Epidermal growth factor receptor inhibition in cancer therapy: biology, rationale and preliminary clinical results

Recent advances in the design of small molecular drugs with acrylamides covalent warheads

In the development of covalent inhibitors, acrylamides warhead is one of the most popular classes of covalent warheads. In recent years, researchers have made different structural modifications to acrylamides warheads, resulting in the creation of fluorinated acrylamide warheads and cyano acrylamide warheads. These new warheads exhibit superior selectivity, intracellular accumulation, and pharmacokinetic properties. Additionally, although ketoamide warheads have been applied in the design of covalent inhibitors for viral proteins, it has not received sufficient attention. Combined with the studies in kinase inhibitors and antiviral drugs, this review presents the structural features and the progression of acrylamides warheads, offering a perspective on future research and development in this field.

Thoracic radiation in combination with erlotinib-results from a phase 2 randomized trial

Background

Radiotherapy (RT) can be used to reduce symptoms and maintain open airways for patients with non-small cell lung cancer when systemic treatment is not sufficient. For some patients, tumor control is not achieved due to radioresistance. Concurrent inhibition of epidermal growth factor receptors has been proposed as a strategy to overcome radioresistance but may increase toxicity. We performed a randomized trial to assess the efficacy, tolerance, and quality of life of concurrent erlotinib and palliative thoracic RT for patients with advanced non-small cell lung cancer.

Methods

Patients were randomized 1:1 to RT alone (arm A) or in combination with erlotinib (arm B). A computed tomography (CT) scan at baseline and one at 4-12 weeks after inclusion was used to evaluate treatment response. Adverse events were registered during treatment and the subsequent 30 days. Health-related quality-of-life questionnaires were completed by the patients at baseline, weeks 2, 6, and 20.

Results

A total of 114 patients were included. Of the 74 patients with CT scans available for evaluation of treatment effect, there were no significant differences in tumor size reduction between the two groups: median 14.5% reduction in the control arm A and 17.0% in the erlotinib arm B (p = 0.68). Overall survival was not significantly different between the two treatment arms: 7.0 and 7.8 months in arm A and arm B, respectively (log-rank p = 0.32). There was no significant increase in adverse events in the experimental arm, other than what is expected from erlotinib treatment alone. Overall, patients reported similar quality of life in both treatment arms.

Conclusion

Concurrent erlotinib and palliative thoracic RT for patients with advanced non-small cell lung cancer was well tolerated but did not improve the efficacy of the RT.

Clinical trial registration

ClinicalTrials.gov, identifier NCT02714530.

Anti‑epidermal growth factor receptor monoclonal antibody therapy in locally advanced head and neck cancer: A systematic review of phase III clinical trials

The present systematic review evaluated the effectiveness of anti-EGFR therapy in combination with radiotherapy (RT) or with chemoradiation compared with the existing standard of care for the treatment of locally advanced head and neck squamous cell carcinoma (LAHNSCC). The PubMed, SCOPUS, EMBASE and COCHRANE databases were searched and 12 phase III randomized controlled trials were included. The effectiveness of the anti-EGFR monoclonal antibody cetuximab was evaluated in nine trials. Nimotuzumab (one trial), zalutumumab (one trial) and panitumumab (one trial) were the monoclonal antibodies evaluated in the remaining three trials. One study tested the effectiveness of adding cetuximab to radical RT and found that patients with LAHNSCC exhibited improvement in locoregional control (LRC), overall survival (OS) and progression-free survival (PFS) compared with those of patients treated with RT alone. A total of three studies tested the effectiveness of adding an anti-EGFR agent to chemoradiation. Of these, a single institution study in which patients received cisplatin at 30 mg/m2 weekly, instead of the standard doses of 100 mg/m2 every 3 weeks or 40 mg/m2 every week, reported significant improvement in PFS with the addition of nimotuzumab to chemoradiotherapy without an improvement in overall survival. However, the other two studies indicated that, when added to standard chemoradiation, the anti-EGFR monoclonal antibodies cetuximab or zalutumumab did not improve survival outcomes. Two phase III trials evaluated RT plus an anti-EGFR agent compared with chemoradiation alone. Of these, one study reported inferior outcomes with cetuximab-RT in terms of OS and LRC, whereas the other study with panitumumab plus RT failed to prove the non-inferiority. Two trials evaluated induction chemotherapy followed by cetuximab-RT compared with chemoradiotherapy and reported no benefits in terms of OS or PFS. Furthermore, one study evaluated induction chemotherapy followed by cetuximab-RT compared with induction chemotherapy followed by chemoradiotherapy and found no improvement in OS or PFS. Finally, three phase III trials tested the effectiveness of cetuximab plus RT in the treatment of human papillomavirus-positive oropharyngeal carcinoma, and found it to be inferior compared with cisplatin-RT in terms of OS, PFS and failure-free survival. Based on the aforementioned findings, it is difficult to conclude that anti-EGFR therapy in any form has an advantage over conventional chemoradiation in the treatment of LAHNSCC.

Computer-Assisted Drug Discovery of a Novel Theobromine Derivative as an EGFR Protein-Targeted Apoptosis Inducer

The overexpression of the Epidermal Growth Factor Receptor (EGFR) marks it as a pivotal target in cancer treatment, with the aim of reducing its proliferation and inducing apoptosis. This study aimed at the CADD of a new apoptotic EGFR inhibitor. The natural alkaloid, theobromine, was used as a starting point to obtain a new semisynthetic (di-ortho-chloro acetamide) derivative (T-1-DOCA). Firstly, T-1-DOCA's total electron density, energy gap, reactivity indices, and electrostatic surface potential were determined by DFT calculations, Then, molecular docking studies were carried out to predict the potential of T-1-DOCA against wild and mutant EGFR proteins. T-1-DOCA's correct binding was further confirmed by molecular dynamics (MD) over 100 ns, MM-GPSA, and PLIP experiments. In vitro, T-1-DOCA showed noticeable efficacy compared to erlotinib by suppressing EGFRWT and EGFRT790M with IC50 values of 56.94 and 269.01 nM, respectively. T-1-DOCA inhibited also the proliferation of H1975 and HCT-116 malignant cell lines, exhibiting IC50 values of 14.12 and 23.39 µM, with selectivity indices of 6.8 and 4.1, respectively, indicating its anticancer potential and general safety. The apoptotic effects of T-1-DOCA were indicated by flow cytometric analysis and were further confirmed through its potential to increase the levels of BAX, Casp3, and Casp9, and decrease Bcl-2 levels. In conclusion, T-1-DOCA, a new apoptotic EGFR inhibitor, was designed and evaluated both computationally and experimentally. The results suggest that T-1-DOCA is a promising candidate for further development as an anti-cancer drug.

An overview of imidazole and its analogues as potent anticancer agents

The quest for novel, physiologically active imidazoles remains an exciting topic of research among medicinal chemists. The imidazole ring is a five-membered aromatic heterocycle that is found in both natural and synthesized compounds. Multiple anticancer drug classes are currently available on the market, but concerns including toxicity, limited efficacy and solubility have lowered the overall therapeutic index. Therefore, the hunt for new potential chemotherapeutic agents persists. The development of imidazole as a reliable and safer alternative to anticancer treatment is generating much attention among experts. Tubulin or microtubule polymerization inhibition and changes in the structure and function of DNA, VEGF, topoisomerase, kinases, histone deacetylases and certain other proteins that affect gene expression are among the putative targets.

