Induction of E-selectin expression on vascular endothelium by digestive system cancer cells

Sialyl LewisX mimic-decorated liposomes for anti-angiogenic everolimus delivery to E-selectin expressing endothelial cells

In this study, we developed novel E-selectin-targeting liposomes, i.e., 3′-(1-carboxy)ethyl sialyl LewisX (3′-CE sLeX) mimic liposomes, for targeted delivery of everolimus (EVE) in anti-angiogenic therapy. We investigated the uptake and efficacy of these E-selectin targeting liposomes in inflammatory cytokine-treated human umbilical vein endothelial cells (HUVECs). The uptake of EVE in 3′-CE sLeX mimic liposomes increased steadily and almost caught up with the uptake of plain EVE at 3 h, which was higher than that in PEGylated liposomes (PEG-liposomes). Inhibition of uptake by anti-E-selectin antibody suggested involvement of E-selectin-mediated endocytotic processes. Migration in cells treated with EVE/3′-CE sLeX mimic liposomes was suppressed by more than half when compared to the control. This treatment was also seen to significantly inhibit the formation of capillary tubes and networks. In addition, Thr389 phosphorylation of pS6 kinase, as a marker of mTOR activity, was remarkably suppressed to less than endogenous levels by EVE/3′-CE sLeX mimic liposomes. In conclusion, the present study demonstrated that EVE/3′-CE sLeX mimic liposomes were intracellularly taken up by E-selectin and prompted anti-angiogenic effects of EVE involved in the mTOR signaling pathway. However, moderate retention of EVE in the liposomes might limit the targeting ability of 3′-CE sLeX mimic liposomes.

Novel E-selectin-targeting liposomes deliver everolimus to E-selectin expressing endothelial cells and accelerate its anti-angiogenic effect.

Pre-metastatic niches: organ-specific homes for metastases

It is well established that organs of future metastasis are not passive receivers of circulating tumour cells, but are instead selectively and actively modified by the primary tumour before metastatic spread has even occurred. Sowing the 'seeds' of metastasis requires the action of tumour-secreted factors and tumour-shed extracellular vesicles that enable the 'soil' at distant metastatic sites to encourage the outgrowth of incoming cancer cells. In this Review, we summarize the main processes and new mechanisms involved in the formation of the pre-metastatic niche.

Tumour Microenvironment: Overview with an Emphasis on the Colorectal Liver Metastasis Pathway

The tumour microenvironment (TME) represents a dynamic network that plays an important role in tumour initiation, proliferation, growth, and metastasis. Cell behaviour may be regulated by interplay of molecular interactions involving positive and negative reinforcement as well as a high level of cross-talk, which determines this system. Additionally, cancer involves cell proliferation, its malignancy defined by the tumour's ability to break down normal tissue architecture and by a dynamic process of invasion and metastasis. The metastatic cascade is regulated by a chain of molecular steps which triggers the progression of the developing cancer cell in the primary tumour into a number of transformations, leading to invasion and proceeding to metastases. Tumour-associated macrophages (TAMs) play a key-role in the progression from inflammatory conditions to cancer; TAMs are also capable of infiltrating the tumour microenvironment. Furthermore, myeloid-derived suppressor cells (MDSCs), a population of inhibitory immune cells, have been reported to increase in various cancer types, although characterising human MDSCs remains difficult, as their phenotype is quite variable. The future of cancer treatment is likely to involve creating more drugs that target these elements as well as others. An overview of the tumour's microenvironment is, therefore, presented in this paper, focusing on the metastatic pathways of primary colorectal cancer to the liver.

Natural history of hepatic metastases from colorectal cancer - pathobiological pathways with clinical significance

Colorectal cancer hepatic metastases represent the final stage of a multi-step biological process. This process starts with a series of mutations in colonic epithelial cells, continues with their detachment from the large intestine, dissemination through the blood and/or lymphatic circulation, attachment to the hepatic sinusoids and interactions with the sinusoidal cells, such as sinusoidal endothelial cells, Kupffer cells, stellate cells and pit cells. The metastatic sequence terminates with colorectal cancer cell invasion, adaptation and colonisation of the hepatic parenchyma. All these events, termed the colorectal cancer invasion-metastasis cascade, include multiple molecular pathways, intercellular interactions and expression of a plethora of chemokines and growth factors, and adhesion molecules, such as the selectins, the integrins or the cadherins, as well as enzymes including matrix metalloproteinases. This review aims to present recent advances that provide insights into these cell-biological events and emphasizes those that may be amenable to therapeutic targeting.

Role of cancer microenvironment in metastasis: focus on colon cancer

One person on three will receive a diagnostic of cancer during his life. About one third of them will die of the disease. In most cases, death will result from the formation of distal secondary sites called metastases. Several events that lead to cancer are under genetic control. In particular, cancer initiation is tightly associated with specific mutations that affect proto-oncogenes and tumour suppressor genes. These mutations lead to unrestrained growth of the primary neoplasm and a propensity to detach and to progress through the subsequent steps of metastatic dissemination. This process depends tightly on the surrounding microenvironment. In fact, several studies support the point that tumour development relies on a continuous cross-talk between cancer cells and their cellular and extracellular microenvironments. This signaling cross-talk is mediated by transmembrane receptors expressed on cancer cells and stromal cells. The aim of this manuscript is to review how the cancer microenvironment influences the journey of a metastatic cell taking liver invasion by colorectal cancer cells as a model.

