Antitumor Effect of Shikonin, a PKM2 Inhibitor, in Cholangiocarcinoma Cell Lines

Abstract

Background/Aim: Pyruvate kinase M2 (PKM2) is an enzyme that is predominantly overexpressed in various types of cancer. The role of PKM2 in liver fluke-associated cholangiocarcinoma (CCA) remains unclear. This study aimed to investigate the antitumor activity of shikonin, a PKM2 inhibitor, in CCA cells. Materials and Methods: Immunohistochemistry and immunoblotting were used to determine PKM2 expression in CCA tissues and cells. Antiproliferative effects of shikonin were evaluated using 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide, colony-formation and trypan blue exclusion assays. The antimetastatic activity of shikonin was determined using the Boyden chamber assay. Mechanisms by which shikonin inhibited CCA progression were determined. Results: PKM2 was overexpressed in CCA compared to normal bile duct epithelial cells. Shikonin significantly inhibited growth, and migration of CCA cells while inducing their death. A mechanistic study revealed that antitumor effects of shikonin in CCA cells depended on increased production of reactive oxygen species. Conclusion: Shikonin may be a novel therapeutic agent for patients with CCA. Cholangiocarcinoma (CCA) is an aggressive malignancy which originates from bile duct epithelia. The highest incidence and mortality rate of CCA was found in Southeast Asian countries, especially in northeastern Thailand (1). Recent epidemiological studies indicated that the incidence of CCA is different according to geographical risk factors and genetic backgrounds. Thamavit et al. showed that the infection with liver fluke, namely Opisthorchis viverrini (OV), is strongly associated with CCA development in Thailand, an area in which OV is endemic (2). Most patients with CCA present with an advanced stage of the disease, leading to a late diagnosis, poor prognosis and a short survival (3). Although surgical resection has remained a good choice for CCA therapy, only a very small number of cases can be operated on and this results in a high recurrence. At present, few neoadjuvant or adjuvant treatments for CCA are available as treatment options for patients with unresectable CCA or for after surgery. Chemoresistance and tumor relapse are still high in patients with CCA (4). Therefore, a new effective therapeutic agent for CCA is needed. Metabolic reprogramming, first described by Hanahan and Weinberg, is a cancer hallmark (5). Most cancer cells prefer to use aerobic glycolysis than mitochondrial metabolism; this is known as the Warburg effect. Up-regulation of glycolytic enzymes have been reported in several cancer types including CCA, suggesting that these enzymes are potential targets for diagnosis and therapy of cancer (6). Pyruvate kinase M2 (PKM2), a key enzyme in the glycolytic pathway, is an isomeric form of pyruvate kinase, occurring in four isoforms: R, L, M1, and M2. PKM2 exhibits two major states, one is a highly active state in the tetrameric form and the other is the less active state in the dimeric form (7). Dimeric PKM2 facilitates the production of glycolytic int...

Docking and ADMET studies for investigating the anticancer potency of Moscatilin on APC10/DOC1 and PKM2 against five clinical drugs

“…Resveratrol influenced the biochemical pathways of Cancer, which aligns with various studies proposed elsewhere [29]. The inhibitory function of Shikonin on PKM2 has been well established through various wet-lab experiments, and the same is also confirmed through the in silico data obtained in the present study [30]. Moscatilin exhibited dual function by affecting the cancer cells exclusively, creating instabilities both in biochemical (glycolytic) and molecular (anaphase separation of chromosomes) cascades.…”

Role of PKM2-Mediated Immunometabolic Reprogramming on Development of Cytokine Storm

“…inhibitor in cancer cells and macrophages (4,36). Studies have reported that SKN inhibits cell proliferation and cell migration, and induces apoptosis partially through the PKM2 related pathways (37)(38)(39)(40). However, the SKN can affect proliferation in a PKM2-independent manner, since its use may not be entirely related to PKM2 inhibition.…”

Cordycepin Sensitizes Cholangiocarcinoma Cells to Be Killed by Natural Killer-92 (NK-92) Cells

“…KKU-100 exhibits the features of poorly-differentiated hilar CCA and was sourced from a 65-year-old female donor with less invasive CCA than that of the KKU-213A [ 27 ]. The other, the poorly differentiated KKU-055, was sourced from a 56-year-old male donor [ 28 ]. Interestingly, the substantial differences of gene expression levels were previously reported among these CCAs, and they have been proposed as the major cause of unsuccessful CCA therapy [ 29 ].…”