Epidermal growth factor receptor directed therapy in head and neck cancer

Therapeutic Potential of Antibody-Drug Conjugate-Based Therapy in Head and Neck Cancer: A Systematic Review

BACKGROUND

Antibody-drug conjugates (ADCs) are designed to deliver potent cytotoxic agents into tumor tissues. During the last two decades, a plethora of ADCs have been successfully developed and used for several indications, including hematologic and solid tumors. In this work, we systematically reviewed the progress in ADC development for the treatment of HNC.

METHODS

This review was registered in PROSPERO database. A comprehensive search was conducted following PRISMA guidelines and using PubMed, Scopus and Web of Science database.

RESULTS

In total, 19 studies were included. Due to the significant heterogeneity of the outcome measures, meta-analysis was not performed, and data were summarized in tables. HNC results are poorly represented in the cohorts of completed clinical trials; published data are mostly focused on safety evaluation rather than efficacy of ADCs.

CONCLUSIONS

Although several novel agents against a wide range of different antigens were investigated, showing promising results at a preclinical level, most of the targets reported in this review are not specific for HNC; hence, the development of ADCs tailored for the HNC phenotype could open up new therapeutic perspectives. Moreover, the results from the present systematic review call attention to how limited is the application of current clinical trials in HNC.

Novel quinazolin-4(3H)-one linked to 1,2,3-triazoles: Synthesis and anticancer activity

In this work, a wide range of novel quinazolin-4(3H)-one linked to 1,2,3-triazoles was designed, synthesized, and evaluated against a panel of three human breast (MDA-MB-231, MCF-7, T-47D), lung (A549), and prostate (PC3) cancer cell lines. Our results revealed that the anticancer activity of the synthesized compounds was selectively affected by the presence of methoxy group on the linker between quinazolinone and 1,2,3-triazole moieties. According to the calculated IC₅₀ values, compounds 6q, 6w, and 6x showed good cytotoxicity against breast cancer cell lines even more effective than the reference drug, etoposide. Compounds 6q and 6u were found to be potent compounds against A549, non-small-cell lung cancer (NSCLC), comparing with erlotinib. Also, the morphological analysis by acridine orange/ethidium bromide double staining test and flow cytometry analysis indicated that potent compounds induced apoptosis in human cancer cell lines. Molecular docking studies were performed to clarify the inhibition mode of compounds 6g, 6u, 6w, and 6x over the EGFR active site. The most promising compounds, 6q and 6u, possessing 3-methoxy group were well oriented to the gatekeeper hydrophobic pocket of EGFR active site and interact well with Ala719, Val702, and Leu820 through hydrophobic interaction.

From Normal Skin to Squamous Cell Carcinoma: A Quest for Novel Biomarkers

Squamous cells carcinoma (SCC) is the second most frequent of the keratinocyte-derived malignancies after basal cell carcinoma and is associated with a significant psychosocial and economic burden for both the patient himself and society. Reported risk factors for the malignant transformation of keratinocytes and development of SCC include ultraviolet light exposure, followed by chronic scarring and inflammation, exposure to chemical compounds (arsenic, insecticides, and pesticides), and immune-suppression. Despite various available treatment methods and recent advances in noninvasive or minimal invasive diagnostic techniques, the risk recurrence and metastasis are far from being negligible, even in patients with negative histological margins and lymph nodes. Analyzing normal, dysplastic, and malignant keratinocyte proteome holds special promise for novel biomarker discovery in SCC that could be used in the future for early detection, risk assessment, tumor monitoring, and development of targeted therapeutic strategies.

Nanoparticle-based targeted therapeutics in head-and-neck cancer

Head-and-neck cancer is a major form of the disease worldwide. Treatment consists of surgery, radiation therapy and chemotherapy, but these have not resulted in improved survival rates over the past few decades. Versatile nanoparticles, with selective tumor targeting, are considered to have the potential to improve these poor outcomes. Application of nanoparticle-based targeted therapeutics has extended into many areas, including gene silencing, chemotherapeutic drug delivery, radiosensitization, photothermal therapy, and has shown much promise. In this review, we discuss recent advances in the field of nanoparticle-mediated targeted therapeutics for head-and-neck cancer, with an emphasis on the description of targeting points, including future perspectives.

