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1.
J Clin Oncol ; 41(3): 425-435, 2023 01 20.
Article in English | MEDLINE | ID: mdl-36649675

ABSTRACT

PURPOSE: Interferon alfa-2b (IFN alpha-2b) exhibits antitumor activity in metastatic melanoma and on this basis has been evaluated as an adjuvant therapy following surgery for deep primary (T4) or regionally metastatic (N1) melanoma. METHODS: A randomized controlled study of IFN alpha-2b (Schering-Plough, Kenilworth, NJ) administered at maximum-tolerated doses of 20 MU/m2/d intravenously (i.v.) for 1 month and 10 MU/m2 three times per week subcutaneously (SC) for 48 weeks versus observation, was conducted by the Eastern Cooperative Oncology Group (ECOG) in 287 patients. RESULTS: A significant prolongation of relapse-free survival (P = .0023, one-sided) and prolongation of overall survival (P = .0237, one-sided) was observed with IFN alpha-2b therapy in this trial, which is now mature with a median follow-up time of 6.9 years. The impact of treatment on relapse rate is most pronounced early during the treatment interval. The overall benefit of treatment in this trial was analyzed stratified by tumor burden and the presence or absence of microscopic nonpalpable and palpable regional lymph node metastasis. The benefit of therapy with IFN alpha-2b was greatest among node-positive strata. Toxicity of IFN alpha-2b required dose modification in the majority of patients, but treatment at > or = 80% of the scheduled dose was feasible in the majority of patients through the IV phase of treatment, and for more than 3 months of SC maintenance therapy. Discontinuation of treatment due to toxicity was infrequent after the fourth month of therapy. CONCLUSION: IFN alpha-2b prolongs the relapse-free interval and overall survival of high-risk resected melanoma patients. The increment in median disease-free survival (from 1 to 1.7 years) and overall survival (from 2.8 to 3.8 years) that results from this therapy is associated with a 42% improvement in the fraction of patients who are continuously disease-free after treatment with IFN (from 26% to 37%) in comparison to observation. IFN alpha-2b is the first agent to show a significant benefit in relapse-free and overall survival of high-risk melanoma patients in a randomized controlled trial.

4.
Oncogene ; 34(46): 5739-48, 2015 Nov 12.
Article in English | MEDLINE | ID: mdl-25728676

ABSTRACT

The resistance of melanoma to current treatment modalities represents a major obstacle for durable therapeutic response, and thus the elucidation of mechanisms of resistance is urgently needed. The crucial functions of activating transcription factor-2 (ATF2) in the development and therapeutic resistance of melanoma have been previously reported, although the precise underlying mechanisms remain unclear. Here, we report a protein kinase C-ɛ (PKCɛ)- and ATF2-mediated mechanism that facilitates resistance by transcriptionally repressing the expression of interferon-ß1 (IFNß1) and downstream type-I IFN signaling that is otherwise induced upon exposure to chemotherapy. Treatment of early-stage melanomas expressing low levels of PKCɛ with chemotherapies relieves ATF2-mediated transcriptional repression of IFNß1, resulting in impaired S-phase progression, a senescence-like phenotype and increased cell death. This response is lost in late-stage metastatic melanomas expressing high levels of PKCɛ. Notably, nuclear ATF2 and low expression of IFNß1 in melanoma tumor samples correlates with poor patient responsiveness to biochemotherapy or neoadjuvant IFN-α2a. Conversely, cytosolic ATF2 and induction of IFNß1 coincides with therapeutic responsiveness. Collectively, we identify an IFNß1-dependent, cell-autonomous mechanism that contributes to the therapeutic resistance of melanoma via the PKCɛ-ATF2 regulatory axis.


