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J R Testa

Publications and source records attributed to J R Testa.

At least 109 records · Page 6Linked to original sources
PubMed1995

Molecular alterations of the AKT2 oncogene in ovarian and breast carcinomas.

The AKT2 gene is one of the human homologues of v-akt, the transduced oncogene of the AKT8 virus, which induces lymphomas in mice. In previous studies, AKT2, which codes for a serine-threonine protein kinase, was shown to be amplified and overexpressed in some human ovarian carcinoma cell lines and amplified in primary tumors of the ovary. To confirm and extend these findings, we conducted a large-scale, multicenter study of AKT2 alterations in ovarian and breast cancer. Southern-blot analysis demonstrated AKT2 amplification in 16 of 132 (12.1%) ovarian carcinomas and in 3 of 106 (2.8%) breast carcinomas. No AKT2 alteration was detected in 24 benign or borderline tumors. Northern-blot analysis revealed overexpression of AKT2 in 3 of 25 fresh ovarian carcinomas which were negative for AKT2 amplification. The difference in the incidence of AKT2 alterations in ovarian and breast cancer suggests a specific role for this gene in ovarian oncogenesis. No significant association was found between AKT2 amplification and amplification of the proto-oncogenes MYC and ERBB2, suggesting that amplification of AKT2 defines an independent subset of breast and ovarian cancers. Ovarian cancer patients with AKT2 alterations appear to have a poor prognosis. Amplification of AKT2 was especially frequent in undifferentiated tumors (4 of 8, p = 0.019), suggesting that AKT2 alterations may be associated with tumor aggressiveness.

Adenocarcinoma↗
PubMed1995

Molecular characterization of 16p deletions associated with inversion 16 defines the critical fusion for leukemogenesis.

The inversion of chromosome 16 [inv(16)] in acute myeloid leukemia (AML) is associated with a p-arm deletion in a subset of patients. The inversion results in two fusion genes: 5'-CBFB/MYH11-3' on 16p and 5'-MYH11/CBFB-3' on 16q. We have studied cells from 42 patients with inv(16) (38 patients) or t(16;16) (four patients) to define the frequency and characteristics of the deletion further. Using fluorescence in situ hybridization (FISH) with probes from cosmids, cosmid contigs, and yeast artificial chromosomes (YACs), we found that six patients with inv(16) had a deletion of between 150 and 350 kb centromeric to the p-arm inversion breakpoint cluster region (p-ibc). This region was shown to contain the 5' portion of the myosin heavy chain (MYH11) gene. YACs containing the p-ibc, which had been useful as FISH probes in the diagnosis of inv(16), detected the inversion in deletion as well as nondeletion patient cells. Thus, the deleted region identified in patients is entirely contained within the human genomic content of the YACs. Southern blot experiments using probes flanking the p-ibc indicated that the deletion removes segments within 10 kb centromeric of the p-ibc. Reverse transcription-polymerase chain reaction (RT-PCR) using primers from the 5' region of CBFB and the 3' region of MYH11 (distal to the p-ibc) produced the 5'-CBFB/MYH11-3' chimeric transcript in inv(16)/del patients. These data confirm that the 5'-CBFB/MYH11-3' chimeric transcript, rather than the reciprocal 5'-MYH11/CBFB-3', is the critical product for chromosome 16-related leukemogenesis.

Acute Disease↗
PubMed1995

Cloning and regional assignment of the human myosin heavy chain 12 (MYH12) gene to chromosome band 15q21.

Sequences encoding 1,235 bp of the human myosin heavy chain 12 (MYH12) gene have been cloned from a human brain cDNA library by PCR amplification. The human sequence is 95.8% identical to the mouse sequence at the amino acid level, indicating that the MYH12 gene has been evolutionarily well conserved. Somatic cell hybrid analysis and in situ hybridization place the MYH12 gene on human chromosome 15, at band q21, and extend distally the known region of chromosome 15 linkage homology on mouse chromosome 9.

Amino Acid Sequence↗
PubMed1995

A microdissection library of the rat renal carcinoma gene region.

Predisposition to hereditary renal carcinoma in the Eker rat involves a mutation of a putative tumor suppressor gene within chromosome band 10q12. We describe the identification of three unique polymorphic sequences in the vicinity of this locus following the microdissection, construction and characterization of a region-specific DNA library for rat chromosome band 10q12.

Animals↗
PubMed1995

Chromosomal localization of a gene, GF1, encoding a novel zinc finger protein reveals a new syntenic region between man and rodents.

