Advances in molecular targeted therapies to increase efficacy of (chemo)radiation therapy

Recent advances in understanding the tumor's biology in line with a constantly growing number of innovative technologies have prompted characterization of patients' individual malignancies and may display a prerequisite to treat cancer at its patient individual tumor vulnerability. In recent decades, radiation- induced signaling and tumor promoting local events for radiation sensitization were explored in detail, resulting the development of novel molecular targets. A multitude of pharmacological, genetic, and immunological principles, including small molecule- and antibody-based targeted strategies, have been developed that are suitable for combined concepts with radiation (RT) or chemoradiation therapy (CRT). Despite a plethora of promising experimental and preclinical findings, however, so far, only a very limited number of clinical trials have demonstrated a better outcome and/or patient benefit when RT or CRT are combined with targeted agents. The current review aims to summarize recent progress in molecular therapies targeting oncogenic drivers, DNA damage and cell cycle response, apoptosis signaling pathways, cell adhesion molecules, hypoxia, and the tumor microenvironment to impact therapy refractoriness and to boost radiation response. In addition, we will discuss recent advances in nanotechnology, e.g., RNA technologies and protein-degrading proteolysis-targeting chimeras (PROTACs) that may open new and innovative ways to benefit from molecular-targeted therapy approaches with improved efficacy.

Synthesis and Evaluation of 2-Amine-4-oxyphosaniline Pyrimidine Derivatives as EGFR L858R/T790M/C797S Mutant Inhibitors

Epidermal growth factor receptor (EGFR) C797S mutation leads to Osimertinib drug resistance by disturbing the covalent biding of Michael acceptor group to the Cys797 residue in the ATP biding cleft. In this manuscript, a class of 2-amine-4-oxyphosaniline pyrimidine derivatives were designed, synthesized and evaluated as new noncovalent reversible EGFR inhibitors against L858R/T790M/C797S (CTL) triple mutant. The kinases inhibitiory activity evaluation showed that four compounds exhibited significant inhibitory activities against CTL (IC₅₀ < 30 nM). In particularly, the most promising compound 7a showed excellent enzymatic inhibitory activity against CTL with IC₅₀ value of 9.9 nM, which was more potent than control compound Osimertinib. Moreover, cell proliferation assays indicated that 7a effectively inhibited H1975-EGFR L858R/T790M/C797S with IC₅₀ value of 0.33 µM. Furthermore, compound 7a displayed good metabolic stabilities in human, rat and mouse liver microsomes, and the putative biding mode of compound 7a with ATP was revealed by molecular docking study. These findings strongly indicated that compound 7a was a promising L858R/T790M/C797S mutant EGFR inhibitor.

Efficacy and toxicity of weekly paclitaxel, carboplatin, and cetuximab as induction chemotherapy or in cases of metastases or relapse for head and neck cancer with a focus on elderly or frail patients

BACKGROUND

Paclitaxel, carboplatin, and cetuximab (PCC) has shown promise as induction chemotherapy and in patients with metastatic/recurrent head and neck cancer (HNC). Given its tolerability, the regimen is used in frail and elderly patients.

METHODS

Software generated the cohort of adult patients with HNC treated with PCC in 2014-2019. Modified RECIST response rate (RR), progression-free survival (PFS), and overall survival (OS) were calculated for the metastatic/recurrent group, and successful induction rate and RR for the induction group. These were also calculated in the elderly/frail subset (EF): age ≥75, performance status ≥2, albumin <3.5.

RESULTS

Fifty-two percent of patients experienced ≥grade 3 toxicities. For metastatic/recurrent disease (N = 58), RR was 22%, mean PFS was 7.1 months. Mean OS was 15.2 months. In the induction cohort (N = 22), 86% reached their endpoint. The RR was 64%. There were no significant differences for EF.

CONCLUSIONS

PCC is well-tolerated with good induction success rate and reasonable PFS/OS in metastatic/recurrent disease.

EGFR Pathway-Based Gene Signatures of Druggable Gene Mutations in Melanoma, Breast, Lung, and Thyroid Cancers

EGFR, BRAF, PIK3CA, and KRAS genes play major roles in EGFR pathway, and accommodate activating mutations that predict response to many targeted therapeutics. However, connections between these mutations and EGFR pathway expression patterns remain unexplored. Here, we investigated transcriptomic associations with these activating mutations in three ways. First, we compared expressions of these genes in the mutant and wild type tumors, respectively, using RNA sequencing profiles from The Cancer Genome Atlas project database (n = 3660). Second, mutations were associated with the activation level of EGFR pathway. Third, they were associated with the gene signatures of differentially expressed genes from these pathways between the mutant and wild type tumors. We found that the upregulated EGFR pathway was linked with mutations in the BRAF (thyroid cancer, melanoma) and PIK3CA (breast cancer) genes. Gene signatures were associated with BRAF (thyroid cancer, melanoma), EGFR (squamous cell lung cancer), KRAS (colorectal cancer), and PIK3CA (breast cancer) mutations. However, only for the BRAF gene signature in the thyroid cancer we observed strong biomarker diagnostic capacity with AUC > 0.7 (0.809). Next, we validated this signature on the independent literature-based dataset (n = 127, fresh-frozen tissue samples, AUC 0.912), and on the experimental dataset (n = 42, formalin fixed, paraffin embedded tissue samples, AUC 0.822). Our results suggest that the RNA sequencing profiles can be used for robust identification of the replacement of Valine at position 600 with Glutamic acid in the BRAF gene in the papillary subtype of thyroid cancer, and evidence that the specific gene expression levels could provide information about the driver carcinogenic mutations.

