Gene/Protein Disease Symptom Drug Enzyme Compound
Pivot Concepts:   Target Concepts:
Query: UNIPROT:P10415 (Bcl-2)
 33,771 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

The failure to treat metastatic cancer with multidrug resistance is a major problem for successful cancer therapy, and the molecular basis for the association of metastatic phenotype with resistance to therapy is still unclear. In this study, we revealed that various metastatic cancer cells showed consistently higher levels of antiapoptotic proteins, including Bcl-2, nuclear factor-kappaB, MDM2, DNA-dependent protein kinase (DNA-PK), and epidermal growth factor receptor (EGFR), and lower levels of proapoptotic proteins, including Bax and p53 than low metastatic parental cells. This was followed by chemo- and radioresistance in metastatic cancer cells compared with their parental cells. EGFR and DNA-PK activity, which are known to be associated with chemo- and radioresistance, were demonstrated to be mutually regulated by each other. Treatment with PKI166, an EGFR inhibitor, suppressed etoposide-induced activation of DNA-PK in A375SM metastatic melanoma cells. In addition, PKI166 enhanced markedly the chemosensitivities of metastatic cancer cell sublines to various anticancer drugs in comparison with those of low metastatic cancer cells. These results suggest that the activities of DNA-PK and EGFR, which is positively correlated with each other, may contribute to metastatic phenotype as well as therapy resistance, and the EGFR inhibitor enhances the effect of anticancer drugs against therapy-resistant metastatic cancer cells via suppression of stress responses, including activation of DNA-PK.
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PMID:Relationship between antiapoptotic molecules and metastatic potency and the involvement of DNA-dependent protein kinase in the chemosensitization of metastatic human cancer cells by epidermal growth factor receptor blockade. 1527 54

The First International Symposium on Melanoma and Other Cutaneous Malignancies, held in New York City on 23-25 April 2004, brought together researchers and clinicians from all over the world to discuss recent advances in the prevention, treatment and diagnosis of melanoma and other cutaneous malignancies. Discussion topics included primary and secondary prevention; advances in surgical therapy, including sentinel and elective lymph node dissection; the biology and pathogenesis of melanoma, including pathways of drug resistance; genomic analysis of melanoma, serum and tumour cell markers; with point and counterpoint sessions debating therapeutic controversies. The role of vaccines in the management of melanoma was discussed, including cell vaccines, dendritic cell-based vaccination and present research to improve the generation of melanoma vaccine-specific immunity. Adjuvant immunotherapy with high-dose IFN-alpha and an ongoing trial with biochemotherapy were debated. In addition, the role of chemotherapy and novel targeted agents in metastatic melanoma were discussed. Among the emerging agents and therapeutic targets presented were Bcl-2 antisense therapy, RAF kinases, heat-shock proteins, thalidomide and newer immunomodulatory drugs, cytotoxic T lymphocyte antigen-4 antibody and topical imiquimod. The symposium also provided an overview of existing and emerging agents and modalities in the management of patients with cutaneous T cell lymphomas, ocular melanoma and melanoma involving brain metastases. Sessions also included case-based learning and devoted ample time to providing 'how to' information for practising physicians.
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PMID:First International Symposium on Melanoma and Other Cutaneous Malignancies. 1533 20

Inhibition of cancer growth by resveratrol (trans-3,5,4'-trihydroxystilbene; RESV), a phytoalexin present in many plant species, is limited by its low bioavailability. Pterostilbene (3,5-dimethoxy-4'-hydroxystilbene; PTER) and quercetin (3,3',4',5,6-pentahydroxyflavone; QUER), two structurally related and naturally occurring small polyphenols, show longer half-life in vivo. In vitro growth of highly malignant B16 melanoma F10 cells (B16M-F10) is inhibited (56%) by short-time exposure (60 min/day) to PTER (40 microm) and QUER (20 microm) (approximate mean values of plasma concentrations measured within the first hour after intravenous administration of 20 mg/kg each polyphenol). Intravenous administration of PTER and QUER (20 mg/kg per day) to mice inhibits (73%) metastatic growth of B16M-F10 cell in the liver, a common site for metastasis development. The anti-metastatic mechanism involves: 1) a PTER-induced inhibition of vascular adhesion molecule 1 expression in the hepatic sinusoidal endothelium, which consequently decreases B16M-F10 cell adhesion to the endothelium through very late activation antigen 4; and 2) a QUER- and PTER-induced inhibition of Bcl-2 expression in metastatic cells, which sensitizes them to vascular endothelium-induced cytotoxicity. Our findings demonstrate that the association of PTER and QUER inhibits metastatic melanoma growth and extends host survival.
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PMID:Association between pterostilbene and quercetin inhibits metastatic activity of B16 melanoma. 1573 13