Discovery of new thieno[2,3-d]pyrimidines as EGFR tyrosine kinase inhibitors for cancer treatment

Background: EGFR has been considered a vital molecular target in cancer management. Aim: The discovery of new thieno[2,3-d]pyrimidine derivatives as EGFR tyrosine kinase inhibitors. Methods: Nine derivatives were designed, synthesized and subjected to in vitro and in silico studies. Results: Compound 7a significantly inhibited the growth of HepG2 and PC3 cells for both EGFR wild-type and EGFRT790M. Compound 7a caused a significant apoptotic effect, arresting HepG2 cells' growth in the S and G2/M phases. Docking and molecular dynamics simulation studies confirmed the correct and stable binding modes of the synthesized compounds against the active sites. Conclusion: Compound 7a is a promising dual EGFR inhibitor for cancer treatment.

EGFR and MMP-9 are associated with neointimal hyperplasia in systemic-to-pulmonary shunts in children with complex cyanotic heart disease

Systemic-to-pulmonary shunt malfunction contributes to morbidity in children with complex congenital heart disease after palliative procedure. Neointimal hyperplasia might play a role in the pathogenesis increasing risk for shunt obstruction. The aim was to evaluate the role of epidermal growth factor receptor (EGFR) and matrix-metalloproteinase 9 (MMP-9) in the formation of neointimal within shunts. Immunohistochemistry was performed with anti-EGFR and anti-MMP-9 on shunts removed at follow-up palliative or corrective procedure. Whole-genome single-nucleotide polymorphisms genotyping was performed on DNA extracted from patients´ blood samples and allele frequencies were compared between the group of patients with shunts displaying severe stenosis (≥ 40% of lumen) and the remaining group. Immunohistochemistry detected EGFR and MMP-9 in 24 of 31 shunts, located mainly in the luminal area. Cross-sectional area of EGFR and MMP-9 measured in median 0.19 mm2 (IQR 0.1-0.3 mm2) and 0.04 mm2 (IQR 0.03-0.09 mm2), respectively, and correlated positively with the area of neointimal measured on histology (r = 0.729, p < 0.001 and r = 0.0479, p = 0.018, respectively). There was a trend of inverse correlation between the dose of acetylsalicylic acid and the degree of EGFR, but not MMP-9, expression within neointima. Certain alleles in epidermal growth factor (EGF) and tissue inhibitor of metalloproteinases 1 (TIMP-1) were associated with increased stenosis and neointimal hyperplasia within shunts. EGFR and MMP-9 contribute to neointimal proliferation in SP shunts of children with complex cyanotic heart disease. SP shunts from patients carrying certain risk alleles in the genes encoding for EGF and TIMP-1 displayed increased neointima.

Tailoring the clinical management of colorectal cancer by 18F-FDG PET/CT

Colorectal cancer (CRC) is among the most commonly diagnosed gastrointestinal malignancies worldwide. It is inadequate to handle in terms of staging and restaging only based on morphological imaging modalities and serum surrogate markers. And the correct and timely staging of CRC is imperative to prognosis and management. When compared to established sequential, multimodal conventional diagnostic methods, the molecular and functional imaging ¹⁸F-FDG PET/CT shows superiorities for tailoring appropriate treatment maneuvers to each patient. This review aims to summarize the utilities of ¹⁸F-FDG PET/CT in CRC, focusing on primary staging, follow-up assessment of tumor responses and diagnostic of recurrence. In addition, we also summarize the technical considerations of PET/CT and the conventional imaging modalities in those patients who are either newly diagnosed with CRC or has already been treated from this cancer.

Design, synthesis and molecular docking of new fused 1H-pyrroles, pyrrolo[3,2-d]pyrimidines and pyrrolo[3,2-e][1, 4]diazepine derivatives as potent EGFR/CDK2 inhibitors

A new series of 1H-pyrrole (6a-c, 8a-c), pyrrolo[3,2-d]pyrimidines (9a-c) and pyrrolo[3,2-e][1, 4]diazepines (11a-c) were designed and synthesised. These compounds were designed to have the essential pharmacophoric features of EGFR Inhibitors, they have shown anticancer activities against HCT116, MCF-7 and Hep3B cancer cells with IC₅₀ values ranging from 0.009 to 2.195 µM. IC₅₀ value of doxorubicin is 0.008 µM, compounds 9a and 9c showed IC₅₀ values of 0.011 and 0.009 µM respectively against HCT-116 cells. Compound 8b exerted broad-spectrum activity against all tested cell lines with an IC₅₀ value less than 0.05 µM. Compound 8b was evaluated against a panel of kinases. This compound potently inhibited CDK2/Cyclin A1, DYRK3 and GSK3 alpha kinases with 10-23% compared to imatinib (1-10%). It has also arrested the cell cycle of MCF-7 cells at the S phase. Its antiproliferative activity was further augmented by molecular docking into the active sites of EGFR and CDK2 cyclin A1.

Ultraviolet Radiation Exposure and its Impacts on Cutaneous Phosphorylation Signaling in Carcinogenesis: Focusing on Protein Tyrosine Phosphatases†

Sunlight exposure is a significant risk factor for UV-induced deteriorating transformations of epidermal homeostasis leading to skin carcinogenesis. The ability of UVB radiation to cause melanoma, as well as basal and squamous cell carcinomas, makes UVB the most harmful among the three known UV ranges. UVB-induced DNA mutations and dysregulation of signaling pathways contribute to skin cancer formation. Among various signaling pathways modulated by UVB, tyrosine phosphorylation signaling which is mediated by the action of protein tyrosine kinases (PTKs) on specific tyrosine residues is highly implicated in photocarcinogenesis. Following UVB irradiation, PTKs get activated and their downstream signaling pathways contribute to photocarcinogenesis by promoting the survival of damaged keratinocytes and increasing cell proliferation. While UVB activates oncogenic signaling pathways, it can also activate tumor suppressive signaling pathways as initial protective mechanisms to maintain epidermal homeostasis. Tyrosine dephosphorylation is one of the protective mechanisms and is mediated by the action of protein tyrosine phosphatases (PTPs). PTP can counteract UVB-mediated PTK activation and downregulate oncogenic signaling pathways. However, PTPs have not been studied extensively in photocarcinogenesis with previous studies regarding their inactivation induced by UVB. This current review will summarize the recent progress in the protective function of PTPs in epidermal photocarcinogenesis.

New pyrimidine-5-carbonitrile derivatives as EGFR inhibitors with anticancer and apoptotic activity: Design, molecular modeling and synthesis

In connection with our efforts on the development of new anticancer agents, herein we report the design and synthesis of new small pyrimidine-5-carbonitrile based derivatives. The target pyrimidines were evaluated...

Distinguishing features of a novel humanized anti-EGFR monoclonal antibody based on cetuximab with superior antitumor efficacy

BACKGROUND

Cetuximab, the first approved EGFR targeting therapeutic antibody, is currently used to treat colorectal cancer and head and neck cancer. While effective, cetuximab is associated with a higher rate of skin rash, infusion reactions, and gastrointestinal toxicity, which was suggested to be linked to the presence of heterogeneous glycan contents on the Fab of the SP2/0-produced cetuximab.

