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Timothy J McDonnell

Publications and source records attributed to Timothy J McDonnell.

At least 37 records · Page 2Linked to original sources
PubMed2003

Inhibition of JAK3 induces apoptosis and decreases anaplastic lymphoma kinase activity in anaplastic large cell lymphoma.

Signal transducer and activator of transcription 3 (STAT3), normally activated by Janus kinase (JAK) in response to cytokine stimulation, has been shown to have oncogenic potential. In addition to JAK, recent data suggest that STAT3 can also be activated by other proteins such as the aberrant fusion protein, NPM-ALK, which is expressed in a subset of systemic anaplastic large cell lymphoma (ALCL). In this study, we investigated the possible role of JAK in activating STAT3 in ALCL using two ALK-positive ALCL cell lines, Karpas 299 and SU-DHL-1. At the steady state, JAK3 showed detectable tyrosine phosphorylation by immunoprecipitation. Treatment with AG490, a JAK inhibitor, decreased but did not completely abrogate tyrosine phosphorylation of JAK3 and STAT3 in a concentration-dependent manner. Similar results were obtained using two other inhibitors of JAK3, WHI-P131 and WHI-P154. These biochemical changes were associated with apoptosis in both cell lines that was coupled with activation of caspase 3 and decreased bcl-xL and bcl-2. Cell cycle analysis revealed a decrease in the S phase, which may be attributed to cyclin D3 downregulation and p21(waf1) upregulation. Importantly, the tyrosine kinase activity of NPM-ALK, as assessed by an in vitro assay, decreased with increasing concentrations of AG490. Our findings highlight the importance of JAK3 in activating STAT3 in ALCL, and that NPM-ALK-mediated activation of STAT3 is influenced by the functional status of JAK3.

Anaplastic Lymphoma Kinase↗
PubMed2003

Translation inhibitors sensitize prostate cancer cells to apoptosis induced by tumor necrosis factor-related apoptosis-inducing ligand (TRAIL) by activating c-Jun N-terminal kinase.

Tumor necrosis factor-related apoptosis-inducing ligand (TRAIL) induces apoptosis in several human tumors both in vitro and in vivo, however, some tumors remain resistant for poorly understood reasons. Using a quantitative DNA fragmentation assay for apoptosis, we have shown that human prostate cancer cells are resistant to a wide range of TRAIL doses up to 500 ng/ml. However, translation inhibitors, such as anisomycin, cycloheximide, emetine, harringtonine, and puromycin, unlike several transcription inhibitors, significantly sensitized PC3-neomycin (PC3-neo) cells to TRAIL-induced apoptosis. These effects were inhibited in PC3 cells engineered to express bcl2 (PC3-bcl2). Translation inhibitors led to activation of c-Jun N-terminal kinase (JNK), which plays a role in this sensitization process because inhibition of JNK activation resulted in protection against TRAIL plus translation inhibitor-induced apoptosis. JNK activation may be required for this process, but it is not sufficient because activation of JNK using an MEKK2 expression vector did not mimic the sensitizing effect of translation inhibitors. Other stress-activated protein kinases, such as ERK and p38, play an insignificant role in determining the apoptotic sensitivity. We conclude that activation of JNK is required for sensitization of PC3 cells to TRAIL-induced apoptosis by translation inhibitors in cells that are otherwise TRAIL-resistant. However, in addition to JNK activation, other aspects of translation inhibition such as the suppressed activity of apoptosis-inhibitory proteins or activation of other signal transduction pathways must also be involved.

Activating Transcription Factor 2↗
PubMed2003

Expression of STAT3 and its phosphorylated forms in mantle cell lymphoma cell lines and tumours.

