Serum Vascular Endothelial Growth Factor C as a Marker of Therapeutic Response to Sirolimus in Lymphangioleiomyomatosis

The dual role of the TSC complex in cancer

The tuberous sclerosis complex (TSC1/TSC2/TBC1D7) primarily functions to inhibit the mechanistic target of rapamycin complex 1 (mTORC1), a crucial regulator of cell growth. Mutations in TSC1 or TSC2 cause tuberous sclerosis complex (TSC), a rare autosomal dominant genetic disorder marked by benign tumors in multiple organs that rarely progress to malignancy. Traditionally, TSC proteins are considered tumor suppressive due to their inhibition of mTORC1 and other mechanisms. However, more recent studies have shown that TSC proteins can also promote tumorigenesis in certain cancer types. In this review, we explore the composition and function of the TSC protein complex, the roles of its individual components in cancer biology, and potential future therapeutic targeting strategies.

Safety and Efficacy of Combined Resveratrol and Sirolimus in Lymphangioleiomyomatosis

BACKGROUND

A critical need exists to develop remission-inducing therapies for lymphangioleiomyomatosis.

RESEARCH QUESTION

Is the addition of resveratrol safe and more efficacious than sirolimus alone in patients with lymphangioleiomyomatosis?

STUDY DESIGN AND METHODS

We conducted a phase 2, dose-escalating, open-label trial of resveratrol in patients with lymphangioleiomyomatosis receiving a stable regimen of sirolimus. Resveratrol was started at 250 mg/d and escalated every 8 weeks to maximum dose of 1,000 mg/d over 24 weeks. The primary outcome was ≥ 42% decline in serum vascular endothelial growth factor D (VEGF-D) levels on combined therapy compared with baseline VEGF-D levels on sirolimus. Secondary objectives included an assessment of the safety profile and the effect on lung function and health-related quality of life (HRQOL). Longitudinal change in outcome measures was assessed using linear mixed models. Adverse effects were tabulated using the National Cancer Institute's Common Terminology Criteria for Adverse Events version 4.

RESULTS

Twenty-five patients with lymphangioleiomyomatosis with a median age of 51 years were enrolled. Pulmonary function parameters at study inclusion were: FEV1: median absolute, 1.72 L; 64% predicted; FVC: median absolute, 2.99 L; 96% predicted; and diffusing capacity of the lungs for carbon monoxide: median absolute, 14.68 mL/mm Hg/min; 37% predicted. The median serum VEGF-D value at baseline was 617 pg/mL. Patients entered the study with a median sirolimus dose of 2 mg/d with median trough level of 6.3 ng/mL. Despite some GI side effects, the addition of resveratrol was well tolerated. Although the primary outcome was not met, a statistically significant reduction in serum VEGF-D levels and improvement in HRQOL during the study was found.

INTERPRETATION

The addition of resveratrol was safe and well tolerated in patients with lymphangioleiomyomatosis taking sirolimus and was associated with modest improvement in HRQOL. Larger controlled trials of this combination might be warranted to assess definitively the usefulness of resveratrol as an additive therapy in lymphangioleiomyomatosis.

TRIAL REGISTRY

ClinicalTrials.gov; No.: NCT03253913; URL: www.

CLINICALTRIALS

gov.

Tuberous sclerosis complex for the pulmonologist

Tuberous sclerosis complex (TSC) is a rare multisystem genetic disorder affecting almost all organs with no sex predominance. TSC has an autosomal-dominant inheritance and is caused by a heterozygous mutation in either the TSC1 or TSC2 gene leading to hyperactivation of the mammalian target of rapamycin (mTOR). TSC is associated with several pulmonary manifestations including lymphangioleiomyomatosis (LAM), multifocal micronodular pneumocyte hyperplasia (MMPH) and chylous effusions. LAM is a multisystem disorder characterised by cystic destruction of lung parenchyma, and may occur in either the setting of TSC (TSC-LAM) or sporadically (S-LAM). LAM occurs in 30–40% of adult females with TSC at childbearing age and is considered a nonmalignant metastatic neoplasm of unknown origin. TSC-LAM is generally milder and, unlike S-LAM, may occur in males. It manifests as multiple, bilateral, diffuse and thin-walled cysts with normal intervening lung parenchyma on chest computed tomography. LAM is complicated by spontaneous pneumothoraces in up to 70% of patients, with a high recurrence rate. mTOR inhibitors are the treatment of choice for LAM with moderately impaired lung function or chylous effusion. MMPH, manifesting as multiple solid and ground-glass nodules on high-resolution computed tomography, is usually harmless with no need for treatment.

Tuberous sclerosis complex is associated with diverse pulmonary manifestations including LAM, multiple micronodular pneumocyte hyperplasia and chylous effusions. LAM occurs in 30–40% of adult females with tuberous sclerosis complex.https://bit.ly/3iLqZ08