APS8 delays tumor growth in mice by inducing apoptosis of lung adenocarcinoma cells expressing high number of α7 nicotinic receptors

Berne, Sabina (author), Čemažar, Maja (author), Frangež, Robert (author), Juntes, Polona (author), Kranjc Brezar, Simona (author), Grandič, Marjana (author), Savarin, Monika (author), Turk, Tom (author)

The alkylpyridinium polymer APS8, a potent antagonist of α7 nicotinic acetylcholine receptors (nAChRs), selectively induces apoptosis in non-small cell lung cancer cells but not in normal lung fibroblasts. To explore the potential therapeutic value of APS8 for at least certain types of lung cancer, we determined its systemic and organ-specific toxicity in mice, evaluated its antitumor activity against adenocarcinoma xenograft models, and examined the in-vitro mechanisms of APS8 in terms of apoptosis, cytotoxicity, and viability. We also measured Ca$^{2+}$ influx into cells, and evaluated the effects of APS8 on Ca$^{2+}$ uptake while siRNA silencing of the gene for α7 nAChRs, CHRNA7. APS8 was not toxic to mice up to 5 mg/kg i.v., and no significant histological changes were observed in mice that survived APS8 treatment. Repetitive intratumoral injections of APS8 (4 mg/kg) significantly delayed growth of A549 cell tumors, and generally prevented regrowth of tumors, but were less effective in reducing growth of HT29 cell tumors. APS8 impaired the viability of A549 cells in a dose-dependent manner and induced apoptosis at micro molar concentrations. Nano molar APS8 caused minor cytotoxic effects, while cell lysis occurred at APS8 >3 µM. Furthermore, Ca$^{2+}$ uptake was significantly reduced in APS8-treated A549 cells. Observed differences in response to APS8 can be attributed to the number of α7 nAChRs expressed in these cells, with those with more AChRs (i.e., A549 cells) being more sensitive to nAChR antagonists like APS8. We conclude that α7 nAChR antagonists like APS8 have potential to be used as therapeutics for tumors expressing large numbers of α7 nAChRs.

• Language: English
• Keywords: lung cancer, antitumor activity, A549, HT29, CHRNA7, alkylpiridinium, SCID mice, toxicity, apoptosis, lung neoplasms, therapy, nicotinic receptors
• Work type: Article
• Typology: 1.01 - Original Scientific Article
• Organization: BF - Biotechnical Faculty; VF - Veterinary Faculty
• Publication status: Published
• Publication version: Version of Record
• Year: 2018
• Number of pages: 17 str.
• Numbering: Vol. 16, iss. 10, art. 367
• PID: 20.500.12556/RUL-132067
• UDC: 577.1
• ISSN on article: 1660-3397
• DOI: 10.3390/md16100367
• COBISS.SI-ID: 4683642
• Publication date in RUL: 11.10.2021

Record is a part of a journal

• Title: Marine drugs
• Shortened title: Mar. drugs
• Publisher: MDPI
• ISSN: 1660-3397
• COBISS.SI-ID: 23578841

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• License: CC BY 4.0, Creative Commons Attribution 4.0 International
• Link: http://creativecommons.org/licenses/by/4.0/
• Description: This is the standard Creative Commons license that gives others maximum freedom to do what they want with the work as long as they credit the author.
• Licensing start date: 03.10.2018