Cytotoxic and Antiproliferative Effects of Chlorella vulgaris Lectin on Colon Cancer Cells

Background/Objectives: Colon cancer is the third most common type of cancer in the world, characterized by a high risk of metastasis, resistance to various drugs, and late diagnosis. In addition, the drugs used for treatment are associated with serious neurological damage, causing acute and chronic pain and compromising the patient’s quality of life. Meanwhile, lectins are proteins capable of exerting cytotoxic action on cells from various tumors in a selective manner, without exerting significant toxicity on healthy cells. Despite this, studies on the potential of lectins obtained from microalgae are still scarce in the literature. In this sense, the objective of this study was to evaluate the antitumor activity of lectin isolated from the microalgae Chlorella vulgaris (CvL) on colorectal cancer cells, HT-29. Methods: The purified lectin was tested for cytotoxicity using MTT colorimetric methods, in addition to clonogenicity, cell cycle, apoptosis, and necrosis tests, analyzed by flow cytometry. Results: The assays demonstrated that the lectin was able to induce cell death in the HT-29 tumor line by approximately 83.75% with an IC50 value of 21.5 µg/mL−1, reduced colony formation by more than 90%, was able to regulate the cell cycle by apoptosis, and did not present significant necrosis. These results show that microalgae lectins have the potential to be exploited in the control of neoplastic cells.