The Gfi1 gene encodes a zinc finger protein which binds DNA and is involved in transcriptional regulation. Gfi1 was assigned to the central portion of mouse Chr 5 by interspecific backcross mapping and to human chromosome band 1p22 and rat chromosome band 14p22 by fluorescence in situ hybridization (FISH). Comparative mapping data presented here describes a new syntenic region between man and rodents.

Animals↗
PubMed1995

Retroviral-like sequences specifically expressed in the rat ovary detect genetic differences between normal and transformed rat ovarian surface epithelial cells.

We have identified a repetitive DNA element in the rat genome that we demonstrate to be suitable to detect molecular genetic differences between normal and malignantly transformed rat ovarian surface epithelial cells by genome scanning. With fluorescence in situ hybridization, we show that these elements are widely distributed in the rat genome, and that a member of this family is present within a homogeneously staining chromosomal region of tumorigenic rat ovarian surface epithelial cells. The homogeneously staining chromosomal region infers the presence of an amplified DNA sequence in the tumor cells, and we provide molecular evidence for an amplicon in this DNA by genome scanning using a probe related to these elements. Sequence analysis revealed that these elements have the structural features of retroviral DNA. We show that they are transcriptionally active in the rat ovary, but not in a wide range of other normal rat tissues. In situ hybridization to ovarian tissue sections revealed that the elements are expressed in granulosa and theca interna cells and in the surface epithelial cells adjacent to preovulatory follicles. Based on this property, we refer to these retroviral-like elements as ovary-specific transcribed sequences. Partial sequence analysis of multiple members of this family and the range in transcript sizes strongly suggest that multiple members of this retrovirus-like family are transcriptionally active. We speculate that binding by one or a combination of ovary-specific transcription factors to regulatory sequences within the genomic ovary-specific transcribed sequences units contributes to the tissue specificity of their expression.

Animals↗
PubMed1994

Predisposition to renal carcinoma in the Eker rat is determined by germ-line mutation of the tuberous sclerosis 2 (TSC2) gene.

Genetic predisposition to neoplasia often involves tumor suppressor genes. One such model of hereditary renal carcinoma was described in the rat by Eker. These tumors share morphologic similarities with human renal cancer. Linkage analysis localized the inherited mutation to rat chromosome band 10q12. This region is syntenic with human chromosome band 16p13.3, the site of the tuberous sclerosis 2 (TSC2) gene. A specific rearrangement of the rat homologue of TSC2 was found to cosegregate with carriers of the predisposing mutation. Tumors with or without loss of heterozygosity expressed only the mutant allele, consistent with the two-hit hypothesis. This mutation gave rise to an aberrant transcript that deletes the 3' end normally containing a region of homology with the catalytic domain of rap1GAP.

Animals↗
PubMed1994

p16 alterations and deletion mapping of 9p21-p22 in malignant mesothelioma.

To determine whether p16 is altered in human malignant mesothelioma (MM), molecular analysis of multiple 9p loci was performed on 40 cell lines and 23 primary tumors from 42 MM patients. We identified homozygous deletions of p16 in 34 (85%) cell lines and a point mutation in 1 line. Down-regulation of p16 was observed in 4 of the remaining cell lines, 1 of which displayed a DNA rearrangement of p16. Homozygous deletions of p16 were identified in 5 of 23 (22%) primary tumors; no mutations or rearrangements were found in these specimens. Four cell lines displayed a single homozygous deletion proximal to or distal to p16; 4 others had 2 nonoverlapping deletions, one involving p16 and the other involving a region proximal to this locus. These data indicate that alterations of p16 are a common occurrence in MM cell lines and, to a lesser extent, in primary tumors. Furthermore, deletions of 9p21-p22 outside of the p16 locus may reflect the involvement of other putative tumor suppressor genes that could also contribute to the pathogenesis of some MMs.

Base Sequence↗
PubMed1994

Spontaneous transformation of rat ovarian surface epithelial cells results in well to poorly differentiated tumors with a parallel range of cytogenetic complexity.

We previously used rat ovarian surface epithelial cells subjected to repetitious growth in vitro to provide experimental evidence in support of a role for incessant ovulation in the etiology of ovarian cancer. We have now initiated a series of 30 independent rat ovarian surface epithelial cell lines. This report describes findings in eight of the cell lines that, based on tumor formation in athymic mice, have undergone malignant transformation. Each of the tumors exhibited chromosomal alterations. Two well to moderately differential tumors had only one or two cytogenetic changes, and they had in common the presence of numerical gains. Each of five poorly differentiated tumors had complex karyotypes with three to eight clonal aberrations, prominent among them being unbalanced rearrangements and numerical losses. Several poorly differentiated tumors also had marker chromosomes, double minutes, or homogeneously staining regions. These findings demonstrate that the malignant tumors produced by spontaneously transformed rat ovarian surface epithelial cell lines range in degree of differentiation, which is paralleled by the cytogenetic complexity. Thus, this model system may fill an important void in future efforts to define the genetic basis of common epithelial tumors of the ovary and many features characteristic of these neoplasms.

