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Biomedical subjects

F Garrido

Publications and source records attributed to F Garrido.

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

Selective upregulation of MHC class I expression in metastatic colonies derived from tumor clones of a murine fibrosarcoma.

Eighteen metastatic nodes derived from the wild-type (GR9) and from 4 different clones (G2, D8, B10, and B9) obtained from a fibrosarcoma were analyzed for H-2 class I and II expression, as well as for adhesion molecules (CD44, CDIIb, CD18, CD49, and CD54). When metastatic nodes were cultured, typed for H-2 antigens, and compared with the H-2 expression of the inducing tumor cell, H-2 Kd and Dd class I expression was greater in most nodes analyzed. In contrast, the Ld molecule remained negative, or showed a minor increase. Class II expression was negative in the wild-type and the tumor clones, and remained so in the metastatic colonies. Analysis of the adhesion molecules revealed no differences between the inducing tumor cells and the metastatic nodes. The only molecule expressed was CD44, which was present in all cells studied and was also inducible by interferon-gamma. The increase in H-2K and H-2D expression was associated with resistance to natural killer cytotoxicity, as observed in the G2 tumor clone and some autologous metastases, such as B9MP2, G2MK2, and G2MLI. In three independent clones of this tumor system (D8, BIOMP6, and B9MP6) we found that tumor cells treated with interferon-gamma had the same altered phenotype, i.e., a selective lack of response of the Ld molecule to induction. These findings add a cautionary note to the well-established idea that tumor cells may lose all class I antigens during tumor progression, and suggest that sometimes this may not be the case. The selective downregulation of Ld and upregulation of Kd and Dd class I expression may give some tumor cells means of escaping both cytotoxic lymphocyte and natural killer immune surveillance.

Animals↗
PubMed1999

Looking for HLA-G expression in human tumours.

Tumour and virus infected cells escape CTLs responses by losing some or all HLA class I molecules. However the NK escape mechanism that uses the HLA-A, -B, and -C tumour deficient variants is unknown. To determine whether HLA-G is expressed on tumour cells and thus favours tumour escape by abolishing NK lysis, we studied HLA-G in a large panel of human tumour tissues and human tumour cell lines of different origin that were previously characterized for HLA-A, -B, and -C expression. We studied HLA-G mRNA transcripts using RT-PCR, and HLA-G1 expression by FACS and immunohistochemical techniques. We found several mRNA transcripts of HLA-G isoforms in most of the samples studied. However, we detected no cell surface expression of HLA-G1 using two specific monoclonal antibodies (mAbs) (87G and 01G). We cannot, however, exclude the possibility that some isoforms other than HLA-G1 may be expressed in some tumours.

Gene Expression↗
PubMed1999

Differential effect on U937 cell differentiation by targeting transcriptional factors implicated in tissue- or stage-specific induced integrin expression.

The inhibition of transcription factor functions was used to define their role in phorbol ester-induced cellular differentiation of a monocytic cell line, U937. We demonstrate a differential effect on cell adhesion and differentiation: antisense or competitive binding with double-stranded oligonucleotides antagonized the functions of AP-1, NF-kappaB, and PU.1 transcriptional factors. In the presence of phorbol 12-myristate 13-acetate (PMA), U937 cells attached to the plastic surface and cells were characterized by marked expression of beta2-integrin molecules on the cell surface. We show that the in vivo differentiation of U937 cells appears to occur normally in the absence of AP-1 activity. In contrast, the addition to the cell culture of phosphorothioate oligonucleotides that contained the NF-kappaB or PU.1 binding sites significantly inhibited U937 differentiation. The absence of NF-kappaB led to pleiotropic effects with a clear reduction in the expression of integrin and other lineage-specific myeloid antigens on the cell surface. In contrast, the absence of PU.1 had a more restricted effect on integrin expresion on the cell surface, probably as a result of blockage of CD18 gene expression.

