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Biomedical subjects

L Larizza

Publications and source records attributed to L Larizza.

At least 91 records · Page 5Linked to original sources
PubMed1991

Karyotypic characterization of a new human embryonal rhabdomyosarcoma cell line.

Chromosomal analysis of an advanced recurrent rhabdomyosarcoma of the embryonal type was performed on cell cultures in the 9th passage of in vitro cultivation. This tumor showed a modal karyotype of 54 and was characterized by multiple numerical and structural chromosome abnormalities, all present in high frequencies. Abnormalities observed in 100% of the cells included a der(1) chromosome with a short unidentified insertion between q31 and q32; a der(1) chromosome, arising from insertion at the same breakpoint of a longer segment with a duplicated 1q31 band and translocation of 13q23----qter to 1p36, a deleted tetrasomic 13q23----qter, and a der(4) chromosome showing 1p36----pter translocated to 4p13. Other common abnormalities included trisomy of chromosomes 8, 13, and 9p, deletions of chromosomes 6, 10, 11, and 12, and presence of marker chromosomes. Characterization of the established line at the 38th passage evidenced the persistence of both the modal karyotype and all the numerical and structural abnormalities previously found. The results of this study provide further evidence of the major involvement of alterations in chromosome 1 in the progression of rhabdomyosarcoma.

Child↗
PubMed1991

Loss of Y chromosome with retention of Y heterochromatin in a marker chromosome from a human melanoma.

A single copy of a der 15 chromosome (m3) characterized by a C- and distamycin A-Dapi-positive region was observed in the -Y hyperploid karyotype of a primary human melanoma (Me 1402). The heterochromatic region was located pericentromerically, adjacent at one end to the NOR region of chromosome 15, and at the other to an unclassifiable chromosomal piece. We established that the C-positive block in the marker chromosome originated from Y heterochromatin by high-stringency in situ hybridization with a DNA probe for the 2.1 Hae III Y-specific repeat. Loss of the Y chromosome in tumors has been considered to be a secondary event associated with malignant evolution. It is significant that Me 1402 cells, which are highly malignant, lack the Y chromosome, but retain its heterochromatic portion in the rearranged m3 chromosome.

Adult↗
PubMed1989

In situ hybridization analysis of interstitial C-heterochromatin in marker chromosomes of two human melanomas.

Two distinct marker chromosomes, presenting with intercalated C- and distamycin A-Dapi-positive regions, were observed in a metastatic and a primary melanoma. To establish the origin of these heterochromatic sequences, we performed in situ hybridization analysis using specific probes for human repetitive DNA. The marker of the primary melanoma, m2, a der 16 chromosome resulting from the translocation of the 1q12-qter segment to band q23 of chromosome 16, showed specific hybridization with Sau3A but not with EcoRI sequences at the interstitial C-band. Thus the origin of this region from the normal chromosome 1 pericentromeric heterochromatin, containing both EcoRI and Sau3A sequences, could be established. On the other hand, the marker of the metastatic melanoma, m1, a der 1 chromosome showing an abnormally banded region inserted between 1q11 and 1q21-qter, failed to give any hybridization signals at the C- and distamycin A-Dapi-positive band when the same EcoRI and Sau3A probes were used. Furthermore, no hybridization was observed using either a probe for SatIII-specific sequences (QP23), mapping to chromosome 9 heterochromatic block, or LS6BB, a ribosomal DNA probe. From these data we speculate that more complex molecular rearrangements may have occurred during the transposition of heterochromatin from its original site to m1. The heterochromatin change found in m1 may be related to advanced stages of malignancy.

Chromosome Banding↗
PubMed1989

Involvement of unstable chromosomal regions containing C-heterochromatin and fragile sites in the integration of amplified dhfr domains.