Expression of the EPHB4 receptor tyrosine kinase in head and neck and renal malignancies--implications for solid tumors and potential for therapeutic inhibition

Solid malignancies are often characterized by overexpression of various receptor tyrosine kinases (RTKs) against which many targeted therapies are currently in use and in active development. EPHB4 has recently emerged as a frequently overexpressed RTK in many types of cancer. Here, we demonstrate expression patterns of EPHB4 in two solid malignancies: squamous cell carcinoma of the head and neck (HNSCC) and renal cell carcinoma (RCC), by immunohistochemical analysis. We demonstrate the first association between EPHB4 expression and progression of HNSCC from normal tissue to dysplasia and to cancer. Interestingly, most RCC subtypes exhibited expression patterns that were opposite from that found in HNSCC, possibly owing to their unique biology and high degree of organ and tumor vasculature. Taken together, these results suggest a possible role for EPHB4 as a therapeutic target in these malignancies.

Genetic and chemical targeting of epithelial-restricted with serine box reduces EGF receptor and potentiates the efficacy of afatinib

EGF receptor (EGFR) is elevated in more than 90% of head and neck squamous cell carcinoma (HNSCC). However, a majority of patients with HNSCC do not respond to anti-EGFR therapeutics. Insensitivity to EGFR inhibitors may be due to kinase-independent actions of EGFR and/or activation of Her2. Strategies to reduce EGFR and Her2 protein levels in concert may be an optimal approach to enhance the efficacy of current anti-EGFR molecules. In this study, knockdown of epithelial-restricted with serine box (ESX) decreased EGFR and Her2 promoter activity, expression, and levels. ESX was elevated in primary HNSCC tumors and associated with increased EGFR and Her2. Genetic ablation of ESX decreased EGFR and Her2 levels and enhanced the antiproliferative effects of EGFR/Her2 tyrosine kinase inhibitors (TKI), lapatinib and afatinib. Biphenyl isoxazolidine, a novel small-molecule ESX inhibitor, reduced EGFR and Her2 levels and potentiated the antiproliferative efficacy of afatinib. Single-agent biphenyl isoxazolidine retarded the in vivo tumorigenicity of CAL27 cells. Importantly, the combination of biphenyl isoxazolidine and afatinib was significantly superior in vivo and resulted in a 100% response rate with a 94% reduction in tumor volume. Targeting EGFR/Her2 levels with an ESX inhibitor and EGFR/Her2 kinase activity with a TKI simultaneously is a highly active therapeutic approach to manage HNSCC. Our work provides evidence to support the further development of ESX inhibitors as an adjuvant to enhance the response rate of patients with HNSCC to current anti-EGFR/Her2 therapeutics.

Head and neck cancer: from anatomy to biology

The 20th century saw great advances in anatomy-based (surgery and radiotherapy) and chemotherapy approaches for treating head and neck squamous cell carcinoma (HNSCC) and improving quality of life (QoL). However, despite these advances, the survival rate in HNSCC remains at ∼50%. Front-line treatments often cause severe toxicity and debilitating long-term impacts on QoL. In recent decades, dramatic advances have been made in our knowledge of fundamental tumor biology and signaling pathways that contribute to oncogenesis and cancer progression. These insights are presenting unprecedented opportunities to develop more effective and less toxic treatments that are specific to particular molecular targets. This review discusses some of the major, potentially targetable, molecular pathways associated with head and neck carcinogenesis. We present the general mechanism underlying the functional components for each signaling pathway, discuss how these components are aberrantly regulated in HNSCC and describe their potential as therapeutic targets. We have restricted our discussion to "drug-able targets" such as oncogenes including those associated with HPV, tumor hypoxia and microRNAs and present these changes in the context of HNSCC patient care. The specific targeting of these pathways to achieve cancer control/remission and reduce toxicity is now challenging conventional treatment paradigms in HNSCC. This new "biologic era" is transforming our ability to target causal pathways and improve survival outcomes in HNSCC.

