Tumor M2-PK: A novel urine marker of bladder cancer

Abstract

Purpose Bladder cancer is a “Warburg-like” tumor characterized by a reliance on aerobic glycolysis and expression of pyruvate kinase M2 (PKM2). PKM2 oscillates between an active tetramer and an inactive dimer. We aim to further characterize PKM2, in particular PKM2 dimer, as a urinary biomarker of bladder cancer and a potential target for treatment. Methods HTB-9, HTB-5, and UM-UC3 bladder cancer cells were assessed for proliferation under differential glucose levels using the hexosaminidase assay. Western blot and Blue-native analysis was performed for protein expression of PKM2. Shikonin, an herb that is known to bind and inhibit PKM2, was utilized to determine if PKM2 has a role in glucose usage and cellular proliferation in bladder cancer cells by caspase activity assay. Institutional review board approval was obtained to collect healthy control and bladder cancer patient urine samples. The ScheBo M2-PK EDTA Plasma Test was performed on urine samples to assess urine Tumor M2-PK values. Results The three bladder cancer cell lines tested all demonstrate statistically significant increases in proliferation when exposed to higher level of glucose (200mg/dL). Similarly, low doses of glucose (25mg/dL) result in reduced proliferation. Increased cell growth in higher glucose concentration correlated with up-regulation of PKM2 protein expression. Shikonin, a PKM2 inhibitor, reduced cell proliferation and switched PKM2 isoforms from the dimer to tetramer. Lastly, dimer PKM2 (Tumor-M2PK) levels were assessed in the urine samples from bladder cancer (Bca) patients and healthy controls. Tumor M2-PK significantly correlated with the presence of BCa in our subjects. Conclusions Our studies demonstrate the potential of PKM2, specifically the dimer (Tumor-M2PK) as a target of drug therapy and as a urinary marker for bladder cancer.

Alteration in glycolytic/cholesterogenic gene expression is associated with bladder cancer prognosis and immune cell infiltration

“…Studies have shown that glycolysis is closely related to BCa development. For instance, upregulation of pyruvate kinase M2 is closely related to tumor growth and chemo-resistance and serves as a potential tumor marker for BCa monitoring [ 27 , 28 ]. Lactic acid dehydrogenase (LDHA) is a key enzyme in glycolysis and its upregulation in BCa promotes glycolysis, thereby facilitating tumor growth and immune evasion [ 29 , 30 ].…”

Evaluation of pyruvate kinase M2 (PKM2) and epidermal growth factor receptor (EGFR) expression and their clinicopathologic significance in bladder urothelial carcinoma

“…Similarly, Zhou et al (2016) demonstrated that PKM2 is strongly expressed in urothelial carcinoma compared to adjacent normal tissue using both western blot and immunohistochemistry. Liu et al (2019) demonstrated that PKM2 levels in urine samples were substantially elevated in most patients with BCa. This indicates the association between the abnormal expression of PKM2 and BCa.…”

Natural products as a means of overcoming cisplatin chemoresistance in bladder cancer

“…Mechanisms delineated in other cancers indicate this is likely due to increased production of ROS by damaged mitochondria that are forced to use mitochondrial metabolism to generate the necessary biological intermediates [ 57 , 58 , 61 ] . Natural products targeting these enzymes have been discovered, and may serve as a source of chemotypes that can be further improved for targeting the Warburg Effect and overcoming cisplatin chemoresistance [ 57 , 62 ] .…”

“…Shikonin and its enantiomer alkannin are napthoquinones derived from Lithospermum erythrorhizon in addition to some Alkanna plant species with noted anti-cancer activity [ 59 ] . Shikonin has direct anti-apoptotic activity in BCa cells and in xenograft tumor models and synergizes with cisplatin [ 59 , 62 ] . The mechanism appears to be through inhibition of PKM2 [ 59 ] .…”