A 10(-3) M methotrexate (MTX)-resistant variant (H2), selected from the murine fibrosarcoma line B77-3T3/AA12, was characterized after 5 (H2 MTXRes I) and 9 (H2 MTXRes II) months of in vitro propagation in the presence of the drug. Southern blot hybridization of wild-type and H2 MTXRes DNAs confirmed amplification of the dhfr gene without apparent rearrangements in its structure. Cytogenetic analysis revealed that double minutes (DMs) predominated in H2 MTXRes I, whereas homogeneously staining regions (HSRs) were the main feature of H2 MTXRes II cells. HSRs, shown to contain dhfr sequences by in situ chromosome hybridization, were localized within two rearranged chromosomes, designated as m1 and m2 because of their derivation from the marker chromosome m of AA12 cells. This chromosome, characterized by two interstitial C bands adjacent to two nonstaining gaps, was no longer observed in H2 MTXRes II cells. A role for nonrandom involvement of chromosome m in the integration of amplified DNA is suggested by the finding of another HSR-chromosome, m3, derived from m, in an independent MTXRes clone (B1). Rearrangement in one of the unstable C-band/gap regions of chromosome m is proposed as the unifying mechanism that may account for the outcome of the three HSR chromosomes observed.

Animals↗
PubMed1989

Malformation syndrome with t(2;22) in a cancer family with chromosome instability.

A de novo unbalanced t(2;22)(q37;q11.2) [corrected], resulting in the deletion of the 22pter-q11 and 2q37-qter regions, was observed in a 12-year-old girl born with a congenital malformation syndrome and later displaying signs of neurologic impairment. Some of the clinical signs observed appear to overlap those found in subjects monosomic in the 22q11 region affected by the DiGeorge syndrome. The chromosomal rearrangement observed may be related to a familial cytogenetic instability that also gives rise to sustained cancer predisposition.

Abnormalities, Multiple↗
PubMed1989

Cytologic and flow cytometric DNA analysis of multinucleated tumor cells and derived microcells.

Microcell production by means of Colcemid-induced micronucleation and subsequent enucleation with the density gradient technique was adjusted for use with the murine T-lymphoma line ESb-M. Modification of the standard protocol for a cell type on which no experiments had previously been performed required careful monitoring of the multiple steps in the procedure in order to optimize the final microcell yield. Traditional microscopic verification may sometimes be ambiguous, due to the lack of a clear cutoff point between small whole cells and cell fragments; in these conditions, the level of variability increases, thus impairing quantitative estimations. Flow cytometric (FCM) analysis of DNA content and size of donor cells and microcells was therefore applied in parallel to provide additional quantitative information. The FCM results supplemented the microscopic data in assessing which fraction recovered from the gradient has the lowest percentage of contaminant whole cells; however, FCM analysis may provide more statistically significant data due to the large size of the sample examined. Moreover, FCM is of prospective use in providing the basis for subsequent sorting of either pure microcells or specific subpopulations of defined DNA content and size.

Animals↗
PubMed1988

Griseofulvin.

