CD44ICD promotes breast cancer stemness via PFKFB4-mediated glucose metabolism

Abstract

CD44 is a single-pass cell surface glycoprotein that is distinguished as the first molecule used to identify cancer stem cells in solid tumors based on its expression. In this regard, the CD44high cell population demonstrates not only the ability to regenerate a heterogeneous tumor, but also the ability to self-regenerate when transplanted into immune-deficient mice. However, the exact role of CD44 in cancer stem cells remains unclear in part because CD44 exists in various isoforms due to alternative splicing.Methods: Gain- and loss-of-function methods in different models were used to investigate the effects of CD44 on breast cancer stemness. Cancer stemness was analyzed by detecting SOX2, OCT4 and NANOG expression, ALDH activity, side population (SP) and sphere formation. Glucose consumption, lactate secretion and reactive oxygen species (ROS) levels were detected to assess glycolysis. Western blot, immunohistochemical staining, ELISA and TCGA dataset analysis were performed to determine the association of CD44ICD and PFKFB4 with clinical cases. A PFKFB4 inhibitor, 5MPN, was used in a xenograft model to inhibit breast cancer development.Results: In this report, we found that the shortest CD44 isoform (CD44s) inhibits breast cancer stemness, whereas the cleaved product of CD44 (CD44ICD) promotes breast cancer stemness. Furthermore, CD44ICD interacts with CREB and binds to the promoter region of PFKFB4, thereby regulating PFKFB4 transcription and expression. The resultant PFKFB4 expression facilitates the glycolysis pathway (vis-à-vis oxidative phosphorylation) and promotes stemness of breast cancer. In addition, we found that CD44ICD and PFKFB4 expressions are generally up-regulated in the tumor portion of breast cancer patient samples. Most importantly, we found that 5MPN (a selective inhibitor of PFKFB4) suppresses CD44ICD-induced tumor development.Conclusion: CD44ICD promotes breast cancer stemness via PFKFB4-mediated glycolysis, and therapies that target PFKFB4 (e.g., 5MPN therapy) may lead to improved outcomes for cancer patients.

Identification of a Subtype of Hepatocellular Carcinoma with Poor Prognosis Based on Expression of Genes within the Glucose Metabolic Pathway

“…Its expression was found to be associated with lymph node metastasis and the TNM stage [39]. The upregulation of PFKFB4 was reported in multiple cancer types and was associated with the aggressiveness of tumors such as in bladder cancer, breast cancer, lung cancer, and ovarian cancer [40][41][42][43]. This is similar to our finding that upregulation of PFKFB4 is associated with aggressiveness of HCC.…”

6-phosphofructo-2-kinase as therapeutic targets in cancer based on an integrated pan-cancer study6-phosphofructo-2-kinase as therapeutic targets in cancer based on an integrated pan-cancer study

“…HIF-1α can activated HRE-D in the promoter region of PFKFB4 bladder cancer cells [29]. PFKFB4 expression facilitated the glycolysis pathway and promotes stemness of breast cancer [30]. In our study, we also found that PFKFB4 expression was associated with stemness of breast cancer.The role of each member as tumor suppressor or promoter in speci c cancer types needs to be con rmed by experiments.…”

Circulating Tumor Cell Clusters: United We Stand Divided We Fall

“…In particular, CD44, a cell surface marker often up-regulated in cancer stem cells (CSC), was overexpressed in CTC clusters. CD44 is involved in the maintenance of stemness signaling of numerous tumor cell types [27]. Similarly, stemness-associated genes were found up-regulated in breast cancer PDX-derived and patient-isolated CTC clusters [6].…”