After 65 years, research is still fun.

In 1946, at the end of World War II, I entered graduate school at Cornell University, where I remained for 44 years. During that time, my laboratory produced more than 300 publications in the field of reproductive biology, including studies on nutrition and reproduction, the role of the hypothalamus in pituitary gonadotropin release, corpus luteum formation and function, hormone assays, and estrous cycle synchronization. At age seventy, I retired from Cornell and accepted the Gordon Cain Endowed Professorship at Louisiana State University, where I continued my work on the bovine corpus luteum and added research on the collection, maturation, in vitro fertilization, and culture of bovine oocytes.

Pharmacokinetics and pharmacodynamics of Phor21-betaCG(ala), a lytic peptide conjugate.

Phor21-betaCG(ala), a 36-amino acid peptide comprised of a lytic peptide (Phor21) conjugated to a modified 15-amino acid segment of the beta-chain of chorionic gonadotropin (betaCG(ala)), selectively kills cancer cells that over-express luteinizing hormone/chorionic gonadotropin (LH/CG) receptors by disrupting cellular membrane structure. These studies were designed to further characterize its in-vitro inhibition and in-vivo destruction of prostate cancer cells, biostability and pharmacokinetics to determine its pharmacokinetic and pharmacodynamic profile. Inhibitory effects of Phor21-betaCG(ala) were tested in PC-3 and Caco-2 cells as well as in nude mice bearing PC-3 cells transfected with the luciferase gene (PC-3.

Immune response to lytic peptides conjugated to a betaCG fragment in treated BALB/C mice.

Hecate-betaCG and Phor14-betaCG(ala) are relatively short, amphipathic alpha-helical cationic peptides with the ability to destroy selectively breast, prostate and ovarian cancer cells. Treatment with proteins and peptides frequently initiated antibody formation. Short peptides may minimize the risk of the immune system mobilization after treatment but it is necessary to investigate whether Hecate-betaCG and Phor14-betaCG(ala) induce the immune system to produce antibody and whether they affect the reproductive organs in normal wild-type mice.

Conjugates of lytic peptides and LHRH or betaCG target and cause necrosis of prostate cancers and metastases.

In a series of in vivo and in vitro experiments, it was shown that membrane disrupting lytic peptides (Hecate, Phor14, or Phor21) conjugated to a 15 amino acid segment of the beta chain of CG or to LHRH were able to target and destroy hormone dependent and independent human prostate cancer xenografts in nude mice. In vitro sensitivity of the cells to the drugs was directly related to LH/CG receptor expression, and pretreatment in vitro or in vivo with estrogens or FSH to enhance LH/CG receptor expression capacity and increased sensitivity to the drugs. Administration of unconjugated Hecate and LHRH was ineffective.

Destruction of breast cancers and their metastases by lytic peptide conjugates in vitro and in vivo.

In a series of in vivo and in vitro experiments, the concept has been established that breast cancer cells that express LH/CG or LHRH receptors can be targeted and destroyed by constructs consisting of a lytic peptide moiety and a 15-amino acid segment of the beta-chain of CG or by an LHRH lytic peptide conjugate. Data obtained in vitro established the validity of this concept, showed the specificities of the Hecate-betaCG, and Phor14 and Phor21-betaCG conjugates in killing cells that express functional LH/CG receptors and proved that the LH/CG receptor capacity is directly related to the compound's specificity. In in vivo experiments, Hecate-betaCG, Phor14-betaCG, and Phor21-betaCG(ala) each caused highly significant reductions of tumor volume and tumor burden in nude mice bearing breast cancer xenografts; Hecate and Phor21 alone or conjugated with non-specific peptides were not effective.

LHRH-conjugated magnetic iron oxide nanoparticles for detection of breast cancer metastases.

Targeted delivery of superparamagnetic iron oxide nanoparticles (SPIONs) could facilitate their accumulation in metastatic cancer cells in peripheral tissues, lymph nodes and bones and enhance the sensitivity of magnetic resonance imaging (MRI). The specificities of luteinizing hormone releasing hormone (LHRH) and luteinizing hormone/chorionic gonadotropin (LH/CG)- bound SPIONs were tested in human breast cancer cells in vitro and were found to be dependent on the receptor expression of the target cells, the time of incubation and showed saturation kinetics. In incubations with MDA-MB-435S.

Targeting breast and prostate cancers through their hormone receptors.

A targeted treatment that effectively destroys human breast, prostate, ovarian, and testicular cancer cells that express luteinizing hormone/chorionic gonadotropin (LH/CG) receptors has been developed. The treatment consists of a conjugate of a membrane-disrupting lytic peptide (Hecate, Phor14, or Phor21) and a 15-amino acid segment of the beta chain of CG. Because these conjugates act primarily by destroying cell membranes, their effects are independent of cell proliferation.

Membrane disrupting lytic peptides for cancer treatments.

Membrane disrupting lytic peptides are abundant in nature and serve insects, invertebrates, vertebrates and humans as defense molecules. Initially, these peptides attracted attention as antimicrobial agents; later, the sensitivity of tumor cells to lytic peptides was discovered. In the last decade intensive research has been conducted to determine how lytic peptides lyse bacteria and tumor cells.