Human blood serum can donor-specifically antagonize effects of EGFR-targeted drugs on squamous carcinoma cell growth

Many patients fail to respond to EGFR-targeted therapeutics, and personalized diagnostics is needed to identify putative responders. We investigated 1630 colorectal and lung squamous carcinomas and 1357 normal lung and colon samples and observed huge variation in EGFR pathway activation in both cancerous and healthy tissues, irrespectively on EGFR gene mutation status. We investigated whether human blood serum can affect squamous carcinoma cell growth and EGFR drug response. We demonstrate that human serum antagonizes the effects of EGFR-targeted drugs erlotinib and cetuximab on A431 squamous carcinoma cells by increasing IC50 by about 2- and 20-fold, respectively. The effects on clonogenicity varied significantly across the individual serum samples in every experiment, with up to 100% differences. EGF concentration could explain many effects of blood serum samples, and EGFR ligands-depleted serum showed lesser effect on drug sensitivity.

Cemiplimab for locally advanced cutaneous squamous cell carcinoma: safety, efficacy, and position in therapy panel

INTRODUCTION

Locally advanced cutaneous squamous cell carcinoma (lacSCC) is rare. Approximately one-fourth of the cases are observed among immunocompromised patients, in particular in solid organ transplant recipients (OTRs). LacSCC has a very poor prognosis. Surgery with or without radiotherapy remains the golden standard of treatment for cSCC. However, in advanced cases, there is a medical need for alternative treatment options. Classic systemic treatments include chemotherapy and/or EGFR inhibitors. Recently the effectiveness of programmed cell death protein-1 (PD-1) inhibitors has been demonstrated for lacSCC. Cemiplimab is a recombinant IgG4 human monoclonal antibody against the PD-1 protein for the intravenous treatment of lacSCC.

AREAS COVERED

The principal studies evaluating the efficacy and safety of cemiplimab for lacSCC are presented.

EXPERT OPINION

Cemiplimab is the first anti-PD-1 antibody that was FDA (2018) and EMA (2019) approved as a systemic treatment for lacSCC and/or metastatic cSCC when curative surgery or radiotherapy is no longer amenable. For this situation, experts currently recommend cemiplimab as a first-line systemic alternative. As cemiplimab therapy is potentially associated with a risk of organ graft rejection, pros and cons should be evaluated for every individual OTR patient with lacSCC.

Duration of Oral Antibiotics Administration for Cetuximab-Induced Acneiform Eruption

BACKGROUND

Acneiform eruption is the most common cutaneous adverse event associated with cetuximab. As it can affect quality of life and adversely affect chemotherapy schedule, additional medical care is required.

OBJECTIVES

To investigate the adherence to and the duration of antibiotic administration to treat cetuximab-induced acneiform eruption.

METHODS

Medical data of patients who were referred to the Department of Dermatology were reviewed from January 2013 to June 2018. Dermatologists assessed the severity of acneiform eruption and prescribed tetracycline-class antibiotics according to the severity every 2 or 4 weeks. We investigated the duration and amount of oral antibiotic administration and analyzed the factors that may affect the control of acneiform eruption statistically.

RESULTS

A total of 207 of 267 patients referred to the Department of Dermatology showed acneiform eruption; 124 patients were treated with minocycline, 34 patients with doxycycline, 27 patients with both, and 22 patients with topical agents. The mean duration of oral antibiotic medication was 82.7 days. A statistical analysis of the factors that prolonged the use of antibiotics for more than 90 days showed that male and younger age were risk factors. Shorter time interval from starting cetuximab to starting antibiotics was associated with longer duration of antibiotic use, statistically.

CONCLUSIONS

Cetuximab-induced acneiform eruption can be well controlled with tetracycline-class antibiotics in about 3 months. It can last longer in male and younger patients. The sooner and the more severe it appears, the longer it can last.

Litmus-Body: A Molecularly Targeted Sensor for Cell-Surface pH Measurements

Precise pH measurements in the immediate environment of receptors is essential for elucidating the mechanisms through which local pH changes associated with diseased phenotypes manifest into aberrant receptor function. However, current pH sensors lack the ability to localize and target specific receptor molecules required to make these measurements. Herein we present the Litmus-body, our recombinant protein-based pH sensor, which through fusion to an anti-IgG nanobody is capable of piggybacking on IgG antibodies for molecular targeting to specific proteins on the cell surface. By normalizing a pH-dependent green fluorescent protein to a long Stokes shift red fluorophore or fluorescent protein, we readily report pH independent of sensor concentration using a single 488 nm excitation. Our Litmus-body showed excellent responsiveness in solution, with a greater than 50-fold change across the regime of physiological pH. The sensor was further validated for use on live cells and shown to be specific to the protein of interest. In complex with our Litmus-body, cetuximab therapeutic antibody retained its functionality in binding and inhibiting ligand interaction of its target epidermal growth factor receptor (EGFR), triggering receptor-mediated endocytosis that allowed tracking of local pH from the cell surface through the endocytic pathway.

