomonocytic cells during differentiation into macrophages.

Monomyelocytic phagocytes originate in the bone marrow and while differentiating into macrophages migrate to inflammatory foci and target tissues by egress from the capillary blood vessels. During such diapedesis, the cells must traverse tissue barriers such as basement membrane, which has type IV collagen as its principal structural element. We studied whether the expression of type IV collagenase activity, invasion through basement membrane, and the response to inflammatory chemoattractants are related to each other and to the process of differentiation of murine M1 myeloid leukemia cells into macrophages. M1 cells stimulated with mouse lung-conditioned medium (MLCM) or interleukin 6 (IL6) differentiate into macrophages by 72 h, as determined by expression of Fc receptors, induction of lysozyme, and morphological changes from blast cells to mature macrophages. During this process of differentiation the invasive ability of the cells and the amount of type IV collagenase in the supernatants from the invading cells continuously increased up to 72 h. Zymographic analysis of supernatants of the invading cells revealed a single 100-kd metalloproteinase with gelatinolytic activity. Chemotaxis towards arachidonic acid metabolites, which are present in inflamed tissues, was detected only in differentiated cells. Studies with thioglycolate (TG)-elicited peritoneal macrophages gave results similar to those obtained with differentiated M1 cells, showing that the ability to invade basement membrane, the expression of type IV collagenase, and the chemotactic response to inflammatory chemoattractants all increased with the differentiation of myeloid cells and reached their highest expression in fully differentiated cells.

Animals↗
PubMed1991

Enhanced tumor growth of both primary and established human and murine tumor cells in athymic mice after coinjection with Matrigel.

Previously we found that the reconstituted basement membrane matrix Matrigel, when premixed with human small-cell lung carcinoma cells and injected subcutaneously into athymic mice, permitted tumor growth, whereas cells injected in the absence of Matrigel did not form tumors. In the present study, we examined additional cell types and determined some of the underlying mechanisms involved in the promotion of tumor formation by Matrigel. The tumor cell lines that we studied included transformed mouse Englebreth-Holm-Swarm tumor cells (T-EHS), human submandibular carcinoma A253 cells, mouse melanoma B16F10 cells, human epidermoid carcinoma KB cells, and human primary renal cell carcinoma cells. When coinjected subcutaneously with Matrigel, these cell lines formed rapidly proliferating tumors. Primary biopsy specimens of human colon carcinoma, when dispersed and coinjected with Matrigel, also formed tumors. Only A253, KB, and B16F10 cells formed small tumors in the absence of Martrigel, but a fivefold to tenfold increase in tumor size was observed in the presence of Matrigel. These data demonstrate a useful method for improving the growth of human tumors in athymic mice.

Animals↗
PubMed1991

Transforming growth factor-beta suppresses the invasiveness of human fibrosarcoma cells in vitro by increasing expression of tissue inhibitor of metalloprotease.

We have investigated the effects of TGF-beta on the ability of the human fibrosarcoma cell line, HT1080, to invade a reconstituted basement membrane (Matrigel) in vitro. Exposure of HT1080 cells to TGF-beta (1-10ng/ml) caused a dose-dependent inhibition of HT1080 cell invasion. Unexpectedly, TGF-beta (10ng/ml) significantly enhanced (10-fold) the mRNA expression of the 68-72kDa latent type IV collagenase. Zymogram analysis revealed a 7-fold increase in the 68-72kDa latent type IV collagenase concomitant with an increase in the activated form (62kDa). TGF-beta induced the 92kDa type IV collagenase to a lesser degree. HT1080 cells exposed to TGF-beta also produced more tissue inhibitor of metalloprotease (TIMP) at both the mRNA (10-fold) and protein levels (5-fold). Although TGF-beta induced both type IV collagenases and TIMP, the net collagenolytic activity in the conditioned media after invasion assay was reduced in the presence of TGF-beta. The data suggest that the inhibition of invasiveness is due, at least in part, to the increased TIMP expression. These data suggest that TGF-beta may play a role in tumor cell invasion by increasing the expression of TIMP.

Cell Line↗
PubMed1991

Basement membrane and the SIKVAV laminin-derived peptide promote tumor growth and metastases.

Laminin, the major glycoprotein component of basement membrane, promotes the malignant phenotype. Cells which are adherent to laminin are more malignant than the non-adherent cells and in certain tumor cells, the number of laminin receptors is positively correlated with malignancy. Laminin also increases collagenase IV activity, an enzyme demonstrated to be critical for tumor spread. A site on laminin, containing the amino acid sequence SIKVAV, has been identified which when injected intravenously with B16F10 melanoma cells, causes an increase in the number of colonies on the surface of the lungs. This peptide does not affect tumor cell arrest in the vasculature or the immune system. It does promote angiogenesis in various in vitro and in vivo models, thereby facilitating tumor cell survival. When a complex mixture of laminin-enriched basement membrane components (Matrigel) is coinjected with tumor cells subcutaneously, tumor incidence and growth increases. Various tumor cell lines and primary isolates, which previously could not form tumors in mice, can be induced to grow rapidly in the presence of Matrigel. Slowly growing tumors or arrested tumors can also be induced to grow more quickly with additional injections of Matrigel. When an SIKVAV-containing synthetic peptide is coinjected with B16F10 tumor cells and Matrigel subcutaneously in mice, larger tumors are formed than that observed with either Matrigel or cells alone. Such studies define the role of laminin in tumor growth and spread and generate new models for studying therapeutic agents. Of particular interest is the ability to grow primary isolates which generally do not grow in mice.