Nitric oxide as a local mediator of prostaglandin F2alpha-induced regression in bovine corpus luteum: an in vivo study.

To test whether nitric oxide (NO) is involved in prostaglandin (PG) F2alpha-induced regression of the bovine corpus luteum (CL) in vivo, heifers were treated as follows: Group 1, saline (3 ml/h); Group 2, dinoprost, an analogue of prostaglandin F2alpha (aPGF2alpha; 5 mg/0.5 h); Group III, Nomega-nitro-L-arginine methyl ester (L-NAME; 200 mg/4 h), an inhibitor of nitric oxide synthase; and Group IV, L-NAME (400 mg/4 h) and aPGF2alpha (5 mg/0.5 h).

Human prostate cancer cells and xenografts are targeted and destroyed through luteinizing hormone releasing hormone receptors.

Background: A conjugate of a lytic peptide, hecate, and a 15-amino acid segment of the beta-chain of chorionic gonadotropin (CG) destroyed human prostate xenografts in nude mice by targeting LH receptors. Since these xenografts also express LHRH receptors, we prepared a LHRH-hecate conjugate and tested its ability to destroy PC-3 cells in vitro and in vivo.

Materials And Methods: LHRH-hecate was added to cultures of PC-3, BRF 41 T, DU145, and LNCaP cells in the presence and absence of steroids.

A novel approach of targeted ablation of mammary carcinoma cells through luteinizing hormone receptors using Hecate-CGbeta conjugate.

Recent studies have shown that human and animal mammary gland carcinoma cell line express luteinizing hormone receptors (LHRs). We have examined the cytotoxic effect of Hecate-CGbeta conjugate, that is, fusion of a lytic peptide (Hecate) and a 15-amino acid fragment of the CGbeta-chain in vitro. To test the hypothesis that the Hecate-CGbeta conjugate selectively abolishes cells possessing LHR, estrogen dependent and independent human breast cancer cell lines (MCF-7; MDA-MB-231) and a mouse Leydig tumor cell line (BLT-1) were treated in vitro with Hecate-CGbeta conjugate and Hecate alone.

Influence of nitric oxide on the secretory function of the bovine corpus luteum: dependence on cell composition and cell-to-cell communication.

The objective of the present study was to investigate the role of cell-to-cell contact in the influence of nitric oxide (NO) on the secretory function of the bovine corpus luteum (CL). In Experiment 1, separate small luteal cells (SLC) or large (LLC) luteal cells were perfused with 100 micro M spermineNONOate, a NO donor, or with 100 micro M Nomega-nitro-L-arginine methyl ester (L-NAME), a NO synthase (NOS) inhibitor; in Experiment 2, a mixture of LLC and SLC and endothelial cells was cultured and incubated with spermineNONOate or L-NAME; in Experiment 3, spermineNONOate was perfused into the CL (100 mg/4 hr) by a microdialysis system in vivo. Perfusion of isolated SLC and LLC with the NO donor or NOS inhibitor (Experiment 1) did not affect (P > 0.

Membrane disrupting lytic peptide conjugates destroy hormone dependent and independent breast cancer cells in vitro and in vivo.

We have prepared conjugates of a membrane disrupting lytic peptide (hecate) and a 15-amino acid segment of the beta-chain of CG and hecate and the decapeptide, luteinizing hormone releasing hormone (LHRH). We have tested the concept that these conjugates will target breast cancer cells expressing LH/CG or LHRH receptors. In previous studies, we were able to destroy prostate cancers in vitro and in vivo with lytic peptide conjugates.

Administration of a nitric oxide synthase inhibitor counteracts prostaglandin F2-induced luteolysis in cattle.

The objective of this study was to determine whether nitric oxide (NO) is produced locally in the bovine corpus luteum (CL) and whether NO mediates prostaglandin F2alpha (PGF2alpha)-induced regression of the bovine CL in vivo. The local production of NO was determined in early I, early II, mid, late, and regressed stages of CL by determining NADPH-d activity and the presence of inducible and endothelial NO synthase immunolabeling. To determine whether inhibition of NO production counteracts the PGF2alpha-induced regression of the CL, saline (10 ml/h; n = 10) or a nonselective NOS inhibitor (Nomega-nitro-l-arginine methyl ester dihydrochloride [L-NAME]; 400 mg/h; n = 9) was infused for 2 h on Day 15 of the estrous cycle into the aorta abdominalis of Holstein/Polish Black and White heifers.

Effects of a lytic peptide conjugated to beta HCG on ovarian cancer: studies in vitro and in vivo.

Objective: The aim of this study was to determine the in vitro and in vivo effects of the lytic peptide, hecate, alone and conjugated to a 15-amino-acid fragment of the beta-chain of hCG (hecate-beta hCG) on the ovarian carcinoma cell line NIH: OVCAR-3 and determine the expression of luteinizing hormone (LH)/human chorionic gonadotropin (hCG) receptors in cell cultures and tumor tissues.

Methods: For in vitro studies, hecate or hecate-beta hCG was added to cultures of ovarian cancer cells in the presence or absence of estradiol or follicle stimulating hormone. The cytotoxicity of lytic peptides was measured by trypan blue exclusion and lactate dehydrogenase release.