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S Pathak

Publications and source records attributed to S Pathak.

At least 73 records · Page 4Linked to original sources
PubMed1994

Androgen-independent cancer progression and bone metastasis in the LNCaP model of human prostate cancer.

Our laboratory has previously reported on the derivation of LNCaP cell sublines from LNCaP tumors maintained in castrated and intact athymic male mice. These LNCaP sublines differ from the parental line in tumorigenicity and androgen dependence. This paper demonstrates that one of these sublines acquired metastatic potential. When inoculated either s.c. or orthotopically, the C4-2 subline metastasized to the lymph node and bone with an incidence of 11-50%. Interestingly, the incidence of osseous metastasis was higher in castrated than in intact male hosts. We evaluated the chromosomal, immunohistochemical, and biochemical characteristics of the LNCaP sublines derived from C4-2 tumors that metastasized to the lymph node and bone. Cytogenetic analysis showed that all sublines were human and shared common marker chromosomes with the parental LNCaP cells. This experimental human prostate cancer model may permit, for the first time, the study of the molecular mechanisms underlying human prostate cancer metastasis.

Animals↗
PubMed1994

Derivation of androgen-independent human LNCaP prostatic cancer cell sublines: role of bone stromal cells.

A model of human prostate cancer was established to study cellular interaction between prostate cancer and bone stroma in vivo. In this model, subcutaneous co-injection of 2 non-tumorigenic human cell lines--LNCaP, a prostate cancer cell line, and MS, a bone stromal cell-line--into intact adult male mice resulted in formation of carcinomas that secreted prostate-specific antigen (PSA), a clinically useful human serum prostate cancer marker. In castrated hosts, upon cellular interaction with bone fibroblasts, we observed the progression of these tumors from an androgen-dependent (AD) to an androgen-independent state (AI). We derived 4 LNCaP cell sublines from the chimeric LNCaP/MS tumors: the M subline from intact hosts and the C4, C4-2 and C5 sublines from castrated hosts. The LNCaP sublines had chromosomal markers similar to those of the parental LNCaP cells and distinctly different from those of the MS bone stromal cell line. Although the parental and derived cell lines expressed similar steady-state levels of ornithine decarboxylase transcript, the sublines expressed 5- to 10-fold higher basal steady-state levels of PSA transcript than did the parental LNCaP cell line. The LNCaP sublines formed 13- to 26-fold more soft-agar colonies than the parental LNCaP cell line. The sublines became tumorigenic, yielding an incidence of tumors in intact athymic mice of 7-75%. The LNCaP sublines C4 and C5 (but not the parental and M cell line) formed tumors in castrated hosts when co-injected with bone fibroblasts. A second-generation LNCaP subline, C4-2, was derived from a chimeric tumor induced by co-inoculating castrated mouse with C4 cells and MS cells. We found that C4-2 subline was tumorigenic when inoculated into castrated hosts in the absence of inductive fibroblasts. Moreover, C4-2 was the only subline capable of forming soft-agar colonies when cultured in serum-free medium. In comparison with the parental LNCaP cells, the C4-2 subline expressed lower steady-state levels of androgen receptor (AR) protein and mRNA transcript and lost its androgen responsiveness in vitro. Our results suggest that certain genetic traits of prostate cancer cells may be selected or altered through an "adaptive" mechanism that involves cellular interaction with the bone stromal cells.

Animals↗
PubMed1994

A tumor suppressor locus within 3p14-p12 mediates rapid cell death of renal cell carcinoma in vivo.

High frequency loss of alleles and cytogenetic aberrations on the short arm of chromosome 3 have been documented in renal cell carcinoma (RCC). Potentially, three distinct regions on 3p could encode tumor suppressor genes involved in the genesis of this cancer. We report that the introduction of a centric fragment of 3p, encompassing 3p14-q11, into a highly malignant RCC cell line resulted in a dramatic suppression of tumor growth in athymic nude mice. Another defined deletion hybrid contained the region 3p12-q24 of the introduced human chromosome and failed to suppress tumorigenicity. These data functionally define a tumor suppressor locus, nonpapillary renal carcinoma-1 (NRC-1), within 3p14-p12, the most proximal region of high frequency allele loss in sporadic RCC as well as the region containing the translocation breakpoint in familial RCC. Furthermore, we provide functional evidence that NRC-1 controls the growth of RCC cells by inducing rapid cell death in vivo.

Animals↗
PubMed1994

Interphase cytogenetics in paraffin-embedded sections from renal cortical neoplasms. Correlation with cytogenetic and flow cytometric DNA ploidy analyses.

