Biomedical subjects

Julie Teruya-Feldstein

Publications and source records attributed to Julie Teruya-Feldstein.

At least 19 recordsLinked to original sources

PubMed2007

Ubiquitination regulates PTEN nuclear import and tumor suppression.

The PTEN tumor suppressor is frequently affected in cancer cells, and inherited PTEN mutation causes cancer-susceptibility conditions such as Cowden syndrome. PTEN acts as a plasma-membrane lipid-phosphatase antagonizing the phosphoinositide 3-kinase/AKT cell survival pathway. However, PTEN is also found in cell nuclei, but mechanism, function, and relevance of nuclear localization remain unclear. We show that nuclear PTEN is essential for tumor suppression and that PTEN nuclear import is mediated by its monoubiquitination. A lysine mutant of PTEN, K289E associated with Cowden syndrome, retains catalytic activity but fails to accumulate in nuclei of patient tissue due to an import defect. We identify this and another lysine residue as major monoubiquitination sites essential for PTEN import. While nuclear PTEN is stable, polyubiquitination leads to its degradation in the cytoplasm. Thus, we identify cancer-associated mutations of PTEN that target its posttranslational modification and demonstrate how a discrete molecular mechanism dictates tumor progression by differentiating between degradation and protection of PTEN.

Active Transport, Cell Nucleus↗

PubMed2006

Mad2 overexpression promotes aneuploidy and tumorigenesis in mice.

Mad2 is an essential component of the spindle checkpoint that blocks activation of Separase and dissolution of sister chromatids until microtubule attachment to kinetochores is complete. We show here that overexpression of Mad2 in transgenic mice leads to a wide variety of neoplasias, appearance of broken chromosomes, anaphase bridges, and whole-chromosome gains and losses, as well as acceleration of myc-induced lymphomagenesis. Moreover, continued overexpression of Mad2 is not required for tumor maintenance, unlike the majority of oncogenes studied to date. These results demonstrate that transient Mad2 overexpression and chromosome instability can be an important stimulus in the initiation and progression of different cancer subtypes.

Aneuploidy↗

PubMed2006

PML inhibits HIF-1alpha translation and neoangiogenesis through repression of mTOR.

Loss of the promyelocytic leukaemia (PML) tumour suppressor has been observed in several human cancers. The tumour-suppressive function of PML has been attributed to its ability to induce growth arrest, cellular senescence and apoptosis. Here we identify PML as a critical inhibitor of neoangiogenesis (the formation of new blood vessels) in vivo, in both ischaemic and neoplastic conditions, through the control of protein translation. We demonstrate that in hypoxic conditions PML acts as a negative regulator of the synthesis rate of hypoxia-inducible factor 1alpha (HIF-1alpha) by repressing mammalian target of rapamycin (mTOR). PML physically interacts with mTOR and negatively regulates its association with the small GTPase Rheb by favouring mTOR nuclear accumulation. Notably, Pml-/- cells and tumours display higher sensitivity both in vitro and in vivo to growth inhibition by rapamycin, and lack of PML inversely correlates with phosphorylation of ribosomal protein S6 and tumour angiogenesis in mouse and human tumours. Thus, our findings identify PML as a novel suppressor of mTOR and neoangiogenesis.

Animals↗

PubMed2006

A CK2-dependent mechanism for degradation of the PML tumor suppressor.

The PML tumor suppressor controls key pathways for growth suppression, induction of apoptosis, and cellular senescence. PML loss occurs frequently in human tumors through unknown posttranslational mechanisms. Casein kinase 2 (CK2) is oncogenic and frequently upregulated in human tumors. Here we show that CK2 regulates PML protein levels by promoting its ubiquitin-mediated degradation dependent on direct phosphorylation at Ser517. Consequently, PML mutants that are resistant to CK2 phosphorylation display increased tumor-suppressive functions. In a faithful mouse model of lung cancer, we demonstrate that Pml inactivation leads to increased tumorigenesis. Furthermore, CK2 pharmacological inhibition enhances the PML tumor-suppressive property in vivo. Importantly, we found an inverse correlation between CK2 kinase activity and PML protein levels in human lung cancer-derived cell lines and primary specimens. These data identify a key posttranslational mechanism that controls PML protein levels and provide therapeutic means toward PML restoration through CK2 inhibition.

