Related Experiment Video
Updated: Aug 13, 2026

Spheroid Assay to Measure TGF-β-induced Invasion
Published on: November 16, 2011
Loss of receptors for transforming growth factor beta in human T-cell malignancies
M E Kadin1, M W Cavaille-Coll, R Gertz
1Department of Pathology, Beth Israel Hospital, Boston, MA 02215.
Abstract:
Ki-1 (CD30)+ cutaneous T-cell lymphomas CTCLs) are slowly progressive lymphomas in which initial spontaneous regression is often observed. To better understand the mechanisms of spontaneous regression and eventual tumor progression in Ki-1+ CTCLs, type beta transforming growth factor (TGF-beta)-mediated growth inhibition of clonally related cell lines derived from two time points, before and after tumor progression, was studied. TGF-beta 1 inhibited colony-forming efficiency (CFE) of a cell line (Mac-1) derived from clinically indolent Ki-1+ CTCLs but failed to inhibit CFE of Mac-2A and -2B cell lines from advanced CTCLs. To determine the basis for TGF-beta 1 resistance in advanced CTCL cells, we looked for possible defects in the expression of cell surface TGF-beta receptors. Mac-1 cells were found to express TGF-beta receptors I and II, which mediate growth inhibition, and the TGF-beta-binding proteoglycan betaglycan. In contrast, receptors I and II were not detected in CTCL lines Mac-2A and -2B even though these cell lines did express betaglycan. Various treatments that unmask or induce TGF-beta receptors in other cells failed to show evidence for these receptors in advanced CTCL cells. Loss of TGF-beta receptor expression in these cells correlated with a marked decrease in TGF-beta receptor II mRNA levels. Loss of cell surface TGF-beta receptors was also found in two of five other patients with T-cell lymphomas including the Sezary syndrome and a noncutaneous T-cell lymphoma, suggesting that loss of TGF-beta receptor expression may be a recurrent feature of human T-cell malignancies.
Insights
Tumor progression in Ki-1 (CD30)+ cutaneous T-cell lymphomas (CTCLs) is linked to a loss of transforming growth factor-beta (TGF-beta) receptors. Advanced CTCL cells lose TGF-beta receptor expression, contributing to tumor growth.
Area of Science:
- Oncology
- Immunology
- Cell Biology
Background:
- Ki-1 (CD30)+ cutaneous T-cell lymphomas (CTCLs) are characterized by slow progression and spontaneous regression.
- Understanding the mechanisms behind regression and progression is crucial for developing effective treatments.
Related Concept Videos
Mitogens and the Cell Cycle
Loss of Tumor Suppressor Gene Functions
When the tumor suppressor genes develop mutations or are lost, cells start growing out of control, leading to cancer. However, a single functional copy of the tumor suppressor gene is enough for the cells to maintain their normal functions and cell...
mTOR Signaling and Cancer Progression
The mTOR pathway or the...
The Retinoblastoma Gene
The first-ever tumor suppressor gene called Rb was identified in retinoblastoma - a rare eye tumor in children. In inherited forms of the disease, a child inherits one defective copy of the Rb gene, which predisposes them to retinoblastoma. However,...
Receptor Downregulation in MVBs
The EGFR can initiate signaling pathways that lead to cell proliferation, migration, and differentiation. Overexpression of EGFR stimulates cells to proliferate. Excessive EGFR activation may...
TGF - β Signaling Pathway

