Cancer during pregnancy is rarely studied due to its low incidence (1:1000). However, as a result of different sociocultural and economic changes, women are postponing pregnancy, so the number of pregnant women with cancer has been increasing in recent years. The importance of studying cancer during pregnancy is not only based on maternal and foetal prognosis, but also on the evolutionary mechanisms of the cell biology of trophoblasts and neoplastic cells, which point out similarities between and suggest new fields for the study of cancer. Moreover, the magnitude of how cancer factors can affect trophoblastic cells, and vice versa, in altering the foetus’s nutrition and health is still a subject to be understood. In this context, the objective of this narrative review was to show that some researchers point out the importance of supplementing branched-chain amino acids, especially leucine, in experimental models of pregnancy associated with women with cancer. A leucine-rich diet may be an interesting strategy to preserve physiological placenta metabolism for protecting the mother and foetus from the harmful effects of cancer during pregnancy.

Skeletal muscle atrophy occurs in several pathological conditions, such as cancer, especially during cancer-induced cachexia. This condition is associated with increased morbidity and poor treatment response, decreased quality of life, and increased mortality in cancer patients. A leucine-rich diet could be used as a coadjutant therapy to prevent muscle atrophy in patients suffering from cancer cachexia. Besides muscle atrophy, muscle function loss is even more important to patient quality of life. Therefore, this study aimed to investigate the potential beneficial effects of leucine supplementation on whole-body functional/movement properties, as well as some markers of muscle breakdown and inflammatory status. Adult Wistar rats were randomly distributed into four experimental groups. Two groups were fed with a control diet (18% protein): Control (C) and Walker 256 tumour-bearing (W), and two other groups were fed with a leucine-rich diet (18% protein + 3% leucine): Leucine Control (L) and Leucine Walker 256 tumour-bearing (LW). A functional analysis (walking, behaviour, and strength tests) was performed before and after tumour inoculation. Cachexia parameters such as body weight loss, muscle and fat mass, pro-inflammatory cytokine profile, and molecular and morphological aspects of skeletal muscle were also determined. As expected, Walker 256 tumour growth led to muscle function decline, cachexia manifestation symptoms, muscle fibre cross-section area reduction, and classical muscle protein degradation pathway activation, with upregulation of FoxO1, MuRF-1, and 20S proteins. On the other hand, despite having no effect on the walking test, inflammation status or muscle oxidative capacity, the leucine-rich diet improved muscle strength and behaviour performance, maintained body weight, fat and muscle mass and decreased some protein degradation markers in Walker 256 tumour-bearing rats. Indeed, a leucine-rich diet alone could not completely revert cachexia but could potentially diminish muscle protein degradation, leading to better muscle functional performance in cancer cachexia.

Background: Skeletal muscle atrophy occurs in several pathological conditions such as cancer, a condition termed cancer cachexia. This condition is associated with an increase in morbidity and poor treatment response, decreasing quality of life, and increased mortality in cancer patients. A leucine-rich diet could be used as a coadjutant therapy preventing muscle atrophy in cancer cachexia hosts. Besides muscle atrophy, muscle function loss is even more important to the patient’s quality of life. Therefore, this study aimed to evaluate the effects of leucine-rich diet on muscle function activity of cachectic Walker 256 tumor-bearing rats and to correlate such effects with molecular pathways of muscle atrophy. Methods: Adult Wistar rats were randomly distributed into four experimental groups. Two groups were fed with a control diet: Control (C) and Walker 256 tumor-bearing (W), and two other groups were fed with a leucine-rich diet: Leucine Control (L) and Leucine Walker 256 tumor-bearing (LW). The functional analysis (walking, behavior, and strength tests) was measured and before and after tumor inoculation. Cachexia parameters such as body weight loss, muscle and fat mass, pro-inflammatory cytokine profile, and molecular and morphological aspects of skeletal muscle were also performed. Results: Walker 256 tumor growth led to muscle function decline, cachexia manifestation symptoms, muscle fiber cross-section area reduction, associated with the altered morphological pattern and classical muscle protein degradation pathway activation, with up-regulation of FoXO1, MuRF1, and 20S proteins. On the other hand, a leucine-rich diet improved muscle strength while reducing the decline of walking and behavior, partially improving the cachexia manifestations and preventing muscle atrophy and protein degradation in Walker 256 tumor-bearing rats. Conclusions: A leucine-rich diet diminished muscle protein degradation and enhanced oxidative pathways, leading to better muscle functional performance.

Cancer during pregnancy presents a delicate coexistence, imposing ethical and professional challenges on both the patient and medical team. In this study, we aimed to explore in a pre-clinical model the impact of tumour evolution in serum, placental and foetal metabolomics profiles during pregnancy in a time-course manner. Pregnant Wistar rats were distributed into two experimental groups: Control (C) and Walker-256 tumour-bearing (W). The rats were euthanised on three different gestational periods: at 12 days post-conception (dpc), at 16 dpc, and at 19 dpc. Serum, placenta and foetal metabolomic profiles were performed by ¹H-NMR spectra following the analyses using Chenomx NMR Analysis Software V8.3. The tumour evolution was exponential, affecting the placental metabolomic profile during all the pregnancy stages. The placental tissue in tumour-bearing dams developed at a lower speed, decreasing the foetus’s weight. Associated with the serum metabolomic changes related to tumour growth, the placental metabolomic alterations impacted many metabolic pathways related to energy provision, protein synthesis and signalling, which directly harmed the foetus’s development. The development of the foetus is clearly affected by the damage induced by the tumour evolution, which alters the metabolic profile of both the serum and the placenta, impairing early embryonic development.

1. MicroRNAs (miRNAs) are small non-coding RNAs comprising 17–25 nucleotides that play a crucial role in the post-transcriptional regulation of gene expression, by targeting mRNAs for degradation o...