OBJECTIVE AND METHODS

To improve efficacy and minimize toxicity of EGFR inhibition treatment, we re-engineered cetuximab by humanizing its Fab regions and minimizing its glycan contents to generate HLX07.

RESULTS

HLX07 binds to EGFR with similar affinity as cetuximab and shows better bioactivity compared to cetuximab in vitro. In vivo studies demonstrated that HLX07 significantly inhibited the growth of A431, FaDu, NCI-H292, and WiDr tumor cells and synergized them with chemotherapeutics and immune simulator agents such as anti-PD-1. In cynomolgus monkeys, 13-week repeat-dose GLP toxicokinetic studies showed minimal-to-mild toxicities in the dose range of up to 60 mg/kg/wk. In the preliminary phase 1 dose-escalation study, HLX07 had showed lower incidence of skin rashes with grade >2 severities.

CONCLUSION

HLX07 is currently under phase 1/2 clinical development. We believe HLX07 would potentially be an alternative for patients who have been suffering from cetuximab-mediated toxicity.

A Comparative Study of Cavitary and Noncavitary Non-small Cell Lung Cancer Patients Treated with CT-Guided Microwave Ablation

PURPOSE

To explore the outcomes of computed tomography‒guided microwave (MW) ablation in patients with cavitary non-small cell lung cancer (NSCLC) and to compare the outcomes of cavitary and noncavitary NSCLC treated with MW ablation.

MATERIALS AND METHODS

A total of 317 patients with NSCLC (194 men and 123 women) treated with MW ablation were include: 19 patients with cavitary NSCLC and 298 patients with noncavitary NSCLC. Complications, progression-free survival (PFS), and overall survival (OS) were evaluated and compared between the 2 groups. The Kaplan-Meier method was used to investigate the correlation of cavity and OS in patients with NSCLC.

RESULTS

A total of 364 MW ablation procedures were performed. Adenocarcinoma was the predominant histopathological subtype in patients with cavitary NSCLC (73.7%). Cavitary NSCLC had an incidence rate of 57.9% in overall complications, which was significantly higher than that of 34.6% for noncavitary NSCLC (P = .040). In a mean follow-up of 27.2 months ± 11.9, the median PFS and OS for cavitary NSCLC were 9.0 months ± 8.5 and 14.0 months ± 10.8, respectively, and those for noncavitary NSCLC were 13.0 months ± 10.7 and 17.0 months ± 10.9, respectively. There was no significant difference in PFS (P = .180) or OS (P = .133) between cavitary and noncavitary NSCLC. In addition, the local recurrence rates for cavitary and noncavitary NSCLC were 15.8% and 21.5%, respectively, and no significant difference was found (P = .765). The Kaplan-Meier method revealed no association between the cavity and OS in patients with NSCLC treated with MW ablation.

CONCLUSIONS

MW ablation was an effective and safe approach for cavitary NSCLC treatment. Compared with noncavitary NSCLC, cavitary NSCLC manifested with more complications but a comparable outcome after MW ablation.

Oxidative stress induces EGFR inhibition-related skin cell death

Cutaneous side effects are often observed in patients treated with chemotherapeutic agents, including those treated with epidermal growth factor receptor (EGFR) inhibitors. These side effects are not fatal but often require dose reduction of chemotherapies. The mechanisms of epidermal growth factor receptor inhibition-related dermatologic toxicities are unclear, and prophylactic approaches are not well-established. To explore the mechanisms of the cutaneous side effects induced by epidermal growth factor receptor inhibition, we analyzed the metabolome using human keratinocyte cells. We first demonstrated that afatinib and lapatinib induced apoptosis in HaCaT cells. Using liquid chromatography-mass spectrometry, we detected 676 and 482 metabolites and compounds in the cells and media, respectively. We observed diverse metabolic alterations, including glycolysis, TCA metabolism, and polyamine metabolism, and also found a change in glutathione metabolites after epidermal growth factor receptor inhibition, which led to the accumulation of reactive oxygen species. Supplementation of N-acetyl cysteine partly rescued the afatinib-induced apoptosis, suggesting that reactive oxygen species are involved in the cytotoxicity of skin cells. We observed epidermal growth factor receptor inhibitor-associated comprehensive metabolic changes in human keratinocyte cells, suggesting that oxidative stress evokes cutaneous side effects induced by EGFR inhibition.

Comparison of gefitinib-induced skin adverse reactions (SAR) in C57BL/6 and FVB/N mice

Epidermal growth factor receptor tyrosine kinase inhibitors (EGFR-TKIs) such as gefitinib, erlotinib, and afatinib, are widely used in clinical practice and remarkably effective in treatment of advanced non-small cell lung cancer. However, there are some adverse effects while taking EGFR-TKIs, among which skin adverse reactions (SAR) are the most common events. At present, the poor outcome of SAR and insufficient research on SAR models need to be addressed. In this study we focused on the SAR models to lay a foundation for mechanism researches. Gefitinib, one of the EGFR-TKIs, was used as SAR inducing agents. We chose C57BL/6 and FVB/N mice as experimental model and they were divided into four groups. The weight and skin moisture of mice were detected every 7 days, itching behavior and abnormal eyelids were tested at 35th day after gavage, and survival rate was also recorded. The weight of unit area hair, length of whiskers and inflammatory cells were evaluated after mice sacrificed. C57BL/6 animals treated with gefitinib showed significant differences in survival rate, weight of unit area hair, skin moisture changes, skin dryness, itching behavior, whisker irregular growth, abnormal eyelids, and inflammatory cells; FVB/N animals treated with gefitinib only showed significant differences in survival rate, whisker irregular growth and abnormal eyelids, compared with the control group, respectively. In this study, we compared the similarities and differences of gefitinib-induced SAR between C57BL/6 and FVB/N mice, which illustrated different patients probably showing different symptoms clinically and provided experimental basis for researching mechanism of EGFR-TKIs induced SAR.

Survival and biomarker analysis for ovarian mucinous carcinoma according to invasive patterns: retrospective analysis and review literature

BACKGROUND

In ovarian mucinous carcinoma, invasive pattern is the important factor but there were less reposts to investigate it. The aim of this study was to examine the association between prognosis and invasive patterns of ovarian mucinous carcinoma and to investigate the biomarkers of the diagnosis and prognosis immunochemically. Patients with ovarian mucinous carcinoma at our institution between 1984 and 2018 were identified. A pathological review was conducted using the 2020 World Health Organization criteria. The prognosis of infiltrative invasion and expansile invasion of ovarian mucinous carcinoma were retrospectively compared. In addition, immunohistochemical staining was conducted for all cases, and the immunohistochemical differences between the two invasive patterns were compared.

RESULTS

After the pathological review, 25 cases with infiltrative invasion and 24 cases with expansile invasion were included. Ovarian mucinous carcinoma with infiltrative invasion showed significantly worse progression-free survival (PFS, p < 0.01) and overall survival (OS, p < 0.01) than those with expansile invasion. Multivariate analysis demonstrated that the pattern of infiltrative invasion was a worse prognostic factor for PFS (hazard ratio 9.01, p < 0.01) and OS (hazard ratio 17.56, p < 0.01). Immunohistochemically, cytokeratin (CK) 5/6 (p = 0.01), cluster of differentiation (CD) 24 (p = 0.02), and epithelial growth factor receptor (EGFR) (p < 0.01) were statistically related to infiltrative invasion. The PFS (p = 0.04) and OS (p = 0.02) of cases with EGFR-positive OMC were worse than those with negative OMC.