A Phase I, open-label, dose escalation study of afatinib, in a 3-week-on/1-week-off schedule in patients with advanced solid tumors

Background A Phase I study to determine the maximum tolerated dose (MTD) and pharmacokinetics of afatinib (BIBW 2992), a novel irreversible ErbB Family Blocker, administered orally once daily in a 3-week-on/1-week-off dosing schedule. Methods Patients with advanced solid tumors received single-agent afatinib at 10, 20, 40, 55 or 65 mg/day. Safety, antitumor activity, pharmacokinetics and pharmacodynamic modulation of biomarkers were assessed. Results: Forty-three patients were enrolled. Dose-limiting toxicities (DLTs) occurred in five patients in the dose escalation phase (1/8 at 40 mg/day; 1/6 at 55 mg/day; 3/6 at 65 mg/day). The MTD was established at 55 mg/day. In the expansion cohort at the MTD, 6 patients experienced a DLT in the first 28-day treatment period. The most frequent DLT was diarrhea. The most common adverse events were diarrhea, rash, nausea, vomiting and fatigue. Overall, the afatinib safety profile in a 3-week-on/1-week-off dose schedule was similar to that of our daily-continuous schedule. Afatinib displayed dose-dependent pharmacokinetics at doses up to and including 55 mg/day, with a terminal half-life suitable for once-daily dosing. Signs of clinical antitumor activity were observed. In biopsies taken from clinically normal forearm skin, afatinib caused a reduced proliferation rate, with a concomitant increase in differentiation of epidermal keratinocytes. Conclusion Afatinib in a 3-week-on/1-week-off schedule showed a good safety profile. The MTD was 55 mg/day, although excess DLTs in the expansion cohort indicated that the 40 mg/day dose would have an acceptable safety profile for future studies. Dose cohorts between 40 and 55 mg/day were not examined in this study.

Targeted therapy in head and neck cancer

Head and neck squamous cell carcinoma (HNSCC) of multi-factorial etiopathogenesis is rising worldwide. Treatment-associated toxicity problems and treatment failure in advanced disease stages with conventional therapies have necessitated a focus on alternative strategies. Molecular targeted therapy, with the potential for increased selectivity and fewer adverse effects, hold promise in the treatment of HNSCC. In an attempt to improve outcomes in HNSCC, targeted therapeutic strategies have been developed. These strategies are focusing on the molecular biology of HNSCC in an attempt to target selected pathways involved in carcinogenesis. Inhibiting tumor growth and metastasis by focusing on specific protein or signal transduction pathways or by targeting the tumor microenvironment or vasculature are some of the new approaches. Targeted agents for HNSCC expected to improve the effectiveness of current therapy include EGFR inhibitors (Cetuximab, Panitumumab, Zalutumumab), EGFR tyrosine kinase inhibitors (Gefitinib, Erloitinib), VEGFR inhibitors (Bevacizumab, Vandetanib), and various inhibitors of, e.g., Src-family kinase, PARP, proteasome, mTOR, COX, and heat shock protein. Moreover, targeted molecular therapy can also act as a complement to other existing cancer therapies. Several studies have demonstrated that the combination of targeting techniques with conventional current treatment protocols may improve the treatment outcome and disease control, without exacerbating the treatment related toxicities. Some of the targeted approaches have been proved as promising therapeutic potentials and are already in use, whereas remainder exhibits mixed result and necessitates further studies. Identification of predictive biomarkers of resistance or sensitivity to these therapies remains a fundamental challenge in the optimal selection of patients most likely to benefit from targeted treatment.

Head and neck tumor cell radiation response occurs in the presence of IGF1

Radiation therapy for head and neck cancer results in severe secondary side-effects in salivary glands. We previously demonstrated that the administration of IGF1 preserves or restores salivary gland function following radiation. Based on these findings, we propose to study the effect of IGF1 on human head and neck carcinoma cells. Head and neck tumor cells treated with radiation have significant reductions in tumor cell survival, as measured by MTT and crystal violet assays, regardless of IGF1 pre-treatment. Head and neck squamous carcinoma cell xenografts treated with concurrent radiation+IGF1 also exhibit significant tumor growth delay; however, growth rates are elevated compared with those in irradiated xenografts. In contrast, administration of IGF1 after radiation treatment has no effect on tumor xenograft growth rates. Analysis of these data suggests that localized delivery may be required for concurrent therapy to prevent secondary side-effects of radiotherapy, while post-therapy administration of IGF1 could be considered for the restoration of salivary function.