The pathogenesis of mantle cell lymphoma (MCL) is incompletely understood, although cyclin D1 overexpression leading to deregulated cell proliferation is probably important. Recent data suggest that interleukin (IL)-10 can increase the proliferative activity of MCL cells. STAT3 (signal transducer and activator of transcription 3) is the signal transducer of IL-10, and STAT3 is activated by phosphorylation. The hypothesis of this study is that STAT3 is activated in MCL. The expression of the two phosphorylated (i.e. active) forms of STAT3, pSTAT3-tyr (phosphorylated at the tyrosine(705) residue) and pSTAT3-ser (phosphorylated at the serine(727) residue), was assessed in four MCL cell lines and 12 MCL tumours using western blots and/or immunofluorescence staining techniques. All MCL cell lines expressed STAT3, but only one had detectable pSTAT3-tyr and none had pSTAT3-ser. Addition of IL-10 rapidly resulted in expression of pSTAT3-tyr but not pSTAT3-ser. All eight cases of frozen MCL tumours examined had detectable pSTAT3-tyr and pSTAT3-ser. Immunofluorescence studies using four formalin-fixed, paraffin wax-embedded MCL tumours demonstrated cytoplasmic localization of STAT3, as opposed to the nuclear localization of the pSTAT3 species. In conclusion, these findings provide evidence that STAT3 is constitutively activated in MCL, supporting the concept that STAT3 signalling may be important in the pathogenesis of these tumours.

Blotting, Western↗
PubMed2003

Expression of Mcl-1 in mantle cell lymphoma is associated with high-grade morphology, a high proliferative state, and p53 overexpression.

Mantle cell lymphoma (MCL) is a distinct type of B-cell non-Hodgkin's lymphoma characterized by the t(11;14)(q13;q32) and cyclin D1 overexpression. Defects in apoptosis may contribute to pathogenesis. This study evaluated the expression of the anti-apoptotic protein Mcl-1 in two MCL cell lines and five frozen MCL tumours (four small-cell, one blastoid/large-cell) using western blot analysis. Mcl-1 expression was also assessed in 36 formalin-fixed, paraffin wax-embedded MCL tumours (24 small-cell, 12 blastoid/large-cell) by immunohistochemistry. Western blot analysis revealed the expected 37 kD protein product in both MCL cell lines and in five frozen tumours, with the blastoid case having the highest expression level. Using a cut-off of >10% immunolabelled cells for Mcl-1, it was found that 12 of 36 MCL tumours were positive. Mcl-1-positive tumours had a higher frequency of blastoid/large-cell morphology (8/12 versus 4/24, p = 0.009), p53 overexpression (3/10 versus 1/23, p = 0.04), and higher Ki67 immuno-labelling (p = 0.002). It is concluded that expression of Mcl-1 in MCL is heterogeneous. A relatively high level of Mcl-1 expression correlates with high-grade morphology, a high proliferative state, and p53 overexpression.

Adult↗
PubMed2003

BCL-2 family proteins in peripheral T-cell lymphomas: correlation with tumour apoptosis and proliferation.

The present study investigated expression levels of the anti-apoptotic proteins BCL-2, BCL-XL and MCL-1 and the pro-apoptotic proteins BAX and BCL-XS in a series of 112 peripheral T-cell lymphomas (PTCLs) classified according to the WHO classification. Using immunohistochemical methods and a 10% cut-off, each protein was detected in a subset of PTCLs: BCL-2 in 46%, BCL-XS in 49%, BAX in 57%, BCL-XL in 57%, and MCL-1 in 65%. The mean percentage of positive cells for these proteins varied significantly among the PTCL types. Only two types of PTCL, ALK-positive anaplastic large cell lymphoma (ALCL) and enteropathy-type T-cell lymphoma, had a distinctive pattern of expression; all were BCL-2-negative and MCL-1-positive. The mean percentage of BAX-positive and BCL-XS-positive tumour cells was higher in ALK-positive ALCL than in ALK-negative ALCL or other types of PTCL (p = 0.06 and p = 0.01, respectively, Kruskal-Wallis test). MCL-1 was detected significantly more frequently (p = 0.01, chi-square test) and at higher levels (p = 0.0001, Kruskal-Wallis test) in ALK-positive ALCL and ALK-negative ALCL than in other PTCL types. The apoptotic rate, evaluated by the TUNEL assay, correlated inversely with BCL-2 expression (p = 0.035). The proliferation index, assessed by the MIB-1 antibody, correlated with expression levels of MCL-1 (R = 0.42, p = 0.003), BCL-2 (R = 0.32, p = 0.027), BAX (R = 0.33, p = 0.014), and BCL-XL (R = 0.34, p = 0.015) (Spearman rank). In conclusion, BCL-2 family proteins are expressed by a subset of PTCLs and their levels correlate with some histological types, apoptotic rate, and proliferation index. Expression of these proteins may explain the poor response of many types of PTCL to standard chemotherapy. These proteins may also provide novel targets for experimental therapy.

