Protein Kinase D1 Signaling in Cancer Stem Cells with Epithelial-Mesenchymal Plasticity
Yichen Guo,
Yinan Jiang,
J. Bart Rose,
Ganji Purnachandra Nagaraju,
Renata Jaskula-Sztul,
Anita B. Hjelmeland,
Adam W. Beck,
Herbert Chen,
Bin Ren
Affiliations
Yichen Guo
Department of Surgery, Heersink School of Medicine, University of Alabama at Birmingham, Birmingham, AL 35294, USA
Yinan Jiang
Department of Surgery, Heersink School of Medicine, University of Alabama at Birmingham, Birmingham, AL 35294, USA
J. Bart Rose
Department of Surgery, Heersink School of Medicine, University of Alabama at Birmingham, Birmingham, AL 35294, USA
Ganji Purnachandra Nagaraju
Department of Medicine, Division of Hematology and Oncology, Heersink School of Medicine, University of Alabama at Birmingham, Birmingham, AL 35294, USA
Renata Jaskula-Sztul
Department of Surgery, Heersink School of Medicine, University of Alabama at Birmingham, Birmingham, AL 35294, USA
Anita B. Hjelmeland
O’Neal Comprehensive Cancer Center, Heersink School of Medicine, University of Alabama at Birmingham, Birmingham, AL 35294, USA
Adam W. Beck
Department of Surgery, Heersink School of Medicine, University of Alabama at Birmingham, Birmingham, AL 35294, USA
Herbert Chen
Department of Surgery, Heersink School of Medicine, University of Alabama at Birmingham, Birmingham, AL 35294, USA
Bin Ren
Department of Surgery, Heersink School of Medicine, University of Alabama at Birmingham, Birmingham, AL 35294, USA
Pancreatic neuroendocrine tumors (pNETs) are extremely diverse and highly vascularized neoplasms that arise from endocrine cells in the pancreas. The pNETs harbor a subpopulation of stem cell-like malignant cells, known as cancer stem cells (CSCs), which contribute to intratumoral heterogeneity and promote tumor maintenance and recurrence. In this study, we demonstrate that CSCs in human pNETs co-express protein kinase PKD1 and CD44. We further identify PKD1 signaling as a critical pathway in the control of CSC maintenance in pNET cells. PKD1 signaling regulates the expression of a CSC- and EMT-related gene signature and promotes CSC self-renewal, likely leading to the preservation of a subpopulation of CSCs at an intermediate EMT state. This suggests that the PKD1 signaling pathway may be required for the development of a unique CSC phenotype with plasticity and partial EMT. Given that the signaling networks connected with CSC maintenance and EMT are complex, and extend through multiple levels of regulation, this study provides insight into signaling regulation of CSC plasticity and partial EMT in determining the fate of CSCs. Inhibition of the PKD1 pathway may facilitate the elimination of specific CSC subsets, thereby curbing tumor progression and metastasis.
