Wnt signaling is one of the key oncogenic pathways in multiple cancers, and targeting this pathway is an attractive therapeutic approach. However, therapeutic success has been limited because of the lack of therapeutic agents for targets in the Wnt pathway and the lack of a defined patient population that would be sensitive to a Wnt inhibitor. We developed a screen for small molecules that block Wnt secretion. This effort led to the discovery of LGK974, a potent and specific small-molecule Porcupine (PORCN) inhibitor. PORCN is a membrane-bound O-acyltransferase that is required for and dedicated to palmitoylation of Wnt ligands, a necessary step in the processing of Wnt ligand secretion. We show that LGK974 potently inhibits Wnt signaling in vitro and in vivo, including reduction of the Wnt-dependent LRP6 phosphorylation and the expression of Wnt target genes, such as AXIN2. LGK974 is potent and efficacious in multiple tumor models at well-tolerated doses in vivo, including murine and rat mechanistic breast cancer models driven by MMTV–Wnt1 and a human head and neck squamous cell carcinoma model (HN30). We also show that head and neck cancer cell lines with loss-of-function mutations in the Notch signaling pathway have a high response rate to LGK974. Together, these findings provide both a strategy and tools for targeting Wnt-driven cancers through the inhibition of PORCN. Significance Targeting the Wnt pathway in cancer is an attractive therapeutic approach. However, success has been limited because of the lack of effective therapeutic agents and the lack of biomarkers to define the patient population that would benefit from such a therapy. Herein, we report the discovery of LGK974, a drug that targets Porcupine, a Wnt-specific acyltransferase. We show that LGK974 potently inhibits Wnt signaling, has strong efficacy in rodent tumor models, and is well-tolerated. We also show that head and neck cancer cell lines with loss-of-function mutations in the Notch signaling pathway have a high response rate to LGK974. Together, these findings provide a strategy and tools for targeting Wnt-driven cancer.

Purpose: To prospectively identify markers of response to therapy and outcome in an organ-sparing trial for advanced oropharyngeal cancer. Patients and Methods: Pretreatment biopsies were examined for expression of epidermal growth factor receptor (EGFR), p16, Bcl-xL, and p53 as well as for p53 mutation. These markers were assessed for association with high-risk human papillomavirus (HPV), response to therapy, and survival. Patient variables included smoking history, sex, age, primary site, tumor stage, and nodal status. Results: EGFR expression was inversely associated with response to induction chemotherapy (IC) (P = .01), chemotherapy/radiotherapy (CRT; P = .055), overall survival (OS; P = .001), and disease-specific survival (DSS; P = .002) and was directly associated with current smoking (P = .04), female sex (P = .053), and lower HPV titer (P = .03). HPV titer was significantly associated with p16 expression (P < .0001); p16 was significantly associated with response to IC (P = .008), CRT (P = .009), OS (P = .001), and DSS (P = .003). As combined markers, lower HPV titer and high EGFR expression were associated with worse OS (ρ_EGFR = 0.008; ρ_HPV = 0.03) and DSS (ρ_EGFR = 0.01; ρ_HPV = 0.016). In 36 of 42 biopsies, p53 was wild-type, and only one HPV-positive tumor had mutant p53. The combination of low p53 and high Bcl-xL expression was associated with poor OS (P = .005) and DSS (P = .002). Conclusion: Low EGFR and high p16 (or higher HPV titer) expression are markers of good response to organ-sparing therapy and outcome, whereas high EGFR expression, combined low p53/high Bcl-xL expression, female sex, and smoking are associated with a poor outcome. Smoking cessation and strategies to target EGFR and Bcl-xL are important adjuncts to the treatment of oropharyngeal cancer.

Background: In accord with the cancer stem cell (CSC) theory, only a small subset of cancer cells are capable of forming tumors. We previously reported that CD44 isolates tumorigenic cells from head and neck squamous cell cancer (HNSCC). Recent studies indicate that aldehyde dehydrogenase (ALDH) activity may represent a more specific marker of CSCs.Methods: Six primary HNSCCs were collected. Cells with high and low ALDH activity (ALDH^high/ALDH^low) were isolated. ALDH^high and ALDH^low populations were implanted into NOD/SCID mice and monitored for tumor development.Results: ALDH^high cells represented a small percentage of the tumor cells (1% to 7.8%). ALDH^high cells formed tumors from as few as 500 cells in 24/45 implantations, whereas only 3/37 implantations of ALDH^low cells formed tumors.Conclusions: ALDH^high cells comprise a subpopulation cells in HNSCCs that are tumorigenic and capable of producing tumors at very low numbers. This finding indicates that ALDH activity on its own is a highly selective marker for CSCs in HNSCC. © 2010 Wiley Periodicals, Inc. Head Neck, 2010

We studied how frequently patients with malignant melanoma have specific antibody to cell surface antigens of cultured autologous melanoma cells as demonstrated by mixed hemadsorption assays. Of 35 patients studied over periods ranging from 1 to 36 months with Stage II, III, and IV disease, two showed consistent and high titered reactivity against autologous melanoma cells, two showed less consistent and intermediate reactivity, seven showed sporatic, low titered reactivity, and the remainder were consistently negative. A detailed analysis was carried out with the sera of one patient with sufficiently high titer against autologous melanoma cells. By direct tests and by absorption analysis with a variety of melanoma and nonmelanoma cell lines which included autologous fibroblasts, the antigen could not be demonstrated on any cell type other than the autologous melanoma.