Subject(s)
Activating Transcription Factor 2/metabolism , Drug Resistance, Neoplasm , Interferon-beta/genetics , Melanoma/genetics , Cell Line, Tumor , Cell Nucleus/metabolism , Down-Regulation , Humans , Melanoma/drug therapy , Melanoma/metabolism , Melanoma/pathology , Promoter Regions, Genetic , Protein Kinase C-epsilon/metabolism , Signal Transduction , Transcription, Genetic
8.
Ann Oncol ; 24(4): 1112-9, 2013 Apr.
Article in English | MEDLINE | ID: mdl-23172636

ABSTRACT

BACKGROUND: Temozolomide (TMZ) is widely used for chemotherapy of metastatic melanoma. We hypothesized that epigenetic modulators will reverse chemotherapy resistance, and in this article, we report studies that sought to determine the recommended phase 2 dose (RP2D), safety, and efficacy of decitabine (DAC) combined with TMZ. PATIENTS AND METHODS: In phase I, DAC was given at two dose levels: 0.075 and 0.15 mg/kg intravenously daily × 5 days/week for 2 weeks, TMZ orally 75 mg/m(2) qd for weeks 2-5 of a 6-week cycle. The phase II portion used a two-stage Simon design with a primary end point of objective response rate (ORR). RESULTS: The RP2D is DAC 0.15 mg/kg and TMZ 75 mg/m(2). The phase II portion enrolled 35 patients, 88% had M1c disease; 42% had history of brain metastases. The best responses were 2 complete response (CR), 4 partial response (PR), 14 stable disease (SD), and 13 progressive disease (PD); 18% ORR and 61% clinical benefit rate (CR + PR + SD). The median overall survival (OS) was 12.4 months; the 1-year OS rate was 56%. Grade 3/4 neutropenia was common but lasted >7 days in six patients. CONCLUSIONS: The combination of DAC and TMZ is safe, leads to 18% ORR and 12.4-month median OS, suggesting possible superiority over the historical 1-year OS rate, and warrants further evaluation in a randomized setting.


Subject(s)
Antineoplastic Combined Chemotherapy Protocols/administration & dosage , Azacitidine/analogs & derivatives , Dacarbazine/analogs & derivatives , Melanoma/drug therapy , Skin Neoplasms/drug therapy , Adult , Aged , Antineoplastic Agents/administration & dosage , Antineoplastic Agents/adverse effects , Antineoplastic Combined Chemotherapy Protocols/antagonists & inhibitors , Azacitidine/administration & dosage , Azacitidine/adverse effects , Azacitidine/pharmacokinetics , Dacarbazine/administration & dosage , Dacarbazine/pharmacokinetics , Decitabine , Disease-Free Survival , Drug Administration Schedule , Drug-Related Side Effects and Adverse Reactions/chemically induced , Drug-Related Side Effects and Adverse Reactions/pathology , Female , Humans , Male , Melanoma/pathology , Middle Aged , Neoplasm Metastasis/drug therapy , Neoplasm Metastasis/pathology , Neoplasm Staging , Skin Neoplasms/pathology , Temozolomide
9.
Br J Cancer ; 105(6): 773-7, 2011 Sep 06.
Article in English | MEDLINE | ID: mdl-21811257

ABSTRACT

BACKGROUND: The DNA repair protein O6-methylguanine-DNA methyltransferase (MGMT) reverses the O6-methylguanine (O6-meG) lesion induced by dacarbazine. Depletion of MGMT can be achieved using O6-meG pseudosubstrates. Herein, we report the first phase I experience of the novel O6-meG pseudosubstrate lomeguatrib, combined with dacarbazine. METHODS: This is a phase I dose-escalation study to determine the maximum tolerated dose and recommended phase II dose (RP2D) of lomeguatrib combined with a single dose of dacarbazine on a 21-day schedule. RESULTS: The vast majority of the 41 patients enrolled had metastatic melanoma (36/41) and most had no previous chemotherapy (30/41). The most frequent non-hematological adverse events (AEs) were nausea (52%), and fatigue (42%). The most frequent AEs of grade 3-4 severity were neutropaenia (42%), leukopaenia (17%), and thrombocytopaenia (12%). Only 1 patient had a partial response and 10 patients had stable disease. CONCLUSION: The RP2D of lomeguatrib was 40 mg orally twice daily for 10 days combined with 400 mg m(-2) of dacarbazine IV on day 2. Oral administration of lomeguatrib substantially increases the haematological toxicity of dacarbazine consistent with experience with other O6-meG pseudosubstrates.