Nonisotopic in situ hybridization (ISH) was performed on archival tissue sections from six renal cortical neoplasms and corresponding normal kidney tissue using pericentrometric (alpha-satellite) probes to chromosomes 1, 3, 7, 8, 10, 11, 12, 16, and 17. The results were correlated with classic cytogenetic analyses and flow cytometric DNA ploidy findings of these neoplasms. Our study shows that intratissue and intertissue ISH spot counts were generally homogeneous in normal kidney tissue and markedly heterogenous in tumor specimens. In all cases the correlation between the DNA Index and the ISH spot numbers was statistically significant. A correlation between modal and numerical chromosomal findings by cytogenetic analysis and ISH spot counts was found in three cases and was discordant in three cases. Our results also show that chromosomes 1, 3, 7, and 17 appear to manifest more propensity for aneuploidy than chromosomes 8, 10, 11, 12, and 16. We conclude that 1) numerical chromosomal aberrations by interphase in-situ hybridization correlate with DNA ploidy analysis in these tumors; 2) certain chromosomes may be more prone to aneuploidy than others; 3) determination of monosomy by ISH is less reliable on paraffin-embedded sections; and 4) the ISH technique complements conventional cytogenetic analysis in providing more information for the determination of cytogenetic aberrations and clonal heterogeneity in solid neoplasms.

Adenocarcinoma, Clear Cell↗
PubMed1993

Lymphotoxin is an autocrine growth factor for Epstein-Barr virus-infected B cell lines.

Because human lymphotoxin (LT) was originally isolated from a lymphoblastoid cell line, we investigated the role of this molecule in three newly established Epstein-Barr virus (EBV)-infected human B cell lines. These lines were derived from acute lymphoblastic leukemia (Z-6), myelodysplastic syndrome (Z-43), and acute myelogenous leukemia (Z-55) patients who had a prior EBV infection. Each lymphoblastoid cell line had a karyotype that was different from that of the original parent leukemic cells, and all expressed B cell, but not T cell or myeloid surface markers. In all three lines, rearranged immunoglobulin heavy chain joining region (JH) bands were found, and the presence of EBV DNA was confirmed by Southern blotting. Z-6, Z-43, and Z-55 cell lines constitutively produced 192, 48, and 78 U/ml LT, respectively, as assessed by a cytotoxicity assay and antibody neutralization. Levels of tumor necrosis factor (TNF) were undetectable. Scatchard analysis revealed that all the cell lines expressed high-affinity TNF/LT receptors with receptor densities of 4197, 1258, and 1209 sites/cell on Z-6, Z-43, and Z-55, respectively. Furthermore, labeled TNF binding could be reversed by both unlabeled TNF, as well as by LT. Studies with p60 and p80 receptor-specific antibodies revealed that the three lines expressed primarily the p80 form of the TNF receptor. When studied in a clonogenic assay, exogenous LT stimulated proliferation of all three cell lines in a dose-dependent fashion at concentrations ranging from 25 to 500 U/ml. Similar results were obtained with [3H]TdR incorporation. Monoclonal anti-LT neutralizing antibodies at concentrations of 25-500 U/ml inhibited cellular multiplication in a dose-dependent manner. It is interesting that in spite of a common receptor, TNF (1,000 U/ml) had no direct effect on Z-55 cell growth, whereas it partially reversed the stimulatory effect of exogenous LT. In addition, TNF inhibited Z-6 and Z-43 cell proliferation, and its suppressive effect was reversed by exogenous LT. Both p80 and p60 forms of soluble TNF receptors suppressed the lymphoblastoid cell line proliferation and their inhibitory effect was partially reversed by LT. Our data suggest that (a) LT is an autocrine growth factor for EBV-transformed lymphoblastoid B cell lines; and (b) anti-LT antibodies, soluble TNF/LT receptors, and TNF itself can suppress the growth of lymphoblastoid cells, probably by modulating or competing with LT.(ABSTRACT TRUNCATED AT 400 WORDS)

Adult↗
PubMed1993

Replication of the A7(74) strain of Semliki Forest virus is restricted in neurons.