Selectins and selectin ligands in extravasation of cancer cells and organ selectivity of metastasis

Metastatic spreading is a dreadful complication of neoplastic diseases that is responsible for most deaths due to cancer. It consists in the formation of secondary neoplasms from cancer cells that have detached from the primary site. The formation of these secondary sites is not random and several clinical observations indicate that the metastatic colonization exhibits organ selectivity. This organ tropism relies mostly on the complementary adhesive interactions between the cancer cells and their microenvironment. In particular, several lines of evidence suggest that the organ selectivity of colon cancer cells for the liver involves the binding of the circulating cancer cells to endothelial E-selectin. The aim of this review is to make an integrative up-date of the mechanisms that govern the organ selectivity of the metastatic process focusing more especially on the role of selectins and selectin ligands.

Serum Protein Expression Predicts Recurrence in Patients With Early-Stage Lung Cancer After Resection

BACKGROUND

Patients with early stage nonsmall-cell lung cancer who have undergone complete resection have a recurrence rate of approximately 50%, predominately due to the development of systemic metastases. This study is a prospective analysis of the expression of seven serum protein markers of invasion and metastasis, collected preoperatively (baseline) and serially after resection, to determine the relationship between marker expression and recurrence.

METHODS

Serum was collected from 196 patients with clinical stage I nonsmall-cell lung cancer who underwent resection over a 5-year period (1996 to 2000). Samples were drawn before resection and 1, 4, 6, 12, 18, and 24 months postoperatively. All patients were followed for at least 24 months or until death. Serum protein levels of vascular endothelial growth factor, hepatocyte growth factor), E-selectin, CD44, basic fibroblast growth factor, urokinase plasminogen activator, and urokinase plasminogen activator receptor were determined using enzyme-linked immunosorbent assay.

RESULTS

To date, 73 patients (37%) have demonstrated recurrence. Baseline levels of only 1 marker (CD44) correlated with pathologic stage (p = 0.02). Analysis of the serial samples demonstrated that recurrence was predicted (before clinical or radiographic determination) by decreasing levels of E-selectin (p = 0.002), increasing levels of CD44 (p = 0.001), and increasing levels of urokinase plasminogen activator receptor (p = 0.03).

CONCLUSIONS

This study demonstrates the potential to predict recurrence after resection in patients with early-stage nonsmall-cell lung cancer using a panel of serum protein markers. Early identification of patients with recurrence may improve the efficacy of systemic therapy.

Serum levels of soluble E-selectin in women with breast cancer

Background

Increasing evidence suggests that E-selectin contributes to tumour growth and metastasis, possibly by increasing angiogenesis and the adhesion of tumour cells to endothelial cells at distant sites. This study aimed to examine the relationship between preoperative levels of circulating soluble E-selectin and breast cancer.

Methods

Sixty-four consecutive women undergoing surgery for invasive breast cancer were studied prospectively. Venous blood samples were collected before the operation. A control group consisted of 16 patients with a benign breast tumour (eight with fibrocystic disease and eight with fibroadenoma). Serum concentrations of soluble E-selectin were measured by the quantitative sandwich enzyme immunoassay technique and compared with clinicopathological information.

Results

The mean(s.d.) serum level of soluble E-selectin in patients with invasive breast cancer was 73·7(20·9) ng/ml, compared with 36·3(5·6) ng/ml in the control group (P < 0·001). Furthermore, the serum levels of soluble E-selectin were significantly higher in women with oestrogen receptor-negative tumours (P = 0·001), poorly differentiated tumours (P < 0·001), more advanced primary tumour stage (P < 0·001), involved lymph nodes (P < 0·001), distant metastases (P < 0·001) and more advanced tumour node metastasis (TNM) stage (P < 0·001). On multivariate analysis, TNM stage (P < 0·001) was found to be an independent factor with regard to higher serum levels of soluble E-selectin.

Conclusion

Preoperative serum levels of soluble E-selectin might reflect the severity of invasive breast cancer; further evaluation is warranted.

Carbohydrate-mediated cell adhesion involved in hematogenous metastasis of cancer

The carbohydrate determinants, sialyl Lewis A and sialyl Lewis X, which are frequently expressed on human cancer cells, serve as ligands for a cell adhesion molecule of the selectin family, E-selectin, which is expressed on vascular endothelial cells. These carbohydrate determinants are involved in the adhesion of cancer cells to vascular endothelium and thus contribute to hematogenous metastasis of cancer. The initial adhesion mediated by these molecules triggers activation of integrin molecules through the action of several cytokines and leads to the extravasation of cancer cells. Cancer cells also produce humoral factors that facilitate E-selectin expression on endothelial cells. The degree of expression of the carbohydrate ligands at the surface of cancer cells is well correlated with the frequency of hematogenous metastasis and prognostic outcome of patients with cancers. The alteration of glycosyltransferase activities that leads to the enhanced expression of these carbohydrate ligands on cancer cell surface are currently being investigated.