Anaplastic Lymphoma Kinase↗
PubMed2003

Regulation of Bcl-2 expression by dihydrotestosterone in hormone sensitive LNCaP-FGC prostate cancer cells.

PURPOSE: Up-regulation of the anti-apoptotic bcl-2 proto-oncogene is associated with androgen independent prostate cancer progression. This observation suggests that the expression of bcl-2 may be negatively regulated by androgens in prostate cancer cells. MATERIALS AND METHODS: The expression of the proto-oncogene bcl-2 was assessed in the hormone sensitive prostate cancer cell line LNCaP-FGC in the presence and absence of a physiological concentration of 1 nM. dihydrotestosterone (DHT). Sequence analysis of the bcl-2 promoter regions demonstrated the presence of 2 potential androgen response elements. Transient transfections of luciferase reporter constructs containing these potential androgen response elements into LNCaP-FGC cells in the presence and absence of DHT were performed. Steady-state transcripts of bcl-2 were assessed using RNase protection assays. RESULTS: Cells cultured in charcoal stripped serum in the presence of DHT resulted in down-regulation of bcl-2 protein. Down-regulation of bcl-2 protein and mRNA by DHT was inhibited by coincubation with the antiandrogen bicalutamide, an agent that competitively inhibits binding of DHT to androgen receptor. Luciferase reporter constructs containing candidate androgen response elements were transrepressed in the presence of DHT. Bcl-2 mRNA was also down-regulated by DHT and this down-regulation could not be abolished by cycloheximide. CONCLUSIONS: Together these results suggest that the suppression of bcl-2 expression by DHT in hormone sensitive LNCaP-FGC prostate cancer cells occurs directly. In addition, these results provide a possible mechanistic basis for the up-regulation (derepression) of bcl-2 observed in hormone independent prostate cancers.

Dihydrotestosterone↗
PubMed2003

Characterization of 4 mantle cell lymphoma cell lines.

CONTEXT: Mantle cell lymphoma (MCL) is a distinct type of B-cell non-Hodgkin lymphoma characterized by t(11;14)(q13;q32) and cyclin D1 overexpression. The pathogenesis of MCL has not been comprehensively studied, which can be attributed in part to the paucity of well-characterized MCL cell lines. OBJECTIVES: We collected 4 previously developed MCL cell lines and performed extensive characterization, including the susceptibly of these cell lines to transduction by adenovirus vectors. Our aim was to facilitate the establishment of an in vitro model that can be reliably used to study the pathogenesis of MCL. METHODS: Standard techniques were used to compare the morphologic, immunophenotypic, and cytogenetic features of the 4 cell lines. In addition, Western blotting was used to investigate the presence of several cell cycle- and apoptosis-related proteins. TP53 DNA sequencing was also performed on the cell lines. The adenoviral transduction efficiency was assessed using an adenoviral vector carrying the gene encoding for the green fluorescence protein (Ad-GFP). RESULTS: All cell lines demonstrated evidence of t(11;14)(q13;q32) and overexpression of cyclin D1. Cyclin D2 was not detectable in all cell lines, whereas cyclin D3 was weakly expressed in JeKo-1 and SP-53. Other abnormalities of the cell cycle G1 phase regulatory pathway were detected, including loss of expression of p53 (JeKo-1) and p16(INK4a) (SP-53 and Granta 519), as well as TP53 mutation (Mino). All cell lines express high levels of cyclin E, c-Myc, Bcl-2, Bax, Bcl-x(L), and Mcl-1. Retinoblastoma protein is hyperphosphorylated in all cell lines. With the exception of Mino, MCL cell lines are highly transducible with adenoviral vectors. CONCLUSION: These cell lines are representative of MCL and can be used as an in vitro model to further explore the pathogenesis of this disease. The susceptibility of these cell lines to gene transfer provides opportunities to evaluate the importance of various oncogenes and tumor suppressor genes that may have an impact on developing effective therapeutic regimens for MCL.

