Table 1.

Antiestrotrophic activity of AFPep and ring-and-tail analogs.

Analog	Tail Amino Acid(s)	Nature of the Side Chain	Inhibition of Uterine Growth^a %	Inhibition of T47D Cell Proliferation^b %
cyclo[EKTOVNOGN]	None	(AFPep)	38 ± 3^*	51 ± 4^*
cyclo[EKTOVNOGN] S	S	Hydrophilic	18 ± 2	22 ± 6
cyclo[EKTOVNOGN] Y	Y	Hydrophilic	21 ± 2	22 ± 3
cyclo[EKTOVNOGN] K	K	Hydrophilic	17 ± 3	18 ± 6
cyclo[EKTOVNOGN] E	E	Hydrophilic	18 ± 3	20 ± 2
cyclo[EKTOVNOGN] FS	FS	Hydrophilic	7 ± 3	NA
cyclo[EKTOVNOGN] YI	YI	Hydrophilic	9 ± 5	24 ± 3
cyclo[EKTOVNOGN] F	F	Hydrophobic	37 ± 2^*	46 ± 2^*
cyclo[EKTOVNOGN] I	I	Hydrophobic	39 ± 2^*	55 ± 6^*
cyclo[EKTOVNOGN] FI	FI	Hydrophobic	46 ± 4^*	66 ± 2^*
Analogs with Disrupted Pharmacophores
cyclo[EKTOVGOGN]	None	None	14 ± 5	NA
cyclo[EKTOVGOGN] FS	FS	Hydrophilic	3 ± 7	NA

All peptides were administered at a dose of 1 μg/mouse intraperitoneally. Values are presented as mean ± S.E. (n = 5).

T47D human cancer cells were treated with the indicated peptides at a concentration of 1 μM. Values are mean ± S.E. (n = 6).

Peptides with inhibition of more than 25 % significantly inhibited estrogen-stimulated growth.

Statistically significantly different from saline control; p < 0.05 Wilcoxon sum of ranks test.