The aim of this study was to clarify the roles of the tumour proliferation marker Ki-67, the anti-apoptotic protein Bcl-2 and the cell cycle regulator p53 in primary cutaneous and metastatic melanoma. One hundred and seventeen primary melanomas and 18 metastatic tissue samples were analysed for immunohistochemical expression of Ki-67, Bcl-2 and p53. The staining results were correlated with disease progression and clinical outcome. The patient population comprised patients diagnosed with melanoma between 1988 and 1991. The clinical follow-up period for disease recurrence was 4.6 years (median; range, 0.2-7.5 years) and the follow-up period for overall survival was 10.0 years (median; range, 8.6-15.6 years). Ki-67 expression was not a prognostic factor in primary melanoma. High Bcl-2 expression was associated with such adverse prognostic factors as male gender, old age of the patient and tumour ulceration. High Bcl-2 expression was also associated with an adverse prognosis in intermediate-thickness (1.01-4.0 mm) melanomas (n=52) for disease-free (P=0.09) and overall (P=0.08) survival. In multivariate analysis, tumour thickness was the strongest prognostic factor for disease-free survival (P<0.01). High p53 expression indicated a poorer prognosis (P=0.05). In metastatic melanoma, the expression levels of Bcl-2 and p53 were lower than those in their primary counterparts (P=0.08 for each). Ki-67 expression showed no remarkable changes. It can be concluded that high p53 expression in tumour cells is associated with a poorer prognosis in primary melanoma, and high Bcl-2 expression in tumour cells is an adverse prognostic marker in intermediate-thickness primary melanoma.
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PMID:Ki-67, Bcl-2 and p53 expression in primary and metastatic melanoma. 1617 64

The urokinase-type plasminogen activator receptor (uPAR) is involved in several biological processes, including proteolysis, adhesion, migration and inflammation. Increased expression of uPAR is associated with metastasis in several tumor types. We studied the biological role of uPAR in melanoma and found that inhibition of uPAR via RNA interference induced massive death in three different metastatic cell lines. Annexin-V staining and caspase activation analysis revealed induction of the mitochondrial apoptotic pathway. The expression of members of the Bcl-2 family (Bax, Bcl-2, Bak and Bcl-x(L)) was changed in a pro-apoptotic manner. uPAR inhibition induced the expression of the tumor suppressor p53 and of its downstream target gene p21. Inhibition of p53 rescued cells from apoptosis indicating that p53 was critical for apoptosis induction. Apoptosis was observed in melanoma cells carrying activating BRAF mutations and occurred in the presence of extracellular signal-regulated kinase (ERK) phosphorylation. uPAR can activate focal adhesion kinase (FAK), which is implicated in adhesion-dependent tumor cell survival. However, inhibition of FAK did not induce apoptosis. Our data suggest a new function of uPAR acting as a survival factor for melanoma by downregulating p53. Inhibition of uPAR induces a pro-apoptotic signalling pathway via p53 that is independent of ERK or FAK signalling. These findings may offer new treatment strategies for metastatic melanoma.
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PMID:Inhibition of urokinase-type plasminogen activator receptor induces apoptosis in melanoma cells by activation of p53. 1711 Sep 57