Mononuclear phagocytes in head and neck squamous cell carcinoma

The head and neck squamous cell carcinoma microenvironments contain many immune cells and their secretory products. Many of these cells belong to the mononuclear phagocyte system. The aim of this review is to study the interactions between mononuclear phagocytes and head and neck squamous cell carcinoma tissue. The role of inflammation in tumours and the cytokine interleukin-6 will be highlighted. Future therapy strategies in the treatment of head and neck cancer might be directed towards mononuclear phagocytes and their cytokine production.

FcgammaRIIIa polymorphisms and cetuximab induced cytotoxicity in squamous cell carcinoma of the head and neck

PURPOSE

The interaction of Fc fragments of antibodies with the Fcgamma receptors is an essential checkpoint in antibody-dependent cellular cytotoxicity (ADCC). Specific polymorphisms at position 158 enhance FcgammaRIIIa affinity for IgG1 and are associated with improved clinical outcome in lymphoma patients treated with IgG1 anti-CD20 antibody. The role of ADCC in the therapeutic effects of the alpha-epidermal growth factor receptor (EGFR) mAb, cetuximab, in patients with squamous cell carcinoma of the head and neck (SCCHN) is poorly defined. We employed three SCCHN cell lines to test two hypotheses: (1) SCCHN is susceptible to cetuximab-mediated ADCC, (2) efficacy of ADCC is associated with polymorphisms at position 158 of FcgammaRIIIa.

EXPERIMENTAL DESIGN

FcgammaRIIIa-158 polymorphisms were determined for healthy donors, and their purified NK cells were used as effector cells against three SCCHN cell lines in ADCC assays. Cytotoxicity levels were compared for each polymorphism class. Proliferation and cell cycle assays were done to examine the direct effects of cetuximab.

RESULTS

Our results indicate that SCCHN is susceptible to cetuximab-mediated ADCC in vitro. NK cytotoxic efficiency correlates with donor 158-polymorphisms in FcgammaRIIIa. Overall cytotoxicity was greatest for individuals having a single V allele when compared to homozygous F/F individuals; the cumulative percent cytotoxicity for each polymorphism among the cell lines was 58.2% V/V, 50.6% V/F, and 26.1% F/F (P < 0.001). Additionally, the presence of a V allele correlated with superior natural cytotoxicity against NK sensitive targets.

CONCLUSION

These data have both prognostic and therapeutic relevance and support the design of a prospective trial to determine the influence of FcgammaRIIIa polymorphisms on the clinical outcome of patients with SCCHN treated with alpha-EGFR mAbs.

PUMA mediates EGFR tyrosine kinase inhibitor-induced apoptosis in head and neck cancer cells

Overexpression of epidermal growth factor receptor (EGFR) is found in over 80% of head and neck squamous cell carcinomas (HNSCC) and associated with poor clinical outcomes. EFGR selective tyrosine kinase inhibitors (TKIs) or antibodies have recently emerged as promising treatments for solid tumors, including HNSCC, though the response rate to these agents is low. p53 upregulated modulator of apoptosis (PUMA), a BH3-only Bcl-2 family protein, is required for apoptosis induced by p53 and various chemotherapeutic agents. In this study, we show that PUMA induction is correlated with EGFR-TKI sensitivity, and is mediated through the p53 family protein p73beta and inhibition of the PI3K/AKT pathway. In some HNSCC cells, the gefitinib-induced degradation of oncogenic Delta Np63 seems to facilitate p73-mediated PUMA transcription. Inhibiting PUMA expression by small hairpin RNA (shRNA) impairs gefitinib-induced apoptosis. Furthermore, PUMA or BH3 mimetics sensitize HNSCC cells to gefitinib-induced apoptosis. Our results suggest that PUMA induction through p73 represents a new mechanism of EGFR inhibitor-induced apoptosis, and provide potential ways for enhancing and predicting the sensitivity to EGFR-targeted therapies in HNSCC.