Subject(s)
Antineoplastic Combined Chemotherapy Protocols/therapeutic use , Dacarbazine/administration & dosage , Melanoma/drug therapy , Neoplasms/drug therapy , O(6)-Methylguanine-DNA Methyltransferase/antagonists & inhibitors , Purines/administration & dosage , Adult , Aged , Antineoplastic Combined Chemotherapy Protocols/adverse effects , Drug Administration Schedule , Female , Humans , Male , Middle Aged
11.
Cancer Gene Ther ; 13(8): 798-805, 2006 Aug.
Article in English | MEDLINE | ID: mdl-16645618

ABSTRACT

Although CD4(+) Type-1T helper (Th1) cells secreting interferon-gamma (IFN-gamma) appear to play an essential role in promoting durable antitumor immunity, we have previously shown that patients with cancer exhibit dysfunctional Th1-type responses against epitopes derived from tumor antigens, such as MAGE-A6. Here, we engineered human dendritic cells (DCs) to secrete high levels of the IFN-gamma-inducing cytokines, interleukin (IL)-12p70 and IL-18, via recombinant adenoviral infection to generate an in vitro stimulus capable of promoting previously deficient patient Th1-type responses. Dendritic cells co-infected with Ad.IL-12 and Ad.IL-18 (DC.IL-12/18) were more effective at stimulating MAGE-A6-specific Th1-type CD4(+) T-cell responses than DCs infected with either of the cytokine vectors alone, control Ad.Psi5 virus or uninfected DCs. Furthermore, we show that DC.IL-12/18 loaded with recombinant MAGE-A6 protein (rMAGE) and used as in vitro stimulators promote Th1-type immunity that is frequently directed against multiple MAGE-A6-derived epitopes. The superiority of DC.IL-12/18-based stimulations in melanoma patients was independent of disease stage or current disease status. Based on these results, we believe this modality may prove clinically useful as a vaccine platform to promote the recovery of tumor antigen-specific, Th1-type CD4(+) T-cell responses in patients with cancer.


Subject(s)
Antigens, Neoplasm/genetics , Dendritic Cells/immunology , Interleukin-12 , Interleukin-18 , Melanoma/therapy , Neoplasm Proteins/genetics , Skin Neoplasms/therapy , Adenoviridae , CD4-Positive T-Lymphocytes/immunology , Cancer Vaccines , Genetic Vectors , Humans , In Vitro Techniques , Interleukin-12/genetics , Interleukin-18/genetics , Melanoma/immunology , Recombinant Proteins , Skin Neoplasms/immunology , Th1 Cells
12.
J Clin Oncol ; 20(8): 2053-7, 2002 Apr 15.
Article in English | MEDLINE | ID: mdl-11956265

