Hyung Ju C. Shin

Detection of Circulating Tumor Cells in Human Peripheral Blood using Surface-Enhanced Raman Scattering Nanoparticles

The detection and characterization of circulating tumor cells (CTC) holds great promise for personalizing medicine and optimizing systemic therapy. However, low specificity, low sensitivity, and the time consuming nature of current approaches have impeded clinical adoption. Here we report a new method using surface-enhanced Raman spectroscopy (SERS) to directly measure targeted CTCs in the presence of white blood cells. SERS nanoparticles with epidermal growth factor peptide as a targeting ligand have successfully identified CTCs in the peripheral blood of 19 patients with squamous cell carcinoma of the head and neck (SCCHN), with a range of 1 to 720 CTCs per milliliter of whole blood. Our technique may provide an important new clinical tool for management of patients with SCCHN and other cancers.

HFT-T, a Targeting Nanoparticle, Enhances Specific Delivery of Paclitaxel to Folate Receptor-Positive Tumors

Nonspecific distribution of chemotherapeutic drugs (such as paclitaxel) is a major factor contributing to side effects and poor clinical outcomes in the treatment of human head and neck cancer. To develop novel drug delivery systems with enhanced efficacy and minimized adverse effects, we synthesized a ternary conjugate heparin-folic acid-paclitaxel (HFT), loaded with additional paclitaxel (T). The resulting nanoparticle, HFT-T, is expected to retain the antitumor activity of paclitaxel and specifically target folate receptor (FR)-expressing tumors, thereby increasing the bioavailability and efficacy of paclitaxel. In vitro experiments found that HFT-T selectively recognizes FR-positive human head and neck cancer cell line KB-3-1, displaying higher cytotoxicity compared to the free form of paclitaxel. In a subcutaneous KB-3-1 xenograft model, HFT-T administration enhanced the specific delivery of paclitaxel into tumor tissues and remarkably improved antitumor efficacy of paclitaxel. The average tumor volume in the HFT-T treatment group was 92.9 +/- 78.2 mm(3) vs 1670.3 +/- 286.1 mm(3) in the mice treated with free paclitaxel. Furthermore, paclitaxel tumors showed a resurgence of growth after several weeks of treatment, but this was not observed with HFT-T. This indicates that HFT-T could be more effective in preventing tumors from developing drug resistance. No significant acute in vivo toxicity was observed. These results indicate that specific delivery of paclitaxel with a ternary structured nanoparticle (HFT-T) targeting FR-positive tumor is a promising strategy to enhance chemotherapy efficacy and minimize adverse effects.

Synergistic inhibition of head and neck tumor growth by green tea (−)-epigallocatechin-3-gallate and EGFR tyrosine kinase inhibitor

One of the mechanisms of the antitumor activity of green tea (−)‐epigallocatechin‐3‐gallate (EGCG) is associated with its effect on epidermal growth factor receptor (EGFR)‐mediated signaling transduction pathways. We investigated whether combining EGCG with the EGFR‐tyrosine kinase inhibitor (EGFR‐TKI) erlotinib may augment erlotinib‐induced cell growth inhibition of squamous cell carcinoma of the head and neck (SCCHN) in a mouse xenograft model. In vitro studies with 5 head and neck cancer cell lines revealed that synergistic cell growth inhibition by the combination of EGCG and erlotinib was associated with significantly greater inhibition of pEGFR and pAKT, increased activation of caspases 9, 3 and PARP compared to the inhibition induced by EGCG or erlotinib alone. Erlotinib inhibited phosphorylation of EGFR, stabilizing EGFR at the plasma membrane, whereas EGCG induced EGFR internalization and ubiquitin‐degradation, ultimately undermining EGFR signaling. The efficacy of the combination treatment was investigated with nude mice (n = 25) orally gavaged with vehicle control, EGCG, erlotinib or the combination at the same doses for 7 days, followed by subcutaneous injection with Tu212 cells. Animals were continuously administered the agents 5 days weekly for 7 weeks. The combined treatment resulted in significantly greater inhibition of tumor growth and delayed tumor progression as a result of increased apoptosis, decreased cell proliferation and reduced pEGFR and pAKT compared to the single agent treatment groups. Our results suggest a synergistic antitumor effect of a combined treatment with EGCG and erlotinib, and provide a promising regimen for future chemoprevention and treatment of SCCHN.

