sirolimus and Hamartoma

Tuberous sclerosis complex is a multisystemic, autosomal dominant genetic disorder with complete penetrance, that can evolve with hamartomas in multiple organs, such as skin, central nervous system, kidney and lung. Due to the wide phenotypic variability, the disease is often not recognized. Tuberous sclerosis complex affects one in 10,000 newborns and most patients are diagnosed during the first 15 months of life. The diagnostic criteria for tuberous sclerosis were reviewed in 2012, at the second International Tuberous Sclerosis Complex Consensus Conference. The diagnosis is based on genetic criteria, by the identification of inactivating pathogenic mutation of tumor suppressor genes TSC1 and TSC2, and clinical criteria, including cutaneous, renal, pulmonary, cardiac and neurological manifestations. The treatment of tuberous sclerosis complex consists, mainly, in management of the symptoms caused by hamartomas and in prevention of organ failure. Multidisciplinary approach is recommended, in order to obtain better clinical outcomes.

Topics: Hamartoma; Humans; Immunosuppressive Agents; Mutation; Sirolimus; Tuberous Sclerosis

Tuberous sclerosis complex is an autosomal dominant disease, with variable expressivity and multisystemic involvement, which is characterised by the growth of benign tumours called hamartomas. The organs that are most commonly affected are the brain, skin, kidneys, eyes, heart and lungs. Of all the children with this disease, 85% present neurological manifestations that, due to their severity, are the main cause of morbidity and mortality. The most significant neurological manifestations are epilepsy, autism spectrum disorders and mental retardation. It has been shown that in tuberous sclerosis complex the genes TSC1 and TSC2 alter the mTOR enzyme cascade, which sets off inhibition of this pathway. The possibility of resorting to treatments applied at the origin, thus inhibiting this pathway, is currently being evaluated.

Topics: Anticonvulsants; Astrocytoma; Autistic Disorder; Brain Diseases; Brain Neoplasms; Drug Design; Epilepsy; Everolimus; Glioma, Subependymal; Hamartoma; Humans; Intellectual Disability; Learning Disabilities; Molecular Targeted Therapy; Signal Transduction; Sirolimus; TOR Serine-Threonine Kinases; Tuberous Sclerosis; Tuberous Sclerosis Complex 1 Protein; Tuberous Sclerosis Complex 2 Protein; Tumor Suppressor Proteins

To describe the clinical course and outcomes of aggressive retinal astrocytic hamartoma (RAH) treated with oral mechanistic target of rapamycin inhibitors (mTORis).. A retrospective clinical case series.. Five patients with genetically confirmed tuberous sclerosis complex and visually significant RAH due to tumor growth or exudation.. In this retrospective clinical case series, a review of electronic medical records was performed to determine baseline and follow-up ophthalmic examination characteristics, along with ancillary imaging findings, in patients receiving off-label treatment with either oral sirolimus or everolimus for symptomatic RAH.. Visual acuity, change in tumor size, degree of exudation, and adverse effects of the mTORis were evaluated.. The 5 patients in this series ranged in age from 8 months to 54 years. Four were treated with sirolimus, and 1 received everolimus. In all the cases, the tumor height was stable or decreased after the treatment (median follow-up duration, 39 months; range, 11-73 months). Exudation improved after the treatment in all the cases. In an 8-month-old infant, frequent upper respiratory tract infections prompted the cessation of treatment. In 1 patient, the mTORi was temporarily withheld because of elevated liver enzyme levels. No other significant adverse effects were noted.. Sirolimus and everolimus should be considered in the management of vision-threatening RAH, particularly in the setting of exudative and rapidly growing tumors. Four of the 5 patients in this series tolerated the oral mTORi and continued with the therapy. There were no serious complications.

Topics: Everolimus; Hamartoma; Humans; Infant; Retinal Diseases; Retrospective Studies; Sirolimus