Adenoviridae↗
PubMed2003

Induction of p53-regulated genes and tumor regression in lung cancer patients after intratumoral delivery of adenoviral p53 (INGN 201) and radiation therapy.

PURPOSE: We designed a prospective single arm Phase II study to evaluate the feasibility and mechanisms of apoptosis induction after Ad-p53 (INGN 201) gene transfer and radiation therapy in patients with non-small cell lung cancer. EXPERIMENTAL DESIGN: Nineteen patients with nonmetastatic non-small cell lung cancer who were not eligible for chemoradiation or surgery were treated as outpatients with radiation therapy to 60 Gy over 6 weeks in conjunction with three intratumoral injections of Ad-p53 (INGN 201) on days 1, 18, and 32. RESULTS: Seventeen of 19 patients completed all planned radiation and Ad-p53 (INGN 201) gene therapy as outpatients. The most common adverse events were grade 1 or 2 fevers (79%) and chills (53%). Three months after completion of therapy, pathologic biopsies of the primary tumor revealed no viable tumor (12 of 19 patients, 63%), viable tumor (3 of 19 patients, 16%), and not assessed (4 of 19 patients, 21%). Computed tomography and bronchoscopic findings at the primary injected tumor revealed complete response (1 of 19 patients, 5%), partial response (11 of 19 patients, 58%), stable disease (3 of 19 patients, 16%), progressive disease (2 of 19 patients, 11%), and not evaluable (2 of 19 patients, 11%). Quantitative reverse transcription-PCR analysis of the four p53 related genes [p21 (CDKN1A), FAS, BAK, and MDM2] revealed that Bak expression was increased significantly 24 h after Ad-p53 (INGN 201) injection and levels of CDKN1A and MDM2 expression were increased over the course of treatment. CONCLUSIONS: Intratumoral injection of Ad-p53 (INGN 201) in combination with radiation therapy is well tolerated and demonstrates evidence of tumor regression at the primary injected tumor. Serial biopsies of the tumor suggest that BAK gene expression is most closely related to Ad-p53 (INGN 201) gene transfer.

Adenoviridae↗
PubMed2003

Epidermal growth factor receptor, cyclooxygenase-2, and BAX expression in the primary non-small cell lung cancer and brain metastases.

PURPOSE: The purpose is to identify biological markers that predict brain metastasis and treatment outcome in non-small cell lung cancer (NSCLC). EXPERIMENTAL DESIGN: Samples were obtained from the primary tumors, lymph nodes, and brain metastases of 29 patients with NSCLC who had undergone resection of both the pulmonary tumors and the brain lesions. Samples from 29 patients matched for age, sex, and histology whose pulmonary tumors were resected served as controls. Samples were stained with H&E as well as immunohistochemical stains for epidermal growth factor receptor (EGFR), cyclooxygenase 2 (COX-2), and BAX. Comparisons were made between patients with and without brain metastasis. Independent investigators determined the percentage of positive cells. RESULTS: There was positive correlation in expression of all three biomarkers between primary lung tumors and lymph node metastases. Significantly higher levels of EGFR were found in lymph node metastases in the control group (P = 0.0147). COX-2 expression in brain lesions correlated with expression in primary tumors (P = 0.023). BAX levels were lower in poorly differentiated tumors in lymph node metastases in the control group (P = 0.01) and in brain metastases (P = 0.045). Low EGFR expression and high COX-2 expression in lymph node metastasis were associated with poorer treatment outcome. CONCLUSIONS: Expression of EGFR, COX-2, and BAX in primary lung tumors did not differ between patients with brain metastases from NSCLC and those without brain metastases. These three biomarkers cannot be used to predict brain metastasis. Studies of other biomarkers are under way in an effort to predict brain metastasis among patients with NSCLC.

