POMC maintains tumor-initiating properties of tumor tissue-derived long-term-cultured breast cancer stem cells

Abstract

The identification and understanding of the molecular network of cancer stem cells (CSCs) have had a profound impact on our view of carcinogenesis and treatment strategy. Unfortunately, a major problem is that serial passages of CSCs from clinical solid tumor specimens currently are not available in any lab, and thus, reported data are difficult to confirm and intensively interrogated. Here, we have generated two tumor tissue-derived breast CSC (BCSC) lines that showed prolonged maintenance over 20 serial passages in vitro, while retaining their tumor-initiating biological properties. We then deciphered the intrinsic mechanism using analyses of mRNA expression array profiles. It has been determined that pro-opiomelanocortin (POMC) is closely related with protein phosphorylation mediated by G-protein-coupled estrogen receptor (GPER) in BCSC. Following, knockdown of POMC inhibits properties of mammosphere formation, CD44 CD24 population, CD44 expression, and clonogenicity ability in BCSC. We found that inhibition of POMC attenuates phosphorylation of AKT2 and GSK3β in BCSC. Further in vivo investigations demonstrated that POMC interference regulates proliferation of BCSC-bearing tumors. Combination of the clinical results that POMC positive expression is frequently upregulated in human breast cancer and POMC positivity correlated with a poor prognosis, POMC is a potential therapeutic target for BCSC. In conclusion, we have successfully established two long-term-cultured BCSC from clinical specimens. We further indicated that POMC acts as a potential therapeutic target and prognostic marker for future treatment of BCSC.

Highly‐expressed P2X7 receptor promotes growth and metastasis of human HOS/MNNG osteosarcoma cells via PI3K/Akt/GSK3β/β‐catenin and mTOR/HIF1α/VEGF signaling

“…EMT is associated with malignant stem cell function, and previous studies indicate that cancer stem cells (CSCs) are involved in tumor metastasis and relapse . To determine whether P2X7 affected stemness of osteosarcoma cells, we sorted CSCs from osteosarcoma cell lines using flow cytometry and treated them with BzATP or A740003.…”

“…EMT is associated with malignant stem cell function, 30 and previous studies indicate that cancer stem cells (CSCs) are involved in tumor metastasis and relapse. [31][32][33][34] To determine whether P2X7 affected stemness of osteosarcoma cells, we sorted CSCs from osteosarcoma cell lines using flow cytometry and treated them with BzATP or A740003. 15% to 50% more CD133 high CSCs were detected in 5 to 125 μM BzATP treated HOS/MNNG cells, but inhibition of P2X7 using an antagonist or shRNA decreased CD133 high CSCs by 50%.…”

Nanoparticle Delivery of miR-34a Eradicates Long-term-cultured Breast Cancer Stem Cells via Targeting C22ORF28 Directly

“…Tumor tissue-derived BCSC (XM322 and XM607) were isolated by fluorescence-activated cell sorting (FACS) as previously described 3 . Cell line-derived BCSC (MDA-MB-231.SC and MCF-7.SC) were purified by magnetic-activated cell sorting (MACS).…”

“…Cell line-derived BCSC (MDA-MB-231.SC and MCF-7.SC) were purified by magnetic-activated cell sorting (MACS). The application of culture medium was as described previously 3 . Further details are available in Supplementary methods.…”

“…It is difficult to make a distinction between therapeutic response and self-differentiation of CSCs. With a goal of unlocking this mystery, we isolated, identified and maintained tumor tissue-derived breast CSCs (BCSC) in our recent reported investigation 3 . In sum, prolonged maintenance of CSCs could be a great benefit for enabling research progress in patients with tumors.…”