Combination Of Biological Agents Research Articles

Sustained Activation of Phosphatidylinositol 3-Kinase/Akt/Nuclear Factor κB Signaling Mediates G Protein-coupled δ-Opioid Receptor Gene Expression

Expression of the delta-opioid receptor gene (dor) is tightly controlled during neuronal differentiation and developmental stages. Such distinct temporal and spatial expression of dor during development suggests a role for the delta-opioid receptor in early developmental events. However, little is known about intracellular signaling pathways that control dor expression. A well established cell line model for the study of gene expression during neuronal differentiation is the rat adrenal pheochromocytoma PC12 cell line. Here we found that the constitutively activated TrkA/phosphatidylinositol 3-kinase/Akt (protein kinase B)/NF-kappaB survival cascade mediates dor expression during nerve growth factor (NGF)-induced differentiation of PC12h cells. Biochemical experiments showed that constitutive phosphorylation of Akt and IkappaBalpha correlates with NGF-induced dor expression. Overexpression of the transcriptional activator NF-kappaB/p65 increased dor promoter activity. Overexpression of the NF-kappaB signaling super inhibitor mutant IkappaBalpha (S32A/S36A) abolished the effect of p65 and blocked NGF-induced activation of NF-kappaB signaling, resulting in a significant reduction in dor promoter activity. Treatment with SN50, an NF-kappaB-specific nuclear translocation peptide inhibitor, inhibited the translocation of NF-kappaB, resulting in a reduction of dor mRNA. The gel shift assay supported the fact that there exists an NF-kappaB-binding site on the dor promoter. RNA interference experiments using NF-kappaB/p65 small interfering RNA confirmed that NF-kappaB signaling is required for dor expression. Our findings not only provide a new mechanistic explanation for NGF-induced dor expression but also shed some light on the molecular mechanism of the temporal and spatial expression of dor and the roles of the delta-opioid receptor during neuronal differentiation.

Integrating basic science and clinical research in bladder cancer: update from the first bladder Specialized Program of Research Excellence (SPORE).

To review the progress of the genitourinary SPORE (Specialized Program of Research Excellence) in bladder cancer. The optimal management of bladder cancer depends on the accurate assessment of the biological potential of the disease. Methotrexate, vincristine, adriamycin and cisplatin (M-VAC) chemotherapy has been the standard of therapy for over a decade. However, there has been no improvement in patient survival. Encouraging preclinical data have resulted in the rapid translation of epidermal growth factor receptor antagonists into the clinic. However, phase I and II single-agent clinical trials in head and neck, lung, and colon cancer failed to match the hope generated by laboratory investigations since only a minority of patients seemed to benefit from this approach. Nonetheless, recent data revealed that non-small-cell lung cancer tumors that responded to single-agent Iressa possessed activating epidermal growth factor receptor mutations. These findings have generated refound interest for epidermal growth factor receptor-dependent tumors that are identified by molecular and pharmacodynamic approaches prior to or early in the course of therapy. Targeted therapy against epidermal growth factor receptor has become one of the primary focuses of the genitourinary SPORE in bladder cancer. The SPORE grant scheme is designed to encourage rapid development of new and innovative cancer research in areas of high priority, in this case bladder cancer. The SPORE has facilitated the advancement of novel epidermal growth factor receptor-targeted therapy, such as the monoclonal antibody IMC-225 and the tyrosine kinase inhibitor ZD1839 (Iressa), from the laboratory to clinical trials. The integration of these new biological agents in combination with chemotherapy, in order to abrogate the progression of advanced bladder cancer, is the prime directive of our current phase II Iressa/docetaxel trial.