Downregulation of Notch1 and its potential correlation with epidermal growth factor receptor signalling in tongue squamous cell carcinoma

We investigated the expression of Notch1 in human oral squamous cell carcinoma (SCC) and explored its potential correlation with epidermal growth factor receptor (EGFR) signalling in oral SCC. Paraffin sections of primary SCC of the tongue and normal mucosa were screened immunohistochemically for Notch1 and EGFR proteins. Human SCC of the tongue Tca8113 cells were treated with AG1478 to block EGFR signalling, and were transfected with the vector that encodes the specific short hairpin RNA (shRNA) that targets EGFR. In SCC of the tongue expression of Notch1 was cancelled except in sites of squamous metaplasia where it was raised, while expression of EGFR was found in the peripheral cells of carcinomas, but not in sites of squamous metaplasia. In normal tongue mucosa, Notch1 was expressed mainly in the stratum corneum, but not in the stratum basale, while EGFR was expressed mainly in the stratum basale, but not in the stratum granulosum or stratum corneum. The blocking of EGFR signalling or the silencing of the EGFR gene resulted in upregulation of Notch1 at mRNA and protein levels in Tca8113 cells. These observations suggest that downregulation of Notch1 in oral SCC may be associated with upregulation of EGFR signalling.

Overview of current and future biologically based targeted therapies in head and neck squamous cell carcinoma

Recent advances in genomics, proteomics, bioinformatics and systems biology have unraveled the complex aberrant signaling networks in cancer. The knowledge accrued has dramatically increased the opportunities for discovery of novel molecular targets for drug development. Major emphasis is being laid on designing new therapeutic strategies targeting multiple signaling pathways for more effective disease management. However, the translation of in vitro findings to patient management often poses major challenges that limit their clinical efficacy. Here we will discuss how understanding the dysregulated signaling networks can explain the pitfalls in translating the laboratory findings from the bench-to-bedside and suggest novel approaches to overcome these problems using head and neck cancer as a prototype. The five year survival rates of HNSCC patients (about 50% at 5 years) have not improved significantly despite advancements in multimodality therapy including surgery, radiation and chemotherapy. Molecular targeted therapies with inhibitors of EGFR and VEGF either alone, or in combination with conventional treatments have shown limited improved efficacy. The key deregulated signaling pathways in head and neck squamous cell carcinoma (HNSCC) include EGFR, Ras, TGFβ, NFκB, Stat, Wnt/β-catenin and PI3-K/AKT/mTOR. The aberrant activities of these interrelated signaling pathways contribute to HNSCC development. In depth understanding of the cross-talks between these pathways and networks will form the basis of developing novel strategies for targeting multiple molecular components for more effective prevention and treatment of HNSCC.

Gene expression profiling identifies genes predictive of oral squamous cell carcinoma

Oral squamous cell carcinoma (OSCC) is associated with substantial mortality and morbidity. To identify potential biomarkers for the early detection of invasive OSCC, we compared the gene expressions of incident primary OSCC, oral dysplasia, and clinically normal oral tissue from surgical patients without head and neck cancer or preneoplastic oral lesions (controls), using Affymetrix U133 2.0 Plus arrays. We identified 131 differentially expressed probe sets using a training set of 119 OSCC patients and 35 controls. Forward and stepwise logistic regression analyses identified 10 successive combinations of genes which expression differentiated OSCC from controls. The best model included LAMC2, encoding laminin-gamma2 chain, and COL4A1, encoding collagen, type IV alpha1 chain. Subsequent modeling without these two markers showed that COL1A1, encoding collagen, type I alpha1 chain, and PADI1, encoding peptidyl arginine deiminase, type 1, could also distinguish OSCC from controls. We validated these two models using an internal independent testing set of 48 invasive OSCC and 10 controls and an external testing set of 42 head and neck squamous cell carcinoma cases and 14 controls (GEO GSE6791), with sensitivity and specificity above 95%. These two models were also able to distinguish dysplasia (n = 17) from control (n = 35) tissue. Differential expression of these four genes was confirmed by quantitative reverse transcription-PCR. If confirmed in larger studies, the proposed models may hold promise for monitoring local recurrence at surgical margins and the development of second primary oral cancer in patients with OSCC.