CONCLUSIONS

Infiltrative invasion was observed to be a prognostic factor showing worse outcomes for ovarian mucinous carcinoma compared to expansile infiltration. CK5/6, CD24, and EGFR might be biomarkers of the diagnosis.

Vandetanib inhibits cell growth in EGFR-expressing cutaneous squamous cell carcinoma

Advanced cutaneous squamous cell carcinoma (SCC) responds poorly to chemotherapy, leading to significant morbidity or death. Overexpression of epidermal growth factor receptor (EGFR) is frequently observed in advanced cutaneous SCC. Vandetanib is a multiple tyrosine kinase targeting vascular endothelial growth factor receptor-2 (VEGFR2), EGFR, and the rearranged during transfection (RET) proto-oncogene. Vandetanib has been reported to inhibit tumor growth in head and neck SCC. However, the efficacy of vandetanib against cutaneous SCC has not been thoroughly investigated. The aim of this study is to evaluate the efficacy of vandetanib against cutaneous SCC in vitro and in vivo. Vandetanib is found to inhibit the proliferation of cutaneous SCC cells as assessed by cell viability and clonogenic assay. Cell death analysis indicates that vandetanib induces cell death in SCC cells but not in normal human keratinocytes or fibroblasts. The in vivo anti-tumor effect of vandetanib is shown in xenograft tumor models using A431 SCC cells. Mechanistically, vandetanib suppresses the phosphorylation of EGFR in SCC cells. Clinically, EGFR expression levels are elevated in cutaneous SCC specimens, relative to normal epidermis. In conclusion, we identified vandetanib as a novel therapeutic option for cutaneous SCC, especially in tumors with high EGFR expression.

Membrane receptor activation mechanisms and transmembrane peptide tools to elucidate them

Single-pass membrane receptors contain extracellular domains that respond to external stimuli and transmit information to intracellular domains through a single transmembrane (TM) α-helix. Because membrane receptors have various roles in homeostasis, signaling malfunctions of these receptors can cause disease. Despite their importance, there is still much to be understood mechanistically about how single-pass receptors are activated. In general, single-pass receptors respond to extracellular stimuli via alterations in their oligomeric state. The details of this process are still the focus of intense study, and several lines of evidence indicate that the TM domain (TMD) of the receptor plays a central role. We discuss three major mechanistic hypotheses for receptor activation: ligand-induced dimerization, ligand-induced rotation, and receptor clustering. Recent observations suggest that receptors can use a combination of these activation mechanisms and that technical limitations can bias interpretation. Short peptides derived from receptor TMDs, which can be identified by screening or rationally developed on the basis of the structure or sequence of their targets, have provided critical insights into receptor function. Here, we explore recent evidence that, depending on the target receptor, TMD peptides cannot only inhibit but also activate target receptors and can accommodate novel, bifunctional designs. Furthermore, we call for more sharing of negative results to inform the TMD peptide field, which is rapidly transforming into a suite of unique tools with the potential for future therapeutics.

Hair eruption initiates and commensal skin microbiota aggravate adverse events of anti-EGFR therapy

Epidermal growth factor receptor (EGFR)-targeted anticancer therapy induces stigmatizing skin toxicities affecting patients' quality of life and therapy adherence. The lack of mechanistic details underlying these adverse events hampers their management. We found that EGFR/ERK signaling is required in LRIG1-positive stem cells during de novo hair eruption to secure barrier integrity and prevent the invasion of commensal microbiota and inflammatory skin disease. EGFR-deficient epidermis is permissive for microbiota outgrowth and displays an atopic-like TH2-dominated signature. The opening of the follicular ostia during hair eruption allows invasion of commensal microbiota into the hair follicle, initiating an additional TH1 and TH17 response culminating in chronic folliculitis. Restoration of epidermal ERK signaling via prophylactic FGF7 treatment or transgenic SOS expression rescues the barrier defect in the absence of EGFR, highlighting a therapeutic anchor point. These data reveal that commensal skin microbiota provoke atopic-like inflammatory skin diseases by invading into the follicular opening of erupting hair.

Kit Protein (CD 117) and Proliferation Index (Ki-67) Evaluation in Well and Poorly Differentiated Neuroendocrine Tumors

Aims and background

Kit protein expression seems to be associated with a poor outcome in cancer patients and may be an important target for new anticancer drugs. We examined by immunohistochemistry the presence of Kit protein in neuroendocrine tumors (NETs) to explore its relationship with histological grade and proliferation index.

Patients and methods

Thirty-five tumor specimens from patients with 24 well differentiated and 11 poorly differentiated NETs were examined for the presence of Kit protein and the proliferation index marker Ki-67.

Results

Eleven specimens were positive for Kit protein expression, 8 of which had poorly-differentiated histology and only 3 had well-differentiated histology. Most of the tumors showing immunopositivity for Kit protein were also characterized by a high proliferation index.

Conclusions

Immunohistochemical positivity for Kit protein is mainly related to poorly differentiated NETs. In our study, the percentage of tumors with immunopositivity for Kit protein was lower than that observed by other authors. This difference could be attributable to the different immunohistochemistry procedures used and to the biological heterogeneity of NETs. The number of Kit protein-positive NETs may justify targeted therapy with a tyrosine kinase receptor-associated inhibitor only in a selected subset of patients, whenever no other therapy is available and an autocrine loop sustained by the Kit receptor and its specific ligand has been demonstrated.

From Biology to Therapy: Improvements of Therapeutic Options in Lung Cancer

Lung cancer is the leading cause of cancer-related mortality around the world, despite effective chemotherapeutic agents, the prognosis has remained poor for a long time. The discovery of molecular changes that drive lung cancer has led to a dramatic shift in the therapeutic landscape of this disease. In "in vitro" and "in vivo" models of NSCLC (Non-Small Cell Lung Cancer), angiogenesis blockade has demonstrated an excellent anti-tumor activity, thus, a number of anti-angiogenic drugs have been approved by regulatory authorities for use in clinical practice. Much more interesting is the discovery of EGFR (Epithelial Growth Factor Receptor) mutations that predict sensitivity to the anti-EGFR Tyrosine Kinase Inhibitors (TKIs), a class of drugs that has shown to significantly improve survival when compared with standard chemotherapy in the first-line treatment of metastatic NSCLC. Nevertheless, after an initial response, resistance often occurs and prognosis becomes dismal. Biomolecular studies on cell line models have led to the discovery of mutations (e.g., T790M) that confer resistance to anti-EGFR inhibitors. Fortunately, drugs that are able to circumvent this mechanism of resistance have been developed and have been recently approved for clinical use. The discovery of robust intratumor lymphocyte infiltration in NSCLC has paved the way to several strategies able to restore the immune response. Thus, agents interfering with PD-1/PD-L1 (Programmed Death) pathways make up a significant portion of the armamentarium of cancer therapies for NSCLC. In all the above-mentioned situations, the basis of the success in treating NSCLC has started from understanding of the mutational landscape of the tumor.

