Oestrogen receptor α-expressing breast cancer cells rely on mitochondria to generate ATP. In their recent research study, Brandie Raddie, Carolyn Klinge and their colleagues aimed to determine how oestradiol and 4-hydroxytamoxifen (4-OHT) affect cellular bioenergetic function in MCF-7 and T47D ERα+ breast cancer cells serum-replete compared with 'serum-starved' cells.
They showed that despite having a higher mitochondria DNA/nuclear DNA ratio than MCF-7 cells, T47D cells have a lower OCR and ATP levels and higher proton leak. Their data demonstrates critical differences in in basal bioenergetics profiles and bioenergetics responses to serum depletion, oestradiol and tamoxifen in these two ERα+ cell lines, likely reflecting cancer cell avoidance of apoptosis.
Aldehyde dehydrogenases (ALDHs) catalyse the conversion of toxic aldehydes into non-toxic carboxylic acids, and in mice the ALDH3 family are responsible for the removal of lipid-derived aldehydes.
In this study, Akio Kihara and colleagues examined the enzyme activity, tissue distribution and subcellular localization of ALDH3B2 and ALDH3B3. The mouse aldehyde dehydrogenases ALDH3B2 and ALDH3B3 exhibit similar substrate specificity, with both found to exhibit broad substrate preferences from medium- to long-chain aldehydes resembling ALDH3A2 and ALDH3B1, but distinct intracellular localization (ALDH3B2, lipid droplets; ALDH3B3, plasma membrane). The C-terminal prenylation and two tryptophan residues (Trp462 and Trp469) are important for the lipid droplet localization of ALDH3B2.
Insulin resistance is a major hallmark of metabolic syndromes, including Type 2 diabetes. Using liver-specific serum- and glucocorticoid-regulated kinase 1 (SGK1) knockout mice, Feifan Guo and colleagues investigated the effect of SGK1 on insulin sensitivity.
In their recently published study, Feifan Guo and colleagues identifies a novel physiological role for SGK1, determining that SGK1 inhibits ERK1/2 (extracellular-signal-regulated kinase 1/2) activity in liver. They also found that SGK1 functions are compromised under insulin-resistant conditions and overexpression of SGK1 by Ad-SGK1 significantly ameliorates insulin resistance, providing new insights into treating insulin resistance and its associated metabolic diseases including Type 2 diabetes.