Gene/Protein Disease Symptom Drug Enzyme Compound
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Query: UMLS:C0027651 (tumor)
 685,946 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

The Erb-B family of receptors plays an important role in lung carcinogenesis and tumor development, and EGFR and HER2 are highly expressed in bronchial preneoplasia. In invasive tumors, EGFR are expressed in 50-90%, and mostly in squamous cell carcinomas, but also in adenocarcinomas and large cell carcinomas, while HER2 is less frequently expressed (20-30%) and mostly expressed in adenocarcinomas. Bronchioloalveolar cell carcinomas may present a distinct EGFR profile compared to the other NSCLCs and evidence and consequences are discussed. The genetic mechanisms responsible for overexpression of EGFR and HER2 proteins might be numerous, including gene dosage (overrepresentation or amplification) as well as translational and post-translational mechanisms. However, for EGFR and HER2 there is a positive correlation between gene copy numbers and level of protein expression demonstrated by fluorescence in situ hybridization analysis and immunochemistry. Gene amplification for EGFR and HER2 is demonstrated in only 5-10% of the tumors. The treatment status and therapeutic limitation with trastuzumab (Herceptin) in lung cancer compared to breast cancer is discussed.
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PMID:Epidermal growth factor family of receptors in preneoplasia and lung cancer: perspectives for targeted therapies. 1286 60

Metastatic breast cancer is a partially chemotherapy-sensitive neoplasm. Docetaxel appears to be the most active single agent for this condition. The platinum coordination complexes are also active, but are seldom used. An emerging literature suggests that taxane-platinum combinations have substantial activity. Trastuzumab, a molecularly targeted therapy for metastatic breast cancer is active as a single agent in HER2-overexpressing disease, and has been demonstrated to augment the activity of other agents in random assignment trials. Preclinical data suggest a powerful synergistic interaction between trastuzumab and both platinum and docetaxel. In early trials, platinum-taxane-trastuzumab combinations have exhibited promising clinical activity. The potential for cardiac toxicity when trastuzumab is combined with the anthracyclines suggests a further rationale for the development of non-anthracycline regimens, especially in the adjuvant setting. Randomized, multicenter, phase III trials in the metastatic and adjuvant setting are currently underway to test the hypothesis that synergistic combinations of docetaxel, platinums, and trastuzumab will result in superior safety as well as efficacy.
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PMID:Platinum-taxane combinations in metastatic breast cancer: an evolving role in the era of molecularly targeted therapy. 1286 1

In solid tumors the predominant genetic mechanism for oncogene activation is through amplification of genes. The HER-2 (also known as ErbB2/c-erbB2/HER-2/neu) oncogene is the most frequently amplified oncogene in breast cancer and is also commonly amplified in other forms of cancer. Alongside its important role in tumor induction, growth and progression, HER-2 is also a target for a new form of chemotherapy. Since 1998, breast cancer patients have been treated with considerable success with Herceptin (trastuzumab), a recombinant antibody designed to block signaling through the HER-2 receptor. In addition to Herceptin, a large number of various HER-2 directed immunological and genetic approaches, either targeting the HER-2 receptor, its signaling pathways or both HER-2 and epidermal growth factor receptor (EGFR) together, have demonstrated promising pre-clinical potential towards HER-2 amplified carcinomas. Moreover, the HER-2 amplicon contains other genes with altered copy numbers that could be used as targets for chemotherapy. The topoisomerase IIalpha (topoIIalpha) gene (TOP2A) is located adjacent to the HER-2 oncogene at the chromosome location 17q12-q21 and is either amplified or deleted, with equal frequency, in almost 90% of HER-2 amplified primary breast tumors. Recent data suggest that amplification or deletion of TOP2A may account for both sensitivity or resistance to topoII-inhibitor-chemotherapy, depending on the specific genetic defect at the TOP2A locus. The understanding of HER-2 amplification and its role in the pathogenesis of cancer is expanding. The number of therapeutic strategies targeting HER-2 signaling pathways will most probably be introduced in the treatment of HER-2 amplified tumors within the next few years. Combining HER-2 targeting therapies with conventional forms of cytotoxic chemotherapy, where additional diagnostics tests such as those ascertaining topoIIalpha status, may be helpful for the ideal selection of patients for the combination therapy of a HER-2 targeting drug together with a cytotoxic drug. The clinical and therapeutic importance of the HER-2 and TOPO2A status of tumor cells in cancer management will only increase within the next few years.
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PMID:HER-2/neu and topoisomerase IIalpha--simultaneous drug targets in cancer. 1287 Oct 52