Adult↗
PubMed2003

Expression of p27(Kip1) and c-Jun activation binding protein 1 are inversely correlated in systemic anaplastic large cell lymphoma.

PURPOSE: p27(Kip1)(p27) is a universal cyclin-dependent kinase inhibitor that inhibits cell cycle transition from G(1) to S phase and is primarily regulated at the post-transcriptional level via the ubiquitin-proteasome pathway. In vitro data suggest that p27 degradation may be accelerated by the c-Jun activation domain binding protein-1 (JAB1), originally identified as a coactivator of the gene regulatory AP-1 proteins. We assessed p27 and JAB1 in systemic anaplastic large cell lymphoma (ALCL), a group of tumors in which a substantial subset overexpresses anaplastic lymphoma kinase (ALK). EXPERIMENTAL DESIGN: The study included 5 ALK-positive ALCL cell lines, namely Karpas 299, JB-6, SR-786, SU-DHL1, and TG-S1, and 66 ALCL tumors (24 ALK positive and 42 ALK negative). The cell lines were analyzed by Western blot methods, and the tumors were assessed immunohistochemically. RESULTS: SU-DHL1 and TG-S1 cells were positive for p27 and negative for JAB1, whereas SR-786 and JB-6 cells were positive for JAB-1 but negative for p27. Karpas 299 expressed p27 at relatively low levels and JAB1 at high levels. Using a 10% cutoff, p27 was positive in 12 of 66 (18.2%) ALCL tumors (5 ALK positive and 7 ALK negative), whereas JAB1 was detected in 47 of 53 (88.7%) tumors (15 ALK positive and 32 ALK negative) assessed. p27 and JAB1 expression were inversely correlated (Spearman r = -0.27, P = 0.03). For 54 ALCL patients with complete follow-up, and in separate analyses of patients with ALK-positive or -negative tumors, p27 expression correlated with poorer prognosis. CONCLUSIONS: p27 is absent or expressed at low levels in most ALCL tumors and inversely correlates with JAB1. These findings suggest that JAB1-mediated degradation of p27, allowing cell cycle progression, may play a role in the pathogenesis of ALCL.

Adult↗
PubMed2003

Suppression of human prostate cancer cell growth by ciprofloxacin is associated with cell cycle arrest and apoptosis.

For hormone resistant prostate cancer (HRPC), chemotherapy is used but the mortality is 100% with a mean survival time of 7-8 months. Our previous studies have shown the chemotherapeutic effect of ciprofloxacin in bladder cancer. At doses 50-400 micro g/ml ciprofloxacin, the concentrations that are normally achieved at doses currently used for the treatment of anti-bacterial infections, inhibited bladder cancer cell growth and induced S/G2M arrest with modulation of key cell cycle regulatory genes and ultimately activated apoptotic processes. In this study, we investigated the effect of ciprofloxacin on androgen independent prostate carcinoma, PC3 cells and compared our results with non-tumorigenic prostate epithelial cells. The main advantage of this fluroquinolone antibiotic is its relative non-toxicity as compared to current chemotherapy, which is not very effective, for the treatment of advanced hormone resistant prostate cancer. PC3 cells as well as normal prostate epithelial cells (MLC8891) were treated with 25-400 micro g/ml ciprofloxacin, and cell counting was done during 3 days of treatment. The cell death was determined using DAPI staining of cell nuclei, 7AAD-staining followed by flow cytometric analysis as well as by activation of caspase-3, a member of the ICE family of enzymes involved in the apoptotic cascade. The cell lysates were analyzed by immunoblotting techniques for the expression of key genes targeted by ciprofloxacin (p21WAF1, Bax and Bcl-2). Translocation of bax was visualized using a fluorescence staining procedure followed by laser confocal microscopic imaging. Treatment of prostate cancer cells with ciprofloxacin resulted in a dose- and time-dependent inhibition of cell growth (70-100% with 50-400 micro g/ml of the drug). There was a concomitant induction of cell cycle arrest at the S and G2/M phases of the cell cycle as well as induction of apoptosis. The CDK inhibitor p21WAF1 was down-regulated as early as 12 h following ciprofloxacin treatment (100-200 micro g/ml for 12-24 h). There was a significant increase in the Bax/Bcl-2 ratio with translocation of Bax, a pro-apoptotic protein, to mitochondria with concomitant activation of caspase 3. These results suggest the potential usefulness of the fluroquinolone, ciprofloxacin as a chemotherapeutic agent for advanced prostate cancer. The fluroquinolone ciprofloxacin showed anti-proliferative and apoptosis inducing activity on prostate cancer cells but not on non-tumorigenic prostate epithelial cells. These effects of ciprofloxacin were mediated by cell cycle arrest at S-G2/M phase of the cell cycle, Bax translocation to mitochondrial membrane and by increasing the Bax/Bcl-2 ratio in PC3 prostate cancer cells. Based on our in vitro results, further in-depth in vivo animal or human investigations are warranted.