The aim of this study was to investigate the therapeutic potential of a cyclin-dependent kinase inhibitor, roscovitine, in cultured melanoma cells and a three-dimensional skin reconstruction model of metastatic melanoma. The modulatory effects of roscovitine on the growth and survival of normal melanocytes and cultured melanoma cell lines were tested. Additionally, we investigated the potential of roscovitine to regulate the growth and differentiation of a metastatic melanoma cell line (A375) in a three-dimensional skin reconstruction culture consisting of A375 cells admixed with normal human keratinocytes embedded within a collagen-constricted fibroblast matrix. We show that roscovitine is able to induce apoptosis in the melanoma cell lines A375, 888, and 624 but not in normal human cultured epithelial melanocytes. The degree of apoptosis within these cell lines correlated with the accumulation of p53 protein and concomitant reduction of X-linked inhibitor of apoptosis protein, with no change in the proteins Bcl-2 and survivin. We also found that roscovitine inhibited the growth and differentiation of A375 melanoma cells within the dermal layer of the skin. The results of this study show that roscovitine has the potential to inhibit the differentiation and invasion of metastatic melanoma and may be useful as a therapy for the treatment of patients with metastatic melanoma.
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PMID:Roscovitine inhibits differentiation and invasion in a three-dimensional skin reconstruction model of metastatic melanoma. 1731 72

Members of the Bcl-2 family of antiapoptotic proteins (Bcl-2, Bcl-XL and Mcl-1) are key regulators of apoptosis. The purpose of the present study was to examine and better define the role of Bcl-2, Bcl-XL and Mcl-1 in the progression of melanoma. Immunohistochemical staining for Bcl-2, Bcl-XL and Mcl-1 was performed on paraffin sections of 100 cases of benign nevi, primary melanoma and metastatic melanoma. Expression was correlated with histopathologic features, clinical progress and expression of transcription factors (AP-2, MITF and p-Stat3). Bcl-2 was expressed in 100% of benign nevi and thin melanoma (<or=1.0 mm) but was less in thick melanoma (>1.0 mm) (88%), subcutaneous (62%) and lymph node metastases (35%). In contrast, Bcl-XL and Mcl-1 were expressed at lower levels in nevi and thin melanoma compared to Bcl-2 but their expression was much higher in thick melanoma and in subcutaneous and lymph node metastases (P<0.0001). Bcl-2 expression was negatively associated with tumor thickness (P<0.05) but Bcl-XL expression increased with increasing tumor thickness (P<0.05) and dermal tumor mitotic rate (P<0.05). Similarly Mcl-1 expression increased with increasing tumor thickness (P<0.09) and dermal tumor mitotic rate (P<0.17). Bcl-2 expression was positively correlated with expression of the transcription factors microphthalmia transcription factor (MITF) and nuclear AP-2 whereas Bcl-XL (and Mcl-1) expression were positively correlated with p-Stat3. This study is the first to show a clear dissociation between changes in Bcl-2 expression (downregulation) and Bcl-XL, Mcl-1 expression (upregulation) during progression of melanoma. The results were also consistent with a role for AP-2 and MITF in regulation of Bcl-2 and pStat3 in regulation of Bcl-XL. These findings have important implications for the development of treatments targeting antiapoptotic proteins in patients with melanoma.
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PMID:Mcl-1, Bcl-XL and Stat3 expression are associated with progression of melanoma whereas Bcl-2, AP-2 and MITF levels decrease during progression of melanoma. 1738 50

Melanoma cells depend on sustained proteasomal function for survival. However, bortezomib, the first proteasome inhibitor in clinical use, is not sufficient to improve the poor prognosis of metastatic melanoma patients. Since the proteasome is also expressed in all normal cell compartments, it is unclear how to enhance the efficacy of bortezomib without exacerbating secondary toxicities. Here, we present pharmacological and genetic analyses of mechanisms of resistance to proteasome inhibition. We focused on Bcl-2, Bcl-x(L) and Mcl-1 as main antiapoptotic factors associated with melanoma progression. Despite an efficient blockage of the proteasome, bortezomib could not counteract the intrinsically high levels of Bcl-2 and Bcl-x(L) in melanoma cells. Moreover, Mcl-1 was only downregulated at late time points after treatment. Based on these results, a combination treatment including (-)-gossypol, an inhibitor of Mcl-1/Bcl-2/Bcl-x(L), was designed and proven effective in vivo. Using a specific RNA interference approach, the survival of bortezomib-treated melanoma cells was found to rely primarily on Mcl-1, and to a lesser extent on Bcl-x(L) (but not on Bcl-2). Importantly, neither Mcl-1 nor Bcl-x(L) inactivation affected the viability of normal melanocytes. This hierarchical requirement of Bcl-2 family members for the maintenance of normal and malignant cells offers a therapeutic window to overcome melanoma chemoresistance in a tumor cell-selective manner.
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PMID:Therapeutic window for melanoma treatment provided by selective effects of the proteasome on Bcl-2 proteins. 1754 28

