New cytotoxic and molecular-targeted therapies of head and neck tumors

NSP 5a3a: a potential novel cancer target in head and neck carcinoma

NSP 5a3a along with three other distinct though similar splice variants were initially identified corresponding to locus HCMOGT-1 on chromosome 17p11.2 [1]. Secondary structure analysis of the novel structural protein (NSP) isoforms revealed similarity to Spectrin like proteins containing coiled coil domains [1]. The NSP 5a3a isoform had been found to be highly expressed in-vitro in particular cancer cell lines while very low to un-detectable levels in normal body tissues [1]. Subsequent investigation of this isoform revealed its novel interaction with B23 [2], a multifunctional nucleolar protein involved in ribosome biogenesis, rRNA transcription, mitosis, cell growth control, and apoptosis [3]. Subsequent investigation, elucidated NSP 5a3a's potential involvement in cellular processes such as ribosome biogenesis and rRNA processing by validating NSP 5a3a's novel interaction with B23 and ribonuclear protein hnRNP-L possibly implicating NSP 5a3a's involvement in cellular activities such as RNA metabolism and processing [4]. In this preliminary investigation, we wanted to observe the effect that over-expressing NSP 5a3a may have on cell cycle and its potential application in cancer treatment in aggressive cancers such as head and neck carcinomas. Over-expressed NSP 5a3a in HN30 cells induced a significant degree of apoptosis, an average of a 10.85 fold increase compared to controls 3 days post-transfection. This effect was more significant then the apoptosis observed between Fadu cells over-expressing NSP 5a3a and its controls. Though, the apoptosis induced in the WI38 control cell line showed an average of a 13.2 fold increase between treated and controls comparable to the HN30 cell line 3 days post-transfection. Molecular analysis indentified a novel p73 dependent mechanism independent of p53 and caspase 3 activity through which NSP 5a3a is inducing apoptosis. We propose NSP 5a3a as a potential therapeutic target for site directed cancer treatment in perhaps certain head and neck carcinomas by induction of apoptosis.

NSP 5a3a: a potential novel cancer target in head and neck carcinoma

NSP 5a3a along with three other distinct though similar splice variants were initially identified corresponding to locus HCMOGT-1 on chromosome 17p11.2 [1]. Secondary structure analysis of the novel structural protein (NSP) isoforms revealed similarity to Spectrin like proteins containing coiled coil domains [1]. The NSP 5a3a isoform had been found to be highly expressed in-vitro in particular cancer cell lines while very low to un-detectable levels in normal body tissues [1]. Subsequent investigation of this isoform revealed its novel interaction with B23 [2], a multifunctional nucleolar protein involved in ribosome biogenesis, rRNA transcription, mitosis, cell growth control, and apoptosis [3]. Subsequent investigation, elucidated NSP 5a3a's potential involvement in cellular processes such as ribosome biogenesis and rRNA processing by validating NSP 5a3a's novel interaction with B23 and ribonuclear protein hnRNP-L possibly implicating NSP 5a3a's involvement in cellular activities such as RNA metabolism and processing [4]. In this preliminary investigation, we wanted to observe the effect that over-expressing NSP 5a3a may have on cell cycle and its potential application in cancer treatment in aggressive cancers such as head and neck carcinomas. Over-expressed NSP 5a3a in HN30 cells induced a significant degree of apoptosis, an average of a 10.85 fold increase compared to controls 3 days post-transfection. This effect was more significant then the apoptosis observed between Fadu cells over-expressing NSP 5a3a and its controls. Though, the apoptosis induced in the WI38 control cell line showed an average of a 13.2 fold increase between treated and controls comparable to the HN30 cell line 3 days post-transfection. Molecular analysis indentified a novel p73 dependent mechanism independent of p53 and caspase 3 activity through which NSP 5a3a is inducing apoptosis. We propose NSP 5a3a as a potential therapeutic target for site directed cancer treatment in perhaps certain head and neck carcinomas by induction of apoptosis.

Cell adhesion molecules, the extracellular matrix and oral squamous carcinoma

Carcinomas are characterized by invasion of malignant cells into the underlying connective tissue and migration of malignant cells to form metastases at distant sites. These processes require alterations in cell-cell and cell-extracellular matrix interactions. As cell adhesion molecules play a role in cell-cell and cell-extracellular matrix adhesion and interactions they are involved in the process of tumour invasion and metastases. In epithelial tissues, receptors of the integrin family mediate adhesion to the adjacent matrix whereas cadherins largely mediate intercellular adhesion. These and other cell adhesion molecules such as intercellular adhesion molecule-1, CD44, dystroglycans and selectins, are involved and undergo changes in carcinomas, which provide possible targets for anti-cancer drug treatments. In the extracellular matrix that is associated with tumours, laminin 5, oncofetal fibronectin and tenascin C appear. The degree of expression of some of these moieties indicates prognosis in oral cancer and offer targets for antibody-directed radiotherapy. Metalloproteases which degrade the extracellular matrix are increased in carcinomas, and their activity is necessary for tumour angiogenesis and consequent invasion and metastases. Metalloprotease inhibitors have begun to produce decreases in mortality in clinical trials. This report provides a brief overview of our current understanding of cell adhesion molecules, the extracellular matrix, tumour invasion and metastasis.