Tuberous sclerosis complex (TSC) is an inherited neurocutaneous disorder. Fifty percent of patients with TSC will develop retinal astrocytic hamartoma (RAH). The mammalian target of rapamycin (mTOR) inhibitors interferes with the pathological mechanisms of TSC. Treatment of RAH with mTOR inhibitors has been described in only a few isolated case reports. The purpose of this study was to assess the effect of mTOR inhibitors on RAH in a small cohort of patients.. The medical records of all consecutive patients with ocular manifestations of TSC that were treated with mTOR inhibitors at the Sheba Medical Center from January 2014 to December 2018 were retrospectively reviewed. Data collection included demographics, medical history, ocular presentation, ocular treatment, and treatment outcome. Tumor size was assessed by a masked observer, before and after treatment. Lesion measurements were made with Heidelberg SD-OCT (HRA + OCT SPECTRALIS), and fundus photos were taken with RetCam3® (Natus, USA) and analyzed by "ImageJ" software.. Eleven patients with tuberous sclerosis and astrocytic hamartoma were treated with mTOR inhibitors in the study period. Of them, 6 children (11 eyes, 20 tumors) had proper imaging of tumor size before and after treatment. The analysis included these 11 eyes. All six patients had non-ocular manifestations of TSC, including dermatologic (n = 5), neurologic (n = 5), and renal (n = 3) involvement. Ocular involvement included in five eyes (45%) tumors near the optic disc and in four eyes (37%) foveal tumors. The mean follow-up duration was 2.15 ± 1.4 years (range 10 months to 4.5 years). The average tumor base reduction in the treated group was 17.8% ± 15.9. The average maximal thickness at baseline was 414 ± 174 μm (range 152-686 μm). There was a 14% ± 7.1 reduction after treatment. None of the tumors showed evidence of growth at the final follow-up.. The findings of this study suggest that mTOR inhibitors can reduce tumor size and that they can be considered as an optional treatment in certain conditions. This preliminary report is the first to quantitatively assess pre- and posttreatment tumor size, in young patients.

Topics: Child; Hamartoma; Humans; Retrospective Studies; Sirolimus; TOR Serine-Threonine Kinases; Tuberous Sclerosis

Topics: Administration, Oral; Adolescent; Adult; Antibiotics, Antineoplastic; Blood Cell Count; Creatinine; Female; Hamartoma; Humans; Liver Function Tests; Male; Retinal Diseases; Sirolimus; Tomography, Optical Coherence; Tuberous Sclerosis; Visual Acuity; Young Adult

Hamartomas are composed of cells native to an organ but abnormal in number, arrangement or maturity. In the tuberous sclerosis complex (TSC), hamartomas develop in multiple organs because of mutations in TSC1 or TSC2. Here we show that TSC2-null fibroblast-like cells grown from human TSC skin hamartomas induced normal human keratinocytes to form hair follicles and stimulated hamartomatous changes. Follicles were complete with sebaceous glands, hair shafts and inner and outer root sheaths. TSC2-null cells surrounding the hair bulb expressed markers of the dermal sheath and dermal papilla. Tumour xenografts recapitulated characteristics of TSC skin hamartomas with increased mammalian target of the rapamycin complex 1 (mTORC1) activity, angiogenesis, mononuclear phagocytes and epidermal proliferation. Treatment with an mTORC1 inhibitor normalized these parameters and reduced the number of tumour cells. These studies indicate that TSC2-null cells are the inciting cells for TSC skin hamartomas, and suggest that studies on hamartomas will provide insights into tissue morphogenesis and regeneration.

Topics: Animals; Biopsy; DNA; Female; Fibroblasts; Gene Expression; Gene Expression Profiling; Hair Follicle; Hamartoma; Humans; Immunohistochemistry; Keratinocytes; Mechanistic Target of Rapamycin Complex 1; Mice; Mice, Nude; Multiprotein Complexes; Neoplasms, Experimental; Proteins; Sequence Analysis, DNA; Sirolimus; Skin Neoplasms; TOR Serine-Threonine Kinases; Transplantation, Heterologous; Tuberous Sclerosis Complex 1 Protein; Tuberous Sclerosis Complex 2 Protein; Tumor Cells, Cultured; Tumor Suppressor Proteins

Miscoordination of growth and proliferation with the cellular stress response can lead to tumorigenesis. Mammalian target of rapamycin (mTOR), a central cell growth controller, is highly activated in some malignant neoplasms, and its clinical implications are under extensive investigation. We show that constitutive mTOR activity amplifies p53 activation, in vitro and in vivo, by stimulating p53 translation. Thus, loss of TSC1 or TSC2, the negative regulators of mTOR, results in dramatic accumulation of p53 and apoptosis in response to stress conditions. In other words, the inactivation of mTOR prevents cell death by nutrient stress and genomic damage via p53. Consistently, we also show that p53 is elevated in TSC tumors, which rarely become malignant. The coordinated relationship between mTOR and p53 during cellular stress provides a possible explanation for the benign nature of hamartoma syndromes, including TSC. Clinically, this also suggests that the efficacy of mTOR inhibitors in anti-neoplastic therapy may also depend on p53 status, and mTOR inhibitors may antagonize the effects of genotoxic chemotherapeutics.

Topics: Animals; Apoptosis; DNA Damage; Food Deprivation; Gene Expression Regulation, Neoplastic; Genes, p53; Hamartoma; Mice; Mutagens; Phosphorylation; Protein Kinases; Sirolimus; TOR Serine-Threonine Kinases; Tuberous Sclerosis; Tuberous Sclerosis Complex 1 Protein; Tuberous Sclerosis Complex 2 Protein; Tumor Suppressor Protein p53; Tumor Suppressor Proteins