Recent advances in understanding the complexities of metastasis

Tumour metastasis is a dynamic and systemic process. It is no longer seen as a tumour cell-autonomous program but as a multifaceted and complex series of events, which is influenced by the intrinsic cellular mutational burden of cancer cells and the numerous bidirectional interactions between malignant and non-malignant cells and fine-tuned by the various extrinsic cues of the extracellular matrix. In cancer biology, metastasis as a process is one of the most technically challenging aspects of cancer biology to study. As a result, new platforms and technologies are continually being developed to better understand this process. In this review, we discuss some of the recent advances in metastasis and how the information gleaned is re-shaping our understanding of metastatic dissemination.

Recent advances in understanding the complexities of metastasis

Tumour metastasis is a dynamic and systemic process. It is no longer seen as a tumour cell-autonomous program but as a multifaceted and complex series of events, which is influenced by the intrinsic cellular mutational burden of cancer cells and the numerous bidirectional interactions between malignant and non-malignant cells and fine-tuned by the various extrinsic cues of the extracellular matrix. In cancer biology, metastasis as a process is one of the most technically challenging aspects of cancer biology to study. As a result, new platforms and technologies are continually being developed to better understand this process. In this review, we discuss some of the recent advances in metastasis and how the information gleaned is re-shaping our understanding of metastatic dissemination.

Glucagon-Like-Peptide-2 Stimulates Lacteal Contractility and Enhances Chylomicron Transport in the Presence of an Intact Enteric Nervous System

Background and Aims

Secretion and transport of intestinal chylomicrons (CMs) via lymphatics to the blood circulation is stimulated primarily by fat ingestion, whereas several other factors have also been shown to play important roles in regulating CM secretion rate. Among these factors, active regulation of lymphatic pumping has not been appreciated to date. The gut peptide and intestinal growth factor glucagon-like peptide-2 (GLP-2) has emerged as a robust enhancer of intestinal lipid mobilization and secretion. The present study aims to elucidate GLP-2's impact on lacteal contractility and assess enteric nervous system (ENS) involvement in GLP-2-induced effects on lipid mobilization.

Methods

Using intravital imaging of a prospero-related homeobox 1-enhanced green fluorescent protein rat model, we assessed GLP-2's effect on lacteal contractility, in the presence and absence of the ENS inhibitor mecamylamine (MEC). Concurrently, to explore the physiological relevance, we examined GLP-2's impact on lymph flow and triglyceride (TG) output in vivo in a rat lymph fistula model.

Results

GLP-2 significantly increased lacteal contractility, and this effect was inhibited by MEC. In the rat lymph fistula model, GLP-2 increased lymph flow, lymph volume, cumulative lymph volume, and TG output while reducing lymph TG concentration. MEC administration blocked these effects of GLP-2. Peak enhancement of lacteal contractility and enhancement of lymph flow in vivo occurred simultaneously with maximal effect at 15-20 minutes post GLP-2 administration, suggesting that GLP-2 enhances lipid transport by stimulating lymphatic contractility.

Conclusion

For the first time, through imaging and concurrent rat lymphatic fistula studies, we demonstrated active regulation of lymphatic contractility as a key determinant of CM secretion and that intact ENS was required to observe this effect.