Dendrimer-epidermal growth factor conjugate displays superagonist activity

Binding of ligands on to epidermal growth factor receptor (EGFR) can stimulate cell growth; therefore, any application employing EGF as a targeting ligand for a "drug carrier" must evaluate the effect of the conjugate on cell growth. We report the synthesis and in vitro biological activity of EGF molecules coupled to a fluorescein-labeled polyamidoamine dendrimer. The conjugate bound and internalized into several EGFR-expressing cell lines in a receptor-specific fashion. The conjugate effectively induced EGFR phosphorylation and acted as a superagonist by stimulating cell growth to a greater degree than free EGF. Concomitant administration of the chemotherapeutic drug methotrexate completely inhibited cell growth to a degree similar to its effect in the absence of the conjugate. Thus, dendrimer-EGF conjugates serve as EGFR superagonists, but this activity can be overcome by chemotherapeutic drugs. The agonist activity of these materials must be taken into consideration when using EGF conjugates for imaging applications.

Aberrant expression of cortactin in head and neck squamous cell carcinoma cells is associated with enhanced cell proliferation and resistance to the epidermal growth factor receptor inhibitor gefitinib

The CTTN gene (formerly designated EMS1), encodes cortactin, a key regulator of dynamic actin networks. Both CTTN and CCND1, the latter encoding the cell cycle regulator cyclin D1, reside at chromosomal locus 11q13, a region commonly amplified in breast cancers and head and neck squamous cell carcinoma (HNSCC). Previously, we identified a novel role for cortactin in cancer cells, whereby cortactin overexpression attenuated ligand-induced down-regulation of the epidermal growth factor (EGF) receptor (EGFR), leading to sustained signaling. However, how this affected growth factor-induced cellular responses was unclear. Here, by modulation of cortactin expression in a panel of HNSCC cell lines, we show that cortactin overexpression enhances serum- and EGF-stimulated proliferation under both anchorage-dependent and anchorage-independent conditions and also increases resistance to anoikis (detachment-induced apoptosis). These effects are associated with increased activation of extracellular signal-regulated kinase and/or AKT. Furthermore, we report that cortactin stabilizes the c-MET receptor tyrosine kinase and enhances hepatocyte growth factor-induced mitogenesis and cell scattering. Therefore, cortactin may modulate signaling by a broader range of receptors than originally proposed and thereby affect a variety of responses. Finally, we have determined that cortactin overexpression, either alone or in combination with cyclin D1 up-regulation, promotes resistance to the EGFR kinase inhibitor gefitinib. These findings indicate that cortactin may play multiple roles in progression of HNSCC and should be evaluated as a marker of prognosis, disease progression, and therapeutic responsiveness, particularly to EGFR-directed agents.

Glottic versus supraglottic tumors: differential molecular profile

Glottis and supraglottis, although anatomically interconnected, are embryologically distinct. Moreover, squamous cell carcinomas arising from these subsites, differ in terms of epidemiology, risk factors, clinical behaviour and prognosis. This study aims to explore any possible differences between their molecular profiles. We investigated in the two tumor types, the expression of epidermal growth factor receptor (EGFR), nuclear factor-kappaB (NF-kappaB) and retinoid X receptor alpha (RXRalpha), principal signal transducers associated with cancer, as well as cyclooxygenase-2 (COX-2), an enzyme induced in malignant neoplasms. The clinical material includes tumor specimens from 61 patients with laryngeal cancer of glottic or supraglottic origin. Subsite groups were matched for gender, age and histological grade. Paraffin-section immunohistochemistry was performed, to detect the aforementioned molecules. Staining patterns were membranic and cytoplasmic for EGFR, purely cytoplasmic for COX-2, nuclear for RXRalpha and cytoplasmic, as well as nuclear, for NF-kappaB. Intense EGFR and RXRalpha expression was significantly associated with glottic tumor descent (P = 0.011 and 0.001, respectively). No significant relationship was established between neoplasm location and expressions of NF-kappaB, COX-2. Our results show that tumors emerging from the two laryngeal regions, are different with regard to their molecular constitution. Upregulation of EGFR and RXRalpha in carcinomas of the glottis, might be important in the design of subsite-specific chemotherapeutic approaches.

Enhancement of docetaxel-induced cytotoxicity by blocking epidermal growth factor receptor and cyclooxygenase-2 pathways in squamous cell carcinoma of the head and neck

PURPOSE

The addition of molecular targeted agents to enhance the cytotoxicity of chemotherapeutic agents is a promising strategy in cancer treatment. The combination of cyclooxygenase-2 inhibitors and epidermal growth factor receptor tyrosine kinase inhibitors, such as celecoxib and ZD1839 (gefitinib), was reported to achieve synergistic cell growth inhibition in squamous cell carcinoma of the head and neck. Therefore, we postulated that the addition of celecoxib and ZD1839 to docetaxel, a cytotoxic agent, might further increase antitumor activity.