Prospective, observational practice survey of applied skin care and management of cetuximab-related skin reactions: PROSKIN study

Purpose

The study aimed to investigate strategies to prevent and treat cetuximab-induced skin reactions and their perceived effectiveness in patients with metastatic colorectal cancer (mCRC) and recurrent/metastatic squamous cell cancer of the head and neck (SCCHN).

Methods

This open-label, prospective observational study was conducted in Switzerland.

Results

A total of 125 patients were included (n = 91 mCRC, n = 34 SCCHN; mean age 63.3 years; 73.6% males). The frequency of acneiform rash grade ≥ 2 increased from 12.6% at week 2 to 21.7% at week 16. The proportion of patients who reported no skin reaction decreased from 75.6% at week 2 to 43.3% at week 16. The most frequently used skin products at any time of observation were moisturizing (77.6%), lipid-regenerating (56.8%) or urea-containing products (52%), systemic antibiotics (49.6%), and vitamin K1 cream (43.2%). There was no clear effectiveness pattern for all product classes: in given patients, either the product showed no effect at all or a moderate/strong effect, consistently over time.

Conclusions

A great variety of low-cost general skin care products were commonly used. According to physician’s preference, systemic antibiotics and vitamin K1 cream are an appropriate approach to prevent or treat cetuximab-related skin toxicity.

A novel ligand-receptor relationship between families of ribonucleases and receptor tyrosine kinases

Pancreatic ribonuclease is known to participate in host defense system against pathogens, such as parasites, bacteria, and virus, which results in innate immune response. Nevertheless, its potential impact to host cells remains unclear. Of interest, several ribonucleases do not act as catalytically competent enzymes, suggesting that ribonucleases may be associated with certain intrinsic functions other than their ribonucleolytic activities. Most recently, human pancreatic ribonuclease 5 (hRNase5; also named angiogenin; hereinafter referred to as hRNase5/ANG), which belongs to the human ribonuclease A superfamily, has been demonstrated to function as a ligand of epidermal growth factor receptor (EGFR), a member of the receptor tyrosine kinase family. As a newly identified EGFR ligand, hRNase5/ANG associates with EGFR and stimulates EGFR and the downstream signaling in a catalytic-independent manner. Notably, hRNase5/ANG, whose level in sera of pancreatic cancer patients, serves as a non-invasive serum biomarker to stratify patients for predicting the sensitivity to EGFR-targeted therapy. Here, we describe the hRNase5/ANG-EGFR pair as an example to highlight a ligand-receptor relationship between families of ribonucleases and receptor tyrosine kinases, which are thought as two unrelated protein families associated with distinct biological functions. The notion of serum biomarker-guided EGFR-targeted therapies will also be discussed. Furthering our understanding of this novel ligand-receptor interaction will shed new light on the search of ligands for their cognate receptors, especially those orphan receptors without known ligands, and deepen our knowledge of the fundamental research in membrane receptor biology and the translational application toward the development of precision medicine.

Effectiveness of Cetuximab in Combination with Concurrent Chemoradiotherapy in Locoregionally Advanced Nasopharyngeal Carcinoma: A 1:2 Propensity Score-matched Analysis

Background: This study aimed to compare concurrent chemoradiotherapy (CCRT) plus cetuximab (C) with CCRT alone in locoregionally advanced nasopharyngeal carcinoma(NPC).

Methods: A total of 682 locoregionally advanced NPC patients who had undergone chemoradiotherapy with or without cetuximab were included. Propensity score-matching method was used to match patients. Progression-free survival (PFS), overall survival (OS), locoregional relapse-free survival (LRFS), and distant metastasis-free survival (DMFS) were compared between the two treatment arms.

Results: After matching, 225 patients were identified for the analysis. Compared to CCRT, CCRT plus C was associated with significantly improved 3-year PFS (83.7% vs 71.9%, P = 0.036), LRFS (98.6% vs 90.2%, P = 0.034) but not OS (91.4% vs 85.4%, P = 0.117). Among patients with T4 and/or N3 category, CCRT plus C significantly prolonged 3-year PFS (81.0% vs 61.4%, P = 0.022) and increased 3-year OS (88.0% vs 77.9%, P = 0.086). No significant differences were observed between CCRT plus C and CCRT alone groups with regard to 3-year PFS, OS, LRFS and DMFS rates in stage III patients. Acute oral and oropharyngeal mucositis during radiotherapy were more common in the CCRT plus C than that in CCRT, but late toxicities were comparable.

Conclusions: This study reveals that patients with locoregionally advanced NPC could benefit from the addition of cetuximab to CCRT, and this therapeutic gain mainly originated from T4 and/or N3 subgroup although suffering more acute moderate to severe toxicities.