Detailed synthesis of the bifunctional chelating agents 2-methyl-6-(p-isothiocyanatobenzyl)-1,4,7,10-tetraazacyclododecane-1,4,7,10-tetraacetic acid (1B4M-DOTA) and 2-(p-isothiocyanatobenzyl)-5, 6-cyclohexano-1, 4, 7, 10-tetraazacyclododecane-1, 4, 7, 10-tetraacetate (CHX-DOTA) are reported. These chelating agents were compared to 2-(p-isothiocyanatobenzyl)-1, 4, 7, 10-tetraazacyclododecane-1, 4, 7, 10-tetraacetic acid (C-DOTA) and 1, 4, 7, 10-Tetraaza-N-(1-carboxy-3-(4-nitrophenyl)propyl)-N', N", N"'-tris(acetic acid) cyclododecane (PA-DOTA) as their (177)Lu radiolabeled conjugates with Herceptin. In vitro stability of the immunoconjugates radiolabeled with (177)Lu was assessed by serum stability studies. The in vivo stability of the radiolabeled immunoconjugates and their targeting characteristics were determined by biodistribution studies in LS-174T xenograft tumor-bearing mice. Relative radiolabeling rates and efficiencies were determined for all four immunoconjugates. Insertion of the 1B4M moiety into the DOTA backbone increases radiometal chelation rate and provides complex stability comparable to C-DOTA and PA-DOTA while the CHX-DOTA appears to not form as stable a (177)Lu complex while exhibiting a substantial increase in formation rate. The 1B4M-DOTAmay have potential for radioimmunotherapy applications.
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PMID:Synthesis and evaluation of novel bifunctional chelating agents based on 1,4,7,10-tetraazacyclododecane-N,N',N",N"'-tetraacetic acid for radiolabeling proteins. 1290 Feb 84

HER-2/neu is overexpressed in several cancers including 30% of breast carcinomas, and correlates with a poor outcome. HER-2/neu-transgenic (neu-N) mice that overexpress the non-transforming rat neu develop spontaneous mammary carcinomas and demonstrate immunotolerance to the neu protein similar to that observed in patients with neu-expressing cancers. In neu-N mice, neu-targeted vaccination induces weak T cell and negligible Ab responses sufficient to delay but not eradicate transplanted neu-expressing tumor. Here we demonstrate that passive infusion of neu-specific mAbs in sequence with whole cell vaccination significantly improves tumor-free survival over either modality alone. Importantly, treatment of neu-N mice with vaccine in combination with two distinct neu-specific Abs is particularly efficacious, preventing tumor in 70% and eradicating established tumor in 30% of neu-N mice. In vivo lymphocyte subpopulation depletion experiments demonstrate that the efficacy of Ab, alone or combined with vaccine, is dependent on both CD4(+) and CD8(+) T cells. Furthermore, the in vivo antitumor effects of vaccine and Ab are associated with a significant increase in the number and function of neu-specific CD8(+) T cells. Collectively, these observations suggest that similarly increased efficacy could be obtained by combining neu-targeted vaccination and neu-specific Abs such as trastuzumab (Herceptin) in patients with neu-expressing cancers.
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PMID:HER-2/neu-specific monoclonal antibodies collaborate with HER-2/neu-targeted granulocyte macrophage colony-stimulating factor secreting whole cell vaccination to augment CD8+ T cell effector function and tumor-free survival in Her-2/neu-transgenic mice. 1290 23

The HER family of transmembrane tyrosine kinase receptors is composed of four members, BER1 to HER4. HER2 is a ligand-orphan receptor expressed in many human tumors and overexpressed in 25-30% of breast cancers. HER2 amplifies the signal provided by other receptors of the HER family by forming heterodimers. The essential role of HER2 in the HER signaling network led to the development of anti-HER2 monoclonal antibodies (MAbs) for cancer therapy. In particular, the humanized MAb trastuzumab (Herceptin) has antitumor activity against HER2-overexpressing human breast tumor cells and is widely used for the treatment of women with HER2 overexpressing breast cancers. Trastuzumab induces HER2 receptor downmodulation and, as a result, inhibits critical signalling pathways (i.e. ras-Raf-MAPK and PI3K/Akt) and blocks cell cycle progression by inducing the formation of p27/Cdk2 complexes. Trastuzumab also inhibits HER2 cleavage, preceding antibody-induced receptor downmodulation, and this effect might contribute to its antitumor activity in some cancers. In vivo, trastuzumab inhibits angiogenesis and induces antibody-dependent cellular cytotoxicity. A limitation of trastuzumab is that its activity is largely restricted to breast cancers with the highest level of HER2 overexpression or HER2 gene amplification. However, there is a large population of breast cancers and of many other tumors that have low or moderate HER2 expression. In such tumors, HER2 functions as a preferred coreceptor to form heterodimers with HER1 (EGFR), HER3 or HER4. For this reason, a humanized monoclonal antibody, called 2C4, that targets the role of HER2 as a coreceptor is under active development. 2C4 binds to a different epitope of HER2 ectodomain than trastuzumab and sterically hinders HER2 recruitment in heterodimers with other HER receptors. This results in the inhibition of signalling by HER2-based heterodimers both in cells with low and high HER2 expression. In vitro and in vivo antitumor activity has been reported in a range of breast and prostate tumor models. Therefore, 2C4 may have potential against a wide variety of solid tumors. Phase I trials are underway.
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PMID:Mechanism of action of anti-HER2 monoclonal antibodies: scientific update on trastuzumab and 2C4. 1290 64