EXPERIMENTAL DESIGN

The combination of celecoxib, ZD1839, and docetaxel was studied for its effect on cell growth and apoptosis by cell growth inhibition and Annexin V assays. The relevant molecular targets of these agents and apoptotic markers were examined by immunoblotting analyses in the presence or absence of these three drugs. Morphologic changes of the microtubule cytoskeleton, a known target of docetaxel, were also evaluated by staining for alpha-tubulin after the combination treatment.

RESULTS

We showed that this triple combination significantly enhanced cell growth inhibition and docetaxel-induced apoptosis. Docetaxel mainly induced caspase-8 activation, whereas the addition of celecoxib and ZD1839 augmented the caspase-8 activation and enhanced caspase-9 activation. One of the underlying mechanisms for augmentation of docetaxel-induced apoptosis by celecoxib and ZD1839 is to further inhibit the activation of prosurvival pathway molecules, such as extracellular signal-regulated kinase and AKT, and the promotion of aberrant apoptosis.

CONCLUSIONS

Our studies suggest that the combination of docetaxel with a cyclooxygenase-2 inhibitor and an epidermal growth factor receptor tyrosine kinase inhibitor may further improve efficacy of docetaxel and other taxane-based therapies in squamous cell carcinoma of the head and neck.

The role of taxanes and targeted therapies in locally advanced head and neck cancer

PURPOSE OF REVIEW

This review presents new data on the role of taxanes and targeted therapies in the management of squamous cell carcinoma of the head and neck.

RECENT FINDINGS

Taxane-containing triplets are clearly superior as an induction regimen in locally advanced squamous cell carcinoma of the head and neck when compared with cisplatin/5 fluorouracil which has been the standard for two decades. Preliminary data suggest that the addition of a taxane to cisplatin/5 fluorouracil as induction regimen followed by chemoradiation may be superior to chemoradiation alone. The addition of cetuximab to radiation prolongs locoregional control and survival without increasing mucositis. Areas of active investigation are the search for epidermal growth factor receptor mutations and the optimal way of integrating epidermal growth factor receptor-directed therapies into standard management. Meanwhile new targets are explored.

SUMMARY

Taxane/cisplatin/5 fluorouracil induction chemotherapy is clearly superior to cisplatin/5 fluorouracil. Epidermal growth factor receptor directed therapies can safely be combined with radiation and the combination shows encouraging results.

Combination of radiotherapy with EGFR antagonists for head and neck carcinoma

The introduction of biologically sound radiation fractionation regimens and combinations of radiotherapy with chemotherapy have gradually improved both the survival of patients with locally advanced head and neck squamous cell carcinoma (HNSCC) and the prospect of organ preservation. Long-term follow-up, however, has shown that some of the radiation-chemotherapy combinations are associated with increased late toxicity. This observation, in conjunction with advances in tumor biology, has led to the launch of investigations into molecular markers and targets for therapeutic interventions. Research on the epidermal growth factor receptor (EGFR)-mediated signaling pathway has enriched our understanding of the biology of HNSCC, in terms of carcinogenesis and cellular processes governing tumor response to therapy. The finding that the addition of an antibody-based inhibitor of the EGFR pathway to radiotherapy significantly improves locoregional control and overall survival rates in patients with locally advanced HNSCC, without increasing radiation-induced toxicity, has resulted in the growing acceptance of such combined regimens as a frontline therapy option for locally advanced HNSCC. Because such therapy has benefited only an additional 10%-15% of patients, studies are being undertaken to identify markers and mechanisms of resistance to EGFR antagonists that are essential for the further refinement of therapy. Overall, preclinical and clinical studies on EGFR have validated the concept that selective tumor radiation sensitization can be achieved by modulating a specific perturbed signaling pathway, and these studies have increased the enthusiasm for developing and investigating other novel agents targeting other cellular processes.

