Glioblastoma

Aspirin is unusually interesting in glioblastoma.

This is not because it has strong clinical trial evidence. It does not. The reason is different. Glioblastoma exposes several aspirin-sensitive vulnerabilities at once, including cancer stem cells, temozolomide resistance, angiogenesis, and Wnt / β-catenin signalling.

The whole field still runs into one hard limit: blood-brain barrier penetration. That is the main reason this page remains largely preclinical. Even so, the mechanism work is deep enough that glioblastoma deserves its own place in the aspirin section. Read the stem-cell paper

Overview

Glioblastoma multiforme, or GBM, is the most aggressive primary brain tumour in adults.

Despite surgery, radiotherapy, and temozolomide, recurrence is almost universal. A major reason is the persistence of glioblastoma stem cells, or GSCs, which are more resistant to treatment and can repopulate the tumour after therapy.

Aspirin is relevant here because it appears to hit several of these recurrence pathways directly. It has shown anti-stem-cell effects, sensitisation to temozolomide and bevacizumab, and suppression of glioblastoma proliferation and invasion through more than one pathway. Read the angiogenesis paper

Key human data

Prevention and epidemiology

This is the only part of the glioblastoma story with a real human population signal.

• AACR 2016 report: Regular aspirin use was associated with about 34% lower glioma risk, with a duration-response pattern. Read the coverage

• Secondary analysis of cardiovascular trials: Long-term low-dose aspirin was associated with lower risk of death from primary brain tumours within the first 10 years of use, with a reported HR of 0.31. Read the paper

These findings are important, but they are not enough to support aspirin as a glioma-prevention standard.

They are best read as supportive epidemiology rather than settled practice.

Post-diagnosis data

This remains the weak area.

There is no human randomised adjuvant trial showing that standard oral aspirin improves survival in glioblastoma. The clinically interesting work is still mechanistic and preclinical.

Mechanistic relevance

Cancer stem-cell targeting

This is one of the strongest reasons the page matters.

Aspirin has shown direct effects on glioblastoma stem cells. In these models, aspirin induced G1 cell-cycle arrest and increased p21 and p27, while reducing Cyclin D1 and Rb1 phosphorylation. Read the stem-cell paper

More importantly, aspirin suppressed several core stem-cell maintenance proteins at the same time:

• Notch1

• Sox2

• Stat3

• Survivin

That combination matters because these proteins help maintain self-renewal, recurrence risk, and treatment resistance in GBM.

The study also suggested this effect was at least partly COX-independent, because adding back PGE2 did not reverse it. Read the stem-cell paper

Temozolomide sensitisation through SHH / GLI1

This is the second major glioblastoma-specific aspirin mechanism.

Acquired temozolomide resistance in glioma is often linked to abnormal Sonic Hedgehog / GLI1 activation. Aspirin has been shown to inhibit this pathway and disrupt the NF-κB–GLI1–ATM loop that helps glioma cells survive DNA damage and repair double-strand breaks after temozolomide exposure. Read the Aging paper

That matters because it is not just another anti-inflammatory effect. It is a resistance-pathway effect that fits the actual treatment pressure GBM patients face.

In cell-line and mouse-model work, combining aspirin with temozolomide produced more tumour-cell death than either treatment alone. Read the Aging paper

Angiogenesis inhibition and bevacizumab sensitisation

GBM is one of the most vascular tumours in oncology.

That makes angiogenesis central to survival and progression. Aspirin has shown anti-angiogenic effects in glioblastoma endothelial cells and has sensitised these cells to temozolomide and bevacizumab in preclinical models. Read the paper

This gives aspirin a plausible place in anti-vascular strategy, even though it remains unproven clinically.

The broader angiogenesis relevance of GBM has been recognised for years. Read the Lancet Neurology article

Wnt / β-catenin suppression

Aspirin has also shown activity against β-catenin / TCF signalling in glioblastoma cell lines.

In U87 and A172 models, it reduced β-catenin-driven transcription and lowered downstream targets such as c-myc, Cyclin D1, and fra-1. That was accompanied by lower proliferation, lower invasion, and more apoptosis. Read the paper

This is interesting because it links glioblastoma to one of aspirin's better-known pathway effects in gastrointestinal cancers, but now in a brain-tumour context.

The blood-brain barrier problem

This is the main reason aspirin is not already a meaningful glioblastoma drug discussion.

Standard oral aspirin has limited ability to reach brain tissue at concentrations likely to reproduce the stronger laboratory effects. The blood-brain barrier, or BBB, remains the central delivery problem. Read the coverage

That means the gap between mechanism and clinical use is larger here than in many other cancers.

A potential formulation solution

The most interesting attempt to solve this has been IP1867B, a soluble aspirin-based formulation designed to improve BBB penetration.

Early laboratory reports suggested that this formulation was substantially more effective than standard treatment combinations in brain-tumour models and damaged tumour cells without the same injury to surrounding healthy tissue. Read the Xtalks summary

This is still early-stage work.

It is not Phase 3 evidence. But it does show that aspirin delivery into brain tumours is not being ignored. It is an active development problem.

Clinical positioning

Why this matters despite being preclinical

Glioblastoma is a disease where standard survival remains poor and recurrence remains the rule.

That changes how preclinical evidence should be read. It does not lower the evidence bar. But it does make mechanistically rich work more worth tracking, especially when it targets the actual failure points of standard care.

Aspirin is not interesting in GBM because it is cheap or familiar.

It is interesting because it appears to hit:

• glioblastoma stem cells

• temozolomide resistance

• angiogenesis

• Wnt / β-catenin signalling

• possibly BBB-optimized formulation development

That is more mechanistic depth than many repurposed agents ever get in this disease.

Practical interpretation

This is not yet a page that supports routine aspirin use in people who already have glioblastoma.

The most useful clinical questions are:

1. Is the discussion about prevention epidemiology, or about post-diagnosis GBM biology?

2. Is there interest in temozolomide resistance, stem-cell persistence, or anti-angiogenic strategy?

3. Is any aspirin discussion being confused with evidence for standard oral aspirin, when the real issue may be brain delivery?

4. Are there relevant trial registers or formulation programs, such as IP1867B, worth monitoring?

That keeps the page evidence-based and avoids overselling a fascinating but still early field.

References

• 2019 stem-cell paper — aspirin targets glioblastoma stem cells and suppresses Notch1, Sox2, Stat3, and Survivin. Read the paper

• 2017 Aging paper — aspirin inhibits SHH / GLI1 and sensitises glioma cells to temozolomide. Read the paper

• 2018 angiogenesis paper — aspirin inhibits glioblastoma endothelial-cell angiogenesis and sensitises to temozolomide and bevacizumab. Read the paper

• 2011 β-catenin paper — aspirin suppresses β-catenin / TCF signalling in GBM models. Read the paper

• AACR 2016 epidemiology signal — regular aspirin use and lower glioma risk. Read the coverage

• Secondary analysis of cardiovascular trials — lower primary-brain-tumour mortality in early long-term aspirin use. Read the paper

• BBB and formulation coverage — aspirin delivery challenges and IP1867B development. Read the coverage

• Early reporting on soluble aspirin formulation for glioblastoma. Read the Xtalks summary

• Background angiogenesis context in glioblastoma. Read the Lancet Neurology article

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