Adenocarcinoma↗
PubMed1994

Deletion mapping of the short arm of chromosome 3 in human malignant mesothelioma.

Previous cytogenetic investigations have revealed frequent deletions and other unbalanced structural rearrangements of 3p in human malignant mesothelioma. We have performed a restriction fragment length polymorphism analysis by using the polymerase chain reaction and primer sets for seven DNA markers to examine loss of heterozygosity (LOH) from 3p in 25 malignant mesotheliomas. Among 24 cases informative at one or more 3p loci, 15 (62.5%) exhibited LOH with at least one marker. Deletion mapping in these tumors indicates that the common region of chromosomal loss resides within band 3p21, in the vicinity of the D3F15S2 locus. These results suggest that allelic loss from 3p21 is a frequent occurrence in malignant mesothelioma and that one or more putative tumor suppressor genes at this site contribute to the pathogenesis of this malignancy.

Alleles↗
PubMed1994

Cytogenetic analysis of 63 non-small cell lung carcinomas: recurrent chromosome alterations amid frequent and widespread genomic upheaval.

A detailed cytogenetic analysis of 63 non-small cell lung carcinomas (NSCLCs) was carried out for identification of recurrent chromosomal alterations. Most specimens displayed very complex karyotypes with multiple numerical and structural changes (median number, 31). Losses of chromosomes 9 (65% of cases) and 13 (71%) were the most frequent numerical changes. Loss of the Y was often observed in tumors from males. Gain of chromosome 7 was also frequent (41%). Chromosome arms 1p, 1q, 3p, 3q, 6q, 7q, 8q, 9p, 11q, 17p, and 19q were particularly prone to rearrangement. The chromosome arm most often contributing to losses was 9p (79%). Other arms that were frequently lost included 3p, 6q, 8p, 9q, 13q, 17p, 18q, 19p, 21q, 22q, and the short arm of each acrocentric chromosome. The percentage of cases with loss of 3p was significantly higher in squamous cell carcinomas (94%) than in adenocarcinomas (60%). There was also a statistically significant increase in the proportion of cases with gains of 1q, 7p, and 11q in adenocarcinomas compared to squamous cell carcinomas. Several recurrent isochromosomes and unbalanced exchanges were found. Among these was i(5p), which was observed in nine tumors, eight of which displayed adenomatous features. An i(8q) was identified in six cases, including five adenocarcinomas. Double minutes and/or homogeneously staining regions were seen in seven specimens. These data indicate that numerous chromosome alterations contribute to the pathogenesis of NSCLC and that, amid this widespread genomic disarray, recurrent abnormalities exist that could have biological and clinical implications.

Adult↗
PubMed1994

Chromosomal localization of the genes encoding the kinetochore proteins CENPE and CENPF to human chromosomes 4q24-->q25 and 1q32-->q41, respectively, by fluorescence in situ hybridization.

CENPE and CENPF are human kinetochore proteins of 312 and approximately 400 kDa, respectively. As part of an effort to characterize the functions of these two proteins, we have used their respective cDNAs to map their human chromosomal locations by fluorescence in situ hybridization. The gene that encodes CENPE, a kinetochore-associated motor protein that is postulated to segregate chromosomes during mitosis, maps to chromosome 4q24-->q25. The CENPF gene, which encodes a structural protein of the kinetochore, maps to chromosome 1q32-->q41 within close proximity to the genetic locus that is linked to Van der Woude syndrome.

Chromosomal Proteins, Non-Histone↗
PubMed1994

Molecular cloning and localization of the human GAX gene to 7p21.

The GAX homeobox gene is expressed in the cardiovascular tissues of the adult rat, including heart, lung, kidney, and blood vessels. In the vasculature it is specifically expressed in quiescent smooth muscle cells, but its expression is rapidly down-regulated when these cells are stimulated to proliferate with mitogens. Since vascular smooth muscle cell proliferation is important in the pathology of blood vessel disorders, the human GAX gene was isolated and characterized. The human GAX cDNA was obtained by an anchored-PCR approach using cDNA templates from cardiovascular tissues and amplification primers designed from sequence information of the rat GAX cDNA and the homeodomain-containing exon of the human GAX gene. The human and rat GAX gene coding sequences are 98% conserved at the amino acid level and 83% conserved at the nucleotide level. Similar to rat, the human homolog contains a CAX trinucleotide repeat N-terminal to the homeodomain that encodes for a stretch of 17 consecutive histidine or glutamine residues. The human GAX locus was mapped by fluorescence in situ hybridization to the short arm of chromosome 7 at band p21. The human cDNA sequence will be useful for analyses of GAX gene expression in cardiovascular diseases.

