Heart Peptide Hormones: Adjunct and Primary Treatments of Cancer.

Four heart hormones, namely atrial natriuretic peptide (ANP), long-acting natriuretic peptide (LANP), vessel dilator and kaliuretic peptide reduce up to 97% of cancer cells in vitro. These four cardiac hormones eliminate up to 80% of human pancreatic adenocarcinomas, two-thirds of human breast carcinomas and up to 86% of human small-cell lung carcinomas growing in athymic mice. ANP given intravenously for 3 hours after 'curative' lung surgery as an adjunct to surgery results in a 2-year relapse-free survival of 91% compared to 75% for those treated with surgery alone. The anticancer mechanisms of action of these peptides involve binding to receptors on the cancer cells, followed by 95% inhibition of the conversion of inactive to active rat sarcoma-bound guanosine triphosphate (RAS)-mitogen-activated protein kinase (MAPK) kinases 1/2 (MEK 1/2) (98% inhibition)-extracellular signal-related kinases 1/2 (ERK1/2) (96% inhibition) cascade in cancer cells. They are dual inhibitors of vascular endothelial growth factor (VEGF) and its VEGF2 receptor (up to 89%). They also inhibit MAPK9, i.e. c-JUN-N-terminal kinase 2. One of the downstream targets of VEGF is ß-catenin, which these peptides inhibit by up to 88%. These four peptide hormones inhibit the Wingless-related integration site (WNT) pathway 68% and WNT secreted-Frizzled protein is reduced by up to 84%. Signal transducer and activator of transcription 3 (STAT3), a final 'switch' that activates gene expression that leads to malignancy, is specifically reduced up to 88% by these peptides but they do not affect STAT1. There is crosstalk between the RAS-MEK 1/2-ERK 1/2 kinase cascade, VEGF, ß-catenin, JNK, WNT, and STAT pathways and each of these pathways and their crosstalk is inhibited by these peptide hormones. They enter the nucleus of cancer cells where they inhibit the proto-oncogenes c-FOS (by up to 82%) and c-JUN (by up to 61%). CONCLUSION: These multiple kinase inhibitors have both adjunct and primary anticancer effects.

Subcutaneous pharmacokinetics of the cardiac hormone vessel dilator.

Vessel dilator, a hormone synthesized in the heart, eliminates 71% of human small-cell lung cancers and 67% of human breast cancers growing in mice when given subcutaneously (s.c.) via osmotic pumps. The pharmacokinetics of s.c. administered vessel dilator have not been evaluated previously. In the present study, the pharmacokinetics of vessel dilator following s.c. bolus (ScB) or 3 h s.c. infusion (ScI) were compared with those following i.v. bolus (IvB) administration in male Fischer 344 rats. The half-life (t½ ) of vessel dilator after ScI, IvB and ScB was 54, 43 and 30 min, respectively. The tmax for vessel dilator after IvB, ScB and ScI administration was 1.5, 23 and 156 min, respectively, whereas the corresponding Cmax values were 3749, 887 and 471 ng/L (normalized against the dose used for ScB and IvB). The area under the curve (AUC0-∞ ) for vessel dilator was 1166, 880 and 1652 ng h/mL (normalized) following IvB, ScB and ScI administration, respectively. The volume of distribution for vessel dilator was 2.38, 0.92 and 1.08 L following IvB, ScB and SCI administration, respectively; corresponding clearance values were 1.69, 1.50 and 0.78 L/h, respectively. Plasma concentrations of vessel dilator after each of the three methods of administration mirrored their predicted concentration-time profiles. We conclude that vessel dilator administered via ScI has a significantly greater AUC and t½ and slowed clearance compared with IvB or ScB administration (P < 0.001), suggesting that s.c. infusion is the preferred method of administration, based on pharmacokinetics, to treat cancers.

Family of peptides synthesized in the human body have anticancer effects.