Biological determinants of radioresistance and their remediation in pancreatic cancer

Despite recent advances in radiotherapy, a majority of patients diagnosed with pancreatic cancer (PC) do not achieve objective responses due to the existence of intrinsic and acquired radioresistance. Identification of molecular mechanisms that compromise the efficacy of radiation therapy and targeting these pathways is paramount for improving radiation response in PC patients. In this review, we have summarized molecular mechanisms associated with the radio-resistant phenotype of PC. Briefly, we discuss the reversible and irreversible biological consequences of radiotherapy, such as DNA damage and DNA repair, mechanisms of cancer cell survival and radiation-induced apoptosis following radiotherapy. We further describe various small molecule inhibitors and molecular targeting agents currently being tested in preclinical and clinical studies as potential radiosensitizers for PC. Notably, we draw attention towards the confounding effects of cancer stem cells, immune system, and the tumor microenvironment in the context of PC radioresistance and radiosensitization. Finally, we discuss the need for examining selective radioprotectors in light of the emerging evidence on radiation toxicity to non-target tissue associated with PC radiotherapy.

Toxicities of systemic agents in squamous cell carcinoma of the head and neck (SCCHN); A new perspective in the era of immunotherapy

Squamous cell carcinoma of the head and neck (SCCHN) is a difficult to treat malignancy and represents the seventh most common cancer worldwide. Systemic therapy has a critical role in the treatment of locally advanced and recurrent/metastatic disease. Cytotoxic chemotherapy has been primarily used along with radiation and surgery, with cisplatin being the standard of care choice of therapy. When contraindications to cisplatin exist, other agents such as carboplatin, taxanes, 5-fluorouracil, and cetuximab are used. Similarly, in the advanced or metastatic setting, platinum agents, taxanes and cetuximab have been predominantly utilized. With the recent approval of novel agents such as pembrolizumab and nivolumab, and their distinct toxicity profiles, an understanding of the potential sequelae of the different systemic agents is essential to the careful selection of agents in the advanced disease setting. Going forward, choosing novel agents will be weighed against traditional chemotherapy, and understanding the toxicities at stake is critical in this process. In addition to providing an overview of the toxicity profile of the different systemic agents, we also provide a perspective into the future of SCCHN treatment.

Artificial nutrition dependence after cetuximab versus cisplatin combined with radiotherapy for advanced head and neck cancer: A propensity score-matched analysis

BACKGROUND

The purpose of this study was to compare the effect of cetuximab-based radiotherapy (RT) with cisplatin-based concomitant chemoradiotherapy (CCRT) on artificial nutrition dependence in locoregional advanced head and neck cancer.

METHODS

We identified patients treated with cetuximab-based RT or CCRT between 2012 and 2014 in a Japanese national database, and used propensity score-matched analyses to evaluate artificial nutrition dependence for 30 days after starting chemotherapy and at hospital discharge.

RESULTS

Of 3935 eligible patients, propensity score matching generated 250 pairs. Thirty-day artificial nutrition dependence was significantly lower in the cetuximab-based RT group than in the CCRT group (25.6% vs 35.2%; odds ratio [OR] = 0.67; 95% confidence interval [CI] = 0.46-0.97; p = .036). No significant difference in artificial nutrition dependence at hospital discharge was shown (6.2% vs 7.2%; OR = 1.07; 95% CI = 0.52-2.17; p = .861). Difference in duration of hospitalization was insignificant.

CONCLUSION

Cetuximab-based RT may reduce short-term artificial nutrition dependence compared to CCRT. © 2016 Wiley Periodicals, Inc. Head Neck 39: 320-325, 2017.

Design, synthesis, and evaluation of cisplatin-containing EGFR targeting bioconjugates as potential therapeutic agents for brain tumors

The aim of this study was to evaluate four different platinated bioconjugates containing a cisplatin (cis-diamminedichloroplatinum [cis-DDP]) fragment and epidermal growth factor receptor (EGFR)-targeting moieties as potential therapeutic agents for the treatment of brain tumors using a human EGFR-expressing transfectant of the F98 rat glioma (F98_EGFR) to assess their efficacy. The first two bioconjugates employed the monoclonal antibody cetuximab (C225 or Erbitux^®) as the targeting moiety, and the second two used genetically engineered EGF peptides. C225-G₅-Pt was produced by reacting cis-DDP with a fifth-generation polyamidoamine dendrimer (G₅) and then linking it to C225 by means of two heterobifunctional reagents. The second bioconjugate (C225-PG-Pt) employed the same methodology except that polyglutamic acid was used as the carrier. The third and fourth bioconjugates used two different EGF peptides, PEP382 and PEP455, with direct coordination to the Pt center of the cis-DDP fragment. In vivo studies with C225-G₅-Pt failed to demonstrate therapeutic activity following intracerebral (ic) convection-enhanced delivery (CED) to F98_EGFR glioma-bearing rats. The second bioconjugate, C225-PG-Pt, failed to show in vitro cytotoxicity. Furthermore, because of its high molecular weight, we decided that lower molecular weight peptides might provide better targeting and microdistribution within the tumor. Both PEP382-Pt and PEP455-Pt bioconjugates were cytotoxic in vitro and, based on this, a pilot study was initiated using PEP455-Pt. The end point for this study was tumor size at 6 weeks following tumor cell implantation and 4 weeks following ic CED of PEP455-Pt to F98 glioma-bearing rats. Neuropathologic examination revealed that five of seven rats were either tumor-free or only had microscopic tumors at 42 days following tumor implantation compared to a mean survival time of 20.5 and 26.3 days for untreated controls. In conclusion, we have succeeded in reformatting the toxicity profile of cis-DDP and demonstrated the therapeutic efficacy of the PEP455-Pt bioconjugate in F98 glioma-bearing rats.