Amino Acid Sequence↗
PubMed1994

Ability to culture resectable non-small cell lung carcinomas is correlated with recurrence.

Present clinicopathologic staging of non-small cell lung cancer is limited in its ability to provide more than a general prognostic estimate in patients with lung cancer who have resectable disease. This study was performed to identify whether the ability to adapt tumor tissue from resectable (stage I to IIIa) non-small cell lung cancer was associated with a poorer prognosis and an increased risk for early tumor recurrence. We attempted to culture a tumor specimen obtained from 90 patients with resectable non-small cell lung cancer. We used a culture medium conditioned by exposure to the lung cancer cell line A549-1, a known producer of autocrine lung cancer growth factors, and provided tumor colony scaffolding using a feeder layer of inactivated fibroblasts, and found these measures improved tumor culture yields. Twenty-two cell lines were obtained, a success rate of 24.4%. Tumor recurrences were more common (79%) among the culture-positive patients than among the culture-negative patients (37.5%; p < 0.002). For all patients, survival at 19 months in the culture-positive patients was 50.0%, compared with 83.6% in the culture-negative patients (p < 0.005). The median survival for the culture-positive patients was 15 months, versus 21.7 months for the culture-negative patients (p < 0.004). The establishment of a culture was a predictor of shortened survival for patients with stage I disease. In patients with stage I disease, survival at 19 months was 54.5% for the culture-positive patients, versus 89% for the culture-negative patients (p < 0.02).(ABSTRACT TRUNCATED AT 250 WORDS)

Carcinoma, Non-Small-Cell Lung↗
PubMed1993

Prolonged subcutaneous administration of recombinant alpha 2b interferon in patients with previously untreated Philadelphia chromosome-positive chronic-phase chronic myelogenous leukemia: effect on remission duration and survival: Cancer and Leukemia Group B study 8583.

We investigated whether recombinant alpha 2b interferon (r alpha 2bIFN) would reduce the proportion of bone marrow Philadelphia chromosome (Ph) cells in chronic-phase chronic myelogenous leukemia (CML) by treating 107 previously untreated patients daily with r alpha 2bIFN at 5 x 10(6)IU/m2 subcutaneously. Patients with complete remission, partial remission, or partial hematologic remission received treatment until progression; those with progressive disease were taken off study and observed for survival. Sixty-three (59%) of the patients achieved at least a partial hematologic remission (24 complete remissions and 39 partial remissions). The median time to response for the 63 responders was 3.4 months, with a median duration of remission of 52 months and with 81% of responders continuing in remission beyond 12 months. The median survival for the 107 patients was 66 months. Of 78 patients with cytogenetic follow-up data, 31 (40%) achieved a partial cytogenetic response (n = 17) or a complete cytogenetic response (n = 14). The percentage of cytogenetic responders among all patients was 29% (31 of 107 patients). The median time to first cytogenetic response was 9 months. A major dose reduction of r alpha 2bIFN (> or = 50%) was required at some time during treatment in 38% of patients, 26% required 10% to 49% dose reductions, and 36% had minor dose reductions of < or = 10%. No association was observed between dose received and the attainment of a cytogenetic response. None of the usual prognostic factors (sex, race, performance status, weight loss, time from diagnosis to treatment, hepatosplenomegaly, age, symptoms, hemoglobin, or platelet, blast, basophil, or white blood cell count) were significantly related to survival. These data provide confirmation that major cytogenetic responses to prolonged administration of subcutaneous r alpha 2bIFN occur in 20% to 38% (95% confidence interval) of chronic-phase Ph-positive patients. Although it is hypothesized that patients achieving major cytogenetic responses to r alpha 2bIFN should have prolonged remission duration and survival compared with nonresponders, analyses of the effect of cytogenetic responders by both "landmark" and time-dependent covariate techniques fail to provide statistically significant evidence for an effect of cytogenetic response on remission duration or survival. This may be due in part to an effect size insufficiently large to be detected with the number of patients treated in this study. Thus, confirmation of remission duration or survival benefit, if any, of r alpha 2bIFN therapy in Ph-positive chronic-phase CML must await the outcome of randomized trials comparing IFN with conventional agents.

Adolescent↗