ABSTRACT

PURPOSE: To correlate the presence of extracapsular spread (ECS) of regional nodal metastases, and micrometastasis near the primary tumor, with disease outcome in the intergroup study E1690 in relation to the impact of recombinant interferon-alfa (rIFN alpha)-2b. PATIENTS AND METHODS: E1690 included 642 patients with American Joint Committee on Cancer stage IIB or III cutaneous melanoma. Patients were randomized into high- and low-dose rIFN alpha-2b treatment arms and an observation arm. Pathologic slides were reviewed for selected parameters from at least half of the subjects in all three arms. Evaluation of the primary tumor included notations regarding ulceration, mitotic activity, thickness, microscopic satellites (MS), and nodal ECS on a standardized pathology form. These data were collated in relation to relapse-free survival (RFS) and overall survival (OS) at 50 months' follow-up and studied using Cox regression analysis. RESULTS: Ulceration, mitotic activity, thickness, and size of tumor-bearing lymph nodes did not show a statistically significant correlation with either OS or RFS across all treatment arms. The presence of MS was correlated with RFS (P =.0008) and OS (P =.05). ECS correlated with RFS (hazard ratio = 1.44, P =.032) but not OS (P =.11). CONCLUSION: The presence of MS (in 6% [18 of 308 patients]) had a significant adverse impact on both RFS (P =.0008) and OS (P =.053). Ulceration, mitotic activity, thickness, and number of positive lymph nodes had no significant effect on OS in this subset study (univariate or multivariate Cox analysis). The presence of ECS in lymph nodes had a significant adverse effect on RFS (P =.032) but not on OS.


Subject(s)
Antineoplastic Agents/therapeutic use , Interferon-alpha/therapeutic use , Melanoma/drug therapy , Melanoma/pathology , Humans , Interferon alpha-2 , Lymphatic Metastasis , Mitotic Index , Neoplasm Staging , Recombinant Proteins , Skin Neoplasms/drug therapy , Skin Neoplasms/pathology , Survival Analysis , Ulcer
13.
Br J Cancer ; 85(11): 1738-45, 2001 Nov 30.
Article in English | MEDLINE | ID: mdl-11742496

ABSTRACT

CD4+ T cells modulate the magnitude and durability of CTL responses in vivo, and may serve as effector cells in the tumour microenvironment. In order to identify the tumour epitopes recognized by tumour-reactive human CD4+ T cells, we combined the use of an HLA-DR4/peptide binding algorithm with an IFN-gamma ELISPOT assay. Two known and three novel CD4+ T cell epitopes derived from the gp 100/pmel17 and tyrosinase melanocyte-associated antigens were confirmed or identified. Of major interest, we determined that freshly-isolated PBMC frequencies of Th1-type CD4+ T recognizing these peptides are frequently elevated in HLA-DR4+ melanoma patients (but not normal donors) that are currently disease-free as a result of therapeutic intervention. Epitope-specific CD4+ T cells from normal DR4+ donors could be induced, however, after in vitro stimulation with autologous dendritic cell pulsed with antigens (peptides or antigen-positive melanoma lysates) or infected with recombinant vaccinia virus encoding the relevant antigen. Peptide-reactive CD4+ T cells also recognized HLA-DR4+ melanoma cell lines that constitutively express the relevant antigen. Based on these data, these epitopes may serve as potent vaccine components to promote clinically-relevant Th1-type CD4+ T cell effector function in situ.


Subject(s)
Epitopes/immunology , Membrane Glycoproteins/immunology , Monophenol Monooxygenase/immunology , Neoplasm Proteins/immunology , Proteins/immunology , Th1 Cells/immunology , Adult , Amino Acid Sequence , CD4-Positive T-Lymphocytes/cytology , CD4-Positive T-Lymphocytes/immunology , Cell Line , Dendritic Cells/immunology , Dendritic Cells/virology , Epitopes/genetics , Female , HLA-DR4 Antigen/immunology , HLA-DR4 Antigen/metabolism , Humans , Male , Melanoma/genetics , Melanoma/immunology , Membrane Glycoproteins/genetics , Membrane Glycoproteins/metabolism , Middle Aged , Molecular Sequence Data , Monophenol Monooxygenase/genetics , Monophenol Monooxygenase/metabolism , Neoplasm Proteins/genetics , Neoplasm Proteins/metabolism , Oligopeptides/genetics , Oligopeptides/immunology , Oligopeptides/metabolism , Protein Binding , Proteins/genetics , Proteins/metabolism , Sequence Homology, Amino Acid , Th1 Cells/cytology , Tumor Cells, Cultured , Vaccinia virus/genetics , Vaccinia virus/growth & development , gp100 Melanoma Antigen
15.
J Clin Oncol ; 19(16): 3622-34, 2001 Aug 15.
Article in English | MEDLINE | ID: mdl-11504744