UNLABELLED: Four peptides synthesized in the heart, namely atrial natriuretic peptide (ANP), vessel dilator, kaliuretic peptide and long-acting natriuretic peptide (LANP), reduce cancer cells in vitro by up to 97%. These four cardiac hormones, in vivo, eliminate up to 86% of human small-cell lung carcinomas, two-thirds of human breast carcinomas, and up to 80% of human pancreatic adenocarcinomas growing in athymic mice. Their anticancer mechanisms of action, after binding to specific receptors on cancer cells, include targeting the Rat sarcoma-bound guanosine triphosphate (RAS) (95% inhibition)-mitogen activated protein kinase kinase 1/2 (MEK-1/2) (98% inhibition)-extracellular signal-related kinases 1/2 (ERK-1/2) (96% inhibition) cascade in cancer cells. They also inhibit MAPK9, i.e. c-JUN-N-terminal kinase 2. They are dual inhibitors of vascular endothelial growth factor (VEGF) and its VEGFR2 receptor (up to 89%). One of their downstream targets of VEGF is ß-Catenin, which they reduce up to 88%. The Wingless-related integration site (WNT) pathway is inhibited by up to 68% and WNT secreted-Frizzled related protein-3 was reduced by up to 84% by the four peptide hormones. A serine/threonine-protein kinase, AKT, derived from "AK" mouse strain with thymomas (T), is reduced by up to 64% by the peptide hormones. Signal transducer and activator of transcription 3 (STAT3), a final "switch" that activates gene expression patterns that lead to malignancy, is decreased by up to 88% by these peptide hormones; STAT3 is specifically reduced as they do not affect STAT1. There is cross-talk between the RAS-MEK-1/2-ERK-1/2 kinase cascade, VEGF, ß-catenin, WNT, JNK and STAT pathways and each of these pathways is inhibited by the cardiac peptides. These peptides have been demonstrated to enter the nucleus of cancer cells where they inhibit the proto-oncogenes c-FOS (up to 82%) and c-JUN (up to 61%). CONCLUSION: The cardiac peptides inhibit multiple targets and cross-talk between the targets within cancer cells.

Reduction of leptin levels by four cardiac hormones: Implications for hypertension in obesity.

Circulating levels of leptin are increased in obesity and have been proposed to contribute to the development of hypertension in obese individuals. Four cardiac hormones, specifically, vessel dilator, long-acting natriuretic peptide (LANP), kaliuretic peptide and atrial natriuretic peptide (ANP), have blood pressure-lowering properties and correlate with the presence of hypertension in obesity. The objective of this study was to determine whether one or more of these cardiac hormones was able to decrease the levels of leptin in the hypothalamus, an area of the brain that has been demonstrated to synthesize more than 40% of leptin in the circulation. The effects of these four cardiac hormones on leptin were examined using dose-response curves in the rat hypothalamus, which synthesizes leptin. Vessel dilator, LANP, kaliuretic peptide and ANP maximally decreased the levels of leptin in hypothalamic cells by 79, 76, 80 and 62%, respectively (P<0.0001 for each). The cardiac hormones decreased leptin levels over a concentration range of 100 pM to 10 µM, with the most significant reductions in leptin levels occurring when the concentrations of the hormones were at micromolar levels. The results of the study suggest that the four cardiac hormones lead to significant reductions in hypothalamic leptin levels, which may be an important mechanism for alleviating leptin-induced hypertension in obesity.

Cardiac hormones target nuclear oncogenes c-Fos and c-Jun in carcinoma cells.