HER2/neu and the epidermal growth factor receptor (EGFR) are significantly overexpressed in several cancer cells. Overexpression of these two receptors accounts for progression of many types of cancer: breast, ovarian, skin, pancreas and brain. In recent years, several approaches to disable the receptor complexes have shown promise. Antibody-based therapy, kinase inhibitors and other inhibitors of signaling molecules are the major approaches. Our group developed the concept that an anti-p185HER2/neu monoclonal antibody might represent a therapeutic for cancer and this has culminated in a clinically useful therapeutic, the humanized monoclonal antibody Herceptin (trastuzumab). We have now developed a small-molecule form of an anti-HER2/neu peptidomimetic (AHNP) that exhibit functions comparable to those of the monoclonal antibody Herceptin. This approach may be considered a new paradigm in receptor-specific tumor therapeutics. A brief review of our approach in developing receptor-specific therapeutic agents for HER2/neu-related cancer is presented.
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PMID:New perspectives on anti-HER2/neu therapeutics. 1293 53

C-erbB-2 (HER2/neu) protein overexpression or amplification has been noted in some solid tumors a molecular target for tumor suppression. C-erbB-2 protein is localized on the membrane surface and is classified in the EGFR family. Trastuzumab is a humanized monoclonal antibody which binds to the extracellular domain of the c-erbB-2 protein in breast cancer cells. Good responders to trastuzumab may be ICH 2 + and FISH positive breast tumors, and ICH 3 + cancer. The response rate is approximately 15% with single administration of trastuzumab. Combination therapy with paclitaxel for the treatment of patients with metastatic cancer may bring more than 60% response and improve time to disease progression. Congestive heart failure associated with trastuzumab may be severe, and combination therapy which includes anthracyclines increases the incidence and severity of cardiac dysfunction. Other toxicities include infusion reaction.
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PMID:[Clinical implications of trastuzumab]. 1293 63

A major limitation in the chemotherapy of cancer results from the lack of tumor specificity displayed by most anticancer drugs. In this regard, a great deal of research has been focused on the development of new chemotherapeutic agents that are able to effectively exploit the differences between neoplastic and normal tissues. Several cancerous tissues and tumors are rich in certain lysosomal enzymes as compared with those found in the normal tissues. Thus, a prodrug can be designed to selectively target such tumor cells where it can be activated to antineoplastic agent by tumor-associated antigen-targeted monoclonal antibody-enzyme conjugate (antibody directed enzyme prodrug therapy strategy) or by the action of an enzyme present at high levels in tumor tissues (prodrug monotherapy strategy). This approach protects the normal cells from the cytotoxic effects of the drug. In the last few years, a number of new MAb-based reagents has been clinically approved (Rituxan, Herceptin and Panorex), and several others are now in advanced clinical trials. This review focuses on the design of several different enzyme/prodrug combinations with an emphasis on mechanistic insight and clinical activity.
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PMID:Selective activation of anthracycline prodrugs for use in conjunction with ADEPT. 1294 62

Immunotherapy (biological therapy) comprises such things as active specific immunotherapy ("cancer vaccines"), nonspecific immunostimulation with cytokines, and the inhibition of suppressor influences exerted or elicited by the tumor. Just as cancer chemotherapy began with the use of single agents and evolved into combination therapy, so immunotherapeutic agents have been combined with each other and with chemotherapy. The alkylating agent cyclophosphamide (Cytoxan; CYC) has been used for many years to inhibit tumor-derived suppressor influences in rodents, and has been exploited for the same use in humans. Combinations of CYC and cancer vaccines such as autologous tumor cells, Melacine, large multivalent immunogen (LMI), and Theratope have been tested with some success in humans for more than a decade. In this use, the CYC is a biological response modifier rather than an antitumor agent, intended to inhibit suppressor influences. CYC and low- to moderate-dose IL-2 has also been a useful regimen in treating human melanomas. IL-2 is itself a useful component of combination immunotherapy, such as with melanoma peptide vaccines, or with interferon alpha-2b, (IFN-alpha), as a dual combination or part of a biochemotherapy regimen. Several different combinations of drugs and biological agents have been used as biochemotherapy for melanoma, but although there are higher response (regression) rates the long-range survival benefits have been marginal, not justifying the severe toxicity. Combinations of 5-fluorouracil (5-FU) and IFN-alpha or levamisole have had efficacy in colon and head and neck cancers, but here the biological agents have been biochemical modulators, not immunotherapy. Although experience with combinations of monoclonal antibodies and chemotherapy has been limited, it appears that trastuzumab (Herceptin) potentiates antitumor therapy in breast cancer but also increases the cardiotoxicity of those regimens.
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PMID:Combinations of anticancer drugs and immunotherapy. 1294


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