Martin P. Graham

Targeting Wnt-driven cancer through the inhibition of Porcupine by LGK974

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. 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.

Genotyping of 73 UM‐SCC head and neck squamous cell carcinoma cell lines

We established multiple University of Michigan Squamous Cell Carcinoma (UM‐SCC) cell lines. With time, these have been distributed to other labs all over the world. Recent scientific discussions have noted the need to confirm the origin and identity of cell lines in grant proposals and journal articles. We genotyped the UM‐SCC cell lines in our collection to confirm their unique identity.

UM-SCC-104: A New human papillomavirus-16–positive cancer stem cell–containing head and neck squamous cell carcinoma cell line†

Few human papillomavirus (HPV)(+) head and neck squamous cell carcinoma (HNSCC) cell lines exist. We established University of Michigan‐squamous cell carcinoma‐104 (UM‐SCC‐104), a new HPV(+) HNSCC cell line from a recurrent oral cavity tumor, and characterized it for the presence of cancer stem cells (CSCs).

High-Risk Human Papillomavirus Detection in Oropharyngeal, Nasopharyngeal, and Oral Cavity Cancers Comparison of Multiple Methods

IMPORTANCE Human papillomaviruses are now recognized as an etiologic factor in a growing subset of head and neck cancers and have critical prognostic importance that affects therapeutic decision making. There is no universally accepted gold standard for high-risk HPV (hrHPV) assessment in formalin-fixed, paraffin-embedded (FFPE) tissue specimens, nor is there a clear understanding of the frequency or role of hrHPV in sites other than oropharynx. OBJECTIVE To determine the optimal assessment of hrHPV in FFPE head and neck tumor tissue specimens. DESIGN, SETTING, PARTICIPANTS In the setting of a large Midwestern referral center, assessment of hrHPV by p16 immunohistochemical staining, in situ hybridization, and polymerase chain reaction (PCR)-MassArray (PCR-MA), with L1 PGMY-PCR and sequencing to resolve method discordance, was conducted for 338 FFPE oropharyngeal, nasopharyngeal, and oral cavity tumor tissue specimens. Relative sensitivity and specificity were compared to develop a standard optimal test protocol. Tissue specimens were collected from 338 patients with head and neck cancer treated during the period 2001 through 2011 in the departments of Otolaryngology, Radiation Oncology, and Medical Oncology. INTERVENTION Patients received standard therapy. MAIN OUTCOMES AND MEASURES Optimal hrHPV identification, detection, and activity in head and neck cancers. RESULTS Using combined PCR-MA with L1 PGMY-PCR and sequencing for conclusive results, we found PCR-MA to have 99.5% sensitivity and 100% specificity, p16 to have 94.2% sensitivity and 85.5% specificity, and in situ hybridization to have 82.9% sensitivity and 81.0% specificity. Among HPV-positive tumors, HPV16 was most frequently detected, but 10 non-HPV16 types accounted for 6% to 50% of tumors, depending on the site. Overall, 86% of oropharynx, 50% of nasopharynx, and 26% of oral cavity tumors were positive for hrHPV. CONCLUSIONS AND RELEVANCE PCR-MA has a low DNA (5 ng) requirement effective for testing small tissue samples; high throughput; and rapid identification of HPV types, with high sensitivity and specificity. PCR-MA together with p16INK4a provided accurate assessment of HPV presence, type, and activity and was determined to be the best approach for HPV testing in FFPE head and neck tumor tissue specimens.

Silencing heat shock protein 27 decreases metastatic behavior of human head and neck squamous cell cancer cells in vitro.

The small heat shock protein 27 (Hsp27) is a molecular chaperone that is involved in a variety of cellular functions in cancer cells. The purpose of this research is to study Hsp27 in vitro metastatic behaviors of head and neck squamous cell carcinoma cells (HNSCC). The expression of Hsp27 in primary and metastatic cell lines derived from the primary HNSCC and a synchronous lymph node metastasis in the same patient was determined using real-time PCR and Western blotting. Proliferation of the primary and metastatic HNSCC cell lines was evaluated using the MTS proliferation assay. Metastatic behavior was assessed using migration and invasion assays. SiRNA knockdown of Hsp27 was performed in the highly migratory metastatic HNSCC cell line. MTS assays showed that the primary (UM-SCC-22A) and metastatic (UM-SCC-22B) HNSCC have similar proliferation rates. However, UM-SCC-22B derived from the metastasis showed 2.3- to 3.6-fold higher migration ability and 2-fold higher invasion ability than UM-SCC-22A. Real-time PCR demonstrated that Hsp27 mRNA is 22.4-fold higher in metastatic UM-SCC-22B than primary UM-SCC-22A. Similarly, Western blotting showed that Hsp27 is rarely detectable in UM-SCC-22A whereas UM-SCC-22B expresses a 25-fold higher level of Hsp27 protein. SiRNA-mediated knockdown of Hsp27 in UM-SCC-22B reduced Hsp27 mRNA expression by nearly 6-fold and protein expression by 23-fold. Furthermore, siRNA knockdown of Hsp27 decreased metastatic behaviors of UM-SCC-22B by 3- to 4-fold in migration and 2-fold in cell invasion reducing cell invasion and migration to levels similar to the primary HNSCC UM-SCC-22A. These data indicate that Hsp27 may regulate metastatic potential of HNSCC cancer cells. Targeting Hsp27 may decrease metastasis in head and neck squamous cell cancer cells.

