Individualized leukemia cell-population profiles in common B-cell acute lymphoblastic leukemia patients / 癌症

Immunophenotype is critical for diagnosing common B-cell acute lymphoblastic leukemia (common ALL) and detecting minimal residual disease. We developed a protocol to explore the immunophenotypic profiles of common ALL based on the expression levels of the antigens associated with B lymphoid development, including IL-7Rα (CD127), cytoplasmic CD79a (cCD79a), CD19, VpreB (CD179a), and sIgM, which are successive and essential for progression of B cells along their developmental pathway. Analysis of the immunophenotypes of 48 common ALL cases showed that the immunophenotypic patterns were highly heterogeneous, with the leukemic cell population differing from case to case. Through the comprehensive analysis of immunophenotypic patterns, the profiles of patient-specific composite leukemia cell populations could provide detailed information helpful for the diagnosis, therapeutic monitoring, and individualized therapies for common ALL.

Effects of heterochromatin in colorectal cancer stem cells on radiosensitivity / 癌症

<p><b>BACKGROUND AND OBJECTIVE</b>Radiotherapy (RT) is a major non-surgical modality in the comprehensive treatment for colorectal adenocarcinoma. The radioresistance of cancer stem cells (CSCs) is a key factor that influences therapeutic effectiveness. This study was to investigate the effects of specific chromosome structure and histone modification in CSCs in colorectal adenocarcinoma radioresistance.</p><p><b>METHODS</b>Samples were collected from resected human colorectal adenocarcinomas. Subcutaneous colorectal cancer model was established in nude mice. Immunohistochemistry showed that xenografts generated from bulk colorectal cancer cells resembled the original tumor specimen. Flow cytometry was performed to sort CSCs (CD133+) and non-CSCs (CD133-) from both resected samples of colorectal adenocarcinoma and xenograft before and after high single-dose radiation. The markers labeling heterochromatin (H3K9me3, HP1-alpha and H3K4me1) and euchromatin (H3K4me3) in CD133+ and CD133- nucleus were detected by immunofluorescence.</p><p><b>RESULTS</b>There was distinct difference in chromatin structure between colorectal CSCs (CD133+) and non-CSCs (CD133-). The chromatin displayed compact patches in CD133+ nucleus, but loosely latticed structure in CD133- nucleus; immunofluorescence verified that the compact patches existing in CSCs was generated from heterochromatin construction. In addition, the vacuole-like defect in heterochromatin regions of CSCs was observed within 24 h after exposure to 10 gray (Gy) single-dose RT. Interestingly, this phenomenon was repaired from 96 h, and recovered to dense plaque structure in heterochromatin regions of CSCs after 144 h. However, no significant difference in non-CSCs was observed after RT exception for a loose chromatin structure.</p><p><b>CONCLUSIONS</b>CSCs play a role in radiosensitivity in colorectal cancer. The mechanism may be related to heterochromatin formation and histone methylation.</p>