Amino Acid Sequence↗

PubMed2006

Autologous transplantation for relapsed or primary refractory peripheral T-cell lymphoma.

Autologous transplantation (ASCT) is the standard of care for chemosensitive relapsed or primary refractory aggressive lymphoma, but little is known about its efficacy in the subset of patients with peripheral T-cell lymphoma (PTCL). We undertook a retrospective review of patients with PTCL who underwent ASCT for relapsed or refractory disease after responding to second-line therapy, excluding patients with indolent histologies and those with anaplastic lymphoma kinase (ALK) expressing anaplastic large cell lymphoma. The results of 24 patients with PTCL were compared with those of 86 consecutive patients with chemosensitive relapsed or primary refractory diffuse large B-cell lymphoma (DLBCL). With a median follow-up time of 6 years for surviving patients with PTCL and DLBCL, the 5-year progression-free survival (PFS) rates for PTCL and DLBCL patients were 24% and 34% respectively (P = 0.14); the corresponding overall survival (OS) rates were 33% and 39% respectively. There were no significant differences between the two groups with respect to time to disease progression or survival after progression. The second-line age-adjusted international prognostic index was the only variable prognostic for PFS and OS in a multivariate analysis. The outcome of ASCT for patients with chemosensitive relapsed or primary refractory PTCL is similar to that for patients with DLBCL.

Adolescent↗

PubMed2006

The combination of the proteasome inhibitor bortezomib and the bcl-2 antisense molecule oblimersen sensitizes human B-cell lymphomas to cyclophosphamide.

PURPOSE: To determine whether the combination of the proteasome inhibitor bortezomib and the bcl-2 antisense molecule oblimersen can sensitize human lymphoma to cyclophosphamide. EXPERIMENTAL DESIGN: Cytotoxicity assays were conducted to determine if there was any additive or synergistic interaction between the combinations of bortezomib, oblimersen, and cyclophosphamide using a standard trypan blue exclusion assay. Based on these experiments, in vivo experiments in severe combined immunodeficiency beige mice were done using human lymphoma xenografts in which different schedules were explored. Bcl-2 and oblimersen levels were determined in treated tumors, some of which were resected at the end of the in vivo experiment and evaluated pathologically. RESULTS: The results suggest that the combination of bortezomib and oblimersen seem to interact in at least an additive fashion, and that the addition of cyclophosphamide to this drug combination can markedly improve tumor cell kill. In addition, it seems that these drug combinations may be schedule-dependent, with a requirement for oblimersen pretreatment. Animals treated with the triplet drug combination in a schedule-dependent manner experienced pathologic complete regression of disease, which was not observed in other treatment cohorts. The addition of bortezomib also seemed to increase the levels of intracellular oblimersen, which resulted in a marked reduction in Bcl-2. Histologic studies confirmed marked necrosis and caspase-3 activation only in the cohort receiving all three drugs. CONCLUSION: The use of Bcl-2-directed therapy and a proteasome inhibitor sensitizes human lymphoma cells to cytotoxic drugs like cyclophosphamide. This combination may offer new opportunities for integrating novel targeted therapies with conventional chemotherapy.

Animals↗

PubMed2006

Comparison of two antibodies for immunohistochemical evaluation of epidermal growth factor receptor expression in colorectal carcinomas, adenomas, and normal mucosa.