Epidermal growth factor receptor, p16, cyclin D1, and p53 staining patterns for inverted papilloma

The aim of this study was better characterize the staining patterns of inverted papilloma (IP) with and without carcinoma by performing immunohistochemistry for p16, epidermal growth factor receptor (EGFR), p53, and cyclin D1 antibodies in a large patient cohort.

Integration of high-risk human papillomavirus into cellular cancer-related genes in head and neck cancer cell lines: HPV integration into cancer genes in HNSCC cell lines

Human papillomavirus (HPV)‐positive oropharyngeal cancer is generally associated with excellent response to therapy, but some HPV‐positive tumors progress despite aggressive therapy. The purpose of this study was to evaluate viral oncogene expression and viral integration sites in HPV16‐ and HPV18‐positive squamous cell carcinoma lines.

In vivo Wnt pathway inhibition of human squamous cell carcinoma growth and metastasis in the chick chorioallantoic model

BackgroundHead and neck squamous cell carcinoma (HNSCC) is an aggressive cancer with poor overall survival. New therapeutic strategies that target specific molecular lesions driving advanced disease are needed. Herein we demonstrate the utility of the chicken chorioallantoic membrane (CAM) assay for in vivo human HNSCC tumor growth and metastasis and the tumor suppressive effects of a new chemotherapeutic agent.MethodsWe tested anti-metastatic effects of a WNT pathway inhibitor, WNT974 (also known as LGK974), which targets porcupine (PORCN) the palmityl-transferase that is essential for secretion of Wnt proteins. CAM assays were performed with 8 HNSCC cell lines: UM-SCC-1, UM-SCC-10A, UM-SCC-10B, UM-SCC-11A, UM-SCC-14A UM-SCC-17A, UM-SCC-17B, UM-SCC-25, and UM-SCC-34.ResultsUM-SCC-1 (University of Michigan Squamous Cell Carcinoma cell line) CAM xenografts contain CD44+ and ALDH+ cancer stem cell (CSC) proportions similar to UM-SCC-1 mouse xenografts supporting the applicability of the CAM assay for study of CSCs. Inhibition of WNT signaling by the PORCN inhibitor WNT974 reduced metastatic spread of UM-SCC cells, especially in UM-SCCs with Notch1 deficiency.ConclusionsOur data demonstrate decreased tumor growth and metastases in tumors from cell lines that showed in vitro responses to WNT974, providing evidence that this agent may have a role in future HNSCC therapy.

Novel method of cell line establishment utilizing fluorescence-activated cell sorting resulting in 6 new head and neck squamous cell carcinoma lines.

The purpose of this study was to present the establishment of new cell lines, which is important to cancer research.

UM-SCC-103: A unique tongue cancer cell line that recapitulates the tumorigenic stem cell population of the primary tumor

Objective: A new head and neck cancer cell line was developed from a highly aggressive HNSCC of the oral cavity diagnosed in a 26-year-old pregnant woman. Methods: Cells from the primary tumor were passaged in culture and genotyped as a unique cell line. The resultant cell line was assessed for its ability to replicate the primary tumor. Results: The primary tumor and cell line contained 19.03% and 19.62% CD44high cells, respectively. CD44high cancer stem cells from UM-SCC-103 formed tumors after flank injections in mice that reconstituted the heterogeneity of the primary tumor. CD44 staining and histology in the primary tumor and tumors grown in vivo from the cell line were similar. CD44high cells from the primary tumor resulted in lung colony formation in 2 out of 2 tail vein injections in mice, whereas CD44low cells did not. Similarly, CD44high cells from UM-SCC-103 formed lung tumors in 2 out of 4 mice, whereas CD44low cells did not. Conclusion: The similarity in marker expression and tumorigenic behavior between the primary tumor and the resulting cell line strongly suggests that the cell line resembles the primary tumor that it was derived from and provides an important new research tool for the study of head and neck carcinomas in young patients.