Anti-Infective Agents↗
PubMed2002

BCL-2 expression in Hodgkin and Reed-Sternberg cells of classical Hodgkin disease predicts a poorer prognosis in patients treated with ABVD or equivalent regimens.

To determine the clinical significance of BCL-2 expression in Hodgkin-Reed-Sternberg (HRS) cells of classical Hodgkin disease (cHD), we correlated its expression with presenting clinical and laboratory features and failure-free survival (FFS). Eligible patients were untreated and negative for HIV-1; they had biopsy-proven cHD. BCL-2 expression was determined immunohistochemically in available pretreatment tissue biopsy specimens without knowledge of clinical outcome. Tumors were considered positive if any HRS cells expressed BCL-2. We identified 707 patients with cHD, whose median age was 30 years; 54% were men. HRS cells expressed BCL-2 in 359 (65%) of 551 nodular sclerosis, 67 (47%) of 143 mixed cellularity, and all 5 lymphocyte depletion. For all patients, the 5-year FFS was 74% versus 84% for tumors with versus without BCL-2 expression (P =.0016, by log-rank test). For the 412 patients treated with adriamycin, bleomycin, vinblastine, and dacarbazine (ABVD) or equivalent regimens, the 5-year FFS for tumors with versus without BCL-2 expression was 74% versus 88% (P =.001, by log-rank test); for the 233 patients with Ann Arbor stage I or II, FFS was 84% versus 92% (P =.04, by log-rank test); and for the 179 patients with Ann Arbor stage III or IV, FFS was 62% versus 81% (P =.006, by log-rank test). Multivariate analysis confirmed that BCL-2 expression is independently associated with inferior FFS along with age 45 or older, Ann Arbor stage IV, low serum albumin and high serum lactate dehydrogenase levels. We conclude that BCL-2 is frequently expressed by HRS cells in cHD and is associated with inferior FFS in patients treated with ABVD or equivalent regimens.

Adolescent↗
PubMed2002

The function of multiple IkappaB : NF-kappaB complexes in the resistance of cancer cells to Taxol-induced apoptosis.

The Rel/NF-kappaB transcription factors play a key role in the regulation of apoptosis and in tumorigenesis by controlling the expressions of specific genes. To determine the role of the constitutive activity of RelA in tumorigenesis, we generated pancreatic tumor cell lines that express a dominant negative mutant of IkappaBalpha (IkappaBalphaM). In this report, we show that the inhibition of constitutive NF-kappaB activity, either by ectopic expression of IkappaBalphaM or by treating the cells with a proteasome inhibitor PS-341 which blocks intracellular degradation of IkappaBalpha proteins, downregulates the expression of bcl-xl. We identified two putative NF-kappaB binding sites (kappaB/A and B) in the bcl-xl promoter and found that these two sites interact with different NF-kappaB proteins. p65/p50 heterodimer interacts with kappaB/A site whereas p50/p50 homodimer interacts with kappaB/B. The bcl-xl promoter reporter gene assays reveal that NF-kappaB dependent transcriptional activation is mainly mediated by kappaB/A site, indicating that bcl-xl is one of the downstream target genes regulated by RelA/p50. Both IkappaBalphaM and PS-341 completely abolish NF-kappaB DNA binding activity; however, PS-341, but not ectopic expression of IkappaBalphaM, sensitized cells to apoptosis induced by Taxol. This is due to the Taxol-mediated reactivation of RelA through phosphorylation and degradation of IkappaBbeta and the re-expression of NF-kappaB regulated bcl-xl gene in these cancer cells as ectopic expression of the bcl-xl gene confers resistance to Taxol-induced apoptosis in PS-341 sensitized cells. These results demonstrate the important function of various NF-kappaB/IkappaB complexes in regulating anti-apoptotic genes in response to apoptotic stimuli, and they raise the possibility that NF-kappaB : IkappaBalpha and NF-kappaB : IkappaBbeta complexes are regulated by different upstream activators, and that NF-kappaB plays a key role in pancreatic tumorigenesis.