CD18 Antigens↗
PubMed1999

A new beta 2 microglobulin mutation found in a melanoma tumor cell line.

Beta2 microglobulin mutations are an important mechanism for HLA class I total loss, (phenotype No. I) and have been described in colon carcinomas, melanomas and lymphomas. We describe a new beta2 microglobulin mutation detected in the melanoma cell line GR-34. The new mutation reported here was identified as a deletion of 4 bases (TTCT) in the highly repetitive sequence CTCTCTCTTTCT located in the leader sequence of the beta2 microglobulin gene at codon 15-16 of exon 1. The mutation produces a frameshift in the open reading frame sequence with the appearance of a stop codon at position 42. We also demonstrate that the second beta2 microglobulin gene is deleted. Comparisons with beta2 microglobulin mutations in other tumor cell lines suggest a mutation hot spot in exon 1.

Aged↗
PubMed1999

Differential effect of protein-bound polysaccharide (PSK) on survival of experimental murine tumors.

The effect of protein-bound polysaccharide (PSK) on the survival of BALB/c and C57BL/6 mice after intravenous injections of syngeneic murine sarcomas (GR9.B9 and Meth-A), LSTRA lymphoma and B16 melanoma cells was studied. Pretreatment of mice with PSK significantly increased survival after the injection of either type of sarcoma cells, although the effect was attenuated when high numbers of cells were injected. Survival was not modified significantly in LSTRA lymphoma or B16 melanoma. Mice pretreated with anti-asialo GMI serum showed significantly decreased survival from all tumors in comparison with untreated mice injected with tumors, regardless of cell dose used. We observed an inverse correlation between H-2 antigen expression and in vitro NK sensitivity of tumor cells from all lines except B16 melanoma cells. These results clearly suggest that pretreatment of mice with PSK prolongs survival and inhibits metastasis formation in mice injected with sarcoma cells, being this effect highly selective, since survival was not improved in mice injected with LSTRA lymphoma or B16 melanoma.

Animals↗
PubMed1998

ACTH and beta-endorphin in transcendental meditation.

We have evaluated the effect of Transcendental Meditation (TM) on the hypothalamo-hypophyseal-adrenal axis diurnal rhythms through the determination of hormone levels. Blood samples were taken at 0900 hours. and at 2000 hours. These samples were taken from 18 healthy volunteers who regularly practice TM and from nine healthy non-meditators. Cortisol, beta-endorphin, and adrenocorticotropic hormone (ACTH) were measured at both hours. TM practitioners showed no diurnal rhythm for ACTH and for beta-endorphin (ACTH, pg/mL, mean +/- SE; 13.8+/-1.2 - 12.1+/-1.5/beta-endorphin, pg/mL; 14.4+/-1.5 - 17.2+/-1.9, at 0900 hours and 2000 hours, respectively), in contrast to control subjects, who showed normal diurnal rhythm for these hormones and for cortisol (ACTH, pg/mL; 19.4+/-1.9 - 11.9+/-2.2/beta-endorphin, pg/mL; 25.4+/-1.7 - 17.7+/-1.1/Cortisol, ng/mL; 201.4+/-13.2 - 71.3+/-6.5, at 0900-2000 hours, respectively, p < 0.01 in the three cases). Practitioners of TM with similar anxiety levels to those of the control group showed a different pattern in the daytime secretion of pituitary hormones. TM thus appears to have a significant effect on the neuroendocrine axis. Because cortisol levels had a normal pattern in the TM group, these results may be due to a change in feedback sensitivity caused by this mental technique.

Adrenocorticotropic Hormone↗
PubMed1998

In vivo and in vitro generation of a new altered HLA phenotype in melanoma-tumour-cell variants expressing a single HLA-class-I allele.

