In this study, we confirm that PTEN mutations in sporadic thyroid cancer are infrequent as we found one point mutation and one heterozygous deletion of PTEN gene in 26 tumors and eight cell lines screened.
Strong correlations (0.68 ≤ r ≤ 1.0) were observed between PIK3C3 and PIM3 in breast cancer, between PIK3C3 and PTEN in breast and ovary cancers, and between PIM3 and PTEN in breast, kidney, liver, and thyroid cancers during disease progression, implicating that the correlations for cancer network gene expressions could serve as a supplement to current clinical biomarkers, such as cancer antigens, for early cancer diagnosis.
We show here that adenosine triphosphate (ATP) regulates PTEN subcellular localization in a variety of different cancer cell lines, including those derived from breast, colon and thyroid carcinomas.
Germline PTEN mutations cause 85% of Cowden syndrome (CS), characterized by a high risk of breast and thyroid cancers, and 65% of Bannayan-Riley-Ruvalcaba syndrome (BRRS), characterized by lipomatosis, hemangiomas and speckled penis.
In conclusion, our data define a novel mechanism of PI3K/AKT hyperactivation and outline a regulatory role for miR-146b in suppressing PTEN expression, a frequent observation in thyroid cancer.
Sequencing of tumor tissue revealed a second hit in PTEN in the thyroid carcinoma and VC, confirmed by a PTEN loss and activation of the PI3K/AKT pathway in immunohistochemistry.
PTEN knockdown in thyroid cancer cell lines stabilized intracellular NIS protein by promoting an interaction with NIS-LARG (leukemia-associated RhoA guanine exchange factor).
Notably, individuals with SDH(var+) alone had the highest thyroid cancer prevalence (24/47) compared with PTEN(mut+) patients (27/105, P = 0.002) or PTEN(mut+)/SDH(var+) carriers (6/22, P = 0.038).
The transcriptional silencing of PTEN was significantly associated with the anaplastic subtype, suggesting that PTEN is involved in the carcinogenesis of highly malignant or late-stage thyroid cancers, whereas this particular mechanism appears to be of minor importance in differentiated follicular thyroid tumors.
Our study shows that low blood PTEN protein expression could serve as a screening molecular correlate to predict for germline PTEN mutation in CS and CS-like presentations of thyroid cancer.
A total of 32 of 225 PTEN mutation+ patients (14%) had thyroid cancer: 52% papillary, 28% follicular-variant papillary, 14% follicular, and 6% anaplastic.
We show that SRC inhibition could rescue SDHD dysfunction-induced cellular phenotype and tumorigenesis only when wild-type PTEN is expressed, in thyroid cancer lines.
Germline mutations in the PTEN gene, which cause Cowden syndrome, are known to be one of the genetic factors for primary thyroid and breast cancers; however, PTEN mutations are found in only a small subset of research participants with non-syndrome breast and thyroid cancers.
Our results suggest that downregulation of PTEN expression at the mRNA level plays a role in PTEN inactivation in thyroid cancer and PTEN exerts its tumour-suppressive effect on thyroid cancer through the inhibition of cell cycle progression alone or both cell cycle progression and cell death.
Whereas PTEN inactivation is uncommon in sporadic thyroid cancer, activation of growth factor pathways that signal through Akt is frequently identified.