Antineoplastic Agents↗
PubMed2002

Evidence that nucleotide excision repair is attenuated in bax-deficient mammalian cells following ultraviolet irradiation.

Nonmelanoma skin cancer (NMSC) is the most frequently diagnosed form of cancer in United States. We have previously described the tumor suppressor role of bax protein in skin carcinogenesis as well as the ability of bax to modulate the apoptotic response of keratinocytes following ultraviolet irradiation. Moreover, we have demonstrated an increase in tumor incidence in bax-null mice compared to control littermates in an in vivo chemical carcinogenesis experiment. In this study, we examined the contribution of bax protein in repair of UVR-mediated DNA lesions. The level of cyclobutane pyrimidine dimers remaining was twofold greater in UVR-treated primary keratinocytes from bax-deficient mice than that of control cells at 48 h (P < 0.03). Similar results were obtained using embryonic fibroblasts and also with a bax-deficient prostate cancer cell line. However, the repair rate of 6-4 pyrimidine pyrimidone photoproducts was unaffected by the absence of bax protein. These findings suggest that bax may have a dual function in its role as tumor suppressor in NMSC. Bax may directly or indirectly facilitate either DNA repair or cell death. Either function would be anticipated to enhance genomic integrity following a genotoxic event through repair or deletion of the damaged cell.

Animals↗
PubMed2002

Association of Ki-67, p53, and bcl-2 expression of the primary non-small-cell lung cancer lesion with brain metastatic lesion.

PURPOSE: The study was conducted to determine whether immunohistochemical analysis of Ki-67, p53, and bcl-2 in patients with non-small-cell lung cancer is associated with a higher rate of brain metastases and whether the intrapatient expression of these biomarkers (in the primary tumors vs. brain lesions) is similar. METHODS AND MATERIALS: At the M. D. Anderson Cancer Center, tumors from 29 case patients with primary lung tumor and brain metastasis and 29 control patients with primary lung tumor but no brain metastasis were resected and examined for immunohistochemical expression. Ki-67, p53, and bcl-2 were analyzed in resected primary lung, lymph node, and metastatic brain tumors. Each control patient was matched by age, gender, and histology to a patient with brain metastasis. RESULTS: No significant differences in patient survival characteristics were detected between the case group and control group. Also, difference in patient outcome between the two groups was not generally predicted by biomarker analysis. However, when the groups were combined, the biomarker analysis was predictive for certain patient outcome end points. Using median values as cutoff points between low and high expression of biomarkers, it was observed that high expression of Ki-67 (>40%) in lung primaries was associated with poorer disease-free survival (p = 0.04), whereas low expression of p53 in lung primaries was associated with poorer overall survival (p = 0.04), and these patients had a higher rate of nonbrain distant metastases (p = 0.02). The patients with brain metastases were particularly prone to developing nonbrain distant metastases if the percentage of p53-positive cells in brain metastases was low (p = 0.01). There was a positive correlation in the expression of Ki-67 (p = 0.02)(r(2) = 0.1608), as well as p53 (p < 0.001) (r(2) = 0.7380), between lung primaries and brain metastases. Compared to Ki-67 and p53, bcl-2 was the least predictive. CONCLUSION: Differences in biomarker expression between the case and control groups did not serve as significant predictors of brain metastasis or patient survival. There was a strong correlation between lung primary biomarker expression and brain metastasis expression for Ki-67 and p53. Univariate analysis showed that low p53 and high Ki-67 expression predicted poor prognosis. This study shows that there may be a strong correlation between biomarker expression in non-small-cell lung cancer primary tumors and their brain metastases.