ABSTRACT

PURPOSE: The American Joint Committee on Cancer (AJCC) recently proposed major revisions of the tumor-node-metastases (TNM) categories and stage groupings for cutaneous melanoma. Thirteen cancer centers and cancer cooperative groups contributed staging and survival data from a total of 30,450 melanoma patients from their databases in order to validate this staging proposal. PATIENTS AND METHODS: There were 17,600 melanoma patients with complete clinical, pathologic, and follow-up information. Factors predicting melanoma-specific survival rates were analyzed using the Cox proportional hazards regression model. Follow-up survival data for 5 years or longer were available for 73% of the patients. RESULTS: This analysis demonstrated that (1) in the T category, tumor thickness and ulceration were the most powerful predictors of survival, and the level of invasion had a significant impact only within the subgroup of thin (< or = 1 mm) melanomas; (2) in the N category, the following three independent factors were identified: the number of metastatic nodes, whether nodal metastases were clinically occult or clinically apparent, and the presence or absence of primary tumor ulceration; and (3) in the M category, nonvisceral metastases was associated with a better survival compared with visceral metastases. A marked diversity in the natural history of pathologic stage III melanoma was demonstrated by five-fold differences in 5-year survival rates for defined subgroups. This analysis also demonstrated that large and complex data sets could be used effectively to examine prognosis and survival outcome in melanoma patients. CONCLUSION: The results of this evidence-based methodology were incorporated into the AJCC melanoma staging as described in the companion publication.


Subject(s)
Melanoma/mortality , Melanoma/pathology , Neoplasm Staging/standards , Skin Neoplasms/mortality , Skin Neoplasms/secondary , Adolescent , Adult , Age Factors , Aged , Aged, 80 and over , Child , Female , Humans , Male , Middle Aged , Neoplasm Metastasis , Predictive Value of Tests , Proportional Hazards Models , Survival Analysis , United States/epidemiology
16.
J Clin Oncol ; 19(16): 3635-48, 2001 Aug 15.
Article in English | MEDLINE | ID: mdl-11504745

ABSTRACT

PURPOSE: To revise the staging system for cutaneous melanoma under the auspices of the American Joint Committee on Cancer (AJCC). MATERIALS AND METHODS: The prognostic factors analysis described in the companion publication (this issue), as well as evidence from the published literature, was used to assemble the tumor-node-metastasis criteria and stage grouping for the melanoma staging system. RESULTS: Major changes include (1) melanoma thickness and ulceration but not level of invasion to be used in the T category (except for T1 melanomas); (2) the number of metastatic lymph nodes rather than their gross dimensions and the delineation of clinically occult (ie, microscopic) versus clinically apparent (ie, macroscopic) nodal metastases to be used in the N category; (3) the site of distant metastases and the presence of elevated serum lactic dehydrogenase to be used in the M category; (4) an upstaging of all patients with stage I, II, and III disease when a primary melanoma is ulcerated; (5) a merging of satellite metastases around a primary melanoma and in-transit metastases into a single staging entity that is grouped into stage III disease; and (6) a new convention for defining clinical and pathologic staging so as to take into account the staging information gained from intraoperative lymphatic mapping and sentinel node biopsy. CONCLUSION: This revision will become official with publication of the sixth edition of the AJCC Cancer Staging Manual in the year 2002.


