Justilien, Verline

A gradual loss of dopamine-producing nerve cells gives rise to a common neurodegenerative Parkinson’s disease (PD). This disease causes a neurotransmitter imbalance in the brain and initiates a cascade of complications in the rest of the body that appears as distressing symptoms which include gait problems, tremor, gastrointestinal (GI) disorders and cognitive decline. To aid dopamine deficiency, treatment in PD patients includes oral medications, in addition to other methods such as deep brain stimulation and surgical lesioning. Scientists are extensively studying molecular and signaling mechanisms, particularly those involving phenotypic transcription factors and their co-regulatory proteins that are associated with neuronal stem cell (SC) fate determination, maintenance and disease state, and their role in the pathogenesis of PD. Advancement in scientific research and “personalized medicine” to augment current therapeutic intervention and minimize the side effects of chemotherapy may lead to the development of more effective therapeutic strategies in the near future. This review focuses on PD and associated GI complications and summarizes the current therapeutic modalities that include stem cell studies and combinatorial drug treatment.

Abstract The Hedgehog (Hh) signaling pathway is critical for embryonic development. In adult tissues, Hh signaling is relatively quiescent with the exception of roles in tissue maintenance and repair. Aberrant activation of Hh signaling is implicated in multiple aspects of transformation, including the maintenance of the cancer stem cell (CSC) phenotype. Preclinical studies indicate that CSCs from many tumor types are sensitive to Hh pathway inhibition and that Hh-targeted therapeutics block many aspects of transformation attributed to CSCs, including drug resistance, relapse, and metastasis. However, to date, Hh inhibitors, specifically those targeting Smoothened [such as vismodegib, BMS-833923, saridegib (IPI-926), sonidegib/erismodegib (LDE225), PF-04449913, LY2940680, LEQ 506, and TAK-441], have demonstrated good efficacy as monotherapy in patients with basal cell carcinoma and medulloblastoma, but have shown limited activity in other tumor types. This lack of success is likely due to many factors, including a lack of patient stratification in early trials, cross-talk between Hh and other oncogenic signaling pathways that can modulate therapeutic response, and a limited knowledge of Hh pathway activation mechanisms in CSCs from most tumor types. Here, we discuss Hh signaling mechanisms in the context of human cancer, particularly in the maintenance of the CSC phenotype, and consider new therapeutic strategies that hold the potential to expand considerably the scope and therapeutic efficacy of Hh-directed anticancer therapy. Clin Cancer Res; 21(3); 505–13. ©2015 AACR.

Abstract Background: Protein kinase C iota (PKCι) is an oncogene that is frequently targeted for tumor-specific gene amplification in human cancers harboring the 3q26 amplicon including Non-Small Cell Lung Carcinoma (NSCLC). PKCι is required for the maintenance of the transformed phenotype of NSCLC cells in vitro and in vivo. In addition, PKCι is critical for lung tumorigenesis in the LSL-K-rasG12D mouse model of NSCLC. Recently, we demonstrated that genetic disruption of Prkcι/λ; in LSL-K-rasG12D mice blocks K-ras-mediated expansion and morphological transformation of bronchioalveolar stem cells (BASCs), the first identifiable step in K-ras-mediated transformation in this model. These results demonstrate that PKCι plays a requisite role in tumor initiation, and suggest that PKCι may serve a similar role in the tumor-initiating activity of lung cancer stem cells. Our current studies aim to identify and characterize the molecular signaling pathway(s) by which PKCι regulates the biology of human lung squamous cell carcinoma (LSCC) tumor initiating cells (TICs) isolated from LSCC cell lines and primary tumors. Methods: Cultures enriched in TICs were established from LSCC lines or primary human LSCC tumors that harbor PRKCI amplification. PKCι expression in TIC cultures was inhibited by lentiviral shRNA, and the effect of PKCι knockdown on their stem-like properties was assessed. Whole genome deep sequencing analysis was performed on mRNA from parental, control TIC and PKCι knockdown TIC cultures in order to identify PKCι-regulated targets and signaling pathways in TICs. Results: LSCC TIC cultures express putative stem cell markers, and exhibit clonal expansion, self-renewal, enhanced anchorage-independent growth and tumorigenic potential in vivo. RNAi-mediated knockdown of PKCι inhibited TIC growth, clonal expansion, transformed growth and tumor initiation. mRNA sequencing revealed that PKCι regulates the expression and function of critical molecules involved in the stem-like phenotype of LSCC TICs. Details of PKCι-mediated signaling in LSCC TICs will be discussed. Conclusions: PKCι is required for maintenance of a highly tumorigenic stem-like population of cells in human LSCC. Given the prevalence of 3q26 amplification in human cancer, PKCι may regulate the biology of TICs in tumor types other than LSCC. Our results provide a rationale for therapeutic targeting of PKCι in LSCC TICs. Citation Format: Verline Justilien, Michael P. Walsh, Syed A. Ali, E. A. Thompson, Alan P. Fields. Protein Kinase C iota is required for the maintenance of a tumor-initiating cell phenotype in lung squamous cell carcinoma. [abstract]. In: Proceedings of the AACR-IASLC Joint Conference on Molecular Origins of Lung Cancer; 2014 Jan 6-9; San Diego, CA. Philadelphia (PA): AACR; Clin Cancer Res 2014;20(2Suppl):Abstract nr B02.