The HER receptor family: a rich target for therapeutic development

PurposeThe key role of the HER family of receptors in cancer has been widely acknowledged. HER receptor activation occurs via ligand binding or nonligand-dependent receptor dimerization, initiating signals that promote tumorigenesis via cell proliferation, survival, migration, adhesion, and differentiation. Therapeutic strategies designed to target and inhibit HER activation that are in clinical development are reviewed, including examples of both small-molecule tyrosine kinase inhibitors and monoclonal antibodies. Materials and methodsA literature review. ResultsTarceva is a potent, highly selective, reversible inhibitor of HER1/epidermal growth factor receptor tyrosine kinase with inhibitory activity against various in vitro and in vivo models of solid human tumors. Phase II trials in refractory non–small-cell lung, head-and-neck, and ovarian cancer have demonstrated clinical activity, including objective responses and prolonged, stable disease. Four Phase III trials are ongoing evaluating primarily the effect on survival of Tarceva in combination with chemotherapy. 2C4 is a humanized anti-HER2 monoclonal antibody that binds to a broad, extracellular epitope, resulting in steric inhibition of HER–receptor complex formation that involves HER2. 2C4 has shown significant activity in xenograft models of prostate, lung, and breast cancer. 2C4's activity, unlike Herceptin's, is not dependent on HER2 amplification. This antibody is in early clinical development. ConclusionThe strategy of targeting the HER system has been further validated by early experience with Tarceva and 2C4. The optimal clinical benefit of these agents will likely involve combinations of biologic agents, with or without traditional chemotherapy, and will be guided by critical predictive diagnostic information.

Systemic therapy for advanced breast cancer.

An intriguing, yet highly logical area of research for breast cancer therapy is the exploration of growth factor pathways. Areas of investigation include epidermal growth factor receptor (EGFR) and vascular endothelial growth factor (VEGF) targeting. Although results of these studies to date have been less than promising, they have yielded important insights into critical factors that must be taken into consideration when devising growth factor-targeted therapies. Even though the results of EGFR and VEGF studies have not met with expectations, several preclinical models assessing new combinations of biologic agents with either hormonal therapy or chemotherapy are beginning to show promise.

Combined-modality therapy of locally advanced cervical cancer.

Six randomized trials of chemoradiotherapy in cervical cancer have demonstrated improvement with cisplatin-based chemoradiotherapy compared with radiation alone or radiation with hydroxyurea. Only one randomized trial (Gynecologic Oncology Group [GOG] 120) compared different cisplatin-based regimens and demonstrated significantly more hematologic and gastrointestinal toxic effects with the combination of cisplatin, fluorouracil, and hydroxyurea than with weekly cisplatin alone. The use of fluorouracil and mitomycin as radiation sensitizers for cervical cancer is based on their activity in chemoradiotherapy for anal carcinoma. However, a three-fold increase in serious late bowel toxicity was seen in patients treated with fluorouracil and mitomycin compared with fluorouracil alone when combined with radiation therapy for cervical cancer. Another randomized trial demonstrated improvement in survival with fluorouracil infusion compared with radiation alone only in early-stage disease. However, the most recently completed randomized trial by the GOG, which compared continuous fluorouracil infusion with weekly cisplatin, was closed when interim analysis demonstrated no potential superiority to the fluorouracil arm. Uncontrolled studies have evaluated the use of carboplatin on several different schedules, but no controlled trials have yet been performed. In metastatic and recurrent cervical cancer, a number of newer agents, including paclitaxel, gemcitabine, topotecan, and vinorelbine, have demonstrated modest single-agent activity and even greater activity in combination with cisplatin. An expanding series of trials will define the role of these new agents combined with cisplatin and radiation therapy for locally advanced cervical cancer. The potential role of biologic agents in combination with chemoradiotherapy also needs to be examined in locally advanced cervical cancer.