Subject(s)
Melanoma/mortality , Melanoma/pathology , Neoplasm Staging/standards , Skin Neoplasms/pathology , Skin Neoplasms/secondary , Humans , Neoplasm Metastasis , Proportional Hazards Models , Survival Analysis , United States/epidemiology
17.
Curr Oncol Rep ; 3(4): 344-52, 2001 Jul.
Article in English | MEDLINE | ID: mdl-11389820

ABSTRACT

There has been much development in the field of targeted therapy for melanoma stemming from efforts to decrease treatment-related toxicities and enhance specific cytotoxicity. This review focuses on three modalities of targeted melanoma therapy based on the biology of the targeting mechanism. The first of these modalities is immunotherapy, which functions to generate a specific antimelanoma immunity. A second modality utilizes metabolic pathways of melanin synthesis to target melanoma cells specifically. A third modality ensues from recent advances in molecular biology and the identification of genes responsible for the malignant transformation of normal melanocytes to melanomas. This work has furthered our understanding of the basis of malignancy, as well as the development of novel strategies aimed at targeting aberrant growth in melanoma.


Subject(s)
Melanoma/therapy , Skin Neoplasms/therapy , Humans , Immunotherapy/methods , Oligonucleotides, Antisense/therapeutic use
18.
Cancer ; 91(9): 1814-21, 2001 May 01.
Article in English | MEDLINE | ID: mdl-11335908

ABSTRACT

BACKGROUND: Although long-term survival in patients with metastatic melanoma (MM) is infrequent, response to a variety of cytotoxic and immunotherapies occurs and survival varies based on the site of metastases. Because different patterns of care of MM are likely to vary substantially in their intensity and resource use, the authors audited care at a regional referral center. METHODS: The records of 100 consecutive new patients with MM who presented at the University of Pittsburgh Cancer Institute (UPCI) after January 1997 were audited. Demographics, disease sites, and treatment prior to presentation at UPCI as well as the diagnostic and therapeutic methods undertaken at UPCI were tracked monthly with regard to inpatient and outpatient activity. RESULTS: The median age of the patient cohort was 51 years was a median 2.2 years after the time of initial diagnosis. Eighty-two percent of the patients had died and only 8% had been lost to long-term follow-up. Eighty-seven percent of patients had been referred to UPCI and 28% had received some treatment prior to presenting at UPCI. The median survival was 9.0 months. The lung was the most common symptomatic site and 38% of patients developed central nervous system (CNS) metastases. Eighty-four percent of patients initially were treated on a research protocol 30% of whom were part of a Phase III study. Twenty-nine percent of the patients were never hospitalized. The most common reason for hospitalization was elective treatment with high-dose interleukin-2. Lifetime hospital days averaged only 7.3 days. Therapeutic actions (if ever given) by category type were surgery in 23% of patients, radiation therapy in 44%, immunotherapy in 75%, and chemotherapy in 51%. Using assigned values for the identified resources used, the approximate cost per patient averaged $59,400. CONCLUSIONS: The current audit of MM patients demonstrated that lung and CNS metastases dominate a broad variety of complications, that clinical trial participation was the norm, that hospitalizations occurred relatively infrequently, and that the direct health care costs of current treatment patterns are among the highest for all malignancies. Medical auditing of contemporary American cancer care provides meaningful insights into its patterns of care.


Subject(s)
Cost of Illness , Melanoma/economics , Adult , Ambulatory Care , Central Nervous System Diseases/etiology , Costs and Cost Analysis , Female , Hospitalization , Humans , Male , Melanoma/mortality , Middle Aged , Survival Rate
19.
J Clin Oncol ; 19(9): 2370-80, 2001 May 01.
Article in English | MEDLINE | ID: mdl-11331315