Oblimersen is an antisense oligonucleotide developed by Genta for systemic use as an injection. It comprises a phosphorothioate backbone linking 18 modified DNA bases. Oblimersen targets the first six codons of Bcl-2 mRNA to form a DNA/RNA complex. The duplex is subsequently recognised as a foreign message and is cleaved enzymatically, thereby destroying the Bcl-2 message. The Bcl-2 protein, which is a potent inhibitor of apoptosis, is overexpressed in many cancers, including follicular lymphomas, breast, colon and prostate cancers, and intermediate-/high-grade lymphomas. By reducing the amount of Bcl-2 protein in cancer cells, oblimersen may enhance the effectiveness of conventional anticancer treatments. Genta has reported results from randomised phase III trials of oblimersen in four different indications: malignant melanoma, chronic lymphocytic leukaemia (CLL), multiple myeloma and acute myleoid leukaemia (AML). A negative opinion has been issued for the company's MAA for the product in the treatment of malignant melanoma in the EU; the EMEA has indicated an additional confirmatory trial is needed in this indication for approval. An NDA for CLL was deemed non-approvable by the US FDA; the company is appealing this decision. The phase III trials in multiple myeloma and AML did not meet their primary endpoints. Phase I and II trials are also underway or have been completed for a range of other cancer types. Genta and sanofi-aventis (formerly Aventis) entered into a collaboration agreement in 2002; however, this agreement was terminated by sanofi-aventis in May 2005. Genta became solely responsible for all costs relating to oblimersen at this time. Genta expanded its Cooperative Research and Development Agreement (CRADA) with the National Cancer Institute in November 2001. The expanded collaboration was to investigate the use of oblimersen in combination with standard anticancer therapy in a broad range of cancers. This expansion occurred following the Gensynergy project, which showed that oblimersen was synergistic with other anticancer therapies. Genta signed a 5-year manufacturing agreement with Avecia Ltd in December 2002 to supply it with oblimersen. Genta's NDA was submitted to the FDA in December 2005 and accepted for review in March 2006. The application was based on data from a phase I/II trial (NCT00021749) of oblimersen alone in approximately 40 patients and a phase III study (NCT00024440) of 241 patients who received fludarabine and cyclo-phosphamide with or without oblimersen. Genta received a Special Protocol Assessment (SPA) from the FDA in October 2006 for a randomised, pivotal, clinical trial of oblimersen in CLL. The trial will be conducted in patients who have not received prior chemotherapy and who would be randomised to receive fludarabine and rituximab with or without oblimersen. This trial has not yet begun.Fast-track status was given to oblimersen for CLL in June 2003 by the FDA. Oblimersen previously obtained orphan drug status in the US and EU for CLL in September 2001. Genta previously submitted the MAA under the centralised licensing procedure and Spain and France were assigned as rapporteur and co-rapporteur countries, respectively. It was supported by an extended 24-month follow-up of patients from a phase III study (NCT00016263) of oblimersen plus dacarbazine. The EMEA validated the MAA for review in January 2006. Genta received a number of scientific questions from the EMEA in June 2006, which the company responded to. Genta intends to file a formal complaint and a request for correction of information with the FDA under the Federal Data Quality Act. The complaint is related to a key statistical analysis of the company's data for oblimersen in the treatment of melanoma used by the FDA at the Oncology Drug Advisory Committee (ODAC) in May 2004. Genta believes that analysis sought to discredit the finding that treatment with oblimersen significantly increased progression-free survival; ODAC previously agreed this endpoint would support full approval in the absence of a survival improvement in patients with advanced melanoma.A rolling NDA submission was submitted to the FDA in the third quarter of 2003; however, Genta and Aventis withdrew the NDA after the application failed to gain marketing approval from the FDA's Oncology Drug Advisory Committee (ODAC). In May 2004, ODAC voted that phase III trial results did not provide substantial evidence of effectiveness to outweigh toxicity of oblimersen treatment in patients with metastatic melanoma. Genta has the option to resubmit this application. The FDA gave oblimersen orphan drug status for malignant melanoma in August 2000. In October 1999, fast-track status was given to oblimersen by the FDA for malignant melanoma when used in combination with dacarbazine. In addition, oblimersen received orphan drug status for malignant melanoma in Australia in October 2006.A phase III study (NCT00016263) of oblimersen in combination with dacarbazine was conducted in patients with malignant melanoma. The combination treatment did not significantly increase overall survival time, but did significantly increase progression-free survival time, compared with dacarbazine treatment alone. The phase III trial enrolled 771 patients at 140 sites in 12 different countries. Patients were randomly assigned to receive dacarbazine alone or in combination with oblimersen. The primary endpoint of this trial was to compare the overall survival between the two treatment arms. Secondary endpoints included comparative analyses of progression-free survival and tumour response. Genta will conduct another phase III study of oblimersen in patients with advanced melanoma. The trial is designed to provide additional safety and efficacy evidence of the drug, in combination with dacarbazine, in patients who have not previously received chemotherapy. Approximately 300 patients are expected to be enrolled in the trial, which is planned to begin during mid-2007, at sites throughout Europe, Australia, and North and South America. Genta is conducting a phase I clinical trial (NCT00409383) to evaluate the combination of oblimersen, ABI 007, and temozolomide in chemotherapy-naive patients with advanced melanoma. This trial was initiated in November 2006 and is the first follow-on study to Genta's phase III trial of oblimersen plus dacarbazine. Oblimersen received orphan drug status in the US and EU for multiple myeloma in September 2001. In addition, fast-track designation was given to oblimersen by the FDA in the same month.A phase I/II clinical study (NCT00062244) of oblimersen was conducted by the NCI in patients with Waldenstrom's macroglobulinaemia, a disease that is similar to multiple myeloma. The study results indicated that oblimersen may be a useful treatment in this group of patients (all had high levels of Bcl-2 expression). In June 2003, Genta and Aventis announced the presentation of clinical data from a phase II trial of oblimersen in combination with docetaxel injection concentrate for patients with advanced HRPC. Researchers reported that these findings validated progression into phase III trials. Genta has licensed eight US patents relating to oblimersen and its backbone chemistry and these expire between 2008 and 2015. Genta has two pending US patent applications that relate to oblimersen. Corresponding patent applications have been filed in Canada, Europe and Japan. Genta owns three US patents relating to methods of using oblimersen that will expire in 2020, and also has approximately 45 corresponding foreign patent applications.
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PMID:Oblimersen: Augmerosen, BCL-2 antisense oligonucleotide - Genta, G 3139, GC 3139, oblimersen sodium. 1776 97

