Clear cell renal cell carcinoma (ccRCC) has a poor prognosis despite novel biological targeted therapies. Tumor aggressiveness and poor survival may correlate with tumor grade at diagnosis and with complex metabolic alterations, also involving glucose and lipid metabolism. However, currently no grade-specific metabolic therapy addresses these alterations. Here we used primary cell cultures from ccRCC of low- and high-grade to investigate the effect on energy state and reduced pyridine nucleotide level, and on viability and proliferation, of specific inhibition of glycolysis with 2-deoxy-D-glucose (2DG), or fatty acid oxidation with Etomoxir. Our primary cultures retained the tissue grade-dependent modulation of lipid and glycogen storage and aerobic glycolysis (Warburg effect). 2DG affected lactate production, energy state and reduced pyridine nucleotide level in high-grade ccRCC cultures, but the energy state only in low-grade. Rather, Etomoxir affected energy state in high-grade and reduced pyridine nucleotide level in low-grade cultures. Energy state and reduced pyridine nucleotide level were evaluated by ATP and reduced 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium (MTT) dye quantification, respectively. 2DG treatment impaired cell proliferation and viability of low-grade ccRCC and normal cortex cultures, whereas Etomoxir showed a cytostatic and cytotoxic effect only in high-grade ccRCC cultures. Our data indicate that in ccRCC the Warburg effect is a grade-dependent feature, and fatty acid oxidation can be activated for different grade-dependent metabolic needs. A possible grade-dependent metabolic therapeutic approach in ccRCC is also highlighted.

Renal-cell carcinomas (RCC) arise from the renal epithelium, account for about 85% of renal cancers, and are characterized by different subtypes having different incidences. The clear-cell (RCCcc) and papillary (RCCpap) subtypes of sporadic RCC account for about 75% and 12% of cases, respectively, and have distinct genetic abnormalities.

Most of Anaplastic Large Cell Lymphoma (ALCL) cases carry the t(2;5; p23;q35) that produces the fusion protein NPM-ALK. NPM-ALK deregulated kinase activity drives several pathways that support malignant transformation of lymphoma cells. We found that in ALK-rearranged ALCL cell lines NPM-ALK was distributed in equal amounts between the cytoplasm and the nucleus. Only the cytoplasmic portion was catalytically active in both cell lines and primary ALCL, whereas the nuclear portion was inactive due to heterodimerization with NPM1. Thus, about 50% of the NPM-ALK is not active and sequestered as NPM-ALK/NPM1 heterodimers in the nucleus. Overexpression or re-localization of NPM-ALK to the cytoplasm by NPM genetic knock-out or knock-down caused ERK1/2 increased phosphorylation and cell death through the engagement of an ATM/Chk2 and γH2AX mediated DNA damage response. Remarkably, human NPM-ALK amplified cell lines resistant to ALK tyrosine kinase inhibitors (TKIs) underwent apoptosis upon drug withdrawal as a consequence of ERK1/2 hyperactivation. Altogether, these findings indicate that an excess of NPM-ALK activation and signaling induces apoptosis via oncogenic stress responses. A “drug holiday” where the ALK TKI treatment is suspended could represent a therapeutic option in cells that become resistant by NPM-ALK amplification.

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IntroductionAlthough estrogen and progesterone play a key role in normal mammary development and in breast cancer, the potential for proliferation and lineage differentiation as well as origin of cells that express the estrogen receptor (ER) in normal breast epithelium are not known. Some evidence suggests that normal human mammary stem/progenitor cells are ER–, but the identity of these cells and the cellular hierarchy of breast epithelium are still subjects of controversy. It is likely that elucidation of these aspects will bring insight into the cellular origin of breast cancer subtypes.MethodsWe used fluorescence-activated cell sorting of primary human mammary epithelial cells along with in vitro and in vivo functional assays to examine the hierarchic relation between cells with aldehyde dehydrogenase enzymatic activity (ALDH+ cells) and ER+ cells in the normal human breast epithelium. We assessed the proliferation and lineage differentiation potential of these cells in vitro and in vivo. A gene reporter assay was used to separate live ER+ and ER– mammary epithelial cells. With shRNA-mediated knockdown, we investigated the role of ALDH isoforms in the functionality of mammary epithelial progenitor cells.ResultsWe describe a cellular hierarchy in the normal human mammary gland in which ER–/ALDH+ cells with functional properties of stem/progenitor cells generate ER+ progenitor cells, which in turn give rise to cells of luminal lineage. We show that the ALDH1A1 isoform, through its function in the retinoic acid metabolism, affects the proliferation and/or early differentiation of stem/progenitor cells and is important for branching morphogenesis.ConclusionsThis study presents direct evidence that ER+ cells are generated by ER–/ALDH+ stem/progenitor cells. We also show that ER+ cells are able to generate cell progeny of luminal lineage in vitro and in vivo. Loss of ALDH1A1 function impairs this process, as well as branching morphogenesis and clonogenicity in suspension culture. This latter effect is reversed by treatment with retinoic acid.