Neoadjuvant chemotherapy and radical radiotherapy associated with cetuximab for laryngeal cancer in a pancreas and renal recipient

The oncological treatment for advanced stage head and neck cancer is based on a combination of cisplatin and cetuximab, and radiotherapy. However, very few data are available on this multimodal approach for this type of cancer in pancreas and renal recipients. We report the case of a pancreas and renal recipient being treated with combined chemoradiotherapy for a locally advanced squamous cancer of the larynx. The patient was under treatment with ciclosporin-based immunosuppressive therapy at the time of cancer diagnosis, which was then replaced by everolimus. After 4 years of follow-up, the patients is still free from disease, with a local complete response, only mild residual dysphonia, and with edema of the chin. Cetuximab plus radiation could be an adequate option for cancer treatment in solid organ transplant recipients affected by locally advanced head and neck cancer; the concomitant use of mammalian target of rapamycin pathway inhibitors may have a synergistic effect in enhancing tumor control in these patients; however, further dedicated studies are warranted.

Management of cutaneous squamous cell carcinoma in patients with epidermolysis bullosa: best clinical practice guidelines

This article summarizes recommendations reached following a systematic literature review and expert consensus on the diagnosis and management of cutaneous squamous cell carcinomas in people with epidermolysis bullosa. The guidelines are intended to help inform decision making by clinicians dealing with this complex complication of a devastating disease.

Nuclear EGFR renders cells radio-resistant by binding mRNA species and triggering a metabolic switch to increase lactate production

BACKGROUND AND PURPOSE

EGFR is translocated into the cell nucleus in response to irradiation, where it is involved in regulation of radio-sensitivity. The aim of this study is to elucidate the functional role of nuclear EGFR.

MATERIAL AND METHODS

To identify EGFR-bound nuclear proteins and mRNAs, Maldi-TOF analysis and mRNA gene arrays were used. Complex formation of proteins was shown by confocal microscopy, immunoprecipitation and Western blotting. The effect of EGFR binding to mRNAs was exhibited by quantitative RT-PCR. Cellular endpoints were shown by Western blotting, mitochondrial mass quantification, lactate quantification and clonogenic survival assays.

RESULTS

Maldi-TOF analysis of proteins bound to nuclear EGFR in response to irradiation showed colocalization with Lamin A and heterogeneous nuclear ribonucleoproteins. Confocal microscopy and Western blotting confirmed this colocalization. Both Lamin A and heterogeneous nuclear ribonucleoproteins are involved in mRNA processing. To support a role of nEGFR in this context after irradiation, we isolated EGFR-bound mRNA and observed an EGFR kinase-dependent mRNA stabilizing effect. With the help of DNA microarrays, we identified mRNAs associated with the Warburg effect that were bound to nuclear EGFR. In this context, we observed radiation-induced HIF1α expression, which triggers inhibition of pyruvate dehydrogenase and blocks the tricarboxylic acid cycle. Consequently, we detected mitophagy and increased lactate production, which is associated with increased treatment resistance. Reduction of nEGFR decreased radiation-induced expression of Hif1α and lactate production.

CONCLUSIONS

We showed that nuclear EGFR selectively binds and stabilizes mRNA involved in the Warburg effect in response to irradiation. As a consequence, cells switch from aerobic to anaerobic glucose metabolism, which can be prevented by HIF1α inhibitor BAY87-2243, Dasatinib, Erlotinib or EGFR siRNA.

The response of head and neck squamous cell carcinoma to cetuximab treatment depends on Aurora kinase A polymorphism

Objectives

The aim of this study was to evaluate the efficiency of cetuximab-based anti-EGFR treatment and Aurora kinase A / B knockdown as a function of Aurora kinase polymorphism in HNSCC cell lines.

Materials and methods

First, protein expression of Aurora kinase A / B and EGFR and Aurora kinase A polymorphism were studied in tumour samples.

The survival and proliferation of Aurora kinase A homo- (Cal27) and heterozygous (HN) HNSCC cell lines was evaluated using a colony formation assay and a flow cytometric assay. Also, aneuploidy was determined. EGFR signalling pathway were visualised by western blotting.

Results

Immunohistochemistry revealed the overexpression of Aurora kinase A / B in HNSCC. The knockdown of each kinase caused a significant decrease in clonogenic survival, independent of Aurora kinase A polymorphism. In contrast, cetuximab treatment impaired clonogenic survival only in the Aurora kinase A-homozygous cell line (Cal27).

Conclusion

This study provides in vitro evidence for the predictive value of Aurora kinase A polymorphism in the efficiency of cetuximab treatment. Resistance to cetuximab treatment can be overcome by simultaneous Aurora kinase A/B knockdown.

