Methods of wound healing and treating hyperproliferative diseases of epidermis comprising administering trunicated keratinocyte growh factor (KGF) having increased biological activity

#The present invention relates generally to keratinocyte growth factor ("KGF"). More specifically, this invention relates to a KGF fragment and analogs thereof having increased biological activity, and decreased cytotoxicity as compared to a mature, recombinant, full length KGF expressed in an insect cell expression system. This KGF fragment lacks the first 23 amino acid residues of the N-terminus of mature, full-length KGF, including a potential glycosylation site. The N-terminus was previously believed to confer upon KGF its epithelial cell specificity.

#KGF belongs to the family of fibroblast growth factors ("FGFs"), the prototype of which is represented by basic FGF ("bFGF"). KGF is, hence, also known as FGF-7. Like other FGFs, KGF is a heparin-binding protein, but unlike other FGFs, it has a unique target cell specificity. In particular, FGFs are generally capable of stimulating the proliferation and differentiation of a variety of cell types derived from the primary or secondary mesoderm as well as from neuroectoderm. KGF is similar to other FGFs in its ability to stimulate epithelial cell proliferation, but is dissimilar to other FGFs in its inability to stimulate endothelial cells or fibroblast proliferation, as discussed in Finch, P. W. et al., Science 245: 752-755 (1989). Mature, full-length KGF, designated herein as KGF.sub.163, is a polypeptide with 163 amino acid residues, and possesses a potential N-glycosylation site at amino acid 14 of the consensus sequence for glycosylation that extends from amino acid residue 14 to 16 at the N-terminus, as indicated in Finch el al. (1989), loc. cit.

#FGFs, including acidic fibroblast growth factor ("aFGF") and basic fibroblast growth factor ("bFGF"), are known to have heparin-binding properties and have the ability to induce the differentiation and proliferation of ventral, as well as dorsal, mesoderm in early blastulae, as discussed in Gospodarowicz et al., Cell. Biol. Rev. 25:307-314 (1991), and Basilico et al., Adv. Cancer Res. 59:115-165 (1992). The response of cells to FGF is mediated through binding thereof to cell surface receptors known as fibroblast growth factor receptors ("FGFRs"), of which there are three interrelated types, as discussed in Hou et al., Science 251:665-668 (1991). High affinity FGFRs are tyrosine kinases and include the flg receptor ("FGFR-1"), the bek receptor ("FGFR-2"), and the K Sam receptor ("FGFR-3"), as discussed in Lee et al., Science 245:57-60 (1989); Dionne et al., EMBO J. 9:2685-2692 (1990); Miki et al., Science 251:72-75 (1991); Miki et al., Proc. Natl. Acad. Sci. USA 89:246-250 (1992); and Dell et al., J. Biol. Chem. 267:21225-21229 (1992).

#FIG. 1 shows the amino acid sequence of the mature, full-length, human KGF polypeptide, beginning with the N-terminus and containing 163 amino acid residues, having a single consensus sequence for glycosylation at amino acid residues 14-16. The amino acid sequence of the mature KGF polypeptide corresponds to amino acids nos. 32 to 194 of SEQ ID NO: 1.

#FIG. 2 shows the pAcC13 expression vector into which the 163 amino acid sequence of KGF has been inserted. The polylinker and flanking sequences shown in FIG. 2 are referred as SEQ ID NO: 19 in the Sequence Listing.

#FIG. 3(A-B) illustrates the protein elution profile (A) and bioactivity profile (B) of the rKGF obtained from a Mono S HR5/5 cation exchange FPLC column.

#It has been surprisingly discovered that a truncated, unglycosylated KGF having a deletion spanning the first 23 N-terminal amino acid residues of mature recombinant KGF ("rKGF"), herein designated the KGF fragment or KGF.sub.des1-23, possesses a much greater biological activity and decreased cytotoxicity on epithelial cells as compared with the mature, full-length rKGF. Generally, the KGF fragment of the present invention retains the specificity of KGF for stimulation of epithelial cell proliferation.

#The following definitions are incorporated herein and are provided for a better understanding of the present invention.

#Definitions