BACKGROUND: c-Fos is a cellular proto-oncogene which dimerizes with c-Jun proto-oncogene to form AP-1 transcription factor, which upregulates transcription of genes involved in proliferation and cancer formation. Four cardiac hormones, that is, long-acting natriuretic peptide (LANP), vessel dilator, kaliuretic peptide (KP) and atrial natriuretic peptide (ANP) with anticancer effects in vivo are potent inhibitors of the Ras-MEK 1/2-ERK 1/2 kinase cascade and signal transducer and activator of transcription-3 (STAT-3) that activate c-Fos and c-Jun. These four cardiac hormones were investigated for their effects on proto-oncogenes c-Fos and c-Jun within the nucleus of cancer cells. MATERIALS AND METHODS: Four cardiac hormones were evaluated for their ability to decrease proto-oncogenes c-Fos and c-Jun, measured by ELISA in extracted nuclei of three human cancer cell lines. RESULTS: Vessel dilator, LANP, KP and ANP over a concentration range of 100 pM-10 µM, maximally decreased c-Fos by 61%, 60%, 61% and 59% in human hepatocellular cancer cells, by 82%, 74%, 78% and 74% in small-cell lung cancer cells, and by 82%, 73%, 78% and 74% in human renal adenocarcinoma cells. c-Jun was maximally reduced by vessel dilator, LANP, KP and ANP by 43%, 31%, 61% and 35% in hepatocellular cancer cells, by 65%, 49%, 59% and 40% in small-cell lung cancer cells, and by 47%, 43%, 57% and 49% in renal cancer cells. CONCLUSION: Four cardiac hormones are potent inhibitors of c-Fos and c-Jun proto-oncogenes within the nucleus of cancer cells.

Central role of ß-catenin in anticancer effects of cardiac hormones.

BACKGROUND: ß-Catenin causes malignant growth of colonic, pancreatic and renal cancer. Four cardiac hormones, namely atrial natriuretic peptide (ANP), vessel dilator, long-acting natriuretic peptide (LANP) and kaliuretic peptide eliminate up to 80% of human pancreatic carcinomas growing in mice. MATERIALS AND METHODS: Four cardiac hormones were evaluated for their ability to reduce the expression of human ß-catenin, measured by enzyme-linked immunosorbent assay (ELISA) in human colorectal, pancreatic and renal cancer cells. RESULTS: Vessel dilator, LANP, kaliuretic peptide, and ANP, over a concentration range of 100 pM to 10 µM, maximally reduced expression of ß-catenin in human colorectal cancer cells by 78%, 71%, 69%, and 83%, respectively. Vessel dilator, LANP, kaliuretic peptide, and ANP reduced ß-catenin expression in human pancreatic cancer cells by 76%, 66%, 72%, and 88%, and by 64%, 54%, 58% and 73%, in human renal cancer cells, respectively. CONCLUSION: Part of the anticancer action of these four cardiac hormones is a potent inhibition of ß-catenin.

Natriuretic peptides' metabolic targets for treatment of cancer.

Four cardiac hormones are synthesized by the atrial natriuretic peptide prohormone gene. These hormones, namely, long-acting natriuretic peptide, vessel dilator, kaliuretic peptide, and atrial natriuretic peptide, help regulate blood pressure and blood volume by causing vasodilation, diuresis, and sodium excretion. These cardiac hormones reduce up to 97% of all cancer cells in vitro. These cardiac hormones eliminate up to 86% of human small-cell lung carcinomas, two thirds of human breast cancers, and up to 80% of human pancreatic adenocarcinomas growing in athymic mice. Their anticancer mechanisms of action, after binding to specific receptors on cancer cells, include targeting the Rat sarcoma-bound guanosine diphosphate conversion to RAS guanosine triphosphate (95% inhibition)-mitogen-activated protein kinase kinase 1/2 (98% inhibition)-extracellular signal-related kinase 1/2 (96% inhibition) cascade in cancer cells. They also reduce c-Jun-N-terminal kinase 2 up to 89%. These multiple kinase inhibitors are also inhibitors of vascular endothelial growth factor (VEGF) and its VEGFR2 receptor (up to 89% inhibition). They reduce ß-catenin up to 88%. They inhibit the WNT pathway up to 68%, and secreted Frizzled-related protein 3 is decreased up to 84%. AKT, a serine/threonine-protein kinase, is reduced up to 64% by the cardiac hormones. Signal transducer and activator of transcription 3, a final "switch" that activates gene expression that leads to malignancy, is decreased by up to 88% by the cardiac hormones. Of importance, the cross talk between the multiple kinases, VEGF, B-catenin, WNT, and STAT pathways is inhibited by the 4 cardiac hormones.

Pituitary tumor with gigantism, acromegaly and preclinical Cushing's disease diagnosed from the 10th row.