Improved synthesis of substituted 6,7-dihydroxy-4-quinazolineamines: tandutinib, erlotinib and gefitinib

The synthesis of three substituted 6,7-dihydroxy-4-quinazolineamines: tandutinib (1), erlotinib (2) and gefitinib (3) in improved yields is reported. The intermediates were characterized by NMR and the purities determined by HPLC.

Expression of KIT, EGFR, HER-2 and tyrosine phosphorylation in undifferentiated thyroid carcinoma: Implication for a new therapeutic approach

The KIT, epidermal growth factor receptor (EGFR) and HER-2 oncoproteins have tyrosine kinase activity and are molecular targets in human cancer therapy. To clarify the significance of KIT, EGFR, and HER-2 in undifferentiated thyroid carcinoma (UTC), the expression of these receptors and tyrosine phosphorylation was examined immunohistochemically in resected cases of UTC and papillary thyroid carcinoma (PTC). KIT, EGFR, and HER-2 were also examined at the protein and mRNA levels in five UTC cell lines. KIT expression (1+), EGFR overexpression (2+/3+), HER-2 expression (1+), and tyrosine phosphorylation were detected immunohistochemically in 40%, 70%, 10%, and 50% of the 10 UTC. In 20 PTC, KIT, EGFR, and HER-2 were not detected, but tyrosine phosphorylation was detected in 25% of cases. In the five UTC cell lines, KIT expression (1+), EGFR overexpression (3+), HER-2 expression (1+), and tyrosine phosphorylation were detected immunocytochemically in 60%, 100%, 20%, and 40%, respectively. Western blot analysis did not detect KIT expression, but did detect EGFR and HER-2 expression in all five cell lines. Real-time polymerase chain reaction detected KIT mRNA in two of the cell lines (40%), EGFR in five (100%), and HER-2 in three (60%). The present findings suggest that EGFR overexpression was involved in the proliferation and development of UTC and was frequently accompanied by tyrosine phosphorylation. Expression of KIT and HER-2 appeared to be weak but significant, suggesting a possible role in the development of UTC. Molecular therapies targeting KIT, EGFR, HER-2, and/or tyrosine phosphorylation might be indicated for UTC.

Review of current treatment practices for carcinoma of the head and neck

The past two decades have witnessed a paradigm shift in the treatment of squamous cell carcinoma of the head and neck. Innovation in chemotherapy, radiotherapy and surgery has led to the assimilation of these modalities into our treatment algorithms. This modern multipart treatment plan has led to improved survival; however, this has come at the cost of increased toxicity. New and future therapies will be more tumour specific and, ideally, less toxic. Current research centres on these tumour-specific therapies with the anticipation of improved survival with decreased toxicity. This article will review the standard of care, recent advances and unfulfilled needs in the treatment of squamous cell carcinoma of the head and neck.

Why do patients with head and neck squamous cell carcinoma experience distant metastases: can they be prevented?

PURPOSE OF REVIEW

This article will examine recent publications that enhance our understanding of this process, and current areas of investigation for therapeutic intervention in preventing and treating metastatic disease.

RECENT FINDINGS

Recent investigations have led to insights into the mechanisms of cellular adhesion, invasion, and angiogenesis. E-cadherin, integrins, and selectins are all pivotal in cell-cell adhesion and communication. Recent advances in the area of tumor angiogenesis have led to our discovery of endostatin, an anti-angiogenic peptide that has potential in treating metastatic head and neck cancer. Current trials looking at sentinel node mapping may allow us to evaluate the nodal status of early head and neck cancer and identify a subset of patients at risk for distant metastasis.

SUMMARY

As our understanding of metastatic disease increases, so will our ability to intervene in the various pathways involved in metastatic evolution. Metastatic cells are likely to respond differently to chemotherapeutic agents. Agents inhibiting specific aspects of invasion, adhesion, and angiogenesis will need to be combined to intervene at these key steps. Continued investigation into the biology of the epidermal growth factor receptor has led to an increased understanding of the mechanisms of abrogation of apoptosis, increased cellular motility, and metastasis. Inhibition of the epidermal growth factor receptor pathway with the monoclonal antibody C-255 has been shown to inhibit these processes and will likely be effective in reducing the development of distant metastasis.

Le récepteur à l'EGF et les cancers des voies aérodigestives supérieures

EGFR is overexpressed and is associated with a poor prognosis in head and neck cancer. Among the biological and cellular effects resulting from EGFR targeting in head and neck cancer there is the capacity to restore apoptotic capacities. Other experimental results put into evidence that DNA-repair activity was reduced by the application of EGFR targeting agents. This context was in favor of a research oriented towards combination between anti-EGFR drugs and cytotoxic agents, particularly irradiation. Supra-additive cytotoxic effects have been observed at the experimental level when combining anti-EGFR drugs with irradiation in head and neck cancer. These experimental data were recently confirmed at the clinical level in locally advanced head and neck cancer.