Tumor-associated macrophages (TAM) in the tumor microenvironment (TME) cooperate with cancer stem cells (CSC) to maintain stemness. We recently identified cluster of differentiation 44 (CD44) as a surface marker defining head and neck squamous cell carcinoma (HNSCC) CSC. PI3K-4EBP1-SOX2 activation and signaling regulate CSC properties, yet the upstream molecular control of this pathway and the mechanisms underlying crosstalk between TAM and CSC in HNSCC remain largely unknown. Because CD44 is a molecular mediator in the TME, we propose here that TAM-influenced CD44 signaling could mediate stemness via the PI3K-4EBP1-SOX2 pathway, possibly by modulating availability of hyaluronic acid (HA), the main CD44 ligand. HNSCC IHC was used to identify TAM/CSC relationships, and in vitro coculture spheroid models and in vivo mouse models were used to identify the influence of TAMs on CSC function via CD44. Patient HNSCCderived TAMs were positively and negatively associated with CSC marker expression at noninvasive and invasive edge regions, respec-tively. TAMs increased availability of HA and increased cancer cell invasion. HA binding to CD44 increased PI3K-4EBP1-SOX2 signaling and the CSC fraction, whereas CD44-VCAM-1 binding promoted invasive signaling by ezrin/PI3K. In vivo, targeting CD44 decreased PI3K-4EBP1-SOX2 signaling, tumor growth, and CSC. TAM depletion in syngeneic and humanized mouse models also diminished growth and CSC numbers. Finally, a CD44 isoform switch regulated epithelial-to-mesenchymal plasticity as standard form of CD44 and CD44v8-10 determined invasive and tumorigenic phenotypes, respectively. We have established a mechanistic link between TAMs and CSCs in HNSCC that is mediated by CD44 intracellular signaling in response to extracellular signals.Significance: These findings establish a mechanistic link between tumor cell CD44, TAM, and CSC properties at the tumor-stroma interface that can serve as a vital area of focus for target and drug discovery.

4 Laryngoscope, 2573-2575, 2018.

Salivary gland cancers (SGC) frequently present with distant metastases many years after diagnosis, suggesting a cancer stem cell (CSC) subpopulation that initiates late recurrences; however, current models are limited both in their availability and suitability to characterize these rare cells. Patient-derived xenografts (PDX) were generated by engrafting patient tissue onto nude mice from one acinic cell carcinoma (AciCC), four adenoid cystic carcinoma (ACC), and three mucoepidermoid carcinoma (MEC) cases, which were derived from successive relapses from the same MEC patient. Patient and PDX samples were analyzed by RNA-seq and Exome-seq. Sphere formation potential and tumorigenicity was assessed by sorting for Aldefluor (ALDH) activity and CD44-expressing subpopulations. For successive MEC relapses we found a time-dependent increase in CSCs (ALDHCD44), increasing from 0.2% to 4.5% (=0.033), but more importantly we observed an increase in individual CSC sphere formation and tumorigenic potential. A 50% increase in mutational burden was documented in subsequent MEC tumors, and this was associated with increased expression of tumor-promoting genes (, and ), decreased expression of tumor-suppressor genes (, and ), and higher expression of CSC-related proteins such as SOX2, MYC, and ALDH1A1. Finally, genomic analyses identified a novel- fusion in an ACC tumor and confirmed previously reported fusions (- and - Sequential MEC PDX models preserved key patient features and enabled the identification of genetic events putatively contributing to increases in both CSC proportion and intrinsic tumorigenicity, which mirrored the patient's clinical course. .

No abstract

Objectives/Hypothesis: Patients with muscle tension dysphonia often demonstrate an elevation in Reflux Symptom Index (RSI) and 10-item Voice Handicap Index (VHI-10) scores, and may be erroneously diagnosed with laryngopharyngeal reflux disease. In this study we assessed the effects of voice therapy on RSI and VHI-10 scores in patients with voice complaints not responsive to antireflux medications. Study Design: Retrospective cohort study. Methods: A study of patients was conducted at a single tertiary-care center over 1 year (January 2012–January 2013). Patients were included if they had dysphonia not responsive to proton pump inhibition, did not have neurologic or neoplastic disease, and participated in at least three voice-therapy sessions in the absence of antireflux therapy. Primary analysis assessed change in RSI scores between the initial and follow-up visits with a laryngologist. Results: A total of 18 patients were included (mean age = 49.9 ± 14.5 years, 89% female, 83% with a primary complaint of dysphonia). From initial to follow-up visit, the median RSI score (18.5 [interquartile range {IQR}, 9.5–22.8] vs. 10.5 [IQR, 4.5–14]; P = .02) and median VHI-10 score (25.5 [IQR, 11.3–30.0] vs. 13.5 [IQR, 9.5–20.8]; P = .03) significantly decreased. A significant inverse correlation was found between the number of voice therapy sessions/month and change in RSI score (r = −0.4; P = .05). Conclusions: In this study of patients with muscle tension dysphonia or vocal hyperfunction not responsive to antireflux therapy, RSI and VHI-10 scores improved following voice therapy. Results suggest that self-reported symptoms typically attributed to laryngopharyngeal reflux disease may actually be secondary to inefficient voice use patterns or anxiety about dysphonia that are responsive to voice therapy.