A new HLA-class-I altered phenotype is described in melanoma. This phenotype is the result of a combination of HLA-B-locus down-regulation and HLA-haplotype loss. The alteration was found in 2 melanoma cell lines generated from 2 patients; one was derived from an in vivo lesion (FM37) and the other was obtained after in vitro immunoselection (R22.2). The R22.2 cell line was isolated from FM55P, a cell line derived from a primary melanoma, after in vitro treatment with a heterologous HLA-A2-restricted cytotoxic-T-lymphocyte (CTL) clone. Two additional cell lines from patient 55 were obtained from 2 s.c. metastases (FM55M1 and FM55M2). Iso-electric focusing and flow-cytometric studies showed a significant reduction in the expression of both HLA-B alleles in all cell lines studied. The expression of HLA-B-locus products recovered completely after IFN-gamma treatment of FM55P, M1 and M2. In contrast, FM37 and R22.2 tumour cells showed an additional HLA defect: the absence of one HLA haplotype. Simple tandem-repeat polymorphism markers spanning chromosome 6 showed that DNA from the 2 samples (FM37 and R22.2) showed loss of heterozygosity (LOH). In both cases, homozygosity was observed on 6p, which maps the HLA region, the final consequence being a tumour cell that expressed a single HLA-class-I allele (HLA-A3 and HLA-A1 respectively). FM37 cells may thus reflect the in vivo counterpart of resistance to lysis by HLA-A2-restricted tumour-infiltrating lymphocytes.

Alleles↗
PubMed1998

Unresponsiveness to interferon associated with STAT1 protein deficiency in a gastric adenocarcinoma cell line.

HC class I expression can be up-regulated by interferons (IFN) and other cytokines. Both IFNalpha and IFNgamma have been shown to exert their effects via a recently discovered signalling pathway by inducing tyrosine phosphorylation of their receptors. Receptors for interferons and other cytokines signal through the action of associated protein tyrosine kinases of the JAK family (Janus kinase) and latent cytoplasmic transcriptional activators from the STAT family (signal transducers and activators of transcription). Here we report a gastric adenocarcinoma cell line, AGS, that is defective in its response to either IFNalpha or IFNgamma. AGS cells display selective alterations only in MHC class I inducibility and not in constitutive MHC class I expression. In nuclear extracts of AGS cells, no binding activity to interferon-responsive elements (GAS/ISRE) was observed. We found that AGS cells showed an extremely low level of STAT1 expression, which may be responsible for the absence of biological response to IFN. Because STAT1-deficient cells are highly sensitive to infection by virus, the absence of these proteins may also contribute to the tumor phenotype, giving the tumor a selective advantage, by inhibiting cell growth suppression mediated by IFN and abetting escape from the T cell antitumor response.

Adenocarcinoma↗
PubMed1998

Differential expression of MHC class II genes in lung tumour cell lines.

Molecular characterization of HLA class II expression was investigated in five lung tumour cell lines at the protein and mRNA levels. The cell lines exhibited a differential expression of HLA-DR, HLA-DP and HLA-DQ products and also showed differences in the inducibility of HLA class II genes by gamma-IFN. Gamma-IFN stimulation induced only HLA-DR expression to varying degrees in three cell lines, while only one cell line showed stimulation for HLA-DP and none for HLA-DQ antigens. These results suggest locus-specific regulation for the three loci. The presence of DR protein on the cell-surface membrane was always positively correlated with the presence of HLA-DR mRNA in the cells. After treatment with 5-azacytidine in the A549 cell line, which expressed the lowest values, there was no effect on HLA class II levels. This suggested that methylation does not play an important role in the lack of MHC class II antigen expression. In addition to studying mRNA levels of HLA class II antigens, we analysed mRNA of the proto-oncogene c-myc and observed a positive correlation of two mRNA: the increments in HLA-DR expression were associated with increments in c-myc expression. This suggests a relationship between the regulatory and HLA-DR antigens control the expression of c-myc and HLA-DR antigens in lung tumour cell lines.

Actins↗
PubMed1998

Increase of large granular lymphocytes in human ejaculate containing antisperm antibodies.