Immunotherapy combined with epidermal growth factor receptor-tyrosine kinase inhibitors in non-small-cell lung cancer treatment

In recent years, targeted therapy and immunotherapy have played important roles in the treatment of patients with non-small-cell lung cancer (NSCLC). Drugs that target epidermal growth factor receptor (EGFR) mutations (eg, gefitinib, erlotinib, icotinib, and osimertinib) are among the most commonly used targeted therapies. Afatinib is an irreversible second-generation EGFR-tyrosine kinase inhibitor (EGFR-TKI), and the LUX-Lung 3 trial demonstrated the superiority of afatinib to cisplatin and pemetrexed in the frontline treatment of treatment-naïve patients with advanced EGFR mutation adenocarcinoma of the lung. Although these drugs show significant therapeutic efficacy, most patients invariably experience disease progression resulting in death. Immunotherapy targeting programmed death-1 (PD-1)/programmed death-ligand 1 (PD-L1) has now been approved for the first-line treatment of patients with advanced NSCLC. These can produce sustained clinical responses by reversing negative regulators of T-cell function; however, immunotherapy response rates remain low, and only a few patients ultimately benefit from this approach. Here, we discuss the potential of EGFR-TKIs for inducing antitumor immunity and the feasibility of their combination with immunotherapy (including PD-1/PD-L1 inhibitors) in NSCLC patients and the associated challenges for clinical application.

The EGFR Inhibitor Gefitinib Enhanced the Response of Human Oral Squamous Cell Carcinoma to Cisplatin In Vitro

Introduction

The epidermal growth factor receptor (EGFR) is highly expressed in a variety of solid tumors including oral cavity squamous cell carcinoma (OSCC) and has been implicated in the resistance of these tumors to cisplatin. This study was performed to determine if the EGFR tyrosine kinase inhibitor gefitinib could enhance the cytotoxic effect of cisplatin on OSCC cells in vitro.

Methods

The expression of EGFR and the phosphorylation of its downstream signaling to ERK, and AKT pathway were detected by Western blotting. Cell proliferation and survival were determined by AlamarBlue and colony formation assay respectively. Cells apoptosis were determined by Western blotting for cleaved PARP protein and by flowcytometry of cells stained with Annexin V and PI.

Results

Cal27, OSC19, and SCC25 cells treated with gefitinib 1 μM demonstrated reduced phosphorylation of EGFR, AKT, and ERK proteins with very limited inhibition of proliferation. Cisplatin inhibited proliferation of the same cell lines in a dose-dependent manner. The concentration producing 50% inhibition (IC₅₀) for cisplatin decreased in the presence of gefitinib 1 μM, and a combination of cisplatin 5 µM and gefitinib 1 µM caused synergistic growth inhibition and synergistic reduction in cell survival. The growth inhibitory effect of the combination was associated with reduced ERK and AKT activation, increased poly ADP ribose polymerase (PARP) cleavage, and increased apoptosis.

Conclusion

Thus, in OSCC cells in vitro, inhibition of EGFR activity with gefitinib enhances the apoptotic effect of cisplatin. This has potential implications for enhancement of cisplatin effectiveness in tumors that over-express the EGFR.

Clinical Significance of Epidermal Growth Factor Receptor Content in Gastric Cancer

The objective of this work was to evaluate the epidermal growth factor receptor (EGFR) content in gastric cancer, its possible relationship with clinicopathological parameters of tumors and its prognostic significance. Membranous EGFR levels were examined by radioligand binding assays in 110 patients with gastric cancer. The mean follow-up period was 30.7 months. EGFR levels of tumors ranged widely, from 0.3 to 510 fmol/mg protein. EGFR levels were significantly higher (p<0.0005) in neoplastic tissue than in paired adjacent mucosa samples (median) (n= 84; 8.7 vs. 3.9 fmol/mg protein). Intratumoral EGFR levels were significantly correlated with tumor stage (p<0.05), and were higher in patients with stage III tumors (median) (7.6, 6.4, 12.3 and 7.5 fmol/mg protein for stages I, II, III and IV, respectively). In addition, the tumor/mucosa ratios of the EGFR content were significantly higher (p<0.05) in patients with stage III tumors (1, 1.8, 3.9, and 0.92, respectively). Although there was no significant relationship between EGFR levels of tumors and overall survival, the results suggest a role for EGFR in tumor progression of gastric cancer.

Design, Synthesis, and Evaluation of Ribose-Modified Anilinopyrimidine Derivatives as EGFR Tyrosine Kinase Inhibitors

The synthesis of a series of ribose-modified anilinopyrimidine derivatives was efficiently achieved by utilizing DBU or tBuOLi-promoted coupling of ribosyl alcohols with 2,4,5-trichloropyrimidine as key step. Preliminary biological evaluation of this type of compounds as new EGFR tyrosine kinase inhibitors for combating EGFR L858R/T790M mutant associated with drug resistance in the treatment of non-small cell lung cancer revealed that 3-N-acryloyl-5-O-anilinopyrimidine ribose derivative 1a possessed potent and specific inhibitory activity against EGFR L858R/T790M over WT EGFR. Based upon molecular docking studies of the binding mode between compound 1a and EGFR, the distance between the Michael receptor and the pyrimidine scaffold is considered as an important factor for the inhibitory potency and future design of selective EGFR tyrosine kinase inhibitors against EGFR L858R/T790M mutants.

Novel ent-Kaurane Diterpenoid from Rubus corchorifolius L. f. Inhibits Human Colon Cancer Cell Growth via Inducing Cell Cycle Arrest and Apoptosis

The tender leaves of Rubus corchorifolius L. f. have been consumed as tea for drinking in China since ancient times. In this study, a novel ent-kaurane diterpenoid was isolated and identified from R. corchorifolius L. f. leaves as ent-kaur-2-one-16β,17-dihydroxy-acetone-ketal (DEK). DEK suppressed the growth of HCT116 human colon cancer cells with an IC₅₀ value of 40 ± 0.21 μM, while it did not cause significant growth inhibition on CCD-18Co human colonic myofibroblasts at up to100 μM. Moreover, DEK induced extensive apoptosis and S phase cell cycle arrest in the colon cancer cells. Accordingly, DEK caused profound effects on multiple signaling proteins associated with cell proliferation, cell death, and inflammation. DEK significantly upregulated the expression levels of pro-apoptotic proteins such as cleaved caspase-3, cleaved caspase-9, cleaved PARP, p53, Bax, and tumor suppressor p21^Cip1/Waf1, downregulated the levels of cell cycle regulating proteins such as cyclinD1, CDK2, and CDK4 and carcinogenic proteins such as EGFR and COX-2, and suppressed the activation of Akt. Overall, our results provide a basis for using DEK as a potential chemopreventive agent against colon carcinogenesis.

Selecting Tumor-Specific Molecular Targets in Pancreatic Adenocarcinoma: Paving the Way for Image-Guided Pancreatic Surgery

PURPOSE

The purpose of this study was to identify suitable molecular targets for tumor-specific imaging of pancreatic adenocarcinoma.

PROCEDURES

The expression of eight potential imaging targets was assessed by the target selection criteria (TASC)-score and immunohistochemical analysis in normal pancreatic tissue (n = 9), pancreatic (n = 137), and periampullary (n = 28) adenocarcinoma.

RESULTS

Integrin αvβ6, carcinoembryonic antigen (CEA), epithelial growth factor receptor (EGFR), and urokinase plasminogen activator receptor (uPAR) showed a significantly higher (all p < 0.001) expression in pancreatic adenocarcinoma compared to normal pancreatic tissue and were confirmed by the TASC score as promising imaging targets. Furthermore, these biomarkers were expressed in respectively 88 %, 71 %, 69 %, and 67 % of the pancreatic adenocarcinoma patients.

