All Hands on Deck: Sustaining Improved Hand Hygiene Compliance in the Operating Room

Hand hygiene is an essential component of infection prevention in the health care setting. Despite diligent efforts, clinicians can be susceptible to hand hygiene misses in fast-paced, complex environments such as the operating room due to systemic factors such as the physical environment, workflow, and sporadic interactions with other personnel. Through the use of human factors and resilience engineering concepts, work-as-done were studied to identify barriers to hand hygiene compliance in the operating rooms of a pediatric hospital in an urban area. The saliency, effort, expectancy, value model was applied to design a multifaceted intervention that resulted in a sustained 95% hand hygiene compliance.

A Pilot Randomized Trial of a Video Patient Decision Aid to Facilitate Early Intervention Referrals From Primary Care

Many young children identified with developmental concerns in pediatric settings do not receive early intervention (EI). We assessed the impact of a video decision aid and text message reminder on knowledge and attitudes regarding developmental delay and EI as well as referral completion. We conducted a pilot randomized controlled trial in an urban setting and enrolled 64 parent-child dyads referred to EI. Compared with controls, participants who received the intervention demonstrated increased knowledge regarding developmental delay and EI as well as more favorable attitudes in certain topics. Although we did not find a significant difference between arms in EI intake and evaluation, we found a pattern suggestive of increased intake and evaluation among participants with low health literacy in the intervention arm. Additional study is needed to identify strategies that improve the EI referral process for families and to understand the potential targeted role for decision aids and text messages.

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 3748: The Mre11/Rad50/Nbs1 (MRN) complex: A critical mediator of chemoresistance and cancer stem cell progression in head and neck squamous cell carcinoma

While platinum-based agents like cisplatin (DDP) are the mainstay of chemotherapeutic options for several tumor types, including ovarian, lung, and head and neck squamous cell carcinoma, resistance to these agents can significantly contribute to treatment failure and increase the need for higher toxic doses. Tumors are heterogeneous in nature, with their growth sustained by a small subpopulation of highly malignant cells, termed cancer stem cells (CSCs). These cells comprise the top of the tumor cell hierarchy, are remarkably chemoresistant, and are associated with tumor recurrence.

Enhanced repair of DNA double stand breaks (DSBs) may compensate for DDP induced damage and contribute to chemoresistance in tumor cells. The Mre11/Rad50/Nbs1 (MRN) complex is a key player in DNA DSB repair, telomere maintenance, and cell cycle checkpoint control, and has been associated with DDP resistance. The present study investigates the role of MRN in the development of a CSC-mediated chemoresistant phenotype and its associated molecular signature.

Human head and neck squamous cell carcinoma (HNSCC) cell lines, a mouse model with human HNSCC, and tissue from HNSCC patients previously treated with DDP monotherapy were used in the study. In order to demonstrate the role of MRN on DDP resistance, two cell lines with significantly different sensitivity to DDP were chosen. In vitro and in vivo studies were performed to evaluate whether the chemoresistant cell line experienced increased CSC levels after DDP treatment, and whether enhanced MRN complex mediated DNA repair could explain this differential response. In addition, we assessed whether disrupting the MRN complex could lead to downregulation of these disparate effects on MRN and DNA repair, in both the CSCs and the rest of the tumor cells, conferring increased sensitivity to DDP. We evaluated both MRN expression and CSC levels, and how they correlated with apoptosis levels in patient tissue resected three days after a three day course of induction DDP monotherapy. Our study demonstrates that CSC levels and MRN expression strongly correlate with chemoresistance in vitro, in vivo, and in human. Importantly, disruption of MRN leads to increased sensitivity of HNSCC cells to DDP treatment.

In conclusion, we propose to elucidate a novel mechanism responsible for CSC mediated chemoresistance, which relies on enhanced DNA DSB repair via upregulation of the MRN complex. Our findings emphasize that disrupting this complex leads to increased sensitivity of HNSCC cells to DDP, potentially reducing the need for high, toxic doses of DDP used clinically and improving treatment outcomes.

Citation Format: Danish Nagda, Shayanne A. Lajud, Taku Yamashita, Sanjeev Kumar, Jun Zheng, Peter Qiao, Orysia Bezpalko, Bert W. O'Malley, Daqing Li. The Mre11/Rad50/Nbs1 (MRN) complex: A critical mediator of chemoresistance and cancer stem cell progression in head and neck squamous cell carcinoma. [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 3748. doi:10.1158/1538-7445.AM2013-3748

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.

Regulated Chitosan-Based Inner-Ear Drug Delivery

Objective: 1) To evaluate a novel system for regulating the chitosan-glycero-phosphate (CGP)-based hydrogel drug delivery to the inner ear. 2) To understand the distribution of gentamicin in the inner ear following CGP drug delivery with and without regulation.

Method: Chitosanase, specifically targeting CGP, was identified and purified for its use as a CGP regulation system. In vitro and in vivo studies were conducted to evaluate the effect of the chitosanase on the inner ear drug delivery and distribution. Gentamicin-Texas Red (GTTR) was used for tracking the drug distribution.

