Prune belly syndrome in surviving males can be caused by Hemizygous missense mutations in the X-linked Filamin A gene

Background

Prune belly syndrome (PBS) is a rare, multi-system congenital myopathy primarily affecting males that is poorly described genetically. Phenotypically, its morbidity spans from mild to lethal, however, all isolated PBS cases manifest three cardinal pathological features: 1) wrinkled flaccid ventral abdominal wall with skeletal muscle deficiency, 2) urinary tract dilation with poorly contractile smooth muscle, and 3) intra-abdominal undescended testes. Despite evidence for a genetic basis, previously reported PBS autosomal candidate genes only account for one consanguineous family and single cases.

Methods

We performed whole exome sequencing (WES) of two maternal adult half-brothers with syndromic PBS (PBS + Otopalatodigital spectrum disorder [OPDSD]) and two unrelated sporadic individuals with isolated PBS and further functionally validated the identified mutations.

Results

We identified three unreported hemizygous missense point mutations in the X-chromosome gene Filamin A (FLNA) (c.4952 C > T (p.A1448V), c.6727C > T (p.C2160R), c.5966 G > A (p.G2236E)) in two related cases and two unrelated sporadic individuals. Two of the three PBS mutations map to the highly regulatory, stretch-sensing Ig19–21 region of FLNA and enhance binding to intracellular tails of the transmembrane receptor β-integrin 1 (ITGβ1).

Conclusions

FLNA is a regulatory actin-crosslinking protein that functions in smooth muscle cells as a mechanosensing molecular scaffold, transmitting force signals from the actin-myosin motor units and cytoskeleton via binding partners to the extracellular matrix. This is the first evidence for an X-linked cause of PBS in multiple unrelated individuals and expands the phenotypic spectrum associated with FLNA in males surviving even into adulthood.

Copy number variations in a population with prune belly syndrome

Prune Belly Syndrome (PBS) is a congenital multisystem myopathy with mild to lethal severity. While of uncertain etiology, 95% male predominance and familial occurrence suggest a genetic basis. As copy number variations (CNVs) can cause unexplained genetic disorders, we tested for novel CNVs in a large PBS population. We genotyped 21 unrelated PBS patients by high-resolution array comparative genomic hybridization (aCGH) and phenotyped using a novel PBS severity scoring system. Available parents were screened for detected CNV via quantitative PCR (qPCR). We additionally screened for recurrence of identified novel candidate CNVs on 106 PBS probands by qPCR. We identified 10 CNVs in 8 of 21 PBS patients tested (38%). Testing confirmed inheritance from an unaffected biological parent in six patients; parental samples were unavailable in two probands. One candidate CNV includes duplication of the X-chromosome AGTR2 gene, known to function in urinary tract development. Subsequent screening of the larger PBS cohort did not identify any recurrent CNVs. Presence of CNV did not correlate with PBS severity scoring. CNVs were uncommon in this large PBS population, but analysis of identified variants may inform disease pathogenesis and reveal targets for therapeutic intervention for this rare, severe disorder.

Abstract 4119: Novel evidence for chemopreventive effects of curcumin and boswellic acid through regulation of mir-27a and mir-34a in human colorectal cancer

Purpose: Colorectal cancer (CRC) is one of the most common causes of cancer-associated mortality worldwide, but it is truly a preventable disease. Accumulating evidence indicates that several dietary botanicals, including curcumin and boswellic acids, have potent anti-inflammatory and anti-tumorigenic properties. However, the molecular mechanisms underlying the anti-cancer potential of these compounds remain poorly understood. More recent data suggest that the chemopreventive effects of these botanicals may in part be mediated through regulation of key cancer-related microRNAs (miRNAs), and their downstream gene targets. This study aimed to determine whether curcumin and 3 acetyl-11-keto-β-boswellic acid (AKBA) exert their anti-tumorigenic effects through modulation of specific miRNAs in CRC cell lines and a xenograft mouse model.

Experimental Design: We first determined the effects of curcumin and AKBA on cellular proliferation, apoptosis and cell cycle dynamics in a panel of CRC cell lines. Next, we used Illumina's Human HT-12 V4 array gene expression arrays to systematically identify specific gene signaling pathways regulated by curcumin and AKBA. Subsequently we used combined bioinformatics and in-silico approaches to identify miRNAs and molecular pathways activated by curcumin and AKBA individually, and their combination. We determined the functional role of curcumin and AKBA-related miRNAs in CRC cell lines, and validated these findings for the chemopreventive efficacy of curcumin and AKBA in a xenograft animal model.

Results: Both curcumin and AKBA inhibited cellular proliferation, induced apoptosis and cell cycle arrests in all CRC cell lines, and these effects were significantly enhanced with combined vis-à-vis individual treatments with the botanicals. Gene-expression arrays revealed that curcumin and AKBA regulated key cell cycle controlling genes including: cMYC, CCND1, CCNE1 and CDK4. Combined bioinformatics and in-silico analysis identified apoptosis, proliferation and cell cycle regulatory signaling pathways as the key modulators of curcumin and AKBA-induced anti-cancer effects, and further discovered miR-27a and miR-34a as the most significantly differentially expressed miRNAs following treatment with the two botanicals. In support of our in vitro findings, mouse xenograft experiments further confirmed that both curcumin and AKBA suppressed tumor size and volume in mice, and that these effects were orchestrated through modulation of miR-27a and miR-34a expression in the animal model.

Conclusion: We provide novel mechanistic evidence for the chemopreventive effects of curcumin and AKBA through regulation of specific miRNAs in CRC. The enhanced anti-tumorigenic effect by combined treatment with these botanicals provides a potential rationale for the use of such diet-based botanicals for the chemoprevention of this malignancy.

Citation Format: Shusuke Toden, Yoshinaga Okugawa, Keun Hur, Thomas A. Jascur, Constanze Burhrmann, Durgha Nattamai, Esperanza Anguiano, Mehdi Shakibaei, C. Richard Boland, Ajay Goel. Novel evidence for chemopreventive effects of curcumin and boswellic acid through regulation of mir-27a and mir-34a in human colorectal cancer. [abstract]. In: Proceedings of the 105th Annual Meeting of the American Association for Cancer Research; 2014 Apr 5-9; San Diego, CA. Philadelphia (PA): AACR; Cancer Res 2014;74(19 Suppl):Abstract nr 4119. doi:10.1158/1538-7445.AM2014-4119