Biological Agents in Rheumatoid Arthritis

Rheumatoid arthritis is a chronic inflammatory disease. Established treatment is limited because of the clinical response or the induction of adverse effects. New biological agents evaluated for treatment of rheumatoid arthritis have shown varied clinical success. These agents target cytokines such as tumour necrosis factor-alpha (TNFalpha), interleukin (IL)-1 or IL-6, or cell surface molecules such as CD4, CD5, CD7, IL-2 receptor, CDw52 or CD54. Amongst these new drugs, only a few have shown clinical effectiveness in double-blind placebo-controlled trials. These include the primatised nondepleting anti-CD4 monoclonal antibody (mAb) CE9.1 (keliximab), the TNFalpha-blocking mAbs cA2 (infliximab) and CDP-571, the human recombinant soluble TNFalpha receptors p55 (lenercept) and p80, as well as the human recombinant IL-1 receptor antagonist protein, anakinra. Thus, only these agents qualify for evaluation of combination treatment in rheumatoid arthritis. Rationales for combination therapy include: combining drugs with different sites of action to increase efficacy or with different toxicities to minimise risk; combining drugs with different kinetics, thus improving clinical activity; using a combination of drugs for the prevention of tachyphylaxis; or using a second drug which helps to prevent or delay the development of resistance to the first one. In addition, combination therapy could help to prevent or minimise adverse effects caused by treatment with biological agents. Based on knowledge from trials with biological agents, and on the different properties attributed to the established disease-modifying antirheumatic drugs (DMARDs) in ex vivo and in vitro studies, we propose evaluation of the following combination regimens involving biological agents. First, biological agents targeting TNFalpha (such as the mAbs cA2 or CDP-571, or the TNFalpha receptor p55-IgG1 fusion protein) given as a single infusion for rapid clinical response could be followed by continuation treatment with methotrexate, possibly combined with chloroquine, azathioprine or cyclosporin. Combination of specific anti-TNFalpha strategies with sulfasalazine should be avoided because of the induction of double-stranded DNA antibodies seen after TNFalpha blockade in vivo and reports on a systemic lupus erythematosus-like syndrome as an adverse effect during treatment with biological agents directed against TNFalpha or with sulfasalazine. Alternatively, continuous inhibition of TNFalpha or IL-1 with TNFalpha receptor p80-IgG1 fusion protein or IL-1 receptor antagonist, respectively, could be combined with methotrexate, with the disadvantage of a slower initial improvement of clinical symptoms. Combination regimens with the primatised CD4 mAb could include methotrexate as concomitant medication, with chloroquine or sulfasalazine as additional medication. Importantly, combination of different biological agents might induce more severe adverse effects than seen with monotherapy. Thus, protocols involving combinations of biological agents with established DMARDs promise better acceptance than combinations of 2 new and as yet unestablished drugs with possibly synergistic adverse effects because of their antigenic properties.

The effects of 13- cis retinoic acid and interferon-α in chronic myelogenous leukemia cells In vivo in patients

The effects of the administration of a 3-day course of 13- cis retinoic acid in combination with interferon a [RA/IFN] on the leukemia cells was measured in vivo in 43 patients with chronic myelogenous leukemia. The administration of RA/IFN was associated with a significant fall in the white blood cell count of patients with chronic-phase disease and with a fall in the percentage S-phase cells in CML patients regardless of the stage of their leukemia. In two thirds of the patients studied the administration of RA/IFN was also associated with an increase in marrow apoptosis. The cytokine combination also suppressed bcl-2 and myc expression in a minority of patients and such expression appears to be associated with response to a treatment regimen which includes RA/IFN. These studies are the first to directly assess the effects of the combination of RA/IFN on chronic myelogenous leukemia cells in vivo in patients. These effects, if seen in other malignant diseases, could account for the therapeutic benefit which has been associated with the administration of this combination of biological agents to patients with malignant disease.

New Directions for Biological Therapy in Rheumatoid Arthritis

Advances in our understanding of the pathogenesis of rheumatoid arthritis (RA), together with developments in hybridoma and molecular technology have opened the way for more directed therapy in this disease. In reviewing the experience so far with T-cell-directed biological agents, we show that the early promise displayed by anti-CD4 monoclonal antibodies in open clinical trials has not been sustained in controlled studies. This outcome provides a challenge to the concept that CD4+ T cells are of prime importance in RA, and prompts a search for alternative therapeutic targets. Agents directed towards other leucocyte antigens such as CD5, CDw52 or the receptor for interleukin 2 have induced clinical responses in early studies, but at the expense of significant toxicity. Newer therapies targeting the monokines tumour necrosis factor alpha (TNF-alpha), IL-1 and IL-6, and the leucocyte adhesion molecule intercellular adhesion molecule 1 (ICAM-1) have provided encouraging clinical improvements and, in the case of anti-TNF-alpha and anti-IL-6, impressive modulation of the acute-phase response. Strategies allowing long-term blockade of such molecules, including antibody reshaping and the use of soluble cytokine receptors are discussed. Finally, the potential for using biological agents in combination with other therapies is outlined.

