High expression of CD133 - stem cell marker for prediction of clinically agressive type of colorectal cancer

Can CD133 Be Regarded as a Prognostic Biomarker in Oncology: Pros and Cons

The CD133 cell membrane glycoprotein, also termed prominin-1, is expressed on some of the tumor cells of both solid and blood malignancies. The CD133-positive tumor cells were shown to exhibit higher proliferative activity, greater chemo- and radioresistance, and enhanced tumorigenicity compared to their CD133-negative counterparts. For this reason, CD133 is regarded as a potential prognostic biomarker in oncology. The CD133-positive cells are related to the cancer stem cell subpopulation in many types of cancer. Recent studies demonstrated the involvement of CD133 in the regulation of proliferation, autophagy, and apoptosis in cancer cells. There is also evidence of its participation in the epithelial-mesenchymal transition associated with tumor progression. For a number of malignant tumor types, high CD133 expression is associated with poor prognosis, and the prognostic significance of CD133 has been confirmed in a number of meta-analyses. However, some published papers suggest that CD133 has no prognostic significance or even demonstrate a certain correlation between high CD133 levels and a positive prognosis. This review summarizes and discusses the existing evidence for and against the prognostic significance of CD133 in cancer. We also consider possible reasons for conflicting findings from the studies of the clinical significance of CD133.

Immunohistochemical Expression of the Stem Cell Marker CD133 in Colorectal Carcinoma

Background Colorectal carcinoma (CRC) is the second-leading cause of cancer-related death. Despite the combined (surgery, chemotherapy, radiotherapy, and immunotherapy) modalities of treatment, the prognosis remains poor, mostly because of recurrence and distant metastasis. Cancer stem cells (CSC) are thought to be responsible for the development and spread of tumors. Hence, targeted therapy against these cells hopes to reduce the chance of recurrence and metastasis and improve the prognosis. Many immune markers have been identified to detect CSC in CRC. Here, we tried to assess the immunohistochemical expression of the stem cell marker CD133 in colorectal carcinoma and its correlation with various pathological parameters. Methodology A total of 51 cases of CRC were analyzed. Immunohistochemistry for CD133 was done after standardization in our laboratory. Expression status was decided based on the total score obtained by multiplying the intensity score by the percentage score. CD133 expression was correlated with the age and gender of the patient, tumor location, histological grade, extent of invasion, lymphovascular invasion (LVI), perineural invasion (PNI), and nodal status. Results High CD133 expression was seen in 21 (41.17%) cases. There was no significant association between CD133 expression and the pathological parameters except the tumor site. CD133 expression was significantly higher as we moved from the proximal colon to the rectum. Conclusions CD133 expression was significantly higher in the distal part of the large intestine as compared to the proximal part. But there was no linear correlation between CD133 expression and histological grade, extent of invasion, or nodal status.

Identification and characterization of a subpopulation of CD133+ cancer stem-like cells derived from SK-UT-1 cells

BACKGROUND

Uterine leiomyosarcoma (ULMS) is a malignant tumor found in the smooth muscle lining the walls of the uterus. Cancer stem cells (CSCs) are responsible for metastasis, drug resistance, and relapse of cancer, resulting in treatment failure. However, little is known about CSCs and their associated-markers in ULMS. We aimed to characterize and identify a subpopulation of CD133⁺ cancer stem-like cells derived from SK-UT-1 cell line.

METHODS

SK-UT-1 cells were sphere-forming cultured in vitro. We also sorted the CD133⁺ cells derived from SK-UT-1 cell line by immunomagnetic beads. CD133⁺ subpopulation and apoptotic cells were detected by flow cytometry. Self-renewal and anchorage-independent growth capabilities were examined using sphere and colony formation assays. The tumorigenicity of the fourth-passage spheres and parental SK-UT-1 cells was used by mouse xenograft model in vivo. Cell proliferation ability and sensitivity to doxorubicin (DXR) were assessed by CCK-8 assay. Cell migration and invasion were tested by wound healing assay or Transwell migration and invasion assays. Expressions of CSC-related marker were analyzed by Western blotting.

RESULTS

The fourth-passage spheres were defined as a CD133⁺ cell population, which was accompanied by increase of sphere and colony forming rate, migration and invasion abilities, as well as drug-resistant properties in vitro. Moreover, the fourth-passage spheres showed a stronger tumorigenic potential in vivo. CD133⁺ cell population sorted from SK-UT-1 line showed an increased ability in sphere and colony formation, proliferation, migration, invasion, resistance to apoptosis after treatment with doxorubicin (DXR) compared with CD133^- cell population. The expression levels of CSCs-related markers (e.g., CD44, ALDH1,BMI1, and Nanog), were significantly elevated in CD133⁺ cells compared with those in CD133^- cells.

CONCLUSIONS

Collectively, our findings indicated that CD133 may be a significant marker for cancer stem-like cells, and it may be a potential therapeutic target for human ULMS.