CONCLUSIONS

The results of this study show that integrin αvβ6, CEA, EGFR, and uPAR are suitable targets for tumor-specific imaging of pancreatic adenocarcinoma.

Combination treatment including targeted therapy for advanced hepatocellular carcinoma

Management of advanced hepatocellular carcinoma (HCC), one of the most lethal cancers worldwide, has presented a therapeutic challenge over past decades. Most patients with advanced HCC and a low possibility of surgical resection have limited treatment options and no alternative but to accept local or palliative treatment. In the new era of cancer therapy, increasing numbers of molecular targeted agents (MTAs) have been applied in the treatment of advanced HCC. However, mono-targeted therapy has shown disappointing outcomes in disease control, primarily because of tumor heterogeneity and complex cell signal transduction. Because incapacitation of a single target is insufficient for cancer suppression, combination treatment for targeted therapy has been proposed and experimentally tested in several clinical trials. In this article, we review research studies aimed to enhance the efficacy of targeted therapy for HCC through combination strategies. Combination treatments involving targeted therapy for advanced HCC are compared and discussed.

Novel targeted therapies in adrenocortical carcinoma

PURPOSE OF REVIEW

Adrenocortical carcinoma is a rare cancer, but one that carries a poor prognosis due to its aggressive nature and unresponsiveness to conventional chemotherapeutic strategies. Over the past 12 years, there has been renewed interest in developing new therapies for this cancer, including identifying key signaling nodes responsible for cell proliferation.

RECENT FINDINGS

Clinical trials of tyrosine kinase inhibitors as monotherapy have generally been disappointing, although the identification of exceptional responders may lead to the identification of targeted therapies that may produce responses in subsets of patients. Agents targeted to the Wnt signaling pathway, a known player in adrenal carcinogenesis, have been developed, although they have not yet been used specifically for adrenal cancer. There is current excitement about inhibitors of acetyl-coA cholesterol acetyl transferase 1, an enzyme required for intracellular cholesterol handling, although trials are still underway. Tools to target other proteins such as Steroidogenic Factor 1 and mechanistic target of rapamycin have been developed and are moving towards clinical application.

SUMMARY

Progress is being made in the fight against adrenocortical carcinoma with the identification of new therapeutic targets and new means by which to attack them. Continued improvement in the prognosis for patients with adrenal cancer is expected as this research continues.

Novel Gefitinib Formulation with Improved Oral Bioavailability in Treatment of A431 Skin Carcinoma

PURPOSE

Oral administration of anticancer agents presents a series of advantages for patients. However, most of the anticancer drugs have poor water solubility leading to low bioavailability.

METHODS

Controlled released spray dried matrix system of Gefitinib with hydroxypropyl β-cyclodextrin, chitosan, hydroxy propyl methyl cellulose, vitamin E TPGS, succinic acid were used for the design of formulations to improve the oral absorption of Gefitinib. Spray drying with a customized spray gun which allows simultaneous/pulsatile flow of two different liquid systems through single nozzle was used to prepare Gefitinib spray dried formulations (Gef-SD). Formulation was characterized by in vitro drug release and Caco-2 permeability studies. Pharmacokinetic studies were performed in Sprague Dawley rats. Efficacy of Gef-SD was carried out in A431 xenografts models in nude mice.

RESULTS

In Gef-SD group 9.14-fold increase in the AUC was observed compared to free Gef. Improved pharmacokinetic profile of Gef-SD translated into increase (1.75 fold compared to Gef free drug) in anticancer effects. Animal survival was significantly increased in Gef formulation treated groups, with superior reduction in the tumor size (1.48-fold) and volumes (1.75-fold) and also increase in the anticancer effects (TUNEL positive apoptotic cells) was observed in Gef-SD treated groups. Further, western blot, immunohistochemical and proteomics analysis demonstrated the increased pharmacodynamic effects of Gef-SD formulations in A431 xenograft tumor models.

CONCLUSION

Our studies suggested that Gefitinib can be successfully incorporated into control release microparticles based oral formulation with enhanced pharmacokinetic and pharmacodynamic activity. This study demonstrates the novel application of Gef in A431 tumor models.

Relationship between Preoperative ¹⁸F-Fluorodeoxyglucose Uptake and Epidermal Growth Factor Receptor Status in Primary Colorectal Cancer

PURPOSE

Both ¹⁸F-fluorodeoxyglucose (¹⁸F-FDG) uptake and epidermal growth factor receptor (EGFR) status are prognostic variables of colorectal cancer (CRC). The aim of this study was to investigate a possible association between ¹⁸F-FDG uptake on preoperative positron emission tomography/computed tomography (PET/CT) and EGFR status in primary CRC.

MATERIALS AND METHODS

Records of 132 patients (66 men and 66 women; mean age=67.1±11.1 years) who underwent ¹⁸F-FDG PET/CT for CRC staging and subsequent bowel resection were reviewed. In primary lesions, ¹⁸F-FDG uptake was semiquantitatively evaluated in terms of maximum standardized uptake value (SUVmax), and EGFR status was determined by immunohistochemistry. Associations of clinicopathological parameters and EGFR status were analyzed by Pearson's chi-square test, multiple logistic regression, and receiver operating characteristic curves.

RESULTS

Eighty-six patients (65.2%) showed EGFR expression. SUVmax was significantly lower in EGFR-negative tumors than in EGFR-expressing tumors (10.0±4.2 vs. 12.1±2.1; p=0.012). It was the only significant parameter correlated with EGFR expression (odds ratio=2.457; relative risk=2.013; p=0.038). At the SUVmax threshold of 7.5, the sensitivity and specificity for predicting EGFR expression were 84.9% and 40.4%, respectively (area under the curve=0.624; p=0.019).

CONCLUSION

Preoperative ¹⁸F-FDG uptake is slightly correlated with EGFR status in primary CRC. Preoperative SUVmax of ¹⁸F-FDG may have a limited role in predicting EGFR expression in such tumors because of its poor specificity.

A Whole-Body Physiologically Based Pharmacokinetic Model of Gefitinib in Mice and Scale-Up to Humans

Gefitinib (Iressa) is a selective and potent EGFR tyrosine kinase inhibitor. It received an accelerated FDA approval in 2003 for the treatment of patients with nonsmall cell lung cancer (NSCLC) and represents the first-line therapy for NSCLC with EGFR mutations. In the work presented herein, the disposition of gefitinib was investigated extensively in mouse in both plasma and 11 organs (liver, heart, lung, spleen, gut, brain, skin, fat, eye, kidney, and muscle) after a single IV dose of 20 mg/kg. Gefitinib demonstrated extensive distribution in most tissues, except for the brain, and tissue to plasma partition coefficients (K pt) ranged from 0.71 (brain) to 40.5 (liver). A comprehensive whole-body physiologically based pharmacokinetic (PBPK) model of gefitinib in mice was developed, which adequately captured gefitinib concentration-time profiles in plasma and various tissues. Predicted plasma and tissue AUC values agreed well with the values calculated using the noncompartmental analysis (<25% difference). The PBPK model was further extrapolated to humans after taking into account the interspecies differences in physiological parameters. The simulated concentrations in human plasma were in line with the observed concentrations in healthy volunteers and patients with solid malignant tumors after both IV infusion and oral administration. Considering the extensive tissue distribution of gefitinib, plasma concentration may not be an ideal surrogate marker for gefitinib exposure at the target site or organ of toxicity (such as the skin). Since our whole-body PBPK model can predict gefitinib concentrations not only in plasma but also in various organs, our model may have clinical applications in efficacy and safety assessment of gefitinib.