Successful Combination Immunotherapy for the Generation In Vivo of Antitumor Activity With Anti-CD3, Interleukin 2, and Tumor Necrosis Factor α

The purpose of this study was to generate lymphokine-activated killer cells via alternative pathways using combinations of biologic agents. Immunotherapy with the mouse anti-CD3 analogue combined with low-dose interleukin 2 (IL-2) and tumor necrosis factor alpha (TNF-alpha) was tested for in vivo antitumor efficacy against established pulmonary metastases from a variety of mouse tumor-cell lines. Administration of a single dose of anti-CD3 followed by low-dose IL-2 and TNF-alpha potentiated reduction of metastases compared with higher doses of IL-2 alone or IL-2 plus TNF-alpha. Treatment with anti-CD3 plus IL-2 plus TNF-alpha significantly prolonged survival and resulted in 60% of the mice achieving long-term survival compared with no survival using single agents or other combinations. The lymphokine-activated killer and natural killer activities of mouse splenocytes increased following treatment with anti-CD3 plus IL-2 plus TNF-alpha. These results indicate that the sequential use of anti-CD3, IL-2, and TNF-alpha for the induction and maintenance of lymphokine-activated killer activity potentiates antitumor activity and provides novel strategies for combination immunotherapy.

Induction of lymphokine-activated killer cytotoxicity with interleukin-2 and tumor necrosis factor-alpha against primary lung cancer targets.

Human peripheral blood mononuclear cells (PBM) activated with recombinant interleukin-2 (IL-2) generate potent lytic activity (LAK) against a variety of malignant cells. IL-2 alone is sufficient for LAK generation, but high concentrations are needed to generate optimal cytotoxicity. Our recent studies based on combinations of biological agents indicated that alternative activation pathways may exist. Synergy for LAK induction was investigated using IL-2 and tumor necrosis factor-alpha (TNF). Single-cell suspensions of primary human lung carcinomas were prepared from seven established cell lines and 32 fresh tumor specimens. Not only were all cell lines sensitive to allogeneic LAK, but also all fresh tumors were sensitive to some degree to both autologous and allogeneic LAK lysis measured by a 4-h 51Cr-release assay. LAK-mediated cytotoxicity, induced with a combination of human recombinant IL-2 (Cetus, 100 U/ml) and TNF (Genentech, 500 U/ml), showed a mean fourfold increase (range 0.7-16.3) over IL-2 alone. No lytic activity was generated from PBM incubated with media or TNF alone. The sequence dependence of adding IL-2 and TNF in enhancing cytolytic activity was also studied. In vitro kinetics data revealed that the addition of TNF 2-6 h before the addition of IL-2 greatly increased LAK activity over that obtained from the simultaneous addition of the two cytokines. These results demonstrated (a) the synergy of IL-2 and TNF for generating LAK; (b) the lysis of fresh primary lung cancer cells by LAK; and (c) the sequence dependence of IL-2 and TNF for the induction of optimal LAK activity.

Biological control of aquatic weeds: perspectives for the tropics

The background of and the means for biological control of aquatic weeds which are of practical significance in the tropics are discussed. There are only a few biological agents available which are expected to be of real importance in the near future, i.e. phytophagous fishes, such as grass carp, and arthropods which feed specifically on water hyacinth. Possibly, biological agents in combination with mechanical/manual methods, or to a lesser extent chemical means of control, could offer a promising perspective for the control of aquatic weeds in the tropics.