From Flu to Foe: Repurposing Tamiflu as a Novel Liver Cancer Treatment

Exploring the scientific evidence for antiviral drug oseltamivir's unexpected potential against hepatocellular carcinoma

Drug Repurposing Liver Cancer Oseltamivir

Introduction: An Unexpected Ally in the Fight Against Cancer

Liver cancer stands as one of the most formidable challenges in modern oncology. As a leading cause of cancer-related mortality worldwide, it claims hundreds of thousands of lives each year, with its incidence steadily rising. Hepatocellular carcinoma (HCC), which accounts for approximately 90% of all primary liver cancer cases, is particularly aggressive and often diagnosed at advanced stages when treatment options are limited 1 .

Liver Cancer Burden

HCC accounts for approximately 90% of primary liver cancer cases and represents a significant global health challenge with limited treatment options at advanced stages.

Drug Repurposing Advantage

The established safety profile and known pharmacokinetics of oseltamivir offer potential for accelerated clinical implementation compared to novel drug compounds.

A New Role for an Old Drug: The Science Behind the Switch

Oseltamivir has long been recognized as a neuraminidase inhibitor, effectively preventing influenza viruses from replicating and spreading within the body. However, the discovery of its potential anti-cancer properties emerged from a fascinating scientific connection: the NEU1 enzyme, a specific type of neuraminidase found in human cells, appears to play a significant role in cancer progression 2 6 .

Oseltamivir's Dual Mechanism

Anti-viral Action

Inhibits influenza neuraminidase

Anti-cancer Action

Inhibits human NEU1 enzyme
Key Insight

NEU1 enzyme is significantly elevated in liver cancer cells and correlates with poor prognosis, making it an attractive therapeutic target 2 6 .

A Key Experiment: The First Evidence Emerges

In 2021, a pivotal study conducted by Huang and colleagues provided the first systematic evidence of oseltamivir's activity against liver cancer 1 5 . This comprehensive investigation employed a multi-faceted approach to validate the drug's effects across various experimental models.

Cell Viability Assessment

Researchers treated liver cancer cell lines (Huh-7 and HepG2) with varying concentrations of oseltamivir and measured cell survival using MTT assays 1 .

Migration and Invasion Testing

Wound healing assays and Transwell experiments examined oseltamivir's impact on cancer cell movement and invasion capabilities 1 .

Cell Death Mechanisms

Flow cytometry and immunoblotting techniques investigated whether oseltamivir triggered apoptosis, autophagy, or both in cancer cells 1 .

In Vivo Validation

Xenograft animal models with human liver cancer cells were treated with oseltamivir to confirm effects in living organisms 1 .

Experimental Results

Cell Viability Impact
Cell Death Mechanisms
Cell Line Primary Death Mechanism Key Molecular Markers Secondary Mechanisms
Huh-7 Autophagy ↑LC3-II/LC3-I ratio, ↑Beclin-1, ↓p62 Minimal apoptosis
HepG2 Apoptosis & Autophagy ↑Apaf-1, ↑cleaved caspase-3, ↑cleaved PARP-1, ↑LC3-II/LC3-I Combined pathway activation

The Scientist's Toolkit: Essential Research Reagents

The investigation into oseltamivir's anti-cancer properties relies on a specific set of research tools and materials that enable precise evaluation of its effects on cancer cells.

Cell Lines

Model systems for studying cancer behavior including Huh-7, HepG2, MHCC97H (cancer) vs. THLE-3, LO2 (normal) 1 2 .

Viability Assays

Measure cell survival after drug treatment using MTT assay, CCK-8 assay 1 2 .

Migration/Invasion Tests

Evaluate cancer cell spread potential through wound healing assay, Transwell assay with Matrigel 1 2 .

Molecular Analysis

Detect protein expression and cell death markers using immunoblotting, flow cytometry, immunofluorescence 1 6 .

The Mechanism Unveiled: How Oseltamivir Fights Liver Cancer

Following the initial discovery of oseltamivir's anti-liver cancer activity, subsequent research has delved deeper into the molecular mechanisms behind these effects. A 2025 study published in Frontiers in Pharmacology provided crucial insights into how oseltamivir disrupts cancer cell function by targeting NEU1 and impacting lipid metabolism 2 6 .

"Oseltamivir, by inhibiting NEU1, promotes a process called lipophagy—a specific type of autophagy that breaks down lipid droplets within cells." 2

Oseltamivir's Dual Mechanism of Action
NEU1 Inhibition

Disrupts signaling pathways that promote cancer aggressiveness

Lipophagy Induction

Depletes lipid resources that cancer cells depend on for survival

Therapeutic Advantage

Liver cancer cells may be more sensitive to oseltamivir than to some conventional chemotherapeutic agents with potentially reduced drug resistance 2 .

A Balanced View: Safety Considerations

When considering repurposing any drug, understanding its safety profile is paramount. Oseltamivir has been used for decades in influenza treatment, with generally favorable safety data. However, a 2025 analysis of the FDA Adverse Event Reporting System did identify hepatotoxicity (liver damage) as a potential concern 7 .

Safety Considerations
  • Hepatotoxicity identified as potential concern 7
  • Median time to hepatotoxic events: less than five days 7
  • Male individuals showed higher susceptibility than female individuals 7
  • Children under 18 years had the fewest reports 7
Positive Safety Findings
  • Generally favorable safety data from decades of use
  • Reduced risk of serious neuropsychiatric events compared to untreated influenza 3
  • Hepatic adverse events relatively uncommon
  • Established safety profile facilitates repurposing
Clinical Implications

These findings highlight the importance of careful patient selection and monitoring if oseltamivir were to be deployed as a cancer therapeutic, particularly with regular liver function tests to detect any potential toxicity early.

The Road Ahead: From Laboratory to Clinic

The journey from laboratory discovery to clinical application is typically long and complex, and oseltamivir's potential repurposing for liver cancer treatment is still in its early stages. While the preclinical data from multiple studies is compelling, definitive clinical trials in human patients with liver cancer have not yet been conducted.

Clinical Trials Needed

Definitive studies in human patients with liver cancer to establish efficacy and optimal dosing.

Biomarker Development

Identification of responsive tumor types based on molecular characteristics.

Combination Therapy

Potential to enhance effectiveness of other chemotherapy drugs in combination regimens.

Conclusion: A Promising Path Forward

The investigation into oseltamivir's potential against liver cancer represents a fascinating case study in scientific serendipity and drug repurposing. What began as a treatment for influenza has revealed unexpected potential against one of oncology's most challenging diseases. The compelling laboratory evidence, demonstrating multiple mechanisms of action including NEU1 inhibition and lipophagy induction, provides a solid foundation for further exploration.

References