Leiomyosarcoma of the head and neck: A 17-year single institution experience and review of the National Cancer Data Base

BACKGROUND

Leiomyosarcoma is a rare neoplasm of the head and neck. The purpose of this study was to present our single-institution case series of head and neck leiomyosarcoma and a review of cases in the National Cancer Data Base (NCDB).

METHODS

Patients with head and neck leiomyosarcoma at the University of Pennsylvania and in the NCDB were identified. Demographic characteristics, tumor factors, treatment paradigms, and outcomes were evaluated for prognostic significance.

RESULTS

Nine patients with head and neck leiomyosarcoma from the institution were identified; a majority had high-grade disease and cutaneous leiomyosarcoma, with a 5-year survival rate of 50%. Two hundred fifty-nine patients with leiomyosarcoma were found in the NCDB; macroscopic positive margins and high-grade disease were associated with poor prognosis (P < .01), and positive surgical margins were related to adjuvant radiation (P < .001).

CONCLUSION

Head and neck leiomyosarcoma presents at a high grade and is preferentially treated with surgery. Several demographic and tumor-specific factors are associated with outcomes and prognosis.

A novel chitosan-hydrogel-based nanoparticle delivery system for local inner ear application

HYPOTHESIS

A chitosan-hydrogel-based nanoparticle (nanohydrogel) delivery system can be used to deliver therapeutic biomaterials across the round window membrane (RWM) into the inner ear in a mouse model.

BACKGROUND

Delivering therapies to the inner ear has always been a challenge for the otolaryngologist. Advances in biomedical nanotechnology, increased understanding of the RWM diffusion properties, and discovery of novel therapeutic targets and agents, have all sparked interest in the controlled local delivery of drugs and biomaterials to the inner ear using nanoparticles (NPs).

METHODS

Fluorescently-labeled liposomal NPs were constructed and loaded into a chitosan-based hydrogel to form a nanohydrogel, and in vitro studies were performed to evaluate its properties and release kinetics. Furthermore, the nanohydrogel was applied to the RWM of mice, and perilymph and morphologic analysis were performed to assess the NP delivery and distribution within the inner ear.

RESULTS

NPs with an average diameter of 160 nm were obtained. In vitro experiments showed that liposomal NPs can persist under physiologic conditions for at least two weeks without significant degradation and that the nanohydrogel can carry and release these NPs in a controlled and sustained manner. In vivo findings demonstrated that the nanohydrogel can deliver intact nanoparticles into the perilymphatic system and reach cellular structures in the scala media of the inner ear of our mouse model.

CONCLUSION

Our study suggests that the nanohydrogel system has great potential to deliver therapeutics in a controlled and sustained manner from the middle ear to the inner ear without altering inner ear structures.

Dual disruption of DNA repair and telomere maintenance for the treatment of head and neck cancer

PURPOSE

Poly(ADP-ribose) polymerases (PARP) and the Mre11, Rad50, and Nbs1 (MRN) complex are key regulators of DNA repair, and have been recently shown to independently regulate telomere length. Sensitivity of cancers to PARPi is largely dependent on the BRCAness of the cells. Unfortunately, the vast majority of cancers are BRCA-proficient. In this study, therefore, we investigated whether a targeted molecular "hit" on the MRN complex, which is upstream of BRCA, can effectively sensitize BRCA-proficient head and neck squamous cell carcinoma (HNSCC) to PARP inhibitor (PARPi).

EXPERIMENTAL DESIGN

Human HNSCC cell lines and a mouse model with HNSCC xenografts were used in this study. In vitro and in vivo studies were conducted to evaluate the effects and underlying mechanisms of dual molecular disruption of PARP and the MRN complex, using a pharmacologic inhibitor and a dominant-negative Nbs1 expression vector, respectively.