A 7'3" basketball player was noted to have 2 to 3 times thicker tissue in his hands than 6'10" players by an endocrinologist sitting 10 rows above the player in a basketball arena. This led to the diagnosis of pituitary gigantism where the history revealed that he was 7'3" at 15 years of age. At age 19 when the acryl enlargement was noted, a diagnostic workup revealed elevated growth hormones and insulin-like growth factor 1 (IGF-1) with a 2 × 1.3 cm pituitary tumor. His history suggested that his epiphyseal plates had closed at age 15, and because he continued to produce IGF-1, he now has acromegaly. His elevated adrenocorticotropic hormone (ACTH) before surgery suggests that he also had preclinical Cushing's disease. After pituitary transsphenoidal surgery, all acryl enlargement in hands and ligaments disappeared. His growth hormone, IGF-1 and ACTH returned to normal 2 weeks after surgery.

Inhibition of AKT in human pancreatic, renal and colorectal cancer cells by four cardiac hormones.

BACKGROUND: Protein kinase-B (AKT) is a serine/threonine protein kinase that has a key role in cell proliferation and cancer cell invasiveness. Four cardiac peptide hormones, namely vessel dilator, atrial natriuretic peptide (ANP), kaliuretic peptide, and long-acting natriuretic peptide (LANP) have anticancer effects both in vitro and in vivo. MATERIALS AND METHODS: Four cardiac hormones were examined for their ability to inhibit AKT, measured with a solid-phase enzyme-linked immunosorbent assay (ELISA) in human colorectal, pancreatic, and renal cancer cells. RESULTS: Vessel dilator, kaliuretic peptide, ANP, and LANP maximally reduced the concentration of AKT by 47%, 45%, 52%, and 46% in human colorectal cancer cells (p<0.0001), by 60%, 61%, 64%, and 59% in human pancreatic carcinoma cells (p<0.0001), and by 31%, 32%, 31%, and 31% in renal adenocarcinoma cells (p<0.001). CONCLUSION: These four cardiac hormones are significant inhibitors of AKT in human cancer cells, as part of their anticancer mechanism(s) of action.

Cardiac hormones for the treatment of cancer.

Four cardiac hormones, namely atrial natriuretic peptide, vessel dilator, kaliuretic peptide, and long-acting natriuretic peptide, reduce up to 97% of all cancer cells in vitro. These four cardiac hormones eliminate up to 86% of human small-cell lung carcinomas, two-thirds of human breast cancers, and up to 80% of human pancreatic adenocarcinomas growing in athymic mice. Their anticancer mechanisms of action, after binding to specific receptors on cancer cells, include targeting the rat sarcoma-bound GTP (RAS) (95% inhibition)-mitogen-activated protein kinase kinase 1/2 (MEK 1/2) (98% inhibition)-extracellular signal-related kinase 1/2 (ERK 1/2) (96% inhibition) cascade in cancer cells. They also inhibit MAPK9, i.e. c-Jun N-terminal kinase 2. They are dual inhibitors of vascular endothelial growth factor (VEGF) and its VEGFR2 receptor (up to 89%). One of the downstream targets of VEGF is ß-catenin, which they reduce up to 88%. The WNT pathway is inhibited up to 68% and secreted frizzled-related protein 3 decreased up to 84% by the four cardiac hormones. AKT, a serine/threonine protein kinase, is reduced up to 64% by the cardiac hormones. STAT3, a final 'switch' that activates gene expression that leads to malignancy, is decreased by up to 88% by the cardiac hormones. STAT3 is specifically decreased as they do not affect STAT1. There is a cross-talk between the RAS-MEK 1/2-ERK 1/2 kinase cascade, VEGF, ß-catenin, WNT, JNK, and STAT pathways and each of these pathways is inhibited by the cardiac hormones.

Cardiac hormones are potent inhibitors of secreted frizzled-related protein-3 in human cancer cells.