AbstractLung cancer is a leading cause of cancer deaths worldwide. Despite advances in chemotherapy, radiation therapy, and surgery, lung cancer continues to have a low 5‐year survival rate, highlighting a dire need for more effective means of prevention, diagnosis, prognosis, and treatment. Mouse models that recapitulate the clinical features of advanced human lung cancer are critical for testing novel therapeutic approaches. This unit describes a highly reproducible, easy‐to‐establish orthotopic murine model of lung cancer, provides methods for in vivo imaging and monitoring of tumor growth, and discusses the usefulness of this model for translational lung cancer research and the development of therapeutic strategies. Curr. Protoc. Pharmacol. 62:14.27.1‐14.27.17. © 2013 by John Wiley & Sons, Inc.

Abstract Matrix metalloproteinase 10 (Mmp10; stromelysin 2) is a member of a large family of structurally related matrix metalloproteinases, many members of which have been implicated in tumor progression, invasion and metastasis. However, emerging evidence suggests a possible role for Mmps in tumor initiation. Here we reveal an unexpected role for Mmp10 in the maintenance and tumorigenicity of mouse lung cancer stem-like cells (CSC). Mouse lung cancer cell cultures enriched in stem-like cells grow as undifferentiated tumor “oncospheres” that express elevated levels of the cancer stem cell markers Aldh1, CD133, Nanog, Notch3, Notch 4, Hey 1 and Hey 2. These cells also express elevated levels of Mmp10 mRNA and secrete elevated levels of Mmp10 protein. Functionally, these lung CSCs exhibit self-renewal, the ability to clonally expand, enhanced transforming potential in vitro, and enhanced tumorigenic properties when injected orthotopically into the lungs of syngeneic mice. RNAi-mediated knockdown of Mmp10 in these cells leads to a loss of stem cell marker gene expression and a dramatic inhibition of oncosphere growth, clonal expansion, transformed growth in vitro, and lung tumor formation and metastasis in vivo. In contrast, oncospheres implanted into syngeneic non-transgenic or Mmp10−/− mice show no significant difference in tumor initiation, growth or metastasis, demonstrating the importance of Mmp10 produced by cancer cells rather than the tumor microenvironment in lung tumor initiation and maintenance. Analysis of gene expression data from human tumors demonstrates that Mmp10 is elevated in many human tumor types including lung, head and neck, esophageal, colon, breast, melanoma, bladder, cervical, ovarian, prostate and brain. Furthermore, gene set enhancement analysis (GSEA) demonstrates that elevated Mmp10 expression correlates with tumor metastasis and with cancer stem-like genomic signatures in human lung tumors. Thus, Mmp10 is required for maintenance of a highly tumorigenic, cancer-initiating, metastatic stem-like cell population in lung cancer. Our data demonstrate for the first time that Mmp10 is a critical lung cancer stem cell gene and novel therapeutic target for lung cancer stem cells. 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 LB-204. doi:1538-7445.AM2012-LB-204