Using flow cytometry, we studied the expression of the CD16 antigen by lymphocytes present in human semen samples from three groups of patients: 60 fertile men attending for vasectomy, 60 sterile patients without antisperm antibodies (ASA) and 18 immunological sterile patients with ASA in their ejaculate. No significant difference was found in the concentration of leukocytes or subpopulations of these cells (monocytes, lymphocytes and granulocytes) between fertile, sterile without ASA and immunological sterile groups. However, we detected a predominance of macrophages/monocytes within the population of seminal leukocytes. No statistically significant difference was found in the absolute number of T and B lymphocytes between the three groups studied. However, a significant increase in the number of CD16+ lymphocytes was observed in the ejaculate of sterile patients with ASA as compared to the other groups. This finding might establish an important parameter in the follow-up and prognosis of patients with immunological sterility.

Adult↗
PubMed1998

High frequency of altered HLA class I phenotypes in invasive colorectal carcinomas.

We analyzed the expression of HLA class I antigens in 78 tumor tissue samples obtained from patients diagnosed as having colorectal carcinomas. A broad panel of mAbs defining HLA monomorphic, locus-specific and allele-specific determinants was used. In addition, an antibody defining HLA-C locus-specific determinant (L31) was also tested. Previous reports on these tumors indicated HLA class I losses of 30 to 40%. At least 73% of the patients in the present study had a detectable HLA class I alteration. These altered HLA phenotypes were classified as total HLA loss (18%) (phenotype I); HLA-A locus-specific loss (9%) (phenotype IIIa); HLA-B locus-specific loss (8%) (phenotype IIIb); HLA-A and B locus losses (2%) and HLA allelic losses (36%) (phenotype IV). We found no HLA-C locus losses. Autologous peripheral blood lymphocyte HLA class I typing was always necessary to define phenotype IV. We also studied the CD3 zeta chain in tumor tissues to correlate possible changes in the CD3 signal transduction pathway with HLA alterations. The CD3 ratio was frequently altered, but this alteration could not be correlated with tumor HLA phenotypes. The high frequency of HLA class I losses in colorectal carcinomas suggests that this finding is a widespread phenomenon and may be required to escape T-cell recognition. It remains to be determined whether HLA expression is "normal" in the rest of the 27% of our patients.

Alleles↗
PubMed1998

Mutations of the beta2-microglobulin gene result in a lack of HLA class I molecules on melanoma cells of two patients immunized with MAGE peptides.

Mutations have been identified in the beta2-microglobulin gene of tumor cells of two metastatic melanoma patients who received immunizations with MAGE peptides. One mutation abolishes the start codon whereas the other introduces a premature stop codon. The second beta2-microglobulin allele of both tumors appears to be lost on the basis of sequence data and loss of microsatellite heterozygosity. The lack of beta2-microglobulin gene product results in the absence of HLA class I antigens on the surface of the tumor cells. This may explain why the tumors of both patients progressed despite the immunization treatment and shows the necessity of analyzing in depth the antigen presentation capability of the tumor cells for the interpretation of clinical trials involving anti-tumor vaccination.

Antigens, Neoplasm↗
PubMed1998

Microsatellite instability in cervical intraepithelial neoplasia.

We studied the incidence of microsatellite instability (MI) in lesions defined as cervical intraepithelial neoplasia (CIN). The human papillomavirus (HPV) status of the tissues was also determined. DNA from tissue samples and autologous lymphocytes were studied for five loci located within or adjacent to the DNA mismatch repair genes. Replicate errors were detected in 7 out of 47 (14.8%) samples of cervical tissue from 24 women. Our results indicate that the defect in DNA repair-associated genes does not appear to be necessary for the selection of clones which progress from dysplasia to carcinoma. Although HPV DNA of highly oncogenic types (16/18) was detected in most cervical lesions and may be an important factor for MI, we also detected MI in two loci in HPV-negative normal tissue, indicating that further events can also be involved in mismatch repair defects.