Secreted frizzled-related proteins (sFRPs) are secreted glycoproteins involved in neoplastic growth. Four hormones synthesized in the heart, namely vessel dilator, atrial natriuretic peptide (ANP), kaliuretic peptide (KP) and long-acting natriuretic peptide (LANP), have anticancer effects both in vitro and in vivo. These heart hormones were evaluated for their ability to inhibit sFRP-3, which is associated with tumor invasiveness, in human pancreatic cancer, colorectal cancer and renal adenocarcinoma cell lines. Vessel dilator, KP, ANP and LANP maximally reduced the concentration of sFRP-3 by 83%, 83%, 84% and 83%, respectively (each at P<0.0001), in the human colorectal adenocarcinoma cells. In the human pancreatic carcinoma cells, the concentration of sFRP-3 was maximally reduced by 77%, 77%, 77% and 78% (each at P<0.0001) secondary to treatment with vessel dilator, KP, ANP and LANP, respectively. In the human renal adenocarcinoma cells, the sFRP-3 was maximally reduced by vessel dilator, KP, ANP and LANP by 68%, 66%, 68% and 66% (each at P<0.0001), respectively. The results indicate that these four cardiac hormones are significant inhibitors (up to 84%) of sFRP-3 in a variety of human cancer cells. Furthermore, these data suggest that the metabolic targeting of sFRP-3 by the cardiac hormones contributes to their anti-cancer mechanism(s) of action.

Potent selective inhibition of STAT 3 versus STAT 1 by cardiac hormones.

Signal transducers and activators of transcription (STATs) are the final "switches" that activate gene expression patterns that lead to human malignancy. Extracellular signal-regulated kinases (ERK 1/2) activate STAT 3; four cardiovascular hormones inhibit ERK 1/2 kinases, leading to the hypothesis that they may also inhibit STATs. These four cardiac hormones, i.e., vessel dilator, long-acting natriuretic peptide (LANP), kaliuretic peptide, and atrial natriuretic peptide (ANP), eliminate human cancers growing in mice. These four cardiac hormones' effects on STATs 1 and 3 were examined in human small-cell lung cancer and human pancreatic adenocarcinoma cells. Vessel dilator, LANP, kaliuretic peptide, and ANP maximally decreased STAT 3 by 88, 54, 55, and 65 %, respectively, at their 1 µM concentrations in human small-cell lung cancer cells and STAT 3 by 66, 57, 70, and 77 % in human pancreatic adenocarcinoma cells, respectively. The cardiac hormones (except LANP) also significantly decreased STAT 3 measured by Western blots. These cardiac hormones did not decrease STAT 1 in either human small-cell lung cancer or pancreatic adenocarcinoma cells. We conclude that these four cardiac hormones are significant inhibitors of STAT 3, but not STAT 1, in human small-cell lung cancer and pancreatic adenocarcinoma cells, which suggests a specificity for these hormones' anticancer mechanism(s) of action enzymology in human cancer cells.

New anticancer agents: hormones made within the heart.

The heart is a sophisticated endocrine gland synthesizing the atrial natriuretic peptide (ANP) prohormone which contains four peptide hormones, namely atrial natriuretic peptide, vessel dilator, kaliuretic peptide and long-acting natriuretic peptide, which decrease up to 97% of human pancreatic, breast, colon, prostate, kidney and ovarian carcinomas, as well as small-cell and squamous cell lung cancer cells within 24 hours in cell culture. In vivo these four cardiac hormones eliminate up to 80% of human pancreatic adenocarcinomas, up to two-thirds of human breast cancers, and up to 86% of human small-cell lung cancers in athymic mice. Their anticancer mechanism(s) target the Rat sarcoma bound guanosine triphosphate (RAS)-mitogen activated protein kinase kinase 1/2 (MEK1/2)-extracellular signal related kinase 1/2 (ERK1/2) kinase cascade in cancer cells. These four cardiac hormones inhibit up to 95% of the basal activity of Ras, 98% of the phosphorylation of MEK1/2 kinases and 96% of the activation of basal activity of ERK1/2 kinases. They also completely block the activity of mitogens such as the ability of epidermal growth factor to stimulate ERK and RAS. In addition to inhibiting these mitogen-activated protein kinases (MAPKs) they also inhibit MAPK9, i.e. c-Jun-N-terminal kinase 2. These multiple kinase inhibitors are cytotoxic and cause cell death of cancer cells but not of normal cells.