The RAS-RAF-MEK-ERK and PI3K-AKT-mTOR signaling pathways are activated through multiple mechanisms and appear to play a major role in melanoma progression. Herein, we examined whether targeting the RAS-RAF-MEK-ERK pathway with the RAF inhibitor sorafenib and/or the PI3K-AKT-mTOR pathway with the mTOR inhibitor rapamycin has therapeutic effects against melanoma. A combination of sorafenib (4 microM) with rapamycin (10 nM) potentiated growth inhibition in all six metastatic melanoma cell lines tested. The absolute enhancement of growth inhibition rates ranged from 13.0-27.8% in different cell lines (P<0.05, combination treatment vs monotreatment). Similar results were obtained with combinations of the MEK inhibitors U0126 (30 microM) or PD98059 (50 microM) with rapamycin (10 nM). The combined treatment of melanoma cells with sorafenib and rapamycin led to an approximately twofold increase of cell death compared with sorafenib monotreatment (P<0.05) as assessed by propidium iodide staining and cell death detection ELISA. Moreover, sorafenib in combination with rapamycin completely suppressed invasive melanoma growth in organotypic culture mimicking the physiological context. These effects were associated with complete downregulation of the antiapoptotic proteins Bcl-2 and Mcl-1. Sorafenib combined with rapamycin appears to be a promising strategy for the effective treatment of melanoma and merits clinical investigation.
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PMID:Combined inhibition of MAPK and mTOR signaling inhibits growth, induces cell death, and abrogates invasive growth of melanoma cells. 1832 81


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