Deletions at chromosome regions 7q11.23 and 7q36 in a patient with Williams syndrome

Thyroid evaluation of children and adolescents with Williams syndrome in Zhejiang Province

BACKGROUND

The objective of the study was to describe the prevalence of abnormal thyroid function and volume in children and adolescents with Williams syndrome (WS) in Zhejiang Province, China.

METHODS

Thyroid function, including thyroid-stimulating hormone (TSH), free triiodothyronine (fT3), free thyroxine (fT4), and thyroid antibodies (thyroid peroxidase and thyroglobulin) were measured in 83 patients with WS, aged 0.2-16.5 years. Twenty-three patients were followed for an average of 1.7 years (0.4-4.1), and multiple TSH determinations were considered. Thyroid ultrasonography was performed on 49 patients.

RESULTS

One patient was diagnosed with overt hypothyroidism, and 23 patients (27%) had subclinical hypothyroidism (SH). Thyroid antibodies were absent in all patients. In five age groups (0-1 years, 1-3 years, 3-6 years, 6-9 years, 9-18 years), the prevalence of patients with subclinical hypothyroidism was 25%, 28.5%, 44.4%, 16.7% and 4.7%, respectively. Through ultrasound examination, 21 patients (42%) were observed to have thyroid hypoplasia (TH), and there were no cases of thyroid haemiagenesis. The incidence rate of TH increased with age, rising from 20% in the youngest group to 66% in the oldest.

CONCLUSIONS

SH and TH is common in children and adolescents with WS. Yearly evaluation of thyroid must be performed in all patients in this population, regardless of the result of the neonatal screening. Age under 6 years and existing thyroid abnormalities are risk factors for developing SH, and a shorter follow-up interval is needed for screening in these individuals, SH is often self-limiting, and clinicians should be alert to overt hypothyroidism.

LIM kinase 1 is required for insulin‑dependent cell growth of osteosarcoma cell lines

Osteosarcoma is a type of malignant bone tumor with high metastasis and poor prognosis. Previous studies have demonstrated the involvement of LIM kinase 1 (LIMK1) in the proliferation of osteosarcoma cells. LIMK1 is overexpressed in human osteosarcoma tissues and cell lines. To further study LIMK1-associated mechanisms, we used shRNA targeted to the LIMK1 gene to block its expression in the osteosarcoma cell lines MG63 and U2OS. Insulin promoted the proliferation of MG63 cells in a time- and dose-dependent manner, however, this insulin induced proliferation was significantly inhibited by transfection of shRNA targeted to the LIMK1 gene, as well as by the PI3K inhibitor LY294002, but not by the mitogen‑activated protein kinase (MAPK) inhibitor PD98059. The level of cofilin phosphorylation was increased significantly following stimulation of insulin for 24 h, indicating the activation of LIMK1. MG63 cell proliferation was also significantly inhibited by 1,25-dihydroxy vitamin D3 (1,25(OH)2D3) in a time-dependent manner. Furthermore, 1,25(OH)2D3 negated the inhibitory effect of LIMK1 shRNA, indicating that LIMK1 is important in the inhibitory pathway of 1,25(OH)2D3. The present study confirms that LIMK1 is important in regulating osteosarcoma cell proliferation via the insulin/PI3K/LIMK1 signaling pathway, thus the development of gene therapy for osteosarcoma targeting LIMK1 is warranted.

Thyroid morphology and subclinical hypothyroidism in children and adolescents with Williams syndrome

OBJECTIVE

To verify the prevalence of morpho-volumetric and functional thyroid abnormalities in young patients with Williams syndrome (WS).

STUDY DESIGN

Ninety-two patients with WS (49 boys and 43 girls, 0.2-17.2 years of age) underwent evaluation of thyroid function by means of thyroid-stimulating hormone (TSH), fT3, and fT4 measurement. Thyroid ultrasonography was performed in 37 patients. Thyroid antibodies (thyroid peroxidase and thyroglobulin) were measured in all patients with abnormal thyroid function tests.

RESULTS

None of our patients had overt hypothyroidism; 29 patients (31.5%) had subclinical hypothyroidism. Thyroid antibodies were absent in all patients. The prevalence of patients with subclinical hypothyroidism was significantly higher in the younger patients. Ultrasonography revealed morphological or volumetric abnormalities of the thyroid gland in 67.5% of patients; these abnormalities were more frequently observed in the older children.

