Related Experiment Video
Updated: Jul 20, 2026
Modeling Paracrine Noncanonical Wnt Signaling In Vitro
Published on: December 10, 2021
WISP-2/CCN5 is involved as a novel signaling intermediate in phorbol ester-protein kinase Calpha-mediated breast
Krishanu Sengupta1, Snigdha Banerjee, Kakali Dhar
1Cancer Research Unit, V.A. Medical Center, Kansas City, Missouri, USA.
Abstract:
PMA and active phorbol esters stimulate the proliferation of various tumor cells, including ER-positive human breast tumor cell lines. However, the specific signaling pathways involved in the PMA-induced mitogenic effect on breast tumor cells have not been fully elucidated. In the present study, we explored the mechanisms associated with the mitogenic influence of PMA on breast tumor cells. Following an acute exposure (i.e., within 2 to 6 h) to PMA (50 nM), a mitogenic effect was observed on WISP-2/CCN5-positive breast tumor cell lines, including MCF-7, ZR-75-1 and SKBR-3 cells, and induction of WISP-2/CCN5 mRNA expression paralleled the observed mitogenic proliferation. This effect was undetected in WISP-2/CCN5 negative MDA-MB-231 breast tumor cells or human mammary epithelial cells with or without ER-alpha transfection. The mitogenic effect of PMA was perturbed by short hairpin RNA (shRNA)-mediated inhibition of WISP-2/CCN5 signaling in MCF-7 cells. Moreover, the upregulation of WISP-2/CCN5 by PMA is not ER dependent but is instead mediated through a complex PKCalpha-MAPK/ERK and SAPK/JNK signaling pathway, which leads to growth stimulation of MCF-7 breast tumor cells. These series of experiments provide the first evidence that WISP-2/CCN5 is a novel signaling molecule that critically participates in the mitogenic action of PMA on noninvasive, WISP-2/CCN5-positive breast tumor cells through PKCalpha-dependent, multiple molecular signal transduction pathways.
Insights
Phorbol 12-myristate 13-acetate (PMA) stimulates breast tumor cell proliferation via WISP-2/CCN5. This effect is mediated by PKCalpha-MAPK/ERK and SAPK/JNK signaling pathways, not estrogen receptors.
Area of Science:
- Molecular Biology
- Cell Biology
- Oncology
Background:
- Phorbol 12-myristate 13-acetate (PMA) and active phorbol esters promote proliferation in various tumor cells, including ER-positive breast cancer cell lines.
- The precise signaling mechanisms underlying PMA's mitogenic effects on breast tumor cells remain incompletely understood.
Purpose of the Study:
- To investigate the molecular mechanisms responsible for the mitogenic effects of PMA on breast tumor cells.
- To identify key signaling molecules and pathways involved in PMA-induced cell proliferation.
Main Methods:
- Exposure of WISP-2/CCN5-positive (MCF-7, ZR-75-1, SKBR-3) and negative (MDA-MB-231) breast tumor cells, as well as mammary epithelial cells, to PMA (50 nM).
- Analysis of WISP-2/CCN5 mRNA expression and cell proliferation.
- Short hairpin RNA (shRNA)-mediated inhibition of WISP-2/CCN5 signaling in MCF-7 cells.
- Investigation of the role of estrogen receptor (ER) and signaling pathways including PKCalpha, MAPK/ERK, and SAPK/JNK.
Main Results:
- PMA induced a mitogenic effect and WISP-2/CCN5 mRNA expression in WISP-2/CCN5-positive breast tumor cell lines within 2-6 hours.
- This mitogenic effect was absent in WISP-2/CCN5-negative cells and ER-alpha transfected mammary epithelial cells.
- Inhibition of WISP-2/CCN5 signaling attenuated the PMA-induced mitogenic effect in MCF-7 cells.
- PMA-induced WISP-2/CCN5 upregulation was independent of ER and involved PKCalpha, MAPK/ERK, and SAPK/JNK signaling.
Conclusions:
- WISP-2/CCN5 is identified as a novel signaling molecule critical for the mitogenic action of PMA on WISP-2/CCN5-positive breast tumor cells.
- The mitogenic effect of PMA is mediated through PKCalpha-dependent activation of multiple signal transduction pathways (MAPK/ERK, SAPK/JNK), independent of estrogen receptor status.
- These findings elucidate a new mechanism for PMA-induced proliferation in specific breast tumor subtypes.
Related Concept Videos
01:41Non-Canonical Wnt Signaling Pathways
01:41Non-Canonical Wnt Signaling Pathways
01:15Amplifying Signals via Second Messengers
02:54Canonical Wnt Signaling Pathway
02:54Canonical Wnt Signaling Pathway
01:16Calmodulin-dependent Signaling
The Ca2+-CaM complex does not have enzymatic activity by itself. Instead, the complex binds downstream target proteins, including membrane proteins or enzymes,...