Pneumatosis cystoides intestinalis after cetuximab chemotherapy for squamous cell carcinoma of parotid gland

Pneumatosis intestinalis, defined as gas in the bowel wall, is often first identified on abdominal radiographs or computed tomography (CT) scans. It is a radiographic finding and not a diagnosis, as the etiology varies from benign conditions to fulminant gastrointestinal disease. We report here a case of pneumatosis intestinalis associated with cetuximab therapy for squamous cell carcinoma of head and neck. The patient underwent laparotomy based on the CT scan and the result was pneumatosis intestinalis without any signs of necrotizing enterocolitis.

Immune biomarkers of anti-EGFR monoclonal antibody therapy

The tumor antigen (TA)-targeted monoclonal antibodies (mAb) cetuximab and panitumumab target the human epidermal growth factor receptor and have been integrated into treatment regimens for advanced squamous cell carcinoma of the head and neck (SCCHN). The therapeutic efficacy of these mAbs has been found to be enhanced when combined with radiotherapy and chemotherapy. However, clinical trials indicate that these findings are limited to fewer than 20% of treated patients. Therefore, identifying patients who are likely to benefit from these agents is crucial to improving therapeutic strategies. Interestingly, it has been noted that TA-targeted mAbs mediate their effects by contributing to cell-mediated cytotoxicity in addition to inhibition of downstream signaling pathways. Here, we describe the potential immunogenic mechanisms underlying these clinical findings, their role in the varied clinical response and identify the putative biomarkers of antitumor activity. We review potential immunological biomarkers that affect mAb therapy in SCCHN patients, the implications of these findings and how they translate to the clinical scenario, which are critical to improving patient selection and ultimately outcomes for patients undergoing therapy.

Potential of a Cetuximab-based radioimmunotherapy combined with external irradiation manifests in a 3-D cell assay

Targeting epidermal growth factor receptor (EGFR)-overexpressing tumors with radiolabeled anti-EGFR antibodies is a promising strategy for combination with external radiotherapy. In this study, we evaluated the potential of external plus internal irradiation by [(90) Y]Y-CHX-A″-DTPA-C225 (Y-90-C225) in a 3-D environment using FaDu and SAS head and neck squamous cell carcinoma (HNSCC) spheroid models and clinically relevant endpoints such as spheroid control probability (SCP) and spheroid control dose 50% (SCD50 , external irradiation dose inducing 50% loss of spheroid regrowth). Spheroids were cultured using a standardized platform. Therapy response after treatment with C225, CHX-A"-DTPA-C225 (DTPA-C225), [(90) Y]Y-CHX-A"-DTPA (Y-90-DTPA) and Y-90-C225 alone or in combination with X-ray was evaluated by long-term monitoring (60 days) of spheroid integrity and volume growth. Penetration kinetics into spheroids and EGFR binding capacities on spheroid cells were identical for unconjugated C225 and Y-90-C225. Spheroid-associated radioactivity upon exposure to the antibody-free control conjugate Y-90-DTPA was negligible. Determination of the SCD50 demonstrated higher intrinsic radiosensitivity of FaDu as compared with SAS spheroids. Treatment with unconjugated C225 alone did not affect spheroid growth and cell viability. Also, C225 treatment after external irradiation showed no additive effect. However, the combination of external irradiation with Y-90-C225 (1 µg/ml, 24 hr) resulted in a considerable benefit as reflected by a pronounced reduction of the SCD50 from 16 Gy to 9 Gy for SAS spheroids and a complete loss of regrowth for FaDu spheroids due to the pronounced accumulation of internal dose caused by the continuous exposure to cell-bound radionuclide upon Y-90-C225-EGFR interaction.

Approval summary: Cetuximab in combination with cisplatin or carboplatin and 5-fluorouracil for the first-line treatment of patients with recurrent locoregional or metastatic squamous cell head and neck cancer

On November 7, 2011, the U.S. Food and Drug Administration approved cetuximab in combination with cisplatin or carboplatin and 5-fluorouracil for the first-line treatment of patients with recurrent locoregional or metastatic squamous cell head and neck cancer. Approval was based on a randomized study of 442 patients conducted outside the U.S. Cisplatin (100 mg/m2 intravenously) or carboplatin (area under the curve 5 intravenously) on day 1 with 5-fluorouracil (1,000 mg/m2/day continuous intravenous infusion days 1-4) were administered every 3 weeks. Cetuximab, 400 mg/m2 intravenously, was administered initially followed by cetuximab, 250 mg/m2 intravenously weekly. After completion of six planned treatment courses, cetuximab patients without progression continued cetuximab 250 mg/m2 weekly. The study used European Union (EU)-approved cetuximab rather than U.S.-approved cetuximab. U.S.-approved cetuximab provides approximately 28% higher exposure relative to EU-approved cetuximab in a pharmacokinetic comparability study in monkeys. Overall survival, the primary efficacy endpoint, was significantly improved in cetuximab-treated patients (hazard ratio [HR]: 0.80; 95% confidence interval [CI]: 0.64-0.98; p = .034, stratified log-rank test). Median survival times were 10.1 and 7.4 months, respectively. Progression-free survival (PFS) was also significantly improved in patients receiving cetuximab (HR: 0.57; 95% CI: 0.46-0.72; p < .0001). Median PFS times were 5.5 and 3.3 months, respectively. Response rates were 35.6% and 19.5% (odds ratio: 2.33; 95% CI: 1.50-3.60; p = .0001). Adverse reactions (≥25%) from cetuximab plus chemotherapy treatment included nausea, anemia, vomiting, neutropenia, rash, asthenia, diarrhea, and anorexia. Conjunctivitis occurred in 10% of cetuximab patients. Other adverse reactions, sometimes severe, included infusion reactions, hypomagnesemia, hypocalcemia, and hypokalemia.

