TGFβ1‐induced cell motility but not cell proliferation is mediated through Cten in colorectal cancer

Abstract

Summary Cten (C‐terminal tensin‐like) is a member of the tensin protein family found in complex with integrins at focal adhesions. It promotes epithelial‐mesenchymal transition (EMT) and cell motility. The precise mechanisms regulating Cten are unknown, although we and others have shown that Cten could be under the regulation of several cytokines and growth factors. Since transforming growth factor beta 1 (TGF‐β1) regulates integrin function and promotes EMT/cell motility, we were prompted to investigate whether TGF‐β1 induces EMT and cell motility through Cten signalling in colorectal cancer. TGF‐β1 signalling was modulated by either stimulation with TGF‐β1 or knockdown of TGF‐β1 in the CRC cell lines SW620 and HCT116. The effect of this modulation on expression of Cten, EMT markers and on cellular function was tested. The role of Cten as a direct mediator of TGF‐β1 signalling was investigated in a CRC cell line in which the Cten gene had been deleted (SW620ΔCten). When TGF‐β1 was stimulated or inhibited, this resulted in, respectively, upregulation and downregulation of Cten expression and EMT markers (Snail, Rock, N‐cadherin, Src). Cell migration and cell invasion were significantly increased following TGF‐β1 stimulation and lost by TGF‐β1 knockdown. TGF‐β1 stimulation of the SW620ΔCten cell line resulted in selective loss of the effect of TGF‐β1 signalling pathway on EMT and cell motility while the stimulatory effect on cell proliferation was retained. These data suggested Cten may play an essential role in mediating TGF‐β1‐induced EMT and cell motility and may therefore play a role in metastasis in CRC.

Cten promotes Epithelial–Mesenchymal Transition (EMT) in colorectal cancer through stabilisation of Src

“…We have found that ROCK1 is a target of Cten 18 and it would seem that Src is able to induce ROCK1 expression. Immunostaining for ROCK1 was performed and cytoplasmic ROCK1 expression was observed (Fig.…”

“…Changes in protein level of Src, ROCK1 and Snail were determined by Western blot and quantified by densitometry (Figure S1). We have previously shown that Snail is a target of Cten and, more recently, we have shown that ROCK1 is a target of Cten . These constructs were used to validate the effect of modulation of Cten expression.…”

“…We have previously shown that Snail is a target of Cten 3 and, more recently, we have shown that ROCK1 is a target of Cten. 18 These constructs were used to validate the effect of modulation of Cten expression. Forced expression of GFP-Cten in HCT116 resulted in up-regulation of Src expression as well as ROCK1 and Snail expression compared to cells transfected with GFP-EV control.…”

Investigating TNS4 in the Colorectal Tumour Microenvironment Using 3D Spheroid Models of Invasion

“…In the absence of TNS4, the effects of TGF-ß stimulation on inducing motility and invasion were abrogated, but TGF-ß-induced proliferation was not affected [12] . Furthermore, TNS4mediated Src stabilization was found to be the responsible for EMT induction in CRC cell lines [13] Nude mice receiving a splenic injection of TNS4 overexpressing HCT116 cells have produced larger splenic tumours and hepatic metastatic nodules compared to the control group [5] .…”

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“…The most explored of these is TNS4 and recently it has been shown that TNS4 is involved in the transduction of extra-celluar signals for a wide variety of growth factors. These data place TNS4 at the heart of a nexus of signalling pathways, the paradigm of which would be EGFR/KRAS/MAPK signalling (Albasri et al, 2011a;Al-Ghamdi et al, 2013;Thorpe et al, 2015;Asiri et al, 2018bAsiri et al, , 2019. In this pathway, TNS4 has been shown to mediate its effect through the reduction of EGFR degradation (Hong et al, 2013) by interacting with the phosphotyrosine residues of EGFR through its SH2 domain (Figure 4).…”