10-Hydroxycamptothecin induces apoptosis in human neuroblastoma SMS-KCNR cells through p53, cytochrome c and caspase
Abstract:
Neuroblastoma (NB), the most common extracranial solid tumor in childhood, remains one of the most challenging types of cancer to treat. Therefore, the search for novel effective drugs for its treatment is essential. The present study used 10-hydroxycamptothecin (HCPT), which is a naturally occurring alkaloid anticancer agent extracted from the Chinese tree, Camptotheca acuminata, and has a strong anticancer activity in vitro and in vivo. HCPT is able to induce apoptosis in cells of various tumor types. However, few studies have been conducted on its efficacy in NB, and its apoptosis-inducing mechanism has not been elucidated. In the present study, the in vitro effects of HCPT on apoptosis in the human NB cell line, SMS-KCNR, and its underlying molecular mechanisms were investigated. Cell proliferation was measured by an MTT assay and apoptosis was measured using DAPI staining and flow cytometric analysis. In addition, western blot analysis was used to evaluate the apoptosis-associated signaling pathways. HCPT was observed to markedly inhibit cell proliferation and induce apoptosis in SMS-KCNR cells at a relatively low concentration (2.5-20 nM). DAPI staining revealed typical apoptotic feature, namely apoptotic body formation. The flow cytometric analysis revealed that the number of apoptotic cells increased from 20.89% (for 2.5 nM) to 97.66% (for 20 nM) following HCPT treatment for 48 h. Western blot analysis revealed that p53, cytoplasmic cytochrome c, cleaved caspase-3 and poly ADP-ribose polymerase (PARP) proteins were significantly upregulated, while the mitochondrial cytochrome c and pro-caspase-3 proteins were downregulated. However, the B-cell lymphoma 2 and Bcl-2-associated X proteins were unaffected. The results indicated that HCPT may inhibit proliferation and induce apoptosis in the SMS-KCNR cells. The possible mechanism of apoptosis induction is the p53-mediated mitochondrial apoptotic signaling pathway, which promotes cytochrome c release and induces apoptosis by activating caspase-3 and PARP. Our study provides experimental evidence for HCPT as a potent therapeutic drug in NB treatment.
Insights
10-hydroxycamptothecin (HCPT) effectively inhibits neuroblastoma (NB) cell growth and induces apoptosis. The study reveals HCPT activates the p53-mediated mitochondrial pathway, offering a promising new therapeutic strategy for this challenging childhood cancer.
Area of Science:
- Oncology
- Pharmacology
- Molecular Biology
Background:
- Neuroblastoma (NB) is a prevalent and challenging childhood extracranial solid tumor.
- Novel therapeutic agents are crucial for improving NB treatment outcomes.
- 10-hydroxycamptothecin (HCPT), a natural alkaloid, exhibits potent anticancer activity but its efficacy and mechanism in NB are underexplored.
Purpose of the Study:
- To investigate the in vitro effects of HCPT on the human NB cell line, SMS-KCNR.
- To elucidate the molecular mechanisms underlying HCPT-induced apoptosis in NB cells.
Main Methods:
- Cell proliferation assessed via MTT assay.
- Apoptosis evaluated using DAPI staining and flow cytometry.
- Apoptosis-associated signaling pathways analyzed by Western blot.
Main Results:
- HCPT significantly inhibited SMS-KCNR cell proliferation and induced apoptosis in a dose-dependent manner (2.5-20 nM).
- Apoptotic features including body formation were observed; apoptotic cell count increased from 20.89% to 97.66%.
- Western blot analysis showed upregulation of p53, cytoplasmic cytochrome c, cleaved caspase-3, and PARP, with downregulation of mitochondrial cytochrome c and pro-caspase-3.
Conclusions:
- HCPT demonstrates potent anti-proliferative and apoptosis-inducing effects on human neuroblastoma cells.
- The mechanism involves the p53-mediated mitochondrial apoptotic pathway, leading to caspase activation and PARP cleavage.
- HCPT shows promise as a potential therapeutic agent for neuroblastoma treatment.
