Many disease states share a central pathophysiological mechanism, with the protein galectin-3 (Gal-3) as a primary regulator. Gal-3 is a β-galactoside–binding lectin that functions both as a pro-inflammatory mediator and a clinically relevant biomarker, with elevated levels observed in cardiovascular disease, cancer, and fibrotic disorders. While Gal-3 plays a beneficial role in normal tissue repair and immune responses, its persistent overexpression contributes to pathological inflammation, fibrosis, and tumor progression.
In cancer, Gal-3 supports tumor cell survival, immune evasion, angiogenesis, extracellular matrix remodeling, and metastatic spread. As a result, Gal-3 has gained attention as a promising therapeutic target. Preclinical studies demonstrate that experimental Gal-3 inhibitors exhibit anti-cancer and anti-metastatic activity in vitro and in animal models.
Targeted inhibition of Gal-3 using natural compounds such as modified citrus pectin (MCP), a bioactive polysaccharide derived from citrus fruit peels, offers a multi-mechanistic approach to modulating cancer progression and systemic inflammation.
The Studies
Research on the use of MCP in cancer treatment is most developed in prostate cancer, where clinical trials are being conducted. While studies on MCP’s role in other types of cancer are still in earlier stages, emerging evidence suggests encouraging potential.
Treatment options for non-metastatic biochemically relapsed prostate cancer after local therapy are minimal, warranting the need for interventions. Without active therapy, 80% of patients progress within 6 months. In a phase 2 clinical trial, researchers studied patients with rising prostate specific antigen (PSA) levels after initial treatment, but no visible spread. Thirty-nine patients were given 4.8 g MCP three times daily. After 18 months of treatment:
- 90% had PSA doubling time (PSADT) improvement (lengthening); PSADT is the most important clinical prognostic factor associated with the development of future metastasis
- 62% had decreased/stable PSA levels
- All had negative scans
- There were no serious side effects, with bloating as the main symptom
These results are encouraging, considering the limited treatment options in this patient population. Larger cohorts and placebo-controlled studies are needed to confirm these beneficial results.
MCP has been studied both in vitro and in vivo across multiple cancer types, including prostate, breast, ovarian, colon, bladder, gastrointestinal, liver, and melanoma. A review of several preclinical studies reveals how MCP works at multiple checkpoints to arrest the metastatic cascade:
- Gal-3 protects cancer cells from apoptosis, whereas MCP normalizes the cell cycle, inducing apoptosis.
- Gal-3 mediates metastatic cell adhesion to the endothelium, whereas MCP inhibits this process.
- Gal-3 mediates tumor cell interactions with extracellular matrix proteins (ECM) associated with the basement membrane and target organ stroma, facilitating continued metastatic growth. MCP reduces these interactions, decreasing tumor invasion.
- Gal-3 promotes angiogenesis by acting as a chemoattractant for endothelial cells, and MCP blocks this process.
Preclinical studies have also shown that MCP improves the sensitivity of cancer cells to several chemotherapy drugs, which has the potential to improve treatment efficacy.
Conclusions
MCP has demonstrated significant anticancer activity in vitro, in animal studies, and in clinical studies. Beyond its anticancer properties, MCP is shown to improve metal detoxification, immune function, cardiovascular function, and reduce fibrosis to the kidney, liver, and adipose tissue. Together, this body of evidence positions MCP as a promising, multi-targeted intervention with applications in oncology and chronic disease management.
