Thyroid hormone suppresses expression of stathmin and associated tumor growth in hepatocellular carcinoma

[helvella]

T3 has some interesting and, perhaps, surprising facets to its importance.

Please don't ask me to explain further! But if anyone can add to our ability to properly understand the paper, please do so.

Thyroid hormone suppresses expression of stathmin and associated tumor growth in hepatocellular carcinoma

Yi-Hsin Tseng, Ya-Hui Huang, Tzu-Kang Lin, Sheng-Ming Wu, Hsiang-Cheng Chi, Chung-Ying Tsai, Ming-Ming Tsai, Yang-Hsiang Lin, Wei-Chun Chang, Ya-Ting Chang, Wei-Jan Chen & Kwang-Huei Lin

Scientific Reports 6, Article number: 38756 (2016)

doi:10.1038/srep38756

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Cell growthOncogenes

Received: 01 June 2016

Accepted: 14 November 2016

Published online: 09 December 2016

Abstract

Stathmin (STMN1), a recognized oncoprotein upregulated in various solid tumors, promotes microtubule disassembly and modulates tumor growth and migration activity. However, the mechanisms underlying the genetic regulation of STMN1 have yet to be elucidated. In the current study, we report that thyroid hormone receptor (THR) expression is negatively correlated with STMN1 expression in a subset of clinical hepatocellular carcinoma (HCC) specimens. We further identified the STMN1 gene as a target of thyroid hormone (T3) in the HepG2 hepatoma cell line. An analysis of STMN1 expression profile and mechanism of transcriptional regulation revealed that T3 significantly suppressed STMN1 mRNA and protein expression, and further showed that THR directly targeted the STMN1 upstream element to regulate STMN1 transcriptional activity. Specific knockdown of STMN1 suppressed cell proliferation and xenograft tumor growth in mice. In addition, T3 regulation of cell growth arrest and cell cycle distribution were attenuated by overexpression of STMN1. Our results suggest that the oncogene STMN1 is transcriptionally downregulated by T3 in the liver. This T3-mediated suppression of STMN1 supports the theory that T3 plays an inhibitory role in HCC tumor growth, and suggests that the lack of normal THR function leads to elevated STMN1 expression and malignant growth.

Full paper freely available here:

nature.com/articles/srep38756

For those who, like me, didn't really know what HCC is...

Hepatocellular carcinoma

From Wikipedia, the free encyclopedia

Hepatocellular carcinoma (HCC), also called malignant hepatoma, is the most common type of liver cancer.

en.wikipedia.org/wiki/Hepat...

[marram]

This extremely interesting. Obviously, the study was focused on hepatic cancer.

The question which comes from this is, if identical studies were carried out on other tumours, and the oncoproteins which are associated specifically with those tumours, would a similar picture emerge?

The evidence is getting stronger that cancer cells are common in the human body, but they are destroyed by the immune system, and when the immune system is compromised, then cancer cells are allowed to grow out of control. Interestingly, many hypothyroid patients have immunity problems - so many report one cold or infection after another.

So many questions, so few answers.