BACKGROUND: Immunohistochemical staining for epidermal growth factor receptor (EGFR) has been used as a criterion for the selection of patients with colon cancer for anti-EGFR therapy. Two antibodies, the PharmDx kit and the 31G7 clone, are used commonly for immunohistochemistry by various laboratories. No comparative studies on the performance of these 2 antibodies are available. METHODS: EGFR status was evaluated in 744 tissue microarray core samples from primary and metastatic colorectal carcinomas, colorectal adenomas, and normal colorectal mucosa with both the PharmDx kit and the clone 31G7 monoclonal antibodies. The stains were compared for staining intensity by using an automated image-analysis system. The intensity of positive staining (brown color) was measured on a scale from 0 to 255. The staining intensity also was scored manually as 0, 1 +, 2 +, and 3 +. RESULTS: Statistically, the median staining intensities scored by the automated system between the 2 antibodies did not differ significantly, although, within each category of samples (normal, adenoma, carcinoma, and metastases), the PharmDx antibody staining was slightly more intense than the clone 31G7 antibody staining. There was a linear correlation between automated image-analysis and manual scoring categories. The median automated image-analysis intensity scores for the 4 manual scoring categories with the PharmDx kit were as follows: 0 staining, 67.5; 1 + staining, 75.5; 2 + staining, 89.6; and 3 + staining, 106.0. The median automated image-analysis intensity scores for the 4 manual scoring categories with the clone 31G7 antibody were as follows: 0 staining, 71.3; 1 + staining, 73.6; 2 + staining, 84.6; and 3 + staining, 99.1. The classification of tumors as EGFR-negative (0 staining) or positive (1 +, 2 +, or 3 + staining) was concordant in 151 of 160 carcinomas (94.4%) with 2 antibodies using manual scoring. Five samples (3%) that scored 1 + with the PharmDx kit antibody scored 0 with the clone 31G7 antibody; whereas 4 samples (2.5%) that scored 1 + with the clone 31G7 antibody scored 0 with the PharmDx kit antibody. CONCLUSIONS: The EGFR expression results obtained by immunohistochemistry using both the EGFR PharmaDx kit and the 31G7 clone were comparable. Either antibody may be used for immunohistochemical detection of EGFR in colorectal carcinomas. In addition, manual scoring had an excellent correlation with automated scoring.

Adenocarcinoma↗

PubMed2006

The schedule-dependent effects of the novel antifolate pralatrexate and gemcitabine are superior to methotrexate and cytarabine in models of human non-Hodgkin's lymphoma.

PURPOSE: Methotrexate is known to synergize with cytarabine [1-beta-D-arabinofuranosylcytosine (ara-C)] in a schedule-dependent manner. The purpose of this article is to compare and contrast the activity of pralatrexate (10-propargyl-10-deazaminopterin)/gemcitabine to the standard combination of methotrexate/ara-C and to determine if schedule dependency of this combination is important in lymphoma. EXPERIMENT DESIGN: Cytotoxicity assays using the standard trypan blue exclusion assay were used to explore the in vitro activity of pralatrexate and gemcitabine against a panel of lymphoma cell lines. Both severe combined imunodeficient beige and irradiated nonobese diabetic/severe combined imunodeficient mouse xenograft models were used to compare and contrast the in vivo activity of these combinations as a function of schedule. In addition, apoptosis assays were conducted. RESULTS: Compared with methotrexate-containing combinations, pralatrexate plus gemcitabine combinations displayed improved therapeutic activity with some schedule dependency. The combination of pralatrexate and gemcitabine was superior to any methotrexate and ara-C combination in inducing apoptosis and in activating caspase-3. In vivo, the best therapeutic effects were obtained with the sequence of pralatrexate --> gemcitabine. Complete remissions were only appreciated in animals receiving pralatrexate followed by gemcitabine. CONCLUSIONS: These data show that the combination of pralatrexate followed by gemcitabine was superior to methotrexate/ara-C in vitro and in vivo, and was far more potent in inducing apoptosis in a large B-cell lymphoma. These data provide strong rationale for further study of this combination in lymphomas where methotrexate and ara-C are used.

Aminopterin↗

PubMed2006

Seeking confidence in the diagnosis of systemic AL (Ig light-chain) amyloidosis: patients can have both monoclonal gammopathies and hereditary amyloid proteins.

Investigators in the United Kingdom have shown that hereditary amyloidosis can be misdiagnosed as Ig light-chain (AL) amyloidosis because family history is an ineffective screen, and tissue staining used to type amyloid is unreliable. Misdiagnosis of AL can lead to inappropriate use of chemotherapy and failure to diagnose a hereditary disease. Over a 3-year period we sought to determine how often both possible sources of amyloidosis occurred in the same patient. We employed an algorithm based on established data and patterns of amyloidosis in order to focus the screening effort. Of 178 consecutive patients referred for amyloidosis, 54 were screened by polymerase chain reaction techniques with primers designed to detect transthyretin, apolipoprotein AI, apolipoprotein AII, fibrinogen Aalpha, and lysozyme variants. Three patients (6% of those screened and 2% of symptomatic patients) had both a monoclonal gammopathy and a hereditary variant. These results justify further study of screening for hereditary variants in patients with apparent AL, and highlight the need for practical techniques for identifying fibrils extracted from tissue.

