Anti-Cancer and Immunomodulatory Activity of a Polyethylene Glycol-Betulinic Acid Conjugate on Pancreatic Cancer Cells

• Main Authors: Pascaline Nanga Fru, Ekene Emmanuel Nweke, Nompumelelo Mthimkhulu, Sindisiwe Mvango, Marietha Nel, Lynne Alison Pilcher, Mohammed Balogun
• Format: Article
• Language: English
• Published: MDPI AG 2021-05-01
• Series: Life
• Subjects: betulinic acid; polyethylene glycol; apoptosis; pancreatic cancer; polymer therapeutics
• Online Access: https://www.mdpi.com/2075-1729/11/6/462

Drug delivery systems involving polymer therapeutics enhance drug potency by improved solubility and specificity and may assist in circumventing chemoresistance in pancreatic cancer (PC). We compared the effectiveness of the naturally occurring drug, betulinic acid (BA), alone and in a polymer conjugate construct of polyethylene glycol (PEG), (PEG–BA), on PC cells (MIA PaCa-2), a normal cell line (Vero) and on peripheral blood mononuclear cells (PBMCs). PEG–BA, was tested for its effect on cell death, immunomodulation and chemoresistance-linked signalling pathways. The conjugate was significantly more toxic to PC cells (<i>p</i> < 0.001, IC₅₀ of 1.35 ± 0.11 µM) compared to BA (IC₅₀ of 12.70 ± 0.34 µM), with a selectivity index (SI) of 7.28 compared to 1.4 in Vero cells. Cytotoxicity was confirmed by increased apoptotic cell death. PEG–BA inhibited the production of IL-6 by 4–5.5 fold compared to BA-treated cells. Furthermore, PEG–BA treatment of MIA PaCa-2 cells resulted in the dysregulation of crucial chemoresistance genes such as <i>WNT3A</i>, <i>TXNRD1</i>, <i>SLC2A1</i> and <i>GATA3</i>. The dysregulation of chemoresistance-associated genes and the inhibition of cytokines such as IL-6 by the model polymer construct, PEG–BA, holds promise for further exploration in PC treatment.