Reactivation of cAMP Pathway by PDE4D Inhibition Represents a Novel Druggable Axis for Overcoming Tamoxifen Resistance in ER-positive Breast Cancer.

Tamoxifen remains an important hormonal therapy for ER-positive breast cancer; however, development of resistance is a major obstacle in clinics. Here, we aimed to identify novel mechanisms of tamoxifen resistance and provide actionable drug targets overcoming resistance. Whole-transcriptome sequencing, downstream pathway analysis, and drug repositioning approaches were used to identify novel modulators [here: phosphodiesterase 4D (PDE4D)] of tamoxifen resistance.

Germ cell and tumor associated piRNAs in the medaka and Xiphophorus melanoma models.

Background: A growing number of studies report an abnormal expression of Piwi-interacting RNAs (piRNAs) and the piRNA processing enzyme Piwi in many cancers. Whether this finding is an epiphenomenon of the chaotic molecular biology of the fast dividing, neoplastically transformed cells or is functionally relevant to tumorigenesisis is difficult to discern at present. To better understand the role of piRNAs in cancer development small laboratory fish models can make a valuable contribution.

Comparative analysis of melanoma deregulated miRNAs in the medaka and Xiphophorus pigment cell cancer models.

Malignant melanoma is the most aggressive and deadly form of skin cancer, with an almost 100% development of resistance to current therapeutic approaches at progression stages. The incidence of melanoma is steadily increasing worldwide. Although many details leading to the development of malignant melanoma are known, the complex process of melanomagenesis is poorly understood.

Cell cycle arrest and apoptosis by expression of a novel TPIP (TPIP-C2) cDNA encoding a C2-domain in HEK-293 cells.

The human TPIP (TPTE and PTEN homologous Inositol lipid Phosphatase) belongs to the PTEN (Phosphatase and TENsin homologue deleted on chromosome 10) family of dual-specific phosphatases and is expressed from the human chromosome 13 as multiple splice-variants, e.g., TPIPα, β, γ mRNAs.

A novel human TPIP splice-variant (TPIP-C2) mRNA, expressed in human and mouse tissues, strongly inhibits cell growth in HeLa cells.

Alternative splicing of mRNAs is known to involve a major regulation of gene expression at RNA level in mammalian cells. The PTEN (Phosphatase and TENsin homologue deleted from the human chromosome 10), TPTE (Transmembrane Phosphatase with TEnsin homology) and TPIP (TPTE and PTEN homologous Inositol lipid Phosphatase) belong to a family of dual-specific lipid and protein phosphatases. PTEN is a well characterized tumor suppressor, which plays crucial role in cell survival, cell cycle regulation, cell proliferation as well as adhesion, motility and migration of cells.