Results: Purified chitosanase was confirmed with Western blot. The in vitro study showed that the chitosanase-based regulation system effectively controlled the gentamicin releasing. The in vivo data concur with in vitro findings and demonstrated that the gentamicin concentration in the inner ear can be successfully regulated by applying the chitosanase. Moreover, the gentamicin inner ear distribution can also be regulated by changing its inner ear concentration.

Conclusion: Our study suggests that the chitosanase-based regulation system can be effectively used for controlled inner ear drug delivery. This system has a potential to stop inner ear drug application when side effects or drug-related toxicities start to occur and should be used for safe drug application in the inner ear.

Creation of Novel Nanocomplexes to Target Head and Neck Cancer

Objective: It is critically important to develop novel targeted strategies that can efficiently inhibit specific molecular pathways in tumor growth and development. The study investigates the potential of adenoviral/chitosan-PEG nanocomplexes with epidermal growth factor (EGF) for the targeting and treatment of EGF receptor (EGFR) overexpressing head and neck cancers (HNC).

Method: A construct with GFP-expressing adenoviral vector was coated with a Chitosan-PEG-EGF nanocomplex. The EGFR-expressing HNC tumor cells labeled with TdTomato were co-cultured with CHO tumor cells with coxsackievirus and adenovirus receptor (CAR), and without EGFR. Fluorescence microscopy was used to detect GFP expression after the treatment with targeted adenoviral/chitosan nanocomplex.

Results: As compared to wild-type adenovirus, the chitosan-PEG polymer coating cloaks the viral nanoparticle and prevents interaction with cells through the native CAR-mediated mechanisms. This significantly reduces nonspecific infection. Due to the TdTomato molecular marker being specifically expressed in the EGFR tumor cell line, the treated EGFR-expressing cells can be visualized by co-registration of GFP and TdTomato. The non-EGFR-expressing cells lack TdTomato and therefore only express the GFP. The adenoviral/chitosan-PEG nanocomplexes with EGF ligand demonstrated significantly increased EGFR tumor cell-specific GFP expression. The tumor cells without EGFR showed no GFP expression.

Conclusion: Our study suggests that the novel EGFR-targeted adenoviral/chitosan-PEG nanocomplex approach can effectively target HNC and has significant potential to deliver therapeutic agents specifically to the HNC tumor sites. It is also possible to track real-time tumor growth and spread through molecular imaging by incorporating fluorescent proteins into the payload.

Abstract 3111: Synthetic lethality in head and neck cancer

Current treatment for advanced stage head and neck squamous cell carcinoma (HNSCC) typically include both radiation and chemotherapy, which is associated with significant morbidity. Our main objective was to explore a novel adjuvant molecular therapy approach to minimize the chemoradiation-induced side effects and toxicities, while maintaining therapeutic anti-tumor effects in HNSCC through the mechanism of synthetic lethality that has been already exploited to a limited extent in clinical trials for breast cancer. It has been demonstrated that synthetic lethality is based on the roles of Poly(ADP-ribose)polymerase-1 (PARP-1) in DNA single-stranded break (SSB) repair, and BRCA-1 and -2 in double-stranded break (DSB) repair. By simply inhibiting PARP-1 in tumor cells carrying a mutation in the Brca genes, one would expect complete tumor regression. The MRN complex (Mre11, Rad50, and Nbs-1) is well recognized as a key sensor of DSBs and acts by recruiting and activating DNA damage response proteins. These concepts led us to investigate the concept of introducing a mutation to the MRN complex, in combination with PARP-1 inhibition, thereby creating “dual hits” that would result in synthetic lethality within tumors expressing wild-type Brca genes such as HNSCC. Human HNSCC tumor cell lines and a mouse model with human HNSCC were used in the study. Wild-type MRN and PARP expressions were detected in these tumor cells. In vitro and in vivo studies were performed to evaluate synthetic lethality effects after combining PARP-1 inhibition with adenovirus-mediated Nbs-1 (Ad-Nbs-1) gene transfer treatment, which we had previously shown to impair MRN expression. Telomere length was measured to investigate the potential mechanism of synthetic lethality. Our study demonstrates that significant synthetic lethality was found with combined PARP-1 inhibition and Ad-Nbs-1 treatment in both in vitro and in vivo experiments; it also suggests that the telomere maintenance may play an important role in synthetic lethality. In conclusion, we propose an important novel mechanism responsible for the synthetic lethality of PARP-1 inhibitors and MRN disruption based on their roles on telomere maintenance. Our findings emphasize the potential benefits of our therapeutic approach and deserve further investigation to help obviate the toxicities associated with existing treatment regimens for HNSCC patients.

Citation Format: {Authors}. {Abstract title} [abstract]. In: Proceedings of the 103rd Annual Meeting of the American Association for Cancer Research; 2012 Mar 31-Apr 4; Chicago, IL. Philadelphia (PA): AACR; Cancer Res 2012;72(8 Suppl):Abstract nr 3111. doi:1538-7445.AM2012-3111