Cancer invasion and metastasis: interacting ecosystems

KAI1 inhibits HGF-induced invasion of pancreatic cancer by sphingosine kinase activity

BACKGROUND

KAI1/CD82 has been reported to attenuate the process of metastases in a variety of tumors; however, its mechanism of action in invasion has not been fully elucidated. The present study aimed to investigate the importance of KAI1 in invasion and its correlation with activation of sphingosine kinase (SPK) in human pancreatic cancer PANC1 and Miapaca-2 cell lines.

METHODS

The expression of KAI1 in PANC1 and Miapaca-2 cells, which was mediated by recombinant adenovirus (Ad-KAI1), was assessed by a flow cytometer and Western blotting. After successful infection was established, in vitro growth curve and invasive ability in Boyden Chamber assay were studied. The presence of KAI1 correlating with c-Met and SPK was detected by co-immunoprecipitation and [gamma-32P] ATP incorporation.

RESULTS

KAI1 genes had no significant effects on the curve representing cell growth. After infection with the KAI1 gene, decreased invasive ability in the Boyden Chamber assay was observed in PANC1 and Miapaca-2 cells that were induced by hepatocyte growth factor. Over-expression of KAI1 in the cells led to the deactivation of SPK and a decreased level of intracellular sphingosine-1-phosphate. No correlation was observed between c-Met and KAI1 during co-immunoprecipitation.

CONCLUSION

The results of this study for the first time demonstrated a regulatory role for KAI1 in SPK activation, which leads to decreased invasive ability in disease progression of human pancreatic cancer.

Critical review: cellular mechanobiology and amoeboid migration

Cell motility is important for tissue homeostasis and plays a central role in various pathologies, notably inflammation and cancer. Research into the critical processes involved in cell migration has so far mostly focused on cell adhesion and proteolytic degradation of the extracellular matrix. However, pharmacological interference with these processes only partially blocks cell motility in vivo. In this review we summarize the arising evidence that the mechanical properties of the cell body have a major role to play in cell motility--especially in a low-adhesion, amoeboid-like migration mode in three-dimensional tissue structures. We summarize the processes determining cell mechanics and discuss relevant measurement technologies including their applications in medical cell biology.

Cancer models in Caenorhabditis elegans

Although now dogma, the idea that nonvertebrate organisms such as yeast, worms, and flies could inform, and in some cases even revolutionize, our understanding of oncogenesis in humans was not immediately obvious. Aided by the conservative nature of evolution and the persistence of a cohort of devoted researchers, the role of model organisms as a key tool in solving the cancer problem has, however, become widely accepted. In this review, we focus on the nematode Caenorhabditis elegans and its diverse and sometimes surprising contributions to our understanding of the tumorigenic process. Specifically, we discuss findings in the worm that address a well-defined set of processes known to be deregulated in cancer cells including cell cycle progression, growth factor signaling, terminal differentiation, apoptosis, the maintenance of genome stability, and developmental mechanisms relevant to invasion and metastasis.

Resident and bone marrow-derived mesenchymal stem cells in head and neck squamous cell carcinoma

Head and neck squamous cell carcinoma (HNSCC) is a major healthcare problem worldwide affecting more than half a million patients each year. Despite considerable advances in the treatment of HNSCC, a high rate of recurrences aggravates the clinical situation and disease outcomes have only modestly improved. Recent insights show that cancer is not only a disease of the transformed epithelium but is also influenced and dependent on its stromal environment. In this review we suggest that resident and bone marrow (BM)-derived mesenchymal stem cells (MSCs) are precursors of the stroma associated with HNSCC and contribute to blood- and lymph angiogenesis, modulate the immune system and produce tumor-associated myofibroblasts. In addition, the impact of radiation therapy on the stromal reaction in HNSCC is discussed. Understanding the mechanisms of how MSCs promote invasive growth and metastasis in HNSCC and respond to cancer management strategies is of profound medical importance and will help us to design improved therapeutic protocols.