Phosphatidylcholine and cholesteryl esters identify the infiltrating behaviour of a clear cell renal carcinoma: 1H, 13C and 31P MRS evidence

Prognostic Effect of Preoperative Apolipoprotein B Level in Surgical Patients with Clear Cell Renal Cell Carcinoma

BACKGROUND

The aim of this study was to assess the prognostic value of the preoperative apolipoprotein B (ApoB) level in surgical patients with clear cell renal cell carcinoma (ccRCC).

MATERIALS AND METHODS

The study included 307 ccRCC patients receiving radical or partial nephrectomy between 2003 and 2012 in our center. The correlations among the preoperative ApoB, clinicopathological parameters, and overall survival (OS) were evaluated.

RESULTS

A total of 193 males (62.9%) and 114 females (37.1%) with ccRCC who underwent radical or partial nephrectomy were enrolled in the present study. The OS at 5 years after the operation was 90.6% for all patients, 87.4% for the lower ApoB group, and 97.0% for the higher-ApoB group. The cause-specific survival (CSS) at 5 years after surgery was 90.2% for all patients, 86.7% for the lower-ApoB group, and 97.0% for the higher-ApoB group. A higher-ApoB level was related to a better OS and CSS in ccRCC patients (p = 0.001 and p < 0.001, respectively). In multivariate analysis, age >60 years (p = 0.008 and p = 0.023) and a lower Apo B level (p = 0.019 and p = 0.018) were independent prognostic factors for OS and CSS, respectively.

CONCLUSIONS

In the Apo apolipoprotein family, the preoperative ApoB level had an important clinical significance for predicting the prognosis and survival rate of ccRCC patients.

Non-invasive differentiation of benign renal tumors from clear cell renal cell carcinomas using clinically translatable hyperpolarized 13C pyruvate magnetic resonance

Localized renal tumors are increasingly detected incidentally at imaging. Conventional imaging cannot reliably differentiate the 20% of these tumors that are benign from malignant renal cell carcinomas (RCCs), leading to unnecessary surgical resection and resulting morbidity associated with surgery. Here, we investigated hyperpolarized 13C pyruvate metabolism in live patient-derived renal tumor tissue slices using a novel magnetic resonance (MR) -compatible bioreactor platform. We demonstrated for the first time that clear cell RCCs (ccRCCs), which account for 70-80% of all RCCs, have increased lactate production as well as rapid lactate efflux compared to benign renal tumors. This difference is attributed to increased lactate dehydrogenase A and monocarboxylate transporter 4 expression in ccRCCs. This distinctive metabolic phenotype can be used to differentiate RCCs from benign renal tumors using clinically translatable hyperpolarized 13C pyruvate MR.

A lipoprotein source of cholesteryl esters is essential for proliferation of CEM-CCRF lymphoblastic cell line

Tumour are characterised by a high content of cholesteryl esters (CEs) stored in lipid droplets purported to be due to a high rate of intracellular esterification of cholesterol. To verify whether and which pathways involved in CE accumulation are essential in tumour proliferation, the effect of CE deprivation, from both exogenous and endogenous sources, on CEM-CCRF cells was investigated. Cholesterol synthesis, esterification and content, low-density lipoprotein (LDL) binding and high-density lipoprotein (HDL)-CE uptake were evaluated in cultured in both conventional and delipidated bovine serum with or without oleic or linoleic acids, cholesteryl oleate, LDL and HDL. High content of CEs in lipid droplets in this cell line was due to esterification of both newly synthesised cholesterol and that obtained from hydrolysis of LDL; moreover, a significant amount of CE was derived from HDL-CE uptake. Cell proliferation was slightly affected by either acute or chronic treatment up to 400 μM with Sz-58035, an acyl-cholesteryl cholesterol esterification inhibitor (ACAT); although when the enzyme activity was continuously inhibited, CE content in lipid droplets was significantly higher than those in control cells. In these cells, analysis of intracellular and medium CEs revealed a profile reflecting the characteristics of bovine serum, suggesting a plasma origin of CE molecules. Cell proliferation arrest in delipidated medium was almost completely prevented in the first 72 h by LDL or HDL, although in subsequent cultures with LDL, it manifested an increasing mortality rate. This study suggests that high content of CEs in CEM-CCRF is mainly derived from plasma lipoproteins and that part of CEs stored in lipid droplets are obtained after being taken up from HDL. This route appears to be up-regulated according to cell requirements and involved in low levels of c-HDL during cancer. Moreover, the dependence of tumour cells on a source of lipoprotein provides a novel impetus in developing therapeutic strategies for use in the treatment of some tumours.