Griseofulvin (GF) is a mycotoxin produced by various species of Penicillium including P. griseofulvum Dierckx, P. janczewski (P. nigricans) and P. patulum. It is active against dermatophytic fungi of different species in the genera Microsporum, Trychophyton and Epidermophyton. Because of its capacity to concentrate in the keratinous layer of the epidermis and its relatively low toxicity in man, it has been extensively used in the therapy of dermatophytoses by oral administration. The biological activity of GF towards fungi is manifested as nuclear and mitotic abnormalities followed by distortions in the hyphal morphology. Mitotic segregation is also induced in fungi by GF treatment. In higher eukaryotes the cytostatic action of GF is essentially due to a mitotic arrest at late metaphase/early anaphase. The cytological effects observable both in vivo and in vitro on different plant and animal cell systems, include C-mitoses, multipolar mitoses and multinuclearity. Prolonged GF treatment in experimental animals provokes biochemical changes consisting mainly of disturbances of porphyrin metabolism, variation in the microsomal cytochrome levels and formation of Mallory bodies. In mice these alterations are followed by the development of multiple hepatomas. Evidence of tumor induction by GF has been obtained in mice and rats, but not in hamsters. GF may also act either as a promoting or a co-carcinogenic agent, depending on the circumstances of its administration. It has been found to increase the frequency of cell transformation induced by polyoma virus, but not to induce cell transformation per se. Induction of sperm abnormalities has been observed in GF-treated mice. The embryotoxic and teratogenic action of GF has been demonstrated in pregnant rats exposed during organogenesis. Genetic effects of GF have been investigated by the following tests: Salmonella/microsome mutagenicity assay, point mutations in mammalian and plant cells, DNA damage and repair, SCE, chromosome aberrations, micronuclei, dominant lethals, aneuploidy in lower and higher eukaryotes. A positive response has been obtained in the assays on numerical chromosome changes in all the systems analyzed; limited or inconclusive evidence has been obtained for SCE and structural chromosome changes. Doubled or highly polyploid sets can be detected in all types of cells during or immediately after GF treatment. A marked increase in chromosome number variation is observed at various times after withdrawal of the drug, with prevailing hyperdiploid and reduced sets in animal cells and plant cells respectively.(ABSTRACT TRUNCATED AT 400 WORDS)

Carcinogens↗
PubMed1987

Mosaicism in the C-banded region of chromosome 1 in cancer families.

Chromosome 1 C-band length mosaicism was detected in lymphocytes from six tumor patients and one healthy subject belonging to three families with a high incidence of cancer. In all cases the variant cell population showed a decreased amount of C-heterochromatin in one chromosome, whereas the C-banded pattern of the homolog was identical to that of the nonvariant cell population. A family tendency to unequal mitotic crossing over, possibly leading to C-band heteromorphism, may explain the high frequency of detection of C-heterochromatin mosaicism in cancer family members (seven of 13 cases studied). The possible role of heterochromatin in inducing cancer has been widely discussed. The special feature of the acquired C-band variants vis-à-vis the inherited ones is that they mark intrinsic genetic instability that may result, through multiple mechanisms, in increased susceptibility to malignancy.

Aged↗
PubMed1987

Cytogenetic instability in a family with gastric cancer recurrence.

An index case with a congenital malformation syndrome enabled detection of a family that had a previous history of spontaneous abortuses and recurrence of neoplasia through three generations. Cytogenetic analysis performed on lymphocytes from 11 subjects in the second and third generation showed karyotypic alterations in both tumor bearers and apparently normal subjects. Chromosome variations consisted of: spontaneous chromosome fragility; chromosome translocations; polymorphisms in the heterochromatic regions in chromosomes Y, #1, #16, #22. The inheritance pattern of all chromosome rearrangements and heteromorphisms observed was established starting with the second generation, and the contribution of specific individuals was identified. Although the relationship between chromosomal instability and predisposition to gastric cancer does not appear to be coincidental, no specific chromosome alteration in normal somatic cells was shared by all members of the family who developed or are at risk of developing tumors.

Adult↗
PubMed1986

Cytogenetic analysis and muscle differentiation in a girl with severe muscular dystrophy.

The uncommon case is described of a girl severely affected with Duchenne muscular dystrophy. Cytogenetic analysis revealed no numerical or structural abnormalities of the X-chromosome in any of the cells examined (leucocytes and myoblasts). No abnormality in morphology, growth pattern or differentiation was observed in the dystrophic muscle cultures as compared with control cultures.

Cell Differentiation↗
PubMed1986

A comparative analysis of collagen III, IV, laminin and fibronectin in Duchenne muscular dystrophy biopsies and cell cultures.

