The BLMH Knockout HT29 Polyclonal Cells represent a CRISPR/Cas9-edited polyclonal cell population derived from the HT29 human colon adenocarcinoma cell line. This product features a targeted disruption of the BLMH gene, which encodes bleomycin hydrolase. The polyclonal nature ensures genetic heterogeneity among the edited cells, providing a robust and representative model for studying gene loss-of-function effects without the confounding factors of single-cell clonal selection.
The HT29 cell line is a well-characterized model of colorectal cancer, originally isolated from a primary human colon adenocarcinoma. These epithelial cells retain key features of intestinal epithelium, including barrier formation and secretory function, and they harbor a mutant p53 tumor suppressor gene. This genetic background mimics common molecular alterations in colorectal tumors and makes HT29 cells ideal for investigating drug resistance mechanisms, tumor progression, and therapeutic interventions.
BLMH functions as a cytosolic cysteine protease that hydrolytically inactivates bleomycin, a glycopeptide antibiotic used in cancer chemotherapy. By cleaving bleomycin, BLMH reduces the drug??s ability to induce DNA double-strand breaks, thereby attenuating downstream activation of ATM kinase and p53-mediated DNA damage signaling. This activity is a major determinant of bleomycin resistance in tumors. In addition, BLMH converts homocysteine-thiolactone to homocysteine, a metabolite involved in methylation reactions and redox regulation. Transcriptional control of BLMH is exerted by the SP1 transcription factor, while its enzymatic activity is inhibited by cystatin C. Thus, BLMH integrates drug detoxification, oxidative stress response, and genomic stability pathways.
Within the HT29 cell context, which possesses mutant p53, the DNA damage response is already compromised, making these cells reliant on alternative survival mechanisms such as BLMH-mediated bleomycin detoxification. CRISPR/Cas9-mediated knockout of BLMH is predicted to restore sensitivity to genotoxic agents by permitting accumulation of unrepaired DNA lesions that activate ATM-driven, p53-independent cell death pathways. Simultaneously, disruption of homocysteine metabolism may impair cellular methylation potential and increase susceptibility to oxidative stress, providing a platform to study metabolic contributions to colorectal cancer progression and neurodegeneration. This model is therefore valuable for dissecting the dual roles of BLMH in chemoresistance and metabolic homeostasis.
Researchers can utilize these polyclonal knockout cells in a variety of functional assays to explore BLMH biology. Standard applications include determination of bleomycin sensitivity through IC50 dose-response curves and clonogenic survival assays, as well as assessment of DNA damage by ??-H2AX immunofluorescence. Homocysteine-thiolactone hydrolase activity can be measured to confirm enzymatic loss. Knockout efficiency and downstream pathway alterations are evaluated by Western blotting and RT-qPCR. Apoptosis induction and cell cycle profiles can be analyzed via Annexin V staining and flow cytometry. Moreover, the cells serve as a screening tool for small-molecule BLMH inhibitors aimed at enhancing chemotherapeutic efficacy. For further information, please contact Ascent Research.