ABSTRACT

PURPOSE: Vaccine alternatives to high-dose interferon alfa-2b therapy (HDI), the current standard adjuvant therapy for high-risk melanoma, are of interest because of toxicity associated with HDI. The GM2 ganglioside is a well-defined melanoma antigen, and anti-GM2 antibodies have been associated with improved prognosis. We conducted a prospective, randomized, intergroup trial to evaluate the efficacy of HDI for 1 year versus vaccination with GM2 conjugated to keyhole limpet hemocyanin and administered with QS-21 (GMK) for 96 weeks (weekly x 4 then every 12 weeks x 8). PATIENTS AND METHODS: Eligible patients had resected stage IIB/III melanoma. Patients were stratified by sex and number of positive nodes. Primary end points were relapse-free survival (RFS) and overall survival (OS). RESULTS: Eight hundred eighty patients were randomized (440 per treatment group); 774 patients were eligible for efficacy analysis. The trial was closed after interim analysis indicated inferiority of GMK compared with HDI. For eligible patients, HDI provided a statistically significant RFS benefit (hazard ratio [HR] = 1.47, P = .0015) and OS benefit (HR = 1.52, P = .009) for GMK versus HDI. Similar benefit was observed in the intent-to-treat analysis (RFS HR = 1.49; OS HR = 1.38). HDI was associated with a treatment benefit in all subsets of patients with zero to > or = four positive nodes, but the greatest benefit was observed in the node-negative subset (RFS HR = 2.07; OS HR = 2.71 [eligible population]). Antibody responses to GM2 (ie, titers > or = 1:80) at days 29, 85, 365, and 720 were associated with a trend toward improved RFS and OS (P2 = .068 at day 29). CONCLUSION: This trial demonstrated a significant treatment benefit of HDI versus GMK in terms of RFS and OS in melanoma patients at high risk of recurrence.


Subject(s)
Cancer Vaccines/immunology , G(M2) Ganglioside/immunology , Interferon-alpha/therapeutic use , Melanoma/drug therapy , Adult , Aged , Disease-Free Survival , Female , Hemocyanins/immunology , Humans , Immunoglobulin G/blood , Immunoglobulin M/blood , Interferon alpha-2 , Interferon-alpha/adverse effects , Male , Melanoma/metabolism , Melanoma/pathology , Middle Aged , Neoplasm Staging , Prospective Studies , Recombinant Proteins , Saponins , Vaccination , Vaccines, Conjugate/immunology
20.
Clin Cancer Res ; 7(3 Suppl): 974s-979s, 2001 Mar.
Article in English | MEDLINE | ID: mdl-11300499

ABSTRACT

Melanoma escapes host defenses through a variety of means, including the elimination of immune effector cells within the tumor microenvironment. We have reported recently that murine and human tumors including melanoma induce premature apoptosis of dendritic cells both in vitro and in vivo. In this study, we have demonstrated that overexpression of the Bcl-2 protein family member Bcl-xL rescued murine dendritic cells (DCs) from melanoma-induced death in vitro. Another successful protection approach was tumor necrosis factor (TNF)-alpha-promoted sustained expression of the antiapoptotic protein Bcl-2 within dendritic cells. This effect of TNF-alpha was mediated by inhibition of mitochondrial cytochrome c release. Thus, both Bcl-xL and Bcl-2 enhance survival of dendritic cells within the tumor microenvironment. In addition, mature DCs were more resistant to melanoma-induced apoptosis than immature dendritic cells. This finding suggests a stage-dependent sensitivity of DCs to tumor-induced cell death. We conclude that: (a) mature DCs might be more suitable for the use of cancer vaccination; and (b) Bcl-2 protein family members such as Bcl-xL and Bcl-2 rescue DCs from tumor-induced premature apoptosis.


Subject(s)
Apoptosis , Cytochrome c Group/antagonists & inhibitors , Dendritic Cells/metabolism , Melanoma/pathology , Mitochondria/metabolism , Proto-Oncogene Proteins c-bcl-2/biosynthesis , Proto-Oncogene Proteins c-bcl-2/metabolism , Tumor Necrosis Factor-alpha/metabolism , Animals , Blotting, Western , Cytochrome c Group/metabolism , DNA Fragmentation , Male , Melanoma, Experimental , Mice , Mice, Inbred C57BL , Transfection , Tumor Cells, Cultured , bcl-X Protein
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