Interaction between epidermal growth factor receptor– and cyclooxygenase 2–mediated pathways and its implications for the chemoprevention of head and neck cancer

Head and neck squamous cell carcinoma is a well-known model for chemoprevention studies because of its field cancerization effect, its multistep carcinogenesis process, and the easy accessibility of biopsies to target lesions. With new understandings of head and neck carcinogenesis and the development of molecular targeted therapy, chemoprevention trials for head and neck squamous cell carcinoma have been rapidly updated. Cyclooxygenase-2 (COX-2) and epidermal growth factor receptor (EGFR) tyrosine kinase inhibitors are gaining significant attention as potential chemopreventive agents. Both COX-2 and EGFR are involved in head and neck carcinogenesis. Targeting COX-2 and EGFR separately has shown promising antitumor activity. Recently, combinations of COX-2 and EGFR tyrosine kinase inhibitors have been reported to show synergistic/additive effects in preclinical studies. Because COX-2 and EGFR tyrosine kinase inhibitors are toxic as single agents in clinical trials, the combination of COX-2 and EGFR tyrosine kinase inhibitors used at lower doses seems more promising than monotherapy with either as a novel strategy in head and neck cancer chemoprevention.

Enhanced Anti-tumor Activity by the Combination of the Natural Compounds (−)-Epigallocatechin-3-gallate and Luteolin: POTENTIAL ROLE OF p53*

Natural dietary agents have drawn a great deal of attention toward cancer prevention because of their wide safety margin. However, single agent intervention has failed to bring the expected outcome in clinical trials; therefore, combinations of chemopreventive agents are gaining increasingly popularity. In the present study, we investigated a combinatorial approach using two natural dietary polyphenols, luteolin and EGCG, and found that their combination at low doses (at which single agents induce minimal apoptosis) synergistically increased apoptosis (3–5-fold more than the additive level of apoptosis) in both head and neck and lung cancer cell lines. This combination also significantly inhibited growth of xenografted tumors in nude mice. The in vivo findings also were supported by significant inhibition of Ki-67 expression and increase in TUNEL-positive cells in xenografted tissues. Mechanistic studies revealed that the combination induced mitochondria-dependent apoptosis in some cell lines and mitochondria-independent apoptosis in others. Moreover, we found more efficient stabilization and ATM-dependent Ser15 phosphorylation of p53 due to DNA damage by the combination, and ablation of p53 using shRNA strongly inhibited apoptosis as evidenced by decreased poly(ADP-ribose) polymerase and caspase-3 cleavage. In addition, we observed mitochondrial translocation of p53 after treatment with luteolin or the combination of EGCG and luteolin. Taken together, our results for the first time suggest that the combination of luteolin and EGCG has synergistic/additive growth inhibitory effects and provides an important rationale for future chemoprevention trials of head and neck and lung cancers.

Chemoprevention of Head and Neck Cancer with Celecoxib and Erlotinib: Results of a Phase Ib and Pharmacokinetic Study

Epidermal growth factor receptor (EGFR) and COX-2 inhibitors synergistically inhibit head and neck squamous cell carcinoma tumorigenesis in preclinical studies. We conducted a phase I and pharmacokinetic study with the erlotinib and celecoxib combination in patients with advanced premalignant lesions. Thirty-six subjects with oral leukoplakia, mild, moderate, or severe dysplasia, or carcinoma in situ were screened for study participation; 12 consented and received therapy for a median of 5.38 months. Erlotinib was escalated following a standard 3+3 design at 50, 75, and 100 mg orally daily and celecoxib was fixed at 400 mg twice daily for 6 months. Biopsy of lesions and cytobrush of normal mucosa were performed at baseline, 3, 6, and 12 months. Erlotinib pharmacokinetics were analyzed in 10 subjects. The maximum tolerated dose of erlotinib with celecoxib 400 mg BID was 50 mg per day with skin rash being the main observed toxicity. Overall histologic response rate was 63% (complete response, 43%; partial response, 14%; stable disease, 29%; and disease progression, 14%). With median follow-up of 36 months, mean time to progression to higher-grade dysplasia or carcinoma was 25.4 months. Downregulation of EGFR and p-ERK in follow-up biopsies correlated with response to treatment. Larger average erlotinib V/F (approximately 308 L) and CL/F (8.3 L/h) compared with previous studies may be related to relatively large average bodyweights. Average erlotinib t1/2 was 25.6 hours. Encouraging responses to the celecoxib and erlotinib combination correlated with EGFR pathway inhibition. Although erlotinib-related rash was the main limitation to dose escalation, the intervention was well tolerated. Cancer Prev Res; 7(3); 283–91. ©2013 AACR.

