MCT1-dependent lactate recycling is a metabolic vulnerability in colorectal cancer cells upon acquired resistance to anti-EGFR targeted therapy.

Despite the implementation of personalized medicine, patients with metastatic CRC (mCRC) still have a dismal overall survival due to the frequent occurrence of acquired resistance mechanisms thereby leading to clinical relapse. Understanding molecular mechanisms that support acquired resistance to anti-EGFR targeted therapy in mCRC is therefore clinically relevant and key to improving patient outcomes. Here, we observe distinct metabolic changes between cetuximab-resistant CRC cell populations, with in particular an increased glycolytic activity in KRAS-mutant cetuximab-resistant CRC cells (LIM1215 and OXCO2) but not in KRAS-amplified resistant DiFi cells. We show that cetuximab-resistant LIM1215 and OXCO2 cells have the capacity to recycle glycolysis-derived lactate to sustain their growth capacity. This is associated with an upregulation of the lactate importer MCT1 at both transcript and protein levels. Pharmacological inhibition of MCT1, with AR-C155858, reduces the uptake and oxidation of lactate and impairs growth capacity in cetuximab-resistant LIM1215 cells both in vitro and in vivo. This study identifies MCT1-dependent lactate utilization as a clinically actionable, metabolic vulnerability to overcome KRAS-mutant-mediated acquired resistance to anti-EGFR therapy in CRC.

Molecular profiling of sponge deflation reveals an ancient relaxant-inflammatory response.

A hallmark of animals is the coordination of whole-body movement. Neurons and muscles are central to this, yet coordinated movements also exist in sponges that lack these cell types. Sponges are sessile animals with a complex canal system for filter-feeding. They undergo whole-body movements resembling "contractions" that lead to canal closure and water expulsion. Here, we combine live 3D optical coherence microscopy, pharmacology, and functional proteomics to elucidate the sequence and detail of shape changes, the tissues and molecular physiology involved, and the control of these movements. Morphometric analysis and targeted perturbation suggest that the movement is driven by the relaxation of actomyosin stress fibers in epithelial canal cells, which leads to whole-body deflation via collapse of the incurrent and expansion of the excurrent canal system. Thermal proteome profiling and quantitative phosphoproteomics confirm the control of cellular relaxation by an Akt/NO/PKG/PKA pathway. Agitation-induced deflation leads to differential phosphorylation of proteins forming epithelial cell junctions, implying their mechanosensitive role. Unexpectedly, untargeted metabolomics detect a concomitant decrease in antioxidant molecules during deflation, reflecting an increase in reactive oxygen species. Together with the secretion of proteinases, cytokines, and granulin, this indicates an inflammation-like state of the deflating sponge reminiscent of vascular endothelial cells experiencing oscillatory shear stress. These results suggest the conservation of an ancient relaxant-inflammatory response of perturbed fluid-carrying systems in animals and offer a possible mechanism for whole-body coordination through diffusible paracrine signals and mechanotransduction.

Quantification of steroid hormones in plasma using a surrogate calibrant approach and UHPLC-ESI-QTOF-MS/MS with SWATH-acquisition combined with untargeted profiling.

In spite of demonstrated lack of accuracy and consistency, quantification of steroid hormones is still most commonly executed via immunoassays. Mass spectrometric methods with triple quadrupole instruments are well established and, because of their proven robustness and sensitivity, best suited for targeted analysis. However, recent studies have shown that high-resolution mass spectrometers, like quadrupole time-of-flight instruments (QTOF), show comparable performance in terms of quantification and can generate additional sample information via untargeted profiling workflows. We demonstrate that adequate accuracy and selectivity for estradiol and testosterone can be achieved with a QTOF by data-independent acquisition with sequential window acquisition of all theoretical fragment-ion mass spectra (SWATH). Besides potential combination of targeted quantification and untargeted profiling, SWATH offers advantages with respect to sensitivity because the reduced total number of MS/MS experiments could be used to increase accumulation time without increasing cycle time. By applying a surrogate calibrant method leading to successful validation, a reliable method for absolute steroid quantification and high potential for steroid profiling has been developed. Linear calibration was achieved in the range from 10 to 1,000 pg mL-1 for 13C3-estradiol and from 20 to 15,000 pg mL-1 for 13C3-testosterone. Results for inter-day precision (13C3-estradiol: 4.5-10.2%; 13C3-testosterone: 5.1-7.8%) and inter-day accuracy (13C3-estradiol: 94.6-112.8%; 13C3-testosterone: 98.2-107.7%) were found to be well acceptable. Eventually, the method has been utilized to measure clinical samples of a study in which male volunteers obtained transdermal estradiol patches and sex hormone levels were quantified in plasma.

Insulin and Estrogen Independently and Differentially Reduce Macronutrient Intake in Healthy Men.

Context: Insulin administration to the central nervous system inhibits food intake, but this effect has been found to be less pronounced in female compared with male organisms. This sex-specific pattern has been suggested to arise from a modulating influence of estrogen signaling on the insulin effect. Objective: We assessed in healthy young men whether pretreatment with transdermal estradiol interacts with the hypophagic effect of central nervous insulin administration via the intranasal pathway. Design, Setting, Participants, and Intervention: According to a 2×2 design, two groups of men (n = 16 in each group) received a 3-day transdermal estradiol (100 µg/24 h) or placebo pretreatment and on two separate mornings were intranasally administered 160 IU regular human insulin or placebo. Main Outcome Measures: We assessed free-choice ad libitum calorie intake from a rich breakfast buffet and relevant blood parameters in samples collected before and after breakfast. Results: Estrogen treatment induced a 3.5-fold increase in serum estradiol concentrations and suppressed serum testosterone concentrations by 70%. Independent of estradiol administration, intranasal insulin reduced the intake of carbohydrates during breakfast, attenuating in particular the consumption of sweet, palatable foods. Estradiol treatment per se decreased protein consumption. We did not find indicators of eating-related interactions between both hormones. Conclusions: Results indicate that, in an acute setting, estrogen does not interact with central nervous insulin signaling in the control of eating behavior in healthy men. Insulin and estradiol rather exert independent inhibiting effects on macronutrient intake.