In neonatal mice the A7(74) and L10 strains of Semliki Forest virus (SFV) are virulent. In 3- to 4-week-old mice the L10 strain is virulent, the A7(74) strain is avirulent. Following intraperitoneal inoculation of 3- to 4-week-old mice both strains produce a transient plasma viremia. This is cleared by IgM antibodies. IgG antibodies of all subclasses are produced. The distribution of viral RNA in the brain as determined by autoradiographic analysis of in situ hybridizations shows that in all cases virus is first apparent as small foci of infected cells around cerebral capillaries. In both neonatal and 3- to 4-week-old mice infected with L10 or neonatal mice infected with A7(74), infection spreads rapidly from the original foci to infect large areas throughout the brain. Both neurons and glial cells are infected resulting in pycnosis and death of the animals. In the brains of 3- to 4-week-old mice infected with A7(74) virus there is little spread from the original perivascular foci. Again neurons and oligodendrocytes are infected but cellular destruction is minimal. The same pattern of A7(74) infection is observed in 3- to 4-week-old athymic nu/nu mice and mice with severe combined immunodeficiency, indicating that failure to spread is not related to specific immune responses. Furthermore, in nu/nu and SCID mice the small restricted foci of A7(74) infection persist. Comparison of the replication of these two viruses by electronmicroscopy shows that although A7(74) virus replicates completely in the neurons of neonatal mice, the virus is unable to bud from the neurons of 3- to 4-week-old mice and aggregates of viral RNA and capsid accumulate. We conclude that there is an age-related restriction of A7(74) replication in mouse neurons and that this restriction is not associated with the maturity of virus-specific immune responses but probably reflects age-related changes in neurons.

Animals↗
PubMed1993

Characterization of the DiFi rectal carcinoma cell line derived from a familial adenomatous polyposis patient.

The DiFi human colorectal cancer cell line was recently established from a familial adenomatous polyposis patient with extracolonic features characteristic of the Gardner syndrome. These cells have now been propagated for 150 passages in standard culture media and vessels without feeder layers or collagen coatings. They retain features of colonic epithelial cells such as surface microvilli, secretory vesicles, and desmosomes. Cytosol of DiFi cells contains a high level (502 U/mg protein) of the mucin CA 19-9. In addition, DiFi cells produce carcinoembryonic antigen, and induce tumors in athymic mice. Cytoskeleton analysis of DiFi cells by fluorescence microscopy showed a pronounced disorganization of actin cable structure. The isozyme genetic signature of DiFi cells is unique (0.01 probability of finding the same genetic signature in a different cell line), differs from that of HeLa cells, and has expressional features seen in other colorectal cell lines. The DiFi cell karyotype is tetraploid, contains many marker chromosomes, and shows numerous episomal particles. Two copies of chromosome 18 were absent, and only a single normal chromosome 17 was found. This parallels detection of allelic losses from DiFi cell DNA at loci on chromosomes 17p and 18 using molecular (cDNA) probes. DiFi cells clearly express transcripts for the c-myc proto-oncogene, the c-myb proto-oncogene, and the p53 tumor suppressor gene. Transforming growth factor beta inhibits DiFi cell growth in soft agar and suppresses c-myc expression in these cells. The value of this cell line in the study of genetic alterations in colorectal cancer is discussed.

Actins↗
PubMed1993

In vitro evaluation of calcium pectinate: a potential colon-specific drug delivery carrier.

Calcium pectinate (CaP)--the insoluble salt of pectin--can potentially be used as a colon-specific drug delivery system. The use of CaP as a carrier was based on the assumption that, like pectin, it can be decomposed by specific pectinolytic enzymes in the colon but that it retains its integrity in the physiological environment of the small bowel. The biodegradation of the carrier was characterized by monitoring the percent cumulative release of the insoluble drug indomethacin, incorporated into pectin or CaP matrices. Compressed tablets of pectin and indomethacin were analyzed for degradation in the presence of Pectinex 3XL, a typical pectinolytic enzyme mixture, and in the presence of the human colonic bacterium Bacteroides ovatus. The degradation of CaP-indomethacin tablets was assessed in the presence of Pectinex 3XL and in rat cecal contents. The release of indomethacin was significantly increased (end-time percentage cumulative release vs control) in the presence of Pectinex 3XL (89 +/- 20 vs 16 +/- 2 for CaP tablets), Bacteroides ovatus (12 and 22 vs 5.2 for pectin tablets), and rat cecal contents (61 +/- 16 vs 4.9 +/- 1.1 for CaP tablets). The weight loss of tablet mass was significantly higher (end-time dry weight vs control) in the presence of Pectinex 3XL (0 vs 75 +/- 6% of initial weight for CaP tablets). These findings indicate the potential of CaP, compressed into tablets with insoluble drug, to serve as a specific drug delivery system to the colon.

Animals↗
PubMed1993

Transformation of immortal, non-tumorigenic osteoblast-like human osteosarcoma cells to the tumorigenic phenotype by nickel sulfate.

