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Updated: Aug 15, 2025
Monitoring Dynamic Changes In Mitochondrial Calcium Levels During Apoptosis Using A Genetically Encoded Calcium Sensor
Published on: April 1, 2011
Calcium signaling induced by 15-deoxy-prostamide-J2 promotes cell death by activating PERK, IP3R, and the
Daniel A Ladin1, Margaret M Nelson2,3, Estefani Cota4
1Medical Doctor Program, Brody School of Medicine, East Carolina University, Greenville, NC 27858, USA.
Abstract:
Melanoma is the deadliest form of skin cancer in the US. Although immunotherapeutic checkpoint inhibitors and small-molecule kinase inhibitors have dramatically increased the survival of patients with melanoma, new or optimized therapeutic approaches are still needed to improve outcomes. 15-deoxy-Δ12,14-prostamide J2 (15d-PMJ2) is an investigational small-molecule that induces ER stress-mediated apoptosis selectively in tumor cells. Additionally, 15d-PMJ2 reduces melanoma growth in vivo. To assess the chemotherapeutic potential of 15d-PMJ2, the current study sought to uncover molecular pathways by which 15d-PMJ2 exerts its antitumor activity. B16F10 melanoma and JWF2 squamous cell carcinoma cell lines were cultured in the presence of pharmacological agents that prevent ER or oxidative stress as well as Ca2+ channel blockers to identify mechanisms of 15d-PMJ2 cell death. Our data demonstrated the ER stress protein, PERK, was required for 15d-PMJ2-induced death. PERK activation triggered the release of ER-resident Ca2+ through an IP3R sensitive pathway. Increased calcium mobilization led to mitochondrial Ca2+ overload followed by mitochondrial permeability transition pore (mPTP) opening and the deterioration of mitochondrial respiration. Finally, we show the electrophilic double bond located within the cyclopentenone ring of 15d-PMJ2 was required for its activity. The present study identifies PERK/IP3R/mPTP signaling as a mechanism of 15d-PMJ2 antitumor activity.
Insights
15-deoxy-Δ12,14-prostamide J2 (15d-PMJ2) triggers cancer cell death by inducing ER stress and calcium release. This mechanism, involving PERK/IP3R/mPTP signaling, highlights 15d-PMJ2 as a potential melanoma therapeutic.
Area of Science:
- Molecular Biology
- Cancer Research
- Cellular Signaling
Background:
- Melanoma remains a deadly skin cancer, necessitating novel therapeutic strategies beyond current immunotherapies and kinase inhibitors.
- 15-deoxy-Δ12,14-prostamide J2 (15d-PMJ2) is an investigational compound demonstrating selective tumor cell apoptosis induction and melanoma growth inhibition.
Purpose of the Study:
- To elucidate the molecular pathways underlying the antitumor activity of 15d-PMJ2 in melanoma.
- To identify the specific cellular mechanisms responsible for 15d-PMJ2-induced cancer cell death.
Main Methods:
- Utilized B16F10 melanoma and JWF2 squamous cell carcinoma cell lines.
- Employed pharmacological agents to modulate ER stress, oxidative stress, and calcium (Ca2+) channels.
- Investigated the role of specific proteins and signaling pathways, including PERK, IP3R, and mitochondrial permeability transition pore (mPTP).
Main Results:
- 15d-PMJ2-induced cell death was dependent on the ER stress protein PERK.
- PERK activation led to Ca2+ release via an IP3R-sensitive pathway, causing mitochondrial Ca2+ overload.
- Mitochondrial Ca2+ overload resulted in mPTP opening, impaired mitochondrial respiration, and cell death, requiring the electrophilic cyclopentenone ring of 15d-PMJ2.
Conclusions:
- The PERK/IP3R/mPTP signaling axis is a critical mechanism mediating the antitumor effects of 15d-PMJ2.
- 15d-PMJ2 exhibits chemotherapeutic potential by targeting essential cellular stress and death pathways in melanoma.
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