Chemoprevention of Head and Neck Cancer by Simultaneous Blocking of Epidermal Growth Factor Receptor and Cyclooxygenase-2 Signaling Pathways: Preclinical and Clinical Studies

Purpose: We investigated the efficacy and underlying molecular mechanism of a novel chemopreventive strategy combining EGF receptor (EGFR) tyrosine kinase inhibitor (TKI) with cyclooxygenase-2 inhibitor (COX-2I). Experimental Design: We examined the inhibition of tumor cell growth by combined EGFR-TKI (erlotinib) and COX-2I (celecoxib) treatment using head and neck cancer cell lines and a preventive xenograft model. We studied the antiangiogenic activity of these agents and examined the affected signaling pathways by immunoblotting analysis in tumor cell lysates and immunohistochemistry (IHC) and enzyme immunoassay (EIA) analyses on the mouse xenograft tissues and blood, respectively. Biomarkers in these signaling pathways were studied by IHC, EIA, and an antibody array analysis in samples collected from participants in a phase I chemoprevention trial of erlotinib and celecoxib. Results: The combined treatment inhibited head and neck cancer cell growth significantly more potently than either single agent alone in cell line and xenograft models, and resulted in greater inhibition of cell-cycle progression at G1 phase than either single drug. The combined treatment modulated the EGFR and mTOR signaling pathways. A phase I chemoprevention trial of combined erlotinib and celecoxib revealed an overall pathologic response rate of 71% at time of data analysis. Analysis of tissue samples from participants consistently showed downregulation of EGFR, pERK, and pS6 levels after treatment, which correlated with clinical response. Conclusion: Treatment with erlotinib combined with celecoxib offers an effective chemopreventive approach through inhibition of EGFR and mTOR pathways, which may serve as potential biomarkers to monitor the intervention of this combination in the clinic. Clin Cancer Res; 19(5); 1244–56. ©2013 AACR.

Combination of Anti-HER3 Antibody MM-121/SAR256212 and Cetuximab Inhibits Tumor Growth in Preclinical Models of Head and Neck Squamous Cell Carcinoma

The EGFR monoclonal antibody cetuximab is the only approved targeted agent for treating head and neck squamous cell carcinoma (HNSCC). Yet resistance to cetuximab has hindered its activity in this disease. Intrinsic or compensatory HER3 signaling may contribute to cetuximab resistance. To investigate the therapeutic benefit of combining MM-121/SAR256212, an anti-HER3 monoclonal antibody, with cetuximab in HNSCC, we initially screened 12 HNSCC cell lines for total and phosphorylated levels of the four HER receptors. We also investigated the combination of MM-121 with cetuximab in preclinical models of HNSCC. Our results revealed that HER3 is widely expressed and activated in HNSCC cell lines. MM-121 strongly inhibited phosphorylation of HER3 and AKT. When combined with cetuximab, MM-121 exerted a more potent antitumor activity through simultaneously inhibiting the activation of HER3 and EGFR and consequently the downstream PI3K/AKT and ERK pathways in vitro. Both high and low doses of MM-121 in combination with cetuximab significantly suppressed tumor growth in xenograft models and inhibited activations of HER3, EGFR, AKT, and ERK in vivo. Our work is the first report on this new combination in HNSCC and supports the concept that HER3 inhibition may play an important role in future therapy of HNSCC. Our results open the door for further mechanistic studies to better understand the role of HER3 in resistance to EGFR inhibitors in HNSCC. Mol Cancer Ther; 13(7); 1826–36. ©2014 AACR.