Epidemiological studies have indirectly linked compounds of chromium, nickel and arsenic to human carcinogenesis. However, there is no evidence that metal compounds can transform human cells to the tumorigenic phenotype in culture. We show here that exposure to 36 microM NiSO4 for 48-96 h results in transformation of an immortal, nontumorigenic, osteoblast-like cell line, HOS TE85, to the tumorigenic phenotype. Continuous passaging following treatment leads to the formation of a few dense foci. The cells isolated and expanded from the foci are morphologically transformed, and form anchorage-independent colonies of the size and abundance comparable to that formed by Kirsten murine sarcoma virus transformed HOS TE85 cells. The transformed cells from tumors in nude mice, have enhanced levels of plasminogen activators and have lost the ability to form model bone matrix on extended culture in the presence of ascorbic acid and beta-glycerophosphate. A number of cell lines have been established from nude mouse tumors. Cytogenetic analysis reveals 16 marker chromosomes and an aberrant chromosome 16. This is the first report of the transformation of a human cell line to tumorigenic phenotype by a metal carcinogen.

Animals↗
PubMed1993

Clonal expansion of cells with trisomy of chromosomes 12 and X in an EBV-transformed lymphoblastoid cell line and establishment of a tumorigenic monoclonal cell line (48,XX,+X,+12).

Clonal expansion of cells with a certain abnormal chromosome constitution has been demonstrated in EBV-transformed lymphoblastoid cell lines, and a new monoclonal tumorigenic cell line (48,XX,+X,+12) has been established. Based on these data and our previous hypothesis that predisposition to tumor development could be associated with inherited susceptibility of certain chromosomes and chromosome regions to breakage, we emphasize that cytogenetic analysis of immortalized cell populations established from normal individuals and cancer patients might be of great importance for predicting development of different primary and secondary malignancies.

Animals↗
PubMed1993

Induction of chromosomal rearrangement by tumor necrosis factors produced by primary B lymphoblastoid cells derived from cancer patients.

We have previously reported the isolation of the cytotoxic factors, tumor necrosis factor-alpha (TNF-alpha), from monocytes and lymphotoxin or TNF-beta, from an established human B lymphoblastoid cell line. In the current study, we examined the production of cytotoxic factors by primary lymphoid cells derived from patients with different malignancies and correlated it with the chromosomal abnormalities in producer cells. Lymphoid cell lines were established from 78 untreated patients with breast carcinoma, 2 with cervical carcinoma, 24 with colon carcinoma, 12 with prostate carcinoma, 3 with melanoma, and the remaining from asymptomatic family members. Lymphoid cells from all 119 patients and their asymptomatic family members constitutively produced as much as 240 units/ml of TNF-beta in vitro. In contrast, TNF-alpha was produced by lymphoid cells from only 6 patients; a related cytokine with similar biological properties to TNF-beta. Sixty-five of these 119 samples were also analyzed for chromosomal abnormalities by standard cytogenetic technique. The production of TNFs was accompanied with varying degrees of chromosomal abnormalities in the cells from all patients. These included both structural and numerical abnormalities. We also examined the direct effect of TNF-beta on the induction of chromosomal abnormalities in growing cultures of both T and B lymphocytes. Our preliminary results indicate that treatment of lymphocytes with this cytokine induced chromosomal rearrangements in a dose-dependent manner. Thus, we provide for the first time both indirect and direct evidence that a soluble mediator such as TNF-beta can induce chromosomal alterations commonly associated with different types of tumors.

B-Lymphocytes↗
PubMed1992

Cytogenetics of epithelial malignant lesions.