Adult↗

PubMed2006

Doxorubicin and dexamethasone followed by thalidomide and dexamethasone is an effective well tolerated initial therapy for multiple myeloma.

Among the drug combinations designed for the initial treatment of multiple myeloma, none has been unequivocally shown to be superior. However, a regimen leading to a high response rate and a low incidence of adverse events is highly desirable. We report the results of a phase II clinical trial involving 45 patients with Durie-Salmon stage II and III multiple myeloma. Doxorubicin and dexamethasone were given for 2 or 3 months followed by thalidomide and dexamethasone for 2 months (AD-TD regimen) with prophylactic antibiotics and daily aspirin (81 mg/d). Among the 42 patients whose response could be assessed, 38 responded to therapy (90.5%). The intent-to-treat response rate was 84.4% with seven complete responses (CR 15.5%), nine near complete responses (nCR 20.0%), and 22 partial responses (PR 48.9%). Two patients had stable disease (4.4%), and two progression of disease (4.4%). Normalization of the free light chain ratio after one or two cycles of treatment was highly predictive of achievement of CR or nCR. Patients tolerated the treatment well although five patients developed thromboembolic complications (11%). AD-TD administered with low dose aspirin for deep vein thrombosis prophylaxis was well tolerated and yielded a high response rate with minimal treatment-related morbidity.

Adult↗

PubMed2006

Drug-induced cutaneous vasculitis in patients with non-Hodgkin lymphoma treated with the novel proteasome inhibitor bortezomib: a possible surrogate marker of response?

Bortezomib is the first proteasome inhibitor to be approved for use in haematological malignancies. Although a rash has been described as a common adverse event associated with the drug, it has not been well characterised. Based on three phase II studies of bortezomib in patients with non-Hodgkin lymphoma (140 assessable patients), we identified 26 patients who developed a unique erythematous maculopapular rash during treatment, six of whom underwent cutaneous biopsy. Punch biopsy in six patients revealed a perivascular lymphocytic infiltrate without evidence of lymphoma, consistent with a non-necrotising cutaneous vasculitis. The combined overall response rate was 41%. The response in the 26 patients who developed a rash was 73%, compared with 33% in patients who did not. The odds ratio for response given the development of a rash was 4.6 (95% CI, 1.7-12.4, P = 0.001). This is the first report to characterise a vasculitic rash associated with bortezomib, and to show a relationship between development of the rash and response to treatment. Unlike classic hypersensitivity type reactions, this vasculitic rash may not necessarily prompt cessation of drug. In fact, the development of an isolated cutaneous vasculitis may portend a better clinical response to bortezomib in some patients.

Aged↗

PubMed2005

Array comparative genomic hybridization reveals genomic copy number changes associated with outcome in diffuse large B-cell lymphomas.

To identify, in high-resolution regions of DNA, the copy number changes associated with outcome in patients with diffuse large B-cell lymphoma (DLBCL), a disease with an approximately 50% mortality rate, we performed array comparative genomic hybridization (array-CGH) on specimens from 64 patients with newly diagnosed DLBCL treated with anthracycline-based chemotherapy. For the entire cohort, 55 commonly gained/lost regions, ranging in size from less than 1 Mbp to entire chromosomes, were identified using 1- to 2-Mbp and 2- to 4-Mbp resolution BAC arrays. Copy number changes of 9 minimal regions significantly correlated with overall survival, of which 6 were 10 Mbp or smaller. On multivariate analysis, loss of chromosomes 2 (2.4-4.1 Mbp) and 16 (33.8-35.6 Mbp) were found to be prognostic indicators of poor survival, independent of clinical features routinely used to predict outcome. Loss of chromosome 1 (78.2-79.1 Mbp) was predictive of good outcome. For a subset of 55 specimens classified according to cell-of-origin expression signature subtype, gain of chromosome 12 (45.4-53.8 Mbp) was found to be significantly associated with the germinal center B-cell-like DLBCL subtype. Overall, array-CGH identified relatively small genomic regions associated with outcome, which, along with follow-up expression studies, may reveal target genes important in DLBCL clinical behavior.