Amino Acid Sequence↗
PubMed1991

Long-term benzodiazepine users 3 years after participation in a discontinuation program.

OBJECTIVE: Clinical status and use of benzodiazepines and other psychotropic drugs at follow-up were assessed in patients who had been chronically dependent on benzodiazepines and had been referred for participation in a discontinuation study. METHOD: Of 123 benzodiazepine-dependent patients screened for entry into a tapered discontinuation program, 48 had completed the program, 38 had not, and 37 had not undergone drug tapering. Follow-up information was obtained through a structured telephone interview and a mail questionnaire that included a global severity scale assessing anxiety and depression and the Hopkins Symptom Checklist. The time to follow-up was 2.7-5.0 years, and the mean +/- SD interval between screening and follow-up was 2.9 +/- 0.9 years. RESULTS: Outcome at follow-up significantly favored the patients who had completed the discontinuation program; 73% were not using benzodiazepines, compared to 39% in the unsuccessful taper group and 14% in the no-taper group. Moderate or marked anxiety was still reported by 35% of the patients who were taking benzodiazepines and 25% of those who were not. At follow-up, 22% of the patients were being treated with nonbenzodiazepine psychotropic agents, primarily antidepressants. CONCLUSIONS: The high percentage of patients who were benzodiazepine-free at follow-up and the continued anxiety and depression present in many patients suggest that some patients may have been taking benzodiazepines because of chronic or recurrent anxiety or depression, not physical dependence.

Anxiety Disorders↗
PubMed1991

Effects of synthetic peptides and protease inhibitors on the interaction of a human ovarian cancer cell line (NIH:OVCAR-3) with a reconstituted basement membrane (Matrigel).

We have investigated the adhesive properties and invasiveness of cells of the human ovarian carcinoma line, NIH:OVCAR-3, in vitro. OVCAR-3 cells exhibited a similar rate of adhesion to all substrates tested including laminin, fibronectin, and collagens I and IV. The synthetic peptide YIGSR-NH2, which corresponds to an attachment site in laminin, inhibited the adhesion of the cells to laminin, but not to fibronectin. In contrast, a GRGDS-NH2 peptide blocked adhesion to fibronectin but not to laminin. OVCAR-3 cells invaded and formed branched colonies on Matrigel. Colony formation was retarded by both YIGSR-NH2 and GRGDS-NH2 peptides. Serine protease inhibitors and human recombinant TIMP, the tissue inhibitor of metalloproteases, inhibited ovarian tumor cell invasion while a synthetic collagenase IV inhibitor (SC-44463) had no effect. These studies suggest that metalloproteases other than collagenase IV may be important for the invasive activity of ovarian cancer cells. It is possible that synthetic peptides with antiadhesive cellular activity and certain antiproteases could be used to control the progressive colonization and invasion of peritoneal surfaces by malignant ovarian cancer cells.

Amides↗
PubMed1990

Differential effects of phorbol ester on the in vitro invasiveness of malignant and non-malignant human fibroblast cells.

The effect of the phorbol ester tumor promoter 12-O-tetradecanoylphorbol 13-acetate (TPA) on cell invasion was studied using an in vitro assay for cell invasion through a reconstituted basement membrane matrix (Matrigel). TPA inhibited the invasiveness of malignant human fibrosarcoma HT1080 cells. In contrast, WI-38 lung fibroblasts, which show a very low invasive capacity, were stimulated (3-fold) to invade Matrigel after exposure to TPA for 48 hours. The inhibitory or stimulatory effects of TPA on cell invasion were correlated with a decrease or an increase in cell motility and collagenase IV activity, respectively. Synthetic diacylglycerols partially mimicked the inhibitory action of TPA on HT1080 cells but failed to stimulate WI-38 cell invasion. Immunoblots demonstrated that in both cell lines the alpha and beta isoforms of protein kinase C were equally down-regulated after a 5 hour exposure to TPA despite the basal low level of protein kinase C polypeptide in the malignant cells. Thus, whereas in WI-38 cells induction of an invasive behavior could be observed in the absence of protein kinase C, in the malignant cells disappearance of the kinase was associated with a non-invasive phenotype.

Blotting, Western↗
PubMed1990

Reconstituted basement membrane (matrigel) and laminin can enhance the tumorigenicity and the drug resistance of small cell lung cancer cell lines.

Small cell lung cancer (SCLC) is a fatal malignancy due to its propensity to metastasize widely and to reoccur after chemotherapy in a drug-resistant form. While most SCLC cell lines are anchorage independent for growth, laminin induced the attachment of five of six SCLC cell lines tested (NCI-N417, NCI-H345, NCI-H146, NCI-H187, NCI-H510, and NCI-H209). NCI-N417 SCLC cells adopted a flattened morphology on laminin, and a classic SCLC cell line (NCI-H345) demonstrated a neuron-like appearance while the other SCLC cell lines except NCI-H187 cells, attached but did not spread. Adhesion to laminin was associated with increased resistance to several cytotoxic drugs. Matrigel, an extract of basement membrane proteins, greatly accelerated tumor growth when coinjected with SCLC cells in athymic mice. A synthetic peptide from the B1 chain of laminin, cyclic-YIGSR (Tyr-Ile-Gly-Ser-Arg), inhibited laminin-induced SCLC cell adhesion and migration in vitro and reduced the size of the tumors they formed when coinjected with matrigel and YIGSR. These results suggest that the interaction of SCLC cells with laminin and possibly with other basement membrane proteins can enhance their tumorigenicity and drug resistance.

Amino Acid Sequence↗