Synergistic Inhibitory Effects of Cetuximab and Cisplatin on Human Colon Cancer Cell Growth via Inhibition of the ERK-Dependent EGF Receptor Signaling Pathway

The purpose of this study was to evaluate the anticancer efficacy of cetuximab combined with cisplatin (combination treatment) on colon cancer growth, as well as its underlying action mechanism. Combination treatment synergistically potentiated the effect of cetuximab on cell growth inhibition and apoptosis induction in HCT116 and SW480 cells. Combination treatment further suppressed the expression of the activated form of epidermal growth factor receptor (EGFR) and MAP kinase (p-ERK and p-p38) and also significantly inhibited the activity of activator protein-1 (AP-1) and nuclear factor kappa B (NF-κB). Additionally, the expression of cyclooxygenase-2 (COX-2) and interleukin-8 (IL-8) mRNA was significantly reduced by the combination treatment as compared to the expression seen for treatment with cetuximab or cisplatin alone. We found that the synergistic inhibitory effects of cetuximab and cisplatin on AP-1 and NF-κB activation, as well as on cell viability, were reversed by pretreatment with an ERK inhibitor. Results demonstrate that combined treatment with cetuximab and cisplatin exerts synergistic anticancer effects on colon cancer cells and also suggest that the ERK pathway plays a critical role in these effects via the suppression of the EGFR signaling pathway, along with the inhibition of COX-2, IL-8, and AP-1 and NF-κB.

Mechanisms underlying skin disorders induced by EGFR inhibitors

The epidermal growth factor receptor (EGFR) is a receptor tyrosine kinase that is frequently mutated or overexpressed in a large number of tumors such as carcinomas or glioblastoma. Inhibitors of EGFR activation have been successfully established for the therapy of some cancers and are more and more frequently being used as first or later line therapies. Although the side effects induced by inhibitors of EGFR are less severe than those observed with classic cytotoxic chemotherapy and can usually be handled by out-patient care, they may still be a cause for dose reduction or discontinuation of treatment that can reduce the effectiveness of antitumor therapy. The mechanisms underlying these cutaneous side effects are only partly understood. Important questions, such as the reasons for the correlation between the intensity of the side effects and the efficiency of treatment with EGFR inhibitors, remain to be answered. Optimized adjuvant strategies to accompany anti-EGFR therapy need to be found for optimal therapeutic application and improved quality of life of patients. Here, we summarize current literature on the molecular and cellular mechanisms underlying the cutaneous side effects induced by EGFR inhibitors and provide evidence that keratinocytes are probably the optimal targets for adjuvant therapy aimed at alleviating skin toxicities.

An in silico analytical study of lung cancer and smokers datasets from gene expression omnibus (GEO) for prediction of differentially expressed genes

Smoking is the leading cause of lung cancer development and several genes have been identified as potential biomarker for lungs cancer. Contributing to the present scientific knowledge of biomarkers for lung cancer two different data sets, i.e. GDS3257 and GDS3054 were downloaded from NCBI׳s GEO database and normalized by RMA and GRMA packages (Bioconductor). Diffrentially expressed genes were extracted by using and were R (3.1.2); DAVID online tool was used for gene annotation and GENE MANIA tool was used for construction of gene regulatory network. Nine smoking independent gene were found whereas average expressions of those genes were almost similar in both the datasets. Five genes among them were found to be associated with cancer subtypes. Thirty smoking specific genes were identified; among those genes eight were associated with cancer sub types. GPR110, IL1RN and HSP90AA1 were found directly associated with lung cancer. SEMA6A differentially expresses in only non-smoking lung cancer samples. FLG is differentially expressed smoking specific gene and is related to onset of various cancer subtypes. Functional annotation and network analysis revealed that FLG participates in various epidermal tissue developmental processes and is co-expressed with other genes. Lung tissues are epidermal tissues and thus it suggests that alteration in FLG may cause lung cancer. We conclude that smoking alters expression of several genes and associated biological pathways during development of lung cancers.

Heterotrimeric G proteins directly regulate MMP14/membrane type-1 matrix metalloprotease: a novel mechanism for GPCR-EGFR transactivation

Agonist stimulation of G protein-coupled receptors (GPCRs) can transactivate epidermal growth factor receptors (EGFRs), but the precise mechanisms for this transactivation have not been defined. Key to this process is the protease-mediated "shedding" of membrane-tethered ligands, which then activate EGFRs. The specific proteases and the events involved in GPCR-EGFR transactivation are not fully understood. We have tested the hypothesis that transactivation can occur by a membrane-delimited process: direct increase in the activity of membrane type-1 matrix metalloprotease (MMP14, MT1-MMP) by heterotrimeric G proteins, and in turn, the generation of heparin-binding epidermal growth factor (HB-EGF) and activation of EGFR. Using membranes prepared from adult rat cardiac myocytes and fibroblasts, we found that MMP14 activity is increased by angiotensin II, phenylephrine, GTP, and guanosine 5'-O-[γ-thio]triphosphate (GTPγS). MMP14 activation by GTPγS occurs in a concentration- and time-dependent manner, does not occur in response to GMP or adenosine 5'-[γ-thio]triphosphate (ATPγS), and is not blunted by inhibitors of Src, PKC, phospholipase C (PLC), PI3K, or soluble MMPs. This activation is specific to MMP14 as it is inhibited by a specific MMP14 peptide inhibitor and siRNA knockdown. MMP14 activation by GTPγS is pertussis toxin-sensitive. A role for heterotrimeric G protein βγ subunits was shown by using the Gβγ inhibitor gallein and the direct activation of recombinant MMP14 by purified βγ subunits. GTPγS-stimulated activation of MMP14 also results in membrane release of HB-EGF and the activation of EGFR. These results define a previously unrecognized, membrane-delimited mechanism for EGFR transactivation via direct G protein activation of MMP14 and identify MMP14 as a heterotrimeric G protein-regulated effector.

KRAS mutation confers resistance to antibody-dependent cellular cytotoxicity of cetuximab against human colorectal cancer cells

Cetuximab is a chimeric IgG1 monoclonal antibody (mAb) that targets the extracellular domain of epidermal growth factor receptor (EGFR). Oncogenic KRAS mutations in tumors have been shown to be a negative predictor of the response of colorectal cancer (CRC) to cetuximab treatment. Cetuximab exerts its therapeutic effects through several mechanisms including antibody-dependent cellular cytotoxicity (ADCC). However, the influence of KRAS mutations on cetuximab-mediated ADCC is not fully understood. Here, we investigated cetuximab-mediated ADCC in two pairs of isogenic CRC cells with or without a KRAS mutation. Peripheral blood mononuclear cells (PBMCs) from healthy volunteers and NK92, a natural killer (NK) cell line that exogenously expresses FcγRIIIa (CD16a), were used as effector cells. In an ADCC assay, perforin-dependent target cell lysis was not affected by the KRAS mutation status. On the other hand, perforin-independent ADCC was observed only in CRC cells with wild-type KRAS, but not in cells with mutant KRAS. Neutralizing experiments revealed that the Fas-Fas ligand (FasL) interaction was responsible for the induction of apoptosis and perforin-independent ADCC. Furthermore, the presence of effector cells clearly enhanced the growth-inhibitory effect of cetuximab only in CRC cells with wild-type KRAS, but not in those with mutant KRAS. These findings suggest that ADCC is an important mode of action of cetuximab and that KRAS mutation impairs the therapeutic effect exerted by cetuximab-mediated ADCC.