Anthracyclines↗

PubMed2005

Evasion of the p53 tumour surveillance network by tumour-derived MYC mutants.

The c-Myc oncoprotein promotes proliferation and apoptosis, such that mutations that disable apoptotic programmes often cooperate with MYC during tumorigenesis. Here we report that two common mutant MYC alleles derived from human Burkitt's lymphoma uncouple proliferation from apoptosis and, as a result, are more effective than wild-type MYC at promoting B cell lymphomagenesis in mice. Mutant MYC proteins retain their ability to stimulate proliferation and activate p53, but are defective at promoting apoptosis due to a failure to induce the BH3-only protein Bim (a member of the B cell lymphoma 2 (Bcl2) family) and effectively inhibit Bcl2. Disruption of apoptosis through enforced expression of Bcl2, or loss of either Bim or p53 function, enables wild-type MYC to produce lymphomas as efficiently as mutant MYC. These data show how parallel apoptotic pathways act together to suppress MYC-induced transformation, and how mutant MYC proteins, by selectively disabling a p53-independent pathway, enable tumour cells to evade p53 action during lymphomagenesis.

Adoptive Transfer↗

PubMed2005

Cell of origin, germinal center versus nongerminal center, determined by immunohistochemistry on tissue microarray, does not correlate with outcome in patients with relapsed and refractory DLBCL.

A number of prognostic factors affect outcome in patients with relapsed or primary refractory diffuse large B-cell lymphoma (DLBCL), including refractory disease and the second-line age-adjusted international prognostic index. In de novo DLBCL, the cell of orgin, as determined by expression microarray analysis or immunohistochemistry (IHC), predicts event-free survival (EFS). We evaluated the cell of origin, as well as other pathologic markers of outcome, on the repeat biopsy specimen of 88 transplantation-eligible patients undergoing ifosfamide, carboplatin, etoposide (ICE) second-line chemotherapy (SLT) followed by high-dose therapy (HDT) and autologous stem cell transplantation (ASCT) to see if were they prognostic in the salvage setting. Pretreatment clinical factors were well balanced between the cohorts. There was no significant difference in response to SLT, HDT, event-free or overall survival based on the cell of origin or any of the common pathologic markers examined. The cell of origin as determined by IHC does not predict outcome in transplantation-eligible patients with relapsed or primary refractory DLBCL.

Aged↗

PubMed2005

Genetic analysis of Pten and Tsc2 functional interactions in the mouse reveals asymmetrical haploinsufficiency in tumor suppression.

The role of tumor suppressor haploinsufficiency in oncogenesis is still poorly understood. The PTEN and TSC2 tumor suppressors function to antagonize mTOR (mammalian target of rapamycin) activation by Akt; hence, compound heterozygous inactivation of Pten and Tsc2 in the mouse may in principle exacerbate the tumor phenotypes observed in the single mutants in a reciprocal manner. In contrast, we found that while Tsc2 heterozygosity unmasks Pten haploinsufficiency in growth and tumor suppression, tumorigenesis in Tsc2+/- mutants is surprisingly not accelerated by Pten heterozygosity, even though mTOR activation is cooperatively enhanced by compound Pten/Tsc2 heterozygosity. We show that the wild-type alleles of both Pten and Tsc2 are retained in prostate tumors from both Pten+/- and Pten+/-Tsc2+/- mice, whereas TSC-related tumor lesions are invariably associated with Tsc2 loss of heterozygosity (LOH) in both Tsc2+/- and Pten+/-Tsc2+/- mice. These findings demonstrate that inactivation of TSC2 is epistatic to PTEN in the control of tumor initiation and progression and, importantly, that both Pten and Tsc2 are haploinsufficient for suppression of tumorigenesis initiated by Pten heterozygosity, while neither Pten nor Tsc2 is haploinsufficient for repression of carcinogenesis arising from Tsc2 heterozygosity, providing a rationale for the differential cancer susceptibility of the two human conditions associated with PTEN or TSC2 heterozygous mutations.