Predictive factors in patients with advanced and metastatic squamous cell carcinoma of the head and neck: a study based on SWOG protocol S0420

To evaluate the prognostic values of different protein expression in the progression of squamous cell carcinoma of the head and neck (SCCHN) patients, we conducted immunohistochemical (IHC) analysis in tissue samples of different patients enrolled on SWOG protocol S0420. S0420 was a phase II trial to evaluate the efficacy and safety of single-agent sorafenib in chemotherapy-naïve patients with metastatic or recurrent SCCHN. The primary end point was response probability, i.e., confirmed complete (CR) and partial response (PR). Sorafenib was administered orally at 400 mg twice daily on a continuous basis in 28-day cycles to eligible patients. Responses were evaluated according to RECIST (Response Evaluation Criteria in Solid Tumors) criteria. IHC analysis was performed for various markers and data were analyzed statistically. IHC data were obtained from 19 patients enrolled on S0420. There was a high frequency of cases with expression of the angiogenesis markers SMA, HIF-1α, Raf-1, VEGF and VEGF-R. None of the markers were significantly associated with response. Negative HER-2 status was associated with longer progression-free survival (PFS), P=0.04. Negative NRP-1 status was associated with longer overall survival (OS), P=0.04. There were no other significant associations. An almost universal overexpression of angiogenesis markers in the samples analyzed supports the evaluation of angiogenesis inhibition as a potential target for therapy. High levels of NRP-1 and HER-2 in SCCHN samples appear to be associated with decreased survival and earlier progression of disease, respectively, in SCCHN patients and may represent targets for therapy.

Investigating the antiproliferative activity of high affinity DNA aptamer on cancer cells

Vascular endothelial growth factor (VEGF) is an angiogenic mitogen involved in promoting tumor angiogenesis inside the body. VEGF is a key protein required for progression of tumor from benign to malignant phenotype. In this study, we investigated the binding affinity of a previously selected 26-mer DNA aptamer sequence (SL₂-B) against heparin binding domain (HBD) of VEGF₁₆₅ protein. The SL₂-B was first chemically modified by introduction of phosphorothioate linkages (PS-linkages). Subsequently, surface plasmon resonance (SPR) spectroscopy and circular dichroism (CD) were used to determine the binding affinity, specificity and to deduce the conformation of PS-modified SL₂-B sequence. Finally, antiproliferative activity of the modified SL₂-B sequence on Hep G2 cancer cells was investigated. Our results demonstrate a marked enhancement in the biostability of the SL₂-B sequence after PS modification. The modified SL₂-B sequence also exhibits enhanced antiproliferative activity against Hep G2 cancer cells in hypoxia conditions. In addition, modified SL₂-B sequence inhibits the expression of Jagged-1 protein, which is one of the ligands to VEGF linked delta/jagged-notch signaling pathway.

mTHPC mediated photodynamic therapy (PDT) of squamous cell carcinoma in the head and neck: a systematic review

OBJECTIVE

Photodynamic therapy (PDT) is used in curative and palliative treatment of head and neck squamous cell carcinoma (HNSCC). To evaluate available evidence on the use of mTHPC (Foscan®) mediated PDT, we conducted a review of the literature.

MATERIALS AND METHODS

A systematic review was performed by searching seven bibliographic databases on database specific mesh terms and free text words in the categories; "head and neck neoplasms", "Photodynamic Therapy" and "Foscan". Papers identified were assessed on several criteria by two independent reviewers.

RESULTS

The search identified 566 unique papers. Twelve studies were included for our review. Six studies reported PDT with curative intent and six studies reported PDT with palliative intent, of which three studies used interstitial PDT. The studies did not compare PDT to other treatments and none exceeded level 3 using the Oxford levels of evidence. Pooling of data (n=301) was possible for four of the six studies with curative intent. T1 tumors showed higher complete response rates compared to T2 (86% vs 63%). PDT with palliative intent was predominantly used in patients unsuitable for further conventional treatment. After PDT, substantial tumor response and increase in quality of life was observed. Complications of PDT were mostly related to non-compliance to light restriction guidelines.

CONCLUSION

The studies on mTHPC mediated PDT for HNSCC are not sufficient for adequate assessment of the efficacy for curative intent. To assess efficacy of PDT with curative intent, high quality comparative, randomized studies are needed. Palliative treatment with PDT seems to increase the quality of life in otherwise untreatable patients.

Novel targeted therapies in head and neck cancer

INTRODUCTION

Molecularly targeted therapy, with the potential for increased selectivity and fewer adverse effects, hold promise in the treatment of HNSCC.