The role of collagen type III and IV (Coll III, IV) in Duchenne muscular dystrophy (DMD) was investigated by the indirect immunofluorescence technique (IIF) both in muscle biopsies and derived cell cultures. Ten dystrophic cases were studied and compared with twelve suitable control cases, extending the IIF analysis to two other representative non-collagenous proteins of the extracellular matrix (ECM), namely fibronectin (FN) and laminin (LM). DMD biopsies generally displayed a thickening of endomysial and/or perimysial connective, as compared to control specimens. All the markers analyzed were found to contribute to this connective proliferation, although from a quantitative point of view the relative involvement decreases progressively from FN through Coll III and IV to LM. However, due to Coll IV selective endomysial localization, Coll IV alteration can be considered a specific indicator of a muscle cell defect. Results from DMD muscle cultures revealed no significant changes in comparison to control cultures, except for Coll IV. A well-organized, Coll IV-containing pericellular matrix was noted in a fraction of DMD cultures as a unique feature seen in no control culture. This alteration was again considered significant since Coll IV is the only marker clearly associated with the myotube component still expressed in vitro. The negative results obtained on the other marker proteins should not however be considered definitive, due to the lack in the simplified in vitro system used of humoral and/or neuronal factors which may be needed to express gene defect(s) in differentiated cells.

Adolescent↗
PubMed1985

Fibronectin, laminin in hybrids of Rous sarcoma virus transformed and normal mouse fibroblasts.

Hybrid clones derived from the fusion of normal and Rous sarcoma virus-transformed 3T3 fibroblasts were analyzed for fibronectin and laminin pattern of expression in order to find a possible correlation with tumorigenicity. Both organization in the pericellular matrix and secretion into the culture media were investigated by immunofluorescence and ELISA techniques. No significant difference in fibronectin or laminin release was found among hybrid clones exhibiting different levels of tumorigenicity. In contrast, distinctive immunofluorescence patterns of concomitant presence of low levels of fibronectin and high levels of laminin were constantly observed in all the tumorigenic clones.

Animals↗
PubMed1985

Role of heterochromatin variation in the instability of a marker chromosome during tumor progression.

Karyotypic evolution of the poorly metastasizing tumorigenic RSV-transformed B77-3T3 fibroblast line was investigated both in highly metastasizing clones (selected by growth in hard agar) and in spontaneous metastases. Analysis of structural chromosome aberrations associated with the transition from the nonmetastatic to the metastatic phenotype was focused on a readily identifiable marker chromosome (A), displaying an extracentromeric heterochromatic region as a main feature promoting genetic instability. Well-defined changes in the structure of this marker were observed, both in vitro and in vivo, and invariably involved C-heterochromatic variation. In the metastatic clones, a specific rearrangement of the A chromosome was selected. This structural variant (B) showed two extracentromeric C-positive regions and probably originated from duplication of the segment of A included between the centromere and the internal C-band. On the other hand, selection of a modified form of chromosome A, not displaying the interpolated C-heterochromatin, had occurred in the extremely rare B77-3T3 spontaneous metastases. The connection among heterochromatin variants, genetic instability, and chromosome aberrations is discussed.

Animals↗
PubMed1984

Suggestive evidence that the highly metastatic variant ESb of the T-cell lymphoma Eb is derived from spontaneous fusion with a host macrophage.

