Lotus Alkaloid Liensinine Rewires HCC Metabolism to Boost Immunotherapy
Liensinine shifts liver cancer cells from glycolysis to oxidative phosphorylation via AMPK-HIF-1α, reshaping the tumor immune microenvironment.
Summary
Liensinine, a natural alkaloid from lotus seeds, potently inhibits hepatocellular carcinoma (HCC) by reprogramming tumor metabolism from aerobic glycolysis to oxidative phosphorylation through activation of the AMPK-HIF-1α axis. This metabolic shift triggers ER stress, increases reactive oxygen species, reduces PD-L1 expression, promotes M1 macrophage polarization, and enhances CD8+ T cell infiltration into tumors. In both subcutaneous xenograft and orthotopic liver cancer mouse models, Liensinine suppressed tumor growth and reduced vascular density. When combined with radiotherapy and anti-PD-L1 immunotherapy, synergistic tumor suppression was observed, suggesting Liensinine as a promising adjunct to existing HCC treatment strategies.
Detailed Summary
Hepatocellular carcinoma (HCC) remains one of the deadliest cancers globally, with limited effective options at advanced stages. Tumor cells in HCC characteristically exploit aerobic glycolysis (the Warburg effect) to fuel rapid growth while simultaneously creating an immunosuppressive tumor microenvironment (TME). Reversing this metabolic phenotype is an attractive therapeutic strategy, and natural compounds offer a largely untapped resource for such interventions.
This study investigated Liensinine, a bisbenzylisoquinoline alkaloid derived from Nelumbo nucifera (lotus seed embryo), as a candidate metabolic and immune modulator in HCC. In vitro, treatment of HUH7 and Hep1-6 HCC cell lines with Liensinine (30–40 µM) produced dose-dependent reductions in cell viability (CCK-8), colony formation, proliferation (EdU assay), and migration (Transwell assay), while significantly increasing apoptosis (Annexin V/PI flow cytometry).
RNA sequencing of Liensinine-treated HUH7 cells identified 4,007 differentially expressed genes. Gene Set Enrichment Analysis (GSEA) showed strong upregulation of the AMPK signaling pathway alongside suppression of glycolysis-related pathways and VEGF signaling. Seahorse metabolic assays confirmed that Liensinine decreased extracellular acidification rates (ECAR, a glycolysis readout) while increasing oxygen consumption rates (OCR, reflecting oxidative phosphorylation). Mechanistically, Liensinine activated AMPK, which in turn suppressed HIF-1α—a master transcriptional regulator of glycolytic gene expression. Liensinine also induced endoplasmic reticulum (ER) stress, evidenced by elevated CHOP and ATF4 levels, which contributed to AMPK activation and further HIF-1α downregulation. Elevated reactive oxygen species (ROS) production was also observed, consistent with the metabolic shift toward mitochondrial respiration.
From an immunological perspective, Liensinine reduced PD-L1 expression on HCC cells, promoted M1 macrophage polarization (using THP-1-derived macrophages and conditioned media experiments), and enhanced CD8+ T cell infiltration in vivo. In tube formation assays, Liensinine-conditioned media suppressed HUVEC angiogenic activity, consistent with the VEGF pathway downregulation seen in RNA-seq. In vivo subcutaneous xenograft (nude mice, Huh7) and orthotopic liver cancer (C57BL/6, Hep1-6-Luc, monitored by bioluminescence and MRI) models confirmed significant tumor growth suppression and reduced vascular density with Liensinine (20 mg/kg IP daily). In the orthotopic model, combining Liensinine with radiotherapy (4 Gy on days 0 and 4) and anti-PD-L1 immunotherapy (100 µg IP on days 3 and 5) produced synergistic tumor suppression with enhanced immune cell infiltration and apoptosis compared to any single modality.
These findings position Liensinine as a multi-target natural compound capable of simultaneously attacking HCC metabolic dependencies and reversing immunosuppression in the TME. Its ability to synergize with existing immunotherapy and radiotherapy regimens makes it an attractive candidate for further translational development, though clinical validation will be essential.
Key Findings
- Liensinine activates AMPK and suppresses HIF-1α, shifting HCC cells from glycolysis to oxidative phosphorylation.
- ER stress induction (elevated CHOP and ATF4) contributes to AMPK activation and metabolic reprogramming.
- Liensinine reduces PD-L1 expression and promotes M1 macrophage polarization and CD8+ T cell tumor infiltration.
- In orthotopic HCC mouse models, Liensinine combined with radiotherapy and anti-PD-L1 produced synergistic tumor suppression.
- Liensinine suppresses VEGF signaling and angiogenesis in vitro and reduces vascular density in vivo.
Methodology
In vitro studies used HUH7 and Hep1-6 HCC cell lines with CCK-8, Annexin V/PI, EdU, Transwell, Seahorse metabolic assays, and RNA-seq with GSEA. In vivo efficacy was assessed in subcutaneous xenograft (nude mice) and orthotopic luciferase-expressing HCC models (C57BL/6 mice) monitored by bioluminescence imaging and MRI, including a tri-modal combination arm with radiotherapy and anti-PD-L1 antibody.
Study Limitations
All in vivo experiments relied on rodent models that incompletely recapitulate human HCC biology and the complexity of human immune responses. Pharmacokinetics, bioavailability, and toxicity of Liensinine in humans have not been characterized. The optimal dosing schedule and potential off-target effects of combining Liensinine with radiotherapy and immunotherapy require further preclinical and clinical investigation.
Enjoyed this summary?
Get the latest longevity research delivered to your inbox every week.