AREAS COVERED

Targeted agents for HNSCC expected to improve the effectiveness of current therapy including HER family, Src-family kinase, cell cycle, MET, AKT, HDAC, PARP, COX inhibitors and antiangiogenesis.

EXPERT OPINION

Epidermal growth factor receptor inhibitors are established in HNSCC and the need now is to find biomarkers for sensitivity to better select patients. Moreover, other pathway inhibitors hold significant promise and are being tested in clinical trials. Angiogenesis inhibition is likely to yield only modest efficacy alone but may augment existing standards. Lastly, one clinical arena where targeted therapies may find secure purchase is in the adjuvant or prevention setting where minimal or preneoplastic disease can be affected by inhibition of a single or few targets.

Monoclonal antibodies for the treatment of cancer

Over the past decade, the clinical utility of monoclonal antibodies has been realized and antibodies are now a mainstay for the treatment of cancer. Antibodies have the unique capacity to target and kill tumor cells while simultaneously activating immune effectors to kill tumor cells through the complement cascade or antibody-dependent cellular cytotoxicity (ADCC). This multifaceted mechanism of action combined with target specificity underlies the capacity of antibodies to elicit anti-tumor responses while minimizing the frequency and magnitude of adverse events. This review will focus on mechanisms of action, clinical applications and putative mechanisms of resistance to monoclonal antibody therapy in the context of cancer.

Inhibition of radiation induced migration of human head and neck squamous cell carcinoma cells by blocking of EGF receptor pathways

Background

Recently it has been shown that radiation induces migration of glioma cells and facilitates a further spread of tumor cells locally and systemically. The aim of this study was to evaluate whether radiotherapy induces migration in head and neck squamous cell carcinoma (HNSCC). A further aim was to investigate the effects of blocking the epidermal growth factor receptor (EGFR) and its downstream pathways (Raf/MEK/ERK, PI3K/Akt) on tumor cell migration in vitro.

Methods

Migration of tumor cells was assessed via a wound healing assay and proliferation by a MTT colorimeritric assay using 3 HNSCC cell lines (BHY, CAL-27, HN). The cells were treated with increasing doses of irradiation (2 Gy, 5 Gy, 8 Gy) in the presence or absence of EGF, EGFR-antagonist (AG1478) or inhibitors of the downstream pathways PI3K (LY294002), mTOR (rapamycin) and MEK1 (PD98059). Biochemical activation of EGFR and the downstream markers Akt and ERK were examined by Western blot analysis.

Results

In absence of stimulation or inhibition, increasing doses of irradiation induced a dose-dependent enhancement of migrating cells (p < 0.05 for the 3 HNSCC cell lines) and a decrease of cell proliferation (p < 0.05 for the 3 HNSCC cell lines). The inhibition of EGFR or the downstream pathways reduced cell migration significantly (almost all p < 0.05 for the 3 HNSCC cell lines). Stimulation of HNSCC cells with EGF caused a significant increase in migration (p < 0.05 for the 3 HNSCC cell lines). After irradiation alone a pronounced activation of EGFR was observed by Western blot analysis.

Conclusion

Our results demonstrate that the EGFR is involved in radiation induced migration of HNSCC cells. Therefore EGFR or the downstream pathways might be a target for the treatment of HNSCC to improve the efficacy of radiotherapy.

Deficiency in TIMP-3 increases cardiac rupture and mortality post-myocardial infarction via EGFR signaling: beneficial effects of cetuximab

Cardiac rupture is a fatal complication of myocardial infarction (MI); however, its underlying molecular mechanisms are not fully understood. This study investigated the role of tissue inhibitor of metalloproteinase-3 (TIMP-3)/matrix metalloproteinase (MMP)/epidermal growth factor (EGF)/transforming growth factor (TGF)-β1 pathway in infarct healing and effects of cetuximab on cardiac rupture after MI. Induction of MI was achieved by left coronary artery ligation in wild-type (WT) and TIMP-3(-/-) mice. TIMP-3 deficiency resulted in a fourfold increase in cardiac rupture and 50% decrease in survival after MI. Hydroxyproline content, collagen synthesis and myofibroblast cell number in the infarct region, and the force required to induce rupture of the infarct scar were significantly decreased, while MMP activity was increased in TIMP-3(-/-) mice. EGF proteins were increased by threefold in TIMP-3(-/-) mice following MI, while TGF-β1 mRNA levels were decreased by 68%. Cell proliferation of cultured adult cardiac myofibroblasts was significantly decreased in TIMP-3(-/-) compared to WT myofibroblasts. EGF treatment significantly decreased collagen synthesis and TGF-β1 expression. Conversely, TGF-β1 treatment increased collagen synthesis in cardiac myofibroblasts. Treatment with cetuximab significantly decreased the incidence of cardiac rupture and improved survival post-MI in TIMP-3(-/-) mice. We conclude that deficiency in TIMP-3 increases cardiac rupture post-MI via EGF/epidermal growth factor receptor (EGFR) signaling which downregulates TGF-β1 expression and collagen synthesis. Inhibition of EGFR by cetuximab protects against cardiac rupture and improves survival post-MI.