Two lines of evidence are reported which suggest that the highly metastatic variant ESb of the T-cell lymphoma Eb is derived from spontaneous fusion with a host macrophage. Firstly, ESb cells are shown to express the macrophage differentiation antigen Mac-1 which was not found on Eb cells or on any other tumor cells tested except the macrophage tumor line Pu5. Secondly, the progression from low to high metastatic capacity could be reproduced in vitro following hybridization of thioguanine-resistant Eb cells (EbTGR) with syngeneic bone-marrow-derived macrophages. Two HAT medium-selected hybrid tumor lines (Eb-F1 and Eb-F2) could be established. They were found to express cell surface markers of both parental lines: T lymphoid differentiation antigens from T-lymphoma and macrophage antigens (Mac-1, class II MHC antigens) from the normal cell fusion partner. The antigens were identified on the hybrids and subclones thereof by means of monoclonal antibodies and 3 different detection assays: cytofluorography, complement-dependent cytotoxicity and immunoprecipitation followed by gel electrophoresis. Animals inoculated s.c. with the parental line EbTGR developed local tumors but not metastases and survived for more than 40 days. In contrast, animals inoculated similarly with Eb-F1 or Eb-F2 cells quickly developed metastases in visceral organs and died as early as 10-14 days following inoculation. In many but not all respects, the in vitro-derived T-lymphoma-macrophage hybrids resembled the spontaneous in vivo-derived variant ESb. These findings, together with the presence of Mac-1 antigen on ESb cells, suggest (1) that ESb variant cells may be derived from spontaneous fusion with a host cell, most likely a macrophage and (2) that somatic cell fusion may be an important mechanism of genetic rearrangements leading to metastatic variants. The new highly metastatic tumor lines which were developed under well-defined in vitro conditions, and their subclones, may become very useful tools for studying the contribution of specific genetic traits and of membrane-related structures to various steps of the metastatic process.

Animals↗
PubMed1984

Acquisition of high metastatic capacity after in vitro fusion of a nonmetastatic tumor line with a bone marrow-derived macrophage.

A low metastatic, thioguanine-resistant murine T lymphoma line (EbTGR) was hybridized in vitro, with the help of polyethylene glycol, with syngeneic bone marrow-derived macrophages. Two HAT-resistant hybrid lines (Eb-F1 and Eb-F2) were obtained from independent fusion cultures. A cytogenetic analysis revealed that most of the macrophage chromosomes except No. 12 had segregated or become rearranged 60 d after fusion, a time at which the cell lines had become stabilized in culture. Syngeneic mice inoculated subcutaneously with the tumor macrophage hybrid lines developed, very quickly, visceral metastases and died after less than 2 wk, while those inoculated with the parental line lived for greater than 6 wk and developed only localized, large primary tumors. The metastatic hybridomas expressed a similar tumor antigen as a spontaneous, in vivo derived, high metastatic variant (ESb) of the same tumor. This suggests that ESb cells might have arisen from a spontaneous fusion with a host macrophage.

Animals↗
PubMed1984

Somatic cell fusion as a source of genetic rearrangement leading to metastatic variants.

Tumor cell populations displaying metastatic properties often have higher gene dosage than their less malignant progenitor tumors, as shown by increased ploidy levels, chromosome duplication and gene amplification. The acquisition by tumor cells of high chromosome numbers may be due to endoreduplication or somatic hybridization either between tumor cells or between tumor and host cells. All such mechanisms increase genetic variability and instability in tumor cells since they trigger a polyploidization-segregation cycle. Among the wide variety of segregants which may emerge from high-ploidy cells, variants with increased malignancy can be positively selected in vivo. Evidence for in vivo fusion of tumor and normal host cells has been reported in different tumor systems. However the attainment by tumor-host hybrids of a higher degree of malignancy has only been observed following substantial chromosome segregation. The involvement of a cell of bone marrow origin as preferential host partner in the fusion process has been proved both by studies on tumor-host hybrids in bone marrow radiation chimeras and in vitro hybridization experiments between non-metastatic tumors and normal lymphoreticular cells which have led to the establishment of metastatic variants. Several different segregational mechanisms may bring about homozygosity or hemizygosity of recessive alleles in tumor-host hybrids, leading to their expression. The marked chromosome dynamics of tumor-host hybrids are also responsible for extensive chromosome rearrangements. At the molecular level these may represent mechanisms causing altered oncogene activity. The activation of new oncogenes by transposition or amplification as well as the amplification of previously activated oncogenes are the mechanisms most likely to be responsible for transition from low to high malignancy, occurring through ploidy changes, such as those produced by somatic mating.

Animals↗