Overexpression of hepatoma-derived growth factor in melanocytes does not lead to oncogenic transformation

Recurrent co-alteration of HDGF and SETDB1 on chromosome 1q drives cutaneous melanoma progression and poor prognosis

A progressive increase in copy number variation (CNV) characterizes the natural history of cutaneous melanoma progression toward later disease stages, but our understanding of genetic drivers underlying chromosomal arm-level CNVs remains limited. To identify candidate progression drivers, we mined the TCGA SKCM dataset and identified HDGF as a recurrently amplified gene whose high mRNA expression correlates with poor patient survival. Using melanocyte-specific overexpression in the zebrafish BRAFV600E -driven MiniCoopR melanoma model, we show that HDGF accelerates melanoma development in vivo. Transcriptional analysis of HDGF compared to control EGFP tumors showed the activation of endothelial/angiogenic pathways. We validated this observation using an endothelial kdrl:mCherry reporter line which showed HDGF to increases tumor vasculature. HDGF is frequently co-altered with the established melanoma driver SETDB1. Both genes are located on chromosome 1q, and their co-amplification is observed in up to 13% of metastatic melanoma. TCGA patients with both genes amplified and/or overexpressed have a worse melanoma specific survival. We tested co-expression of HDGF and SETDB1 in the MiniCoopR model, which resulted in faster and more aggressive melanoma development than either gene individually. Our work identifies the co-amplification of HDGF and SETDB1 as a functional driver of melanoma progression and poor patient prognosis.

Role of melanoma inhibitory activity in melanocyte senescence

The protein melanoma inhibitory activity (MIA) is known to be expressed in melanoma and to support melanoma progression. Interestingly, previous studies also observed the expression of MIA in nevi. Concentrating on these findings, we revealed that MIA expression is correlated with a senescent state in melanocytes. Induction of replicative or oncogene-induced senescence resulted in increased MIA expression in vitro. Notably, MIA knockdown in senescent melanocytes reduced the percentage of senescence-associated beta-Gal-positive cells and enhanced proliferation. Using the melanoma mouse model Tg(Grm1), MIA-deficient mice supported the impact of MIA on senescence by showing a significantly earlier tumor onset compared to controls. In melanocytes, MIA knockdown led to a downregulation of the cell cycle inhibitor p21 in vitro and in vivo. In contrast, after induction of hTERT in human melanoma cells, p21 regulation by MIA was lost. In summary, our data show for the first time that MIA is a regulator of cellular senescence in human and murine melanocytes.

CIB1: a small protein with big ambitions

Calcium- and integrin-binding protein 1 (CIB1) is a small, ubiquitously expressed protein that was first identified as an intracellular binding partner of a platelet-specific α-integrin cytoplasmic tail. Although early studies revealed a role for CIB1 in regulating platelet integrin activity, recent studies have indicated a more diverse role for CIB1 in many different cell types and processes, including calcium signaling, migration, adhesion, proliferation, and survival. Increasing evidence also points to a novel role for CIB1 in cancer and cardiovascular disease. In addition, an array of CIB1 binding partners has been identified that provide important insight into how CIB1 may regulate these processes. Some of these binding partners include the serine/threonine kinases, p21-activated kinase 1 (PAK1), apoptosis signal-regulating kinase 1 (ASK1), and polo-like kinase 3 (PLK3). Structural and mutational studies indicate that CIB1 binds most or all of its partners via a well-defined hydrophobic cleft. Although CIB1 itself lacks known enzymatic activity, it supports the PI3K/AKT and MEK/ERK oncogenic signaling pathways, in part, by directly modulating enzymes in these pathways. In this review, we discuss our current understanding of CIB1 and key questions regarding structure and function and how this seemingly diminutive protein impacts important signaling pathways and cellular processes in human health and disease.-Leisner, T. M., Freeman, T. C., Black, J. L., Parise, L. V. CIB1: a small protein with big ambitions.

HDGF: a novel jack-of-all-trades in cancer

HDGF is an important regulator of a broad range of cancer cell activities and plays important roles in cancer cell transformation, apoptosis, angiogenesis and metastasis. Such a divergent influence of HDGF on cancer cell activities derives from its multiple inter- and sub-cellular localizations where it interacts with a range of different binding partners. Interestingly, high levels of HDGF could be detected in patients' serum of some cancers. This review is focused on the role of HDGF in tumorigenesis and metastasis, and provides insight for application in clinical cancer therapy as well as its clinical implications as a prognostic marker in cancer progression.

Critical multiple angiogenic factors secreted by glioblastoma stem-like cells underline the need for combinatorial anti-angiogenic therapeutic strategies

Glioblastomas are the most frequent adult primary brain tumors that still remain fatal despite major clinical efforts. As in other solid tumors, populations of glioblastoma stem-like cells (GSCs) endowed with tumor initiating and therapeutic resistance properties have been identified. Glioblastomas are highly vascularized tumors resulting in a rich dialog between GSCs and endothelial cells. In one direction, endothelial cells and their secreted proteins are able to sustain GSC properties while, in turn, GSCs can promote neoangiogenesis, modulate endothelial cell functions and may even transdifferentiate into endothelial cells. Accordingly, targeting tumor vasculature seems a promising issue despite incomplete and transient results obtained from anti-vascular endothelial growth factor therapeutic trials. Recent findings of novel GSC-secreted molecules with pro-angiogenic properties (Semaphorin 3A, hepatoma-derived growth factor) open the path to the design of a concerted attack of glioblastoma vasculature that could overcome the development of resistance to single-targeted therapies while keeping away the toxicity of the treatments.

Downregulation of hepatoma-derived growth factor contributes to retarded lung metastasis via inhibition of epithelial-mesenchymal transition by systemic POMC gene delivery in melanoma

The prognosis of malignant melanoma is poor due to high incidence of metastasis, underscoring the demand for development of novel therapeutic strategies. Stress hormone pro-opiomelanocortin (POMC) is the precursor for several anti-inflammatory peptides that hold promise for management of cancer-related diseases. The present study evaluated the antimetastatic potential and mechanism of POMC therapy for metastatic melanoma. Adenovirus-mediated POMC gene delivery potently inhibited the invasiveness of human and mouse melanoma cells. Moreover, after induction of lung metastasis, systemic POMC expression significantly reduced the foci formation and neovascularization in lungs. Mechanistic studies revealed that POMC therapy inhibited the epithelial-mesenchymal transition (EMT) of melanoma cells by upregulation of E-cadherin and downregulation of vimentin and α-smooth muscle actin (α-SMA). In addition, microarray analysis unveiled POMC gene transfer reduced the mRNA level of multiple prometastatic factors, including hepatoma-derived growth factor (HDGF). Cell culture and immunohistochemical studies further confirmed that POMC gene delivery significantly decreased the expression of HDGF in melanoma cells and tissues. Despite stimulating the invasion and EMT, exogenous HDGF supply only partially attenuated the POMC-mediated invasion inhibition and EMT change in melanoma cells. Finally, we delineated the contribution of melanocortins to POMC-induced inhibition of invasion, HDGF downregulation, and E-cadherin upregulation. Together, these results indicate that HDGF downregulation participates in POMC-induced suppression of metastasis and EMT in melanoma.