Adult↗
PubMed2002

Hepatocyte growth factor/scatter factor binds to small heparin-derived oligosaccharides and stimulates the proliferation of human HaCaT keratinocytes.

Hepatocyte growth factor/scatter factor (HGF/SF) acts via a dual receptor system consisting of the MET tyrosine kinase receptor and heparan sulfate or dermatan sulfate proteoglycans. In optical biosensor binding assays, competition by oligosaccharides for binding of HGF/SF to immobilized heparin showed that disaccharides failed to compete, whereas tetrasaccharides inhibited HGF/SF binding (IC(50) 8 microg/ml). The inhibitory potency of the oligosaccharides increased as their length increased by successive disaccharide units, to reach a maximum (IC(50) 1 microg/ml) at degree of polymerization (dp) 10. In binding assays, HGF/SF was found to bind directly to oligosaccharides as small as dp 4, and the binding parameters were similar for oligosaccharides of dp 4-14 (k(a) 2.2-45.3 x 10(6) m(-1) s(-1), k(d) 0.033-0.039 s(-1), and K(d) 9-16 nm). In human keratinocytes, HGF/SF stimulated DNA synthesis, and this was dependent on a sustained phosphorylation of p42/44(MAPK). In chlorate-treated and hence sulfated glycosaminoglycan-deficient HaCaT cells, the stimulation of DNA synthesis by HGF/SF was almost abolished. Heparin-derived oligosaccharides from dp 2 to dp 24 were added together with HGF/SF to chlorate-treated cells to determine the minimum size of oligosaccharides able to restore HGF/SF activity. At restricted concentrations of oligosaccharides (4 ng/ml), HGF/SF required decasaccharides, whereas at higher concentrations (100 ng/ml) even tetrasaccharides were able to partly restore DNA synthesis. The results suggest that HGF/SF binds to a tetrasaccharide and that although this is sufficient to enable the stimulation of DNA synthesis, longer oligosaccharides are more efficient, perhaps by virtue of their ability to bind more easily other molecules.

Binding, Competitive↗
PubMed2002

Apoptotic rate in peripheral T-cell lymphomas. A study using a tissue microarray with validation on full tissue sections.

Peripheral T-cell lymphomas (PTCLs) are a heterogeneous group of non-Hodgkin lymphomas with a wide spectrum of clinicopathologic features, and apoptosis mechanisms may have a role in lymphomagenesis. We assessed apoptotic rate (AR) in 112 PTCLs using a tissue microarray developed in our laboratory and a modified terminal deoxynucleotidyl transferase-mediated dUTP nick-end labeling assay. The mean AR was 1.47% +/- 1.38% for the entire group of PTCLs (range, 0.06%-5.15%), and AR varied significantly among different tumor types. In mycosis fungoides, the mean AR was 0.74%; angioimmunoblastic T-cell lymphoma, 1.02%; PTCL, not otherwise specified, 1.38%; cutaneous anaplastic large cell lymphoma (ALCL), 1.41%; anaplastic lymphoma kinase protein (ALK)-negative ALCL, 1.43%; extranodal natural killer/T-cell lymphoma of nasal type, 2.04%; ALK-positive ALCL, 2.95%; and enteropathy-type T-cell lymphoma, 3.06%. Mean AR was higher in PTCL with large cell vs small/medium cell morphologic features (1.66% +/- 1.1% vs 0.99% +/- 1.0%). In a subset of 33 PTCLs, the tissue microarray results comparedfavorably with those obtained in full tissue sections. We conclude that the highest ARs in PTCLs are found in enteropathy-type T-cell lymphoma and ALK-positive ALCL, and that AR can be assessed reliably by using a tissue microarray.

Anaplastic Lymphoma Kinase↗