Cetuximab in the treatment of head and neck cancer

Approaches to the treatment of locally advanced and recurrent and/or metastatic squamous cell carcinoma of the head and neck (SCCHN) have been limited by their toxicity. Effective, better tolerated approaches are urgently required. Cetuximab is an immunoglobulin G(1) monoclonal antibody that specifically targets the epidermal growth factor receptor (EGFR), which is commonly expressed in a number of solid tumors, including SCCHN, where it is associated with poor prognosis. Cetuximab is approved in 56 countries for use in the treatment of EGFR-expressing metastatic colorectal cancer that has progressed on irinotecan-containing therapy and has recently received approval in Europe and the USA for use in the treatment of SCCHN. A randomized Phase III study has demonstrated that cetuximab plus radiotherapy can significantly improve locoregional control and prolong overall survival compared with radiotherapy alone. Cetuximab has also been confirmed to be effective as monotherapy in recurrent and/or metastatic SCCHN that has progressed on platinum-containing therapy. Clinical studies have demonstrated that cetuximab is well tolerated and does not significantly increase the side effects associated with radiotherapy or chemotherapy. This article presents the rationale for EGFR inhibition in the management of head and neck cancers, and the preclinical and clinical evidence for the use of cetuximab in the treatment of SCCHN.

A phase I trial of intermittent high-dose gefitinib and fixed-dose docetaxel in patients with advanced solid tumors

PURPOSE

Based on our mouse xenograft model demonstrating that intermittent high-dose gefitinib sensitizes tumors to subsequent treatment with taxanes, we initiated this phase I trial to explore docetaxel in combination with escalating doses of intermittent gefitinib (Iressa) given prior to docetaxel.

METHODS

This was a phase I study where patients with advanced cancer were treated with escalating doses of gefitinib (1,000, 1,500, 2,250, 3,000 mg) on days 1 and 2 followed by docetaxel (75 mg/m2) on day 3 of a 21 day cycle. Gefitinib pharmacokinetic data were obtained on days 1, 2, and 3 of cycles 1 and 2 at each dose level.

RESULTS

18 patients were enrolled in this study with the most frequent tumor types being non-small cell lung cancer and head and neck squamous cell cancer. The dose-limiting toxicity was neutropenia (n=1 at dose level 2, n=2 at dose level 4). Rash, diarrhea, and fatigue were the most common grade 1-2 toxicities. Pharmacokinetic data indicated no accumulation of gefitinib between cycles 1 and 2 and no clear correlation between gefitinib plasma levels and toxicity. Partial responses were observed in one patient with head and neck squamous cell carcinoma and one patient with anaplastic thyroid cancer.

CONCLUSION

The recommended dose for phase II studies is gefitinib 2,250 mg on days 1 and 2, followed by docetaxel 75 mg/m2 on day 3.

Reducing the "risk" of chemoprevention: defining and targeting high risk--2005 AACR Cancer Research and Prevention Foundation Award Lecture

Two large-scale, phase III cancer prevention trials, the Breast Cancer Prevention Trial (BCPT) of tamoxifen and Prostate Cancer Prevention Trial (PCPT) of finasteride, concluded with strikingly positive and simultaneously problematic results: reduced cancer risks but a major adverse finding with each agent that prevented its widespread use in the community. For most moderate-risk people, such as those studied in the BCPT and PCPT, the benefit of reduced breast or prostate cancer does not outweigh the major risk of tamoxifen (endometrial cancer in the BCPT) or apparent risk of finasteride (high-grade prostate cancer in the PCPT). Promising interventions with biologically active substances are likely to have adverse, perhaps unforeseen effects, especially with long-term preventive use. Acceptance of such agents will depend heavily on the level of cancer risk of the target population. This article outlines research in molecularly identified high-risk oral intraepithelial neoplasia that creates the clinical opportunity for optimizing the risk-benefit ratio of agents to prevent oral cancer. Two other major research efforts focused on improving preventive agent risk-benefit ratios are molecular-targeted research designed to target away from known adverse signaling pathways and multidisciplinary research based on the PCPT that will develop comprehensive models of prostate cancer risk (especially of aggressive prostate cancer) and pharmacoecogenetic models for identifying high-risk men most likely to benefit from (and not be harmed by) finasteride or similar (5alpha-reductase inhibiting) agents. Defining and targeting high-risk populations, developing molecular-targeted approaches, and developing accurate pharmacoecogenetic models promise to reduce the risk of chemoprevention and ultimately to reduce the risk and burden of major cancers.