Human cancer stem cell culture compositions comprising Erbb2 variants and methods of use thereof
The present invention provides compositions and methods for the culture and maintenance of cancer stem cells. More particularly, the present invention provides the identification of cancer stem cell specific markers and methods of recognizing the same for the detection of tumors, for facilitating the prognosis of a patient with a tumor, and for the treatment of various cancers. The invention also provides antibodies that specifically recognize the disulfide linked Erbb2Δ16 homodimer, an Erbb2Δ16/Erbb3 heterodimer, or post-translational modifications of Erbb2 that are specific to Erbb2 of variant hESCs. In addition, the invention provides a modified defined media useful in the absence of a feeder layer and in the absence of serum or serum replacement, that comprises a basal salt nutrient solution, bFGF, IGF-I, and Activin A, and wherein the composition does not comprise heregulin. The invention further relates to the use of an Erbb2 variant isoform to generate robust cell cultures that are independent of heregulin.
1. An isolated polypeptide comprising the amino acid sequence of SEQ ID NO:3 or a sequence having at least 99% amino acid sequence identity to full length SEQ ID NO:3, wherein said isolated polypeptide is an Erbb2 variant having a deletion of the amino acid sequence encoded by exon 16 of SEQ ID NO:1, and the amino acid residue at position 1155 of said SEQ ID NO:3 is not a proline residue.
2. The isolated polypeptide of claim 1 , comprising the amino acid sequence of SEQ ID NO:3.
3. The isolated polypeptide of claim 1 , wherein said Erbb2 variant has an alanine residue at amino acid position 1155 of SEQ ID NO:3.
4. The isolated polypeptide of claim 1 , wherein said Erbb2 variant differs in its glycosylation profile from the wild type Erbb2 isoform encoded by SEQ ID NO:1.