Compared with the placebo, mTOR inhibitors significantly reduced tumor volume in both angiomyolipoma (AML) (RR = 24.69, 95% CI = 3.51,173.41, P = 0.001) and subependymal giant cell astrocytoma (SEGA) (RR = 27.85, 95% CI = 1.74,444.82, P = 0.02).
Also included is the utilization of mTOR inhibitors in both advanced renal cell carcinoma (RCC) and in patients with tuberous sclerosis complex (TSC) associated angiomyolipoma (AML).
Increased activation of the mTOR pathway is observed in patients and animal models of renal transplant rejection, autosomal dominant polycystic kidney disease, renal cell carcinoma, diabetic nephropathy, lupus nephritis, and angiomyolipoma.
NMI individuals showed more frequent bilateral and larger renal angiomyolipomas (p = 0.001; p = 0.003) and pulmonary involvement (trend) than patients with TSC1 pathogenic variants.
This Review describes important advances in the TSC field and highlights several remaining critical knowledge gaps: the factors that promote aggressive behaviour by a subset of TSC-associated RCCs; the molecular mechanisms underlying early-onset cystogenesis in TSC2-PKD1 contiguous gene deletion syndrome; the effect of early, long-term mTORC1 inhibition on the development of TSC renal disease; and the identification of the cell or cells of origin of angiomyolipomas.
Using RNA-Seq, we identified (1) Insulin-like Growth Factor (IGF2) as one of the genes with the highest fold-change difference between human TSC2-null and TSC2-expressing angiomyolipoma cells from a patient with LAM, and (2) the mouse IGF2 homolog Igf2, as a top-ranking gene according to fold change between Tsc2-/- and Tsc2+/+ mouse embryo fibroblasts (MEFs).
However, rapamycin further increased uPA expression in TSC2-null tumor cells and immortalized TSC2-null angiomyolipoma cells, but not in cells with intact TSC.
Our study showed that patients with TSC2 mutations had higher frequency of hypomelanotic macules and dental enamel pits and larger angiomyolipomas (AMLs) than patient populations with non-TSC2 mutations through analysis of the correlated mutation findings with clinical features.
Treatment with mammalian target of rapamycin (mTOR) inhibitors can reduce tumour size and is indicated in patients with TSC-associated renal angiomyolipomas >3 cm in diameter.
In general, TSC2 disease was more severe than TSC1, with more subependymal giant cell astrocytomas and angiomyolipomas, higher incidence of pharmacoresistant epileptic seizures, and more severe neuropsychiatric disorders.
The establishment of a connection between TSC and mTOR led to the clinical use of drugs known as mTOR inhibitors (like rapamycin, also known as sirolimus and everolimus), which are becoming an increasingly interesting tool in the management of TSC-associated features, such as subependymal giant cell astrocytomas, renal angiomyolipomas, and also epilepsy.
The exosome-mediated mechanisms may also operate in the cells of angiomyolipoma (AML), which develops as a result of mutations in TSC1/TSC2 genes in TSC patients, because we observed the reactivation of mammalian target of rapamycin and Notch pathways, driven by the delivery of Rheb and Notch1 esRNA, in AML cells depleted of Rheb that were treated with the exosomes purified from AML cells with the constitutively high Rheb levels.
Our results indicate that TSC2 and less commonly TSC1 alterations are the primary essential driver event in angiomyolipoma/LAM, whereas other somatic mutations are rare and likely do not contribute to tumor development.
Our results indicate that TSC2 and less commonly TSC1 alterations are the primary essential driver event in angiomyolipoma/LAM, whereas other somatic mutations are rare and likely do not contribute to tumor development.
Urotensin-II-induced proliferation and migration were reproduced in TSC2-deficient human angiomyolipoma cells, but not in those stably expressing TSC2.
Remarkable progress in basic and translational research, in addition to several randomized controlled trials worldwide, has led to regulatory approval of the use of mTOR inhibitors for the treatment of renal angiomyolipomas, brain subependymal giant cell astrocytomas and pulmonary lymphangioleiomyomatosis, but further research is needed to establish full indications of therapeutic treatment.
The exosome-mediated mechanisms may also operate in the cells of angiomyolipoma (AML), which develops as a result of mutations in TSC1/TSC2 genes in TSC patients, because we observed the reactivation of mammalian target of rapamycin and Notch pathways, driven by the delivery of Rheb and Notch1 esRNA, in AML cells depleted of Rheb that were treated with the exosomes purified from AML cells with the constitutively high Rheb levels.