RESULTS

Our findings demonstrate that downregulation of the MRN complex disrupts homologous recombination, and, when combined with PARPi, leads to accumulation of lethal DNA double-strand breaks. Moreover, we show that PARPi and MRN complex disruption induces significantly shortening telomere length. Together, our results demonstrate that dual disruption of these pathways causes significant cell death in BRCA-proficient tumor cells both in vitro and in vivo.

CONCLUSION

Our study, for the first time, elucidates a novel mechanism for MRN complex and PARP inhibition beyond DNA repair, demonstrating the feasibility of a dual disruption approach that extends the utility of PARPi to the treatment of BRCA-proficient cancers.

Biliverdin's regulation of reactive oxygen species signalling leads to potent inhibition of proliferative and angiogenic pathways in head and neck cancer

BACKGROUND

In this study, we evaluate whether the use of biliverdin (BV), a natural non-toxic antioxidant product of haeme catabolism, can suppress head and neck squamous cell carcinoma (HNSCC) cell proliferation and improve the tumour survival both in vitro and in vivo. Furthermore, we investigate whether this therapeutic outcome relies on BV's potent antioxidant effect on reactive oxygen species (ROS)-mediated signalling.

METHODS

Two well-characterised HNSCC cell lines and a mouse model with human HNSCC were used for this study. In vitro, the effect of BV on ROS was assayed. Subsequently, critical regulatory proteins involved in growth, antiapoptotic, and angiogenic pathways were investigated by western blot analysis. In addition, the antiproliferative effect of BV was also evaluated using the clonogenic assay. Moreover, tumour growth inhibition was assessed using a mouse model with HNSCC.

RESULTS

Biliverdin treatment resulted in decreased ROS, leading to suppression of proliferation and angiogenesis pathways of HNSCC, significantly decreasing the expression and phosphorylation of oncogenic factors such as epidermal growth factor receptor (EGFR), phosphorylation of Akt, and expression of angiogenic marker and transcription factor, hypoxia-inducible factor1-α (HIF1-α). Furthermore, this downregulation of ROS by BV led to a significant suppression of tumour growth in vivo.

CONCLUSIONS

Our study demonstrates the efficacy of a novel therapeutic approach using BV as an antitumour agent against HNSCC through its effect on EGFR/Akt and HIF1-α/angiogenesis signal transduction pathways. Our findings indicate that BV's inhibitory effect on these tumorigenic pathways relies on its antioxidant effect, and may extend its therapeutic potential to other solid cancers.

Abstract 2263: Biliverdin inhibits head and neck cancer cell growth via activation of retinoblastoma signaling pathway

Head and neck cancer patients often present with advanced disease and, despite advances in chemoradiation treatment protocols, continue to have a poor prognosis while experiencing severe treatment induced toxicity. There is an increased demand for natural, and non-toxic agents for treatment, which can be either used alone or in combination with our therapies. In this study, we are using biliverdin (BV), an antioxidant bile pigment, which is oxidized from bilirubin. As a potent antioxidant, accumulating data from observations in experimental and human studies indicate that the BV may be protective against certain diseases, including cancer. Based on our own observations that BV suppresses cell proliferation in head and neck squamous cell carcinoma (HNSCC) cells and clinical observations finding a lesser incidence of cancer in healthy individuals with slightly elevated serum bilirubin levels, we hypothesized that BV might suppress tumor cell proliferation. The present study looks to evaluate whether BV treatment can suppress cell proliferation in HNSCC cells in vitro and in vivo, and to elucidate the potential mechanism through which it exerts this effect.