Role of cyclooxygenase-2 in tumor progression and survival of head and neck squamous cell carcinoma

Inhibition of cyclooxygenase-2 (COX-2) pathways may have significant implications for the prevention and treatment of head and neck squamous cell carcinoma (HNSCC). COX-2 is overexpressed in both premalignant lesions and invasive HNSCC. We examined COX-2 expression by immunohistochemistry in normal tissues, different stages of premalignant lesions, and carcinoma in situ (CIS). We also evaluated the correlation between COX-2 expression and clinical characteristics of HNSCC patients. Tissue specimens were obtained from the following: premalignant lesions from 25 subjects enrolled in a biochemoprevention trial, tumor samples collected at diagnosis from 38 HNSCC patients enrolled in an induction chemotherapy trial, and normal control tissues from 10 noncancer, nonsmoking subjects. COX-2 was expressed in early and intermediate stages of premalignant lesions, increasing first in the basal and parabasal layers, then lower spinous, and upper spinous layers. This correlation was noted in normal epithelium (P < 0.0001), histologically normal in-field samples (P < 0.0001), low-grade dysplasia (P = 0.024), and moderate-grade dysplasia (P = 0.009), but was lost in the majority of high-grade dysplasia/CIS (P = 0.896). COX-2 expression was also noted to increase progressively through the early stages of premalignancy, and to decrease in severe/CIS stage and invasive carcinoma. COX-2 expression in tumors from patients treated with induction chemotherapy was correlated with overall survival after controlling for clinical variables. These findings elucidate the differential expression pattern of COX-2 in stages of head and neck premalignant lesions and invasive carcinoma, supporting the rationale for COX-2 inhibition as an important strategy for cancer chemoprevention. Further validation of COX-2 expression is needed in prospective ongoing chemoprevention trials.

Efficacy, long-term toxicity, and mechanistic studies of gold nanorods photothermal therapy of cancer in xenograft mice

Significance This is a systematic in vivo study of gold nanorods (AuNRs)-assisted plasmonic photothermal therapy (AuNRs-PPTT) for cancer. We have optimized the properties of our AuNRs and the conditions of PPTT to achieve maximal induction of tumor apoptosis. To examine the molecular mechanisms of action of AuNRs-PPTT, we used quantitative proteomics to study protein expression levels in mouse tumor tissues and found the apoptosis pathway to be significantly perturbed. We report a long-term toxicity study (up to 15 months in the mouse model) that showed no toxicity of the AuNRs. Together, these data suggest that our AuNRs-PPTT has potential as an approach to cancer therapy. Gold nanorods (AuNRs)-assisted plasmonic photothermal therapy (AuNRs-PPTT) is a promising strategy for combating cancer in which AuNRs absorb near-infrared light and convert it into heat, causing cell death mainly by apoptosis and/or necrosis. Developing a valid PPTT that induces cancer cell apoptosis and avoids necrosis in vivo and exploring its molecular mechanism of action is of great importance. Furthermore, assessment of the long-term fate of the AuNRs after treatment is critical for clinical use. We first optimized the size, surface modification [rifampicin (RF) conjugation], and concentration (2.5 nM) of AuNRs and the PPTT laser power (2 W/cm2) to achieve maximal induction of apoptosis. Second, we studied the potential mechanism of action of AuNRs-PPTT using quantitative proteomic analysis in mouse tumor tissues. Several death pathways were identified, mainly involving apoptosis and cell death by releasing neutrophil extracellular traps (NETs) (NETosis), which were more obvious upon PPTT using RF-conjugated AuNRs (AuNRs@RF) than with polyethylene glycol thiol-conjugated AuNRs. Cytochrome c and p53-related apoptosis mechanisms were identified as contributing to the enhanced effect of PPTT with AuNRs@RF. Furthermore, Pin1 and IL18-related signaling contributed to the observed perturbation of the NETosis pathway by PPTT with AuNRs@RF. Third, we report a 15-month toxicity study that showed no long-term toxicity of AuNRs in vivo. Together, these data demonstrate that our AuNRs-PPTT platform is effective and safe for cancer therapy in mouse models. These findings provide a strong framework for the translation of PPTT to the clinic.