PKM2 & the Warburg Effect

The PKM2 story is the centre of the shikonin literature.

It is the main reason this compound appears across so many different cancer models.

What the Warburg effect means

Cancer cells often rely on aerobic glycolysis.

They convert glucose to lactate even when oxygen is available.

That looks inefficient.

It is actually useful for fast-growing tumours because it preserves carbon skeletons for nucleotide, amino-acid, and lipid synthesis.

Why PKM2 matters

Pyruvate kinase M2 helps control the final glycolytic step.

In tumours, PKM2 is also more than a metabolic enzyme.

Its dimeric form helps route glycolytic intermediates into biomass production and can support nuclear transcriptional programmes linked to survival.

That is why tumour cells favour it.

What shikonin does here

Shikonin inhibits PKM2 and reduces glycolytic throughput.

The main downstream effects include:

• less lactate production

• less ATP availability

• less anabolic support for proliferation

• weaker PKM2-linked transcriptional support in pathways such as STAT3 and ER-related signalling

This has been shown in breast, bladder, oesophageal, hepatocellular, and pancreatic models.

Why this is clinically relevant

PKM2 is attractive because it is much more tumour-linked than many broad metabolic targets.

That raises the hope of at least partial cancer-cell selectivity.

It also means the mechanism can travel across cancer types instead of staying locked inside one subtype.

The main limit

PKM2 inhibition alone does not solve cancer.

Tumours can shift metabolic routes.

That is why shikonin is most interesting when PKM2 inhibition sits beside apoptosis, necroptosis, endocrine disruption, or combination therapy.

Bottom line

If one mechanism explains why shikonin keeps reappearing in oncology papers, this is it.

PKM2 gives the compound a real unifying biology across cancer types.

Key references

Lv C et al. (2021). Shikonin inhibits ESCC tumour growth by suppressing PKM2-mediated aerobic glycolysis. Journal of Cancer.
https://www.jcancer.org/v12p4830.htm

Shikonin differentially regulates glucose metabolism via PKM2 and the Warburg Effect. Life Sciences (2021).
https://www.sciencedirect.com/science/article/abs/pii/S0024320520315496

Li Z et al. (2018). PKM2 in resistant cancer cells — necroptosis link. PMC.
https://pmc.ncbi.nlm.nih.gov/articles/PMC6231221/

Ahmad F et al. (2024). PKM2/metabolic findings across breast cancer subtypes. Journal of Pharmacy and Pharmacology.
https://academic.oup.com/jpp/article/76/8/967/7656703