HNSCC cell lines, with varying resistance to chemoradiation, and a mouse model with human HNSCC xenografts were used in this study. As potential effectors, we analyzed key proteins that are involved in apoptosis and cell cycle progression. In vitro, we investigated the effect of BV on five HNSCC cell lines and the signaling pathways involved in BV action on tumor cell proliferation using western blots. We also analyzed the antiproliferative effects of the BV by the colorimetric 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyl tetrazolium bromide (MTT) assay and cell cycle analysis where BV caused cell cycle arrest by hypophosphorylation (activating) of the retinoblastoma (Rb) tumor suppressor protein in HNSCC cells. Ex vivo, we found significant suppression of xenograft tumor growth in HNSCC cells pretreated with BV before intradermal injection in nude mice as compared to controls. In vivo, tumor growth was assessed in BALB/c nude mice bearing HNSCC xenografts that were treated with BV. The signaling pathway responsible for this action included dephosphorylation of epidermal growth factor receptor (EGFR), Akt, NF-κB, and hypophosphorylation of the Rb tumor suppressor protein as well as caspase activation.

Our study provides a rationale for a novel therapeutic approach using exogenous BV, a nontoxic antioxidant product of heme catabolism, as an anti-cancer agent against HNSCC through its effect on the Rb/Akt/NF-κB signal transduction pathway. Our findings indicate that BV's actions on these key tumorogenic pathways may extend its therapeutic potential to head and neck cancer.

Citation Format: Jun Zheng, Danish A. Nagda, Shayanne A. Lajud, Sanjeev Kumar, Anas Mouchli, Orysia Bezpalko, Bert W. O'Malley, Daqing Li. Biliverdin inhibits head and neck cancer cell growth via activation of retinoblastoma signaling pathway. [abstract]. In: Proceedings of the 104th Annual Meeting of the American Association for Cancer Research; 2013 Apr 6-10; Washington, DC. Philadelphia (PA): AACR; Cancer Res 2013;73(8 Suppl):Abstract nr 2263. doi:10.1158/1538-7445.AM2013-2263

A regulated delivery system for inner ear drug application

OBJECTIVE

We have recently developed a novel inner ear drug delivery system using chitosan glycerophosphate (CGP) hydrogel loaded with drugs commonly used for treatment of inner ear diseases, significantly improving the drugs' sustained delivery. The goal of this study is to evaluate the effectiveness of chitosanase as a "switch off" mechanism for this drug delivery system when side effects and potential ototoxicities appear during treatment. To evaluate this effect, we tested gentamicin (GENT) in the inner ear following CGP delivery with/without regulation.

METHODS

Purified chitosanase was obtained and used for regulating the CGP delivery system. In vitro studies were performed to evaluate the effect of the interaction between chitosanase and CGP-hydrogel loaded with GENT or Texas Red-labeled GENT (GTTR). In vivo studies were performed using our mouse model to investigate the regulatory effect of chitosanase application on the delivery of GENT to the inner ear. To assess the potential drug rerouting regulatory effect of chitosanase the GTTR fluorescence intensity was evaluated at the round window niche (RWN) and the Eustachian tube (ET). To further characterize this regulatory effect, GENT concentration in the perilymph of the inner ear was analyzed by chromatographic tandem mass spectrometry (LC-MS/MS), and the uptake in the inner ear cells was measured using fluorescence microscopy following CGP delivery with/without chitosanase application.

RESULTS

The chitosanase effectively digested the CGP-hydrogel, quickly releasing GENT and GTTR from the system in vitro. When reacted with GENT alone chitosanase did not produce any reducing sugars and did not affect GENT's antimicrobial activity. In vivo GTTR was effectively rerouted from the RWN to the ET, limiting its uptake in inner ear hair cells. Concurrent with these findings, GENT concentration in the inner ear perilymph was significantly decreased after chitosanase application.

CONCLUSION

Our study findings suggest that, for the first time, sustained and controlled inner ear drug delivery can be successfully regulated enhancing its translation potential for clinical application. The use of chitosanase to digest the CGP-hydrogel results in the rerouting of the loaded drug away from the RWN, effectively downregulating its delivery to the inner ear. This important modification to our drug delivery system has the ability to deliver therapy to the inner ear until desired effect is achieved and to stop this process when side effects or treatment-related ototoxicities start to occur, providing a novel and salient approach for safe and effective delivery to the inner ear.