Early assessment of tumor response to gefitinib treatment by noninvasive optical imaging of tumor vascular endothelial growth factor expression in animal models

Epidermal growth factor receptor (EGFR) expression is upregulated in many types of tumors, and the EGFR tyrosine kinase inhibitor gefitinib has high potential as an anticancer drug. However, accumulating clinical evidence has indicated that only a subset of patients benefit from gefitinib treatment. This study aimed to determine whether optical imaging of vascular endothelial growth factor (VEGF) expression can be an early biomarker for tumor response to gefitinib therapy.

METHODS

A VEGF-targeting fluorescent probe Dye-BevF(ab')2 was prepared and tested in vivo. Longitudinal optical imaging studies using Dye-BevF(ab')2 were performed in both 22B (gefitinib-resistant) and A549 (gefitinib-responsive) tumor models at different times (days 0, 2, and 5) before and after gefitinib treatment. The imaging results were validated by ex vivo immunofluorescence staining and enzyme-linked immunosorbent assay.

RESULTS

Dye-BevF(ab')2 exhibited high specificity for VEGF in vivo. There was no significant change in the Dye-BevF(ab')2 uptake in gefitinib-treated 22B tumors, compared with the control group. In contrast, the A549 tumor uptake of Dye-BevF(ab')2 in the gefitinib-treated group was significantly lower on days 2 and 5 than that in the control group and at the baseline. An in vivo gefitinib treatment study confirmed that 22B tumors were gefitinib-resistant, whereas A549 tumors were gefitinib-responsive. Immunofluorescence staining and enzyme-linked immunosorbent assay confirmed that changes in the Dye-BevF(ab')2 uptake were correlated with VEGF expression levels in tumors.

CONCLUSION

Optical imaging of VEGF expression with Dye-BevF(ab')2 can be used for the early assessment of tumor response to gefitinib therapy. This approach may also be valuable for preclinical high-throughput screening of novel antiangiogenic drugs.

Synergistic effect of nanosecond pulsed electric field combined with low-dose of pingyangmycin on salivary adenoid cystic carcinoma

Adenoid cystic carcinoma (ACC) is one of the most common malignant neoplasms in salivary glands. To evaluate the therapeutic effects of nanosecond pulsed electric field (nsPEF) combined with pingyangmycin (PYM) on salivary gland adenoid cystic carcinoma (SACC), ACC high metastatic cell line (SACC-LM) and low metastatic cell line (SACC‑83) were tested by CCK-8 assay, cell clonogenic assay, flow cytometry and Transwell assay. Extracellular matrix metalloproteinase inducer (EMMPRIN) expression was tested by western blotting to verify the synergistic mechanism of nsPEF and PYM. The results showed that nsPEF inhibited the cell proliferation of both cell lines, and the inhibitory effect was strongly associated with time and electrical field strength. Moreover, PYM combined with nsPEF may enhance the suppression effect significantly, even at a very low dose (0.01 µg/ml). The synergistic effects may contribute to the downregulation of EMMPRIN expression resulting from the application of nsPEF. For SACC, nsPEF combined with chemotherapy agents may be a valuable strategy not only to improve the treatment effect and prognosis, but also to reduce the side-effects of chemotherapy.

177Lu-labeled antibodies for EGFR-targeted SPECT/CT imaging and radioimmunotherapy in a preclinical head and neck carcinoma model

Epidermal growth factor receptor (EGFR) has been well characterized as an important target for cancer therapy. Immunotherapy based on EGFR-specific antibodies (e.g., panitumumab and cetuximab) has shown great clinical promise. However, increasing evidence has indicated that only a subgroup of patients receiving these antibodies will benefit from them, and even patients who do initially experience a major response may eventually develop therapeutic resistance. In this study, we investigated whether panitumumab and cetuximab can serve as delivery vehicles for tumor-targeted radionuclide therapy in a preclinical tumor model that did not respond to immunotherapy. The in vitro toxicity and cell binding properties of panitumumab and cetuximab were characterized. Both antibodies were conjugated with 1,4,7,10-tetraazadodecane-N,N',N",N"'-tetraacetic acid (DOTA) and radiolabeled with (177)Lu. Small-animal SPECT/CT, biodistribution, and radioimmunotherapy (RIT) studies of (177)Lu-DOTA-panitumumab ((177)Lu-Pan) and (177)Lu-DOTA-cetuximab ((177)Lu-Cet) were performed in the UM-SCC-22B tumor model. Both (177)Lu-Pan and (177)Lu-Cet exhibited favorable tumor targeting efficacy. The tumor uptake was 20.92 ± 4.45, 26.10 ± 5.18, and 13.27 ± 1.94% ID/g for (177)Lu-Pan, and 15.67 ± 3.84, 15.72 ± 3.49, and 7.82 ± 2.36% ID/g for (177)Lu-Cet at 24, 72, and 120 h p.i., respectively. RIT with a single dose of 14.8 MBq of (177)Lu-Pan or (177)Lu-Cet significantly delayed tumor growth. (177)Lu-Pan induced more effective tumor growth inhibition due to a higher tumor uptake. Our results suggest that panitumumab and cetuximab can function as effective carriers for tumor-targeted delivery of radiation, and that RIT is promising for targeted therapy of EGFR-positive tumors, especially for those tumors that are resistant to antibody-based immunotherapy.

Expression of EGFR and HPV-associated p16 in oropharyngeal carcinoma: correlation and influence on prognosis after radiotherapy in the randomized DAHANCA 5 and 7 trials

AIM

EGFR and HPV-associated p16 are among the most investigated biomarkers in head and neck cancer. The aim was to investigate the correlation and interaction between these two markers and to evaluate their potential prognostic significance when combined.

MATERIALS AND METHODS

336 Oropharyngeal carcinomas treated with primary radiotherapy (66-68 Gy, 2fx/day, 10-12 Gy/week) and with known EGFR/p16-status estimated semiquantitatively by immunohistochemistry were included in the study. Data were evaluated by EGFR-expression (high/low) and p16-status (positive/negative) consequently dividing tumours into four groups by combination of the biomarkers. Patient/tumour characteristics and complete 5-year follow-up were available.

RESULTS

Low EGFR-expression was significantly more common in p16-positive tumours compared to p16-negative, p < 0.0001. p16 positivity showed a strong prognostic impact (p < 0.0001, HR = 0.22 [0.13-0.38]), whereas EGFR was a weak prognostic marker when local control was used as endpoint (p = 0.03, HR = 0.53 [0.29-0.94]). Combination of EGFR/p16 did not add significant information to p16 alone and by multivariable analysis only p16 showed significant prognostic information for all evaluated endpoints.

CONCLUSIONS

Both EGFR and p16 bear prognostic information in oropharyngeal cancer, although p16 is, by far, the strongest prognostic factor. The markers seem to be correlated and this might have influence when evaluating the effect of EGFR inhibition in oropharyngeal tumours.