Editorial [ Hot Topic: Novel Targets for Cancer Therapy (Executive Editor: E. Bergmann-Leitner) ]

The current issue of CPD focuses on novel targets for cancer therapy as well as the development of therapies that take advantage of newly emerging information on carcinogenesis and tumor survival mechanisms. Such treatments may hold the key to successful cancer treatment and long-term survival of patients with otherwise poor prognosis. T. Okamoto et al. [1] review the regulatory function of NF-κ B for various genes involved in cell cycle progression, inhibition of apoptosis and other cellular processes. This makes NF-κ B a crucial factor in the promotion of carcinogenesis and tumor progression. Moreover, NF-κ B is involved in inflammatory responses reminding us of the link between chronic inflammation and carcinogenesis. The authors discuss the feasibility of targeted cancer therapy using NF-κ B and its signaling cascade as a molecular target. C. Leonetti and G. Zupi [2] summarize the studies on antisense oligonucleotides targeting various pathways involved in the regulation of proliferation, apoptosis and angiogenesis. The authors focus in their review on the use of antisense oligonucleotides targeting oncogenes and the combination of such treatment with chemotherapeutic drugs or signaling inhibitors. The provided information is then discussed in respect to the feasibility of such treatments in clinical settings. I. Zavrski et al. [3] give a comprehensive overview of the crucial role proteasomes play in destabilizing cell growth and survival by selectively degrading cellular proteins that are involved in the regulation of cell proliferation, growth and apoptosis. This feature makes the proteasome a potential target for anticancer treatments. The authors report on various proteasome inhibitors and their clinical efficacies. P. Tassone et al. [4] report on a very exciting new approach that is based on cell biological studies and involves the identification of survival factors. Understanding the micromilieu of the tumor and the cellular response of cancer cells to stress situations caused by the expansion of the tumor and the changes in the micromilieu is the key to comprehending the adaptations that the tumor constantly performs in order to survive. The authors report on the establishment of in vivo models that simulate these conditions and the utilization of such models for the development of novel anticancer therapies. R. Longo et al. [5] comprehensively convey the latest progress in targeted therapies for breast cancers; these therapies encompass humanized antibodies directed against growth factor receptors as well as anti-angiogenic compounds. The authors add to the review of achieved milestones an essential discussion on the remaining challenges in the development of efficacious treatments especially for patients with poor prognosis. C. Oehler et al. [6] summarize the efforts made in combining radio- and chemotherapy in order to sensitize inherently radio-resistant tumors to radiotherapy. Such radio-sensitizing drugs target various aspects of the intercellular communication network and can affect either individual cells or the entire tumor tissue. Based on recently obtained insights into the cellular responses involved in carcinogenesis and radiation responses, various reaction patterns have been identified (i.e., Repair, Reassortement, Repopulation and Reoxygenation). The authors discuss the current approaches of sensitization in the light of these reaction patterns. S. Mocellin et al. [7] review the efforts to take advantage of a powerful immune factor, tumor necrosis factor (TNF) in cancer therapies. TNF had originally been described as a molecule that affects the neovasculature of tumor cells. Later, studies have shown that tumor cells have receptors for TNF and can undergo apoptosis upon ligation of the receptor. However resistance to TNF can occur early on in tumorigenesis and thus tumor cells of more advanced cancers may be resistant to the effects of TNF. Another disadvantage of the clinical use of TNF is its systemic toxicity. The authors concisely summarize the biological, cancer-related properties of TNF and the efforts to overcome the disadvantages of TNF in order to make it a cancer-specific toxic drug........