Chromosomal abnormalities have been believed to be responsible for neoplastic transformation and tumor growth for a long time. The confirming observations are of two types: (1) primary cytogenetic alterations that are responsible for tumor initiation and (2) secondary abnormalities that are acquired late and are associated with tumor growth, heterogeneity, and metastasis. Primary chromosomal abnormalities (such as the 13q deletion in retinoblastoma, 11p deletion in Wilms' tumor, 3p anomalies in renal cell carcinoma, and 5q deletion in colorectal carcinomas) first were identified in lymphocyte cultures as constitutional defects. Later, similar types of defects were observed as tumor-specific aberrations from patients whose lymphocytes otherwise had normal chromosomes. Recently, it has become clear that classes of known cancer-related genes (dominant protooncogenes and recessive tumor-suppressor or anti-oncogenes) are located at those hot spots that are involved in neoplasia-associated chromosomal alterations. In breast carcinoma, such a specific chromosomal alteration has not been identified conclusively in lymphocyte cultures, although chromosome 1 alterations have been observed in cell lines, directly processed effusions, and primary breast tumors. Lymphocyte cultures; primary tumors; and established cell lines from breast carcinomas, colorectal carcinomas, and renal cell carcinomas were analyzed to identify (1) primary chromosomal alterations precisely and (2) secondary cytogenetic defects that are associated with these most common solid adult neoplasms. Peripheral blood analysis indicated that chromosomes 1, 17, and 18 in breast carcinomas; chromosomes 3 and 14 in renal cell carcinomas; and chromosomes 5, 12, and 17 in colorectal carcinomas were involved nonrandomly in structural anomalies in a small number of lymphocyte cells (1-4%). These chromosomal aberrations were considered primary defects because of their involvement as marker formations in tumor cells; other structural and numeric abnormalities also were found. These results indicate that lymphocyte chromosomal analysis might identify those at high risk for breast, colorectal, and renal cell carcinomas, among other malignant lesions. Such identifications could facilitate early selection for primary and secondary cancer prevention or interventional trials.

Chromosome Aberrations↗
PubMed1992

The use of molecular genetic markers to demonstrate the effect of organ environment on clonal dominance in a human renal-cell carcinoma grown in nude mice.

Transduction of the SN12C human renal-cell carcinoma line with the neoR gene produces a genetically "tagged" cell population within which individual clones can be identified if they dominate the tumor during its growth in vivo. We used this technique to determine whether the clones that dominate the primary local tumor and its metastases are the same or different when the tumor is growing in different organ sites in nude mice. The results show that clonal dominance is influenced by the organ environment in which the primary tumor grows, i.e., distinct clones dominated in the kidney, colon and subcutaneous sites. In addition, tumors grown in the orthotopic site (kidney) were all populated by the same dominant clones, and each distant visceral metastasis retained the same clonality. SN12C neoR-cells grown in an epithelial, ectopic site (colon) produced tumors with uniquely different dominant clones, and their visceral metastases retained the dominant pattern expressed by the parent tumor from which they were derived. In contrast, SN12C tumors growing subcutaneously showed a random pattern of clonal dominance in both their primary and metastatic sites. Parallel cytogenetic analyses could not demonstrate these patterns. We conclude that the organ environment significantly influences clonal dominance of human renal carcinoma and that tumor injection into orthotopic sites may produce a more reproducible selection of dominant clones.

Animals↗
PubMed1992

Trisomy 12 in Epstein-Barr virus-transformed lymphoblastoid cell lines of normal individuals and patients with nonhematologic malignancies.

Karyotypes of 36 lymphoblastoid cell lines established by Epstein-Barr virus (EBV) transformation of peripheral blood lymphocytes (PBL) of eight normal individuals and 28 patients with various nonhematologic malignancies were analyzed. In seven lines (19.4%), cells with trisomy 12 were noted, with clonality in two of these lines. In two of 11 metaphases with such trisomy, chromosome 12 was involved in structural rearrangements [t(8;12)(q12;p12) and t(12;12)(q11;q24)]. No cells with trisomy 12 were observed in phytohemagglutinin (PHA)-stimulated PBL cultures of these individuals. In 250 individuals (normal and with nonhematologic malignancies) examined in our laboratory in the last 5 years, extra copies of chromosome 12 in PHA-stimulated PBL cultures were observed in only five of 23,216 cells (0.02%). There were no cases of clonality in these samples. The frequency of an extra chromosome 12 was comparable to that of the other chromosomes except 21 and X, whose frequency of occurrence was 0.08% and 0.09%, respectively. These findings should be considered random events in PHA-stimulated PBL. On the contrary, in lymphoblastoid cell lines established by EBV transformation, trisomy of chromosome 12 was the most frequent numerical abnormality. It was observed in 64.7% of all cases with chromosome gains and therefore could not be considered a random occurrence. The specificity of this phenomenon for EBV transformation is supported by the results of cytogenetic analysis of eight lymphoblastoid cell lines established by an alternative procedure in our laboratory [1]. In 400 cells analyzed not a single cell with trisomy 12 was observed. We suggest that EBV transformation might either randomly induce formation of such cells in immortalized B-cell populations or show potentially blastomogenic cells or proneness to their formation in certain individuals who could be predisposed to develop lymphoproliferative diseases, especially chronic lymphocytic leukemia (CLL) in which trisomy of chromosome 12 is the most common alteration.

Breast Neoplasms↗