Adult↗
PubMed1997

Integration of high-risk human papillomavirus DNA is linked to the down-regulation of class I human leukocyte antigens by steroid hormones in cervical tumor cells.

A crucial event in the malignant progression of cervical intraepithelial neoplasia appears to be the up-regulation of high-risk human papillomavirus (HPV) early gene expression. Steroid hormones have been linked to the progression from premalignant to neoplastic status in HPV positive lesions. This report demonstrates that at physiological levels, the glucocorticoid hormone hydrocortisone consistently down-regulates class I human leukocyte antigen (HLA) surface expression in HPV-positive cervical tumor cells but can up-regulate expression in HPV-negative epithelial tumor lines. Suppression of HLA expression was also seen with progesterone, another steroid hormone. The hydrocortisone-mediated modulation of HLA expression is dependent on integration and transcription of the HPV genome and can be blocked by Ru38486, an antagonist of both glucocorticoid and progesterone receptors, indicating the role of these receptors in mediating HLA suppression. The data suggest that HPV integration events in cervical epithelia correlate with hormone-dependent HLA suppression, possibly contributing to the avoidance of tumor recognition by cytotoxic T cells. These studies imply that clinical use of steroids may be contraindicated in HPV-positive individuals who have early premalignant cervical disease or neoplasia but provide evidence that the antiprogestin Ru38486 may be useful in the management of early stage cervical disease.

Carcinoma↗
PubMed1997

Altered MHC class I antigens in tumors.

MHC class I antigens are lost or downregulated in invasive tumors compared with autologous normal tissues. This is observed in most of the newly induced experimental tumors analyzed if they are cloned before passaging in vivo. Similarly, this is observed in 40%-90% of human tumors using the available panel of anti-HLA class I monoclonal antibodies. In both systems the tumor populations are heterogeneous for H-2/HLA expression and composed of clones that express different amounts of MHC class I antigens. This heterogeneity may have a profound influence on tumor behavior, considering the role that MHC antigens play in T and natural killer cell-mediated responses. It is possible that the tumor escape mechanisms from T and natural killer cells select variants that express a particular MHC class I altered phenotype. We review the MHC changes detected in different experimental as well as human tumors and demonstrate the relevance of these altered H-2/HLA tumor phenotypes for implementing immunotherapeutic strategies based on T or natural killer cell-mediated responses.

Animals↗
PubMed1997

Implications for immunosurveillance of altered HLA class I phenotypes in human tumours.

HLA class I downregulation is a frequent event associated with tumour invasion and development. Altered HLA class I tumour phenotypes can have profound effects on T-cell and natural killer (NK)-cell antitumour responses. Here, Federico Garrido and colleagues analyse these altered tumour phenotypes in detail, indicating their potential relevance for implementation of immunotherapeutic protocols and strategies to overcome tumour escape mechanisms.

HLA Antigens↗
PubMed1997

Class I major histocompatibility complex antigens and tumor ploidy in breast and bronchogenic carcinomas.

We determined the frequency of expression of the major histocompatibility complex antigens HLA-A,B,C in tumor cells from 207 primary tumor lesions of breast and bronchogenic carcinomas, to see if the expression of theses antigens was linked with several clinicopathological parameters associated with tumor aggressivity, such as abnormal cellular DNA content. We compared tumor tissues with nonneoplastic tissues and tissues from 15 benign breast lesions. HLA class I expressor and nonexpressor tumor cells were determined by using immunohistochemical stains (PAP and APAAP methods) and antibodies against these antigens. Reduction of HLA class I antigen was detected in 65 tumors (31.7%) and was significantly associated with poor tumor differentiation and abnormal cellular DNA content (p < 0.001). These characteristics might define a group of aggressive tumors in which the decrease of HLA class I antigens would enable tumor cells to avoid eliciting host immune responses. On the other hand, the altered regulatory mechanisms, of tumors with abnormal cellular DNA content, might modulate the expression of HLA class I molecules.

Breast Neoplasms↗