Animals↗

PubMed2005

Cytologic features of plasmablastic lymphoma.

BACKGROUND: Plasmablastic lymphomas (PBLs) were originally described exclusively in human immunodeficiency virus (HIV)-positive patients who presented with jaw or oral mucosa involvement. Recent studies have reported this neoplasm also in patients without HIV infection and involving sites other than head and neck. This lymphoma has a heterogeneous morphologic presentation but distinct phenotype. METHODS: Cytologic features from four cases of histologically confirmed PBL were evaluated. The cytology specimens were evaluated for criteria as follow: cellularity, cell size and shape, pleomorphism, cytoplasmic characteristics, chromatin pattern, nucleolar features, and mitotic figures. RESULTS: Specimens evaluated were two head and neck fine needle aspiration specimens, one anal smear, and one cerebrospinal fluid specimen. Atypical lymphocytes ranged from intermediate to large in size and demonstrated slight nuclear pleomorphism. The cytoplasm varied from scant to moderate in the alcohol-fixed slides. Nuclei were round with vesicular chromatin. Nucleoli varied from a prominent one to multiple small ones. Multinucleated cells and mitotic figures were easily identified in three of four cases. Tingible-body histiocytes were seen in one case. Ancillary studies in two cases demonstrated expression of CD138 with lack of CD20 expression. CONCLUSION: PBL is a variant of large cell lymphoma with heterogeneous cytologic findings but distinct immunophenotype. Knowledge of the cytomorphologic spectrum of PBLs and detection of CD138 expression by flow cytometry can be helpful in achieving a correct diagnosis.

Biopsy, Needle↗

PubMed2005

Role of the proto-oncogene Pokemon in cellular transformation and ARF repression.

Aberrant transcriptional repression through chromatin remodelling and histone deacetylation has been postulated to represent a driving force underlying tumorigenesis because histone deacetylase inhibitors have been found to be effective in cancer treatment. However, the molecular mechanisms by which transcriptional derepression would be linked to tumour suppression are poorly understood. Here we identify the transcriptional repressor Pokemon (encoded by the Zbtb7 gene) as a critical factor in oncogenesis. Mouse embryonic fibroblasts lacking Zbtb7 are completely refractory to oncogene-mediated cellular transformation. Conversely, Pokemon overexpression leads to overt oncogenic transformation both in vitro and in vivo in transgenic mice. Pokemon can specifically repress the transcription of the tumour suppressor gene ARF through direct binding. We find that Pokemon is aberrantly overexpressed in human cancers and that its expression levels predict biological behaviour and clinical outcome. Pokemon's critical role in cellular transformation makes it an attractive target for therapeutic intervention.

Animals↗

PubMed2005

Diffuse large B-cell lymphomas with plasmablastic differentiation.

Recent evidence suggests that diffuse large B-cell lymphoma (DLBCL) with plasmablastic differentiation represents a clinically heterogeneous spectrum with different clinicopathologic characteristics representing distinct entities. Subtypes of DLBCL with plasmablastic features and terminal B-cell differentiation include plasmablastic lymphoma (PBL) of oral mucosa type; PBL with plasmacytic differentiation; primary effusion lymphoma (PEL); KSHV-positive solid lymphoma/extracavitary PEL/HHV-8 associated DLBCL; and DLBCL expressing ALK. In contrast, PBL associated with multicentric Castleman disease, DLBCL with secretory differentiation, pyothorax-associated lymphoma, and atypical Burkitt lymphoma with plasmacytoid differentiation have morphologic appearances of plasma cell differentiation but maintain a mature B-cell (CD20 positive) phenotype. These tumors as well as extramedullary plasmablastic tumors secondary to multiple myeloma or plasmacytomas are included in the differential diagnosis. In this review, we discuss recently described clinicopathologic insights, case observations, and recently reported molecules involved in terminal B-cell or plasma cell differentiation and their possible roles in disease pathogenesis.

Adult↗