CONCLUSIONS

Subclinical hypothyroidism is a frequent but stable finding in young children with WS. The great majority of patients with WS >10 years, either with normal or hypoplastic thyroid, have normal thyroid function. Therefore, we suggest yearly monitoring of thyroid function and sonographic studies at least once in patients with WS. Treatment should be reserved for the patients with overt hypothyroidism or for those whose thyroid function shows signs of progressive deterioration.

Fluorescent in situ hybridization in liver cell touch preparations from autopsy

The objective of the present study was to develop a simplified and low-cost protocol for the investigation of congenital anomalies of chromosomal etiology by fluorescent in situ hybridization (FISH) using probes for chromosomes X, 18, 13/21 in liver cell touch preparations obtained from autopsies performed at the University Hospital of the Faculty of Medicine of Ribeirão Preto. Liver touch preparations were obtained from 11 autopsy cases and fixed in 95% ethanol or methanol:acetic acid (3:1). The FISH technique was carried out according to the protocol of Pinkel with modifications, using probes for chromosomes X, 18, 13/21. There was no significant difference in labeling intensity, quantity of nuclei, or number of signals present per nucleus between the materials fixed with the two fixatives. Similar results were obtained with different times of storage up to 14 months at -20 degrees C. We concluded that the use of touch preparations pretreated with acetic acid and fixed in 95% ethanol represents an efficient, practical, and low-cost method of cell preparation for FISH analysis.

Genetic deletion of sonic hedgehog causes hemiagenesis and ectopic development of the thyroid in mouse

Thyroid dysgenesis encountered in 85% of patients with congenital hypothyroidism is a morphologically heterogeneous condition with primarily unknown pathogenesis. Here we identify sonic hedgehog (Shh) as a novel regulator of thyroid development. In Shh knockout mice the thyroid primordium is correctly specified in the pharyngeal endoderm, but budding and dislocation are slightly delayed. In late development the thyroid fails to form a bilobed gland. Instead a single thyroid mass is found unilaterally and mostly to the left of the midline. Thyroid-specific transcription factors (TTF-1 and TTF-2) and thyroglobulin are expressed indicating terminal differentiation. Strikingly, TTF-1- and TTF-2-positive cells aberrantly develop in the presumptive trachea of Shh-/- embryos. The ectopic tissue buds ventrolaterally into the adjacent mesenchyme, and less extensively into the tracheal lumen, forming follicle-like structures that accumulate thyroglobulin. Shh mRNA is not expressed in the thyroid precursor cells at any developmental stage. The results indicate that Shh signaling indirectly governs the symmetric bilobation of the thyroid during late organogenesis. Shh also seems to repress inappropriate thyroid differentiation in nonthyroid embryonic tissues. This study provides clues to the molecular mechanisms that might be dysregulated in thyroid hemiagenesis and development of ectopic thyroid tissue outside the thyroglossal duct.

LIM kinase 1 is essential for the invasive growth of prostate epithelial cells: implications in prostate cancer

Mammalian LIM kinase 1 (LIMK1) is involved in reorganization of actin cytoskeleton through inactivating phosphorylation of the ADF family protein cofilin, which depolymerizes actin filaments. Maintenance of the actin dynamics in an ordered fashion is essential for stabilization of cell shape or promotion of cell motility depending on the cell type. These are the two key phenomena that may become altered during acquisition of the metastatic phenotype by cancer cells. Here we show that LIMK1 is overexpressed in prostate tumors and in prostate cancer cell lines, that the concentration of phosphorylated cofilin is higher in metastatic prostate cancer cells, and that a partial reduction of LIMK1 altered cell proliferation by arresting cells at G2/M, changed cell shape, and abolished the invasiveness of metastatic prostate cancer cells. We also show that the ectopic expression of LIMK1 promotes acquisition of invasive phenotype by the benign prostate epithelial cells. Our data provide evidence of a novel role of LIMK1 in regulating cell division and invasive property of prostate cancer cells and indicate that the effect is not mediated by phosphorylation of cofilin. Our study correlates with the recent observations showing a metastasis-associated chromosomal gain on 7q11.2 in prostate cancer, suggesting a possible gain in LIMK1 DNA (7q11.23).