Novel dual inhibitors of vascular endothelial growth factor and VEGFR2 receptor.

BACKGROUND: Vascular endothelial growth factor (VEGF) helps control tumour growth via causing new capillaries growth in tumours. Four cardiac hormones [i.e. vessel dilator, long-acting natriuretic peptide (LANP), kaliuretic peptide (KP) and atrial natriuretic peptide (ANP)] that eliminate up to up to 86% of human small-cell lung cancers growing in mice were investigated for their effects on VEGF and the VEGFR2/KDR/Flk-1 receptor. The VEGFR2 receptor is the main receptor mediating VEGF's cancer-enhancing effects. MATERIALS AND METHODS: Four cardiac hormones were evaluated for their ability to decrease VEGF/VEGFR2 measured by ELISAs in three human cancer cell lines. RESULTS: Vessel dilator, LANP, KP and ANP, over a concentration range of 100 pM to 10 µM, maximally decreased the VEGFR2 receptor in human pancreatic adenocarcinoma cells by 48%, 49%, 74% and 83%. Vessel dilator, LANP, KP and ANP decreased the VEGFR2 receptor by 77%, 89%, 88% and 67% in human small-cell lung cancer cells and by 48%, 92%, 64% and 71% in human prostate cancer cells. These results were confirmed with the cardiac hormones also decreasing the VEGFR2 receptor measured by Western blots. VEGF itself in pancreatic carcinoma cells was decreased by 42%, 58%, 36% and 40% by vessel dilator, LANP, KP and ANP. VEGF levels were decreased 25%, 23%, 17% and 23% in small-cell lung cancer cells and decreased by 24%, 20%, 23% and 24% in prostate cancer cells by vessel dilator, LANP, KP and ANP. CONCLUSION: Four cardiac hormones are the first dual inhibitors of VEGF and the VEGFR2/KDR/Flk-1 receptor.

Cardiac hormones are c-Jun-N-terminal kinase 2-inhibiting peptides.

BACKGROUND: Four cardiac peptide hormones, namely vessel dilator, long-acting natriuretic peptide (LANP), kaliuretic peptide, and atrial natriuretic peptide (ANP) have anticancer effects. MATERIALS AND METHODS: The effects of these four cardiac hormones on human c-Jun-N-terminal kinase 2 (JNK2) were examined in human small cell lung cancer and human prostate cancer cells. RESULTS: Vessel dilator, LANP, kaliuretic peptide and ANP maximally reduced expression of JNK2 by 89%, 56%, 45%, and 28%, respectively (each at p<0.0001) in human small cell lung cancer cells. In human prostate adenocarcinoma cells, JNK2 was maximally decreased 76%, 56%, 45%, (each at p<0.0001), and 28% (p<0.01) secondary to vessel dilator, LANP, kaliuretic peptide and ANP, respectively. CONCLUSION: These results indicate that four cardiac hormones are significant inhibitors (by up to 89%) of JNK2 in human small cell lung cancer cells and up to 76% in human prostate adenocarcinoma cells as part of their anticancer mechanism(s) of action.

Four cardiac hormones cause death of human cancer cells but not of healthy cells.

BACKGROUND: Four cardiac hormones, namely, vessel dilator, long-acting natriuretic peptide, atrial natriuretic peptide and kaliuretic peptide, have anticancer effects but whether they cause cell death of human cancer cells or normal cells is unknown. MATERIALS AND METHODS: These cardiac hormones were examined for their ability to cause cell death quantified by measurement of nuclear matrix proteins 41/7 which is a function of the number of dead or dying cells. RESULTS: Each of these cardiac hormones caused cell death in up to 36% (p < 0.0001) of the pancreatic adenocarcinoma cells and up to 28% (p<0.0001) of the prostate cancer cells over a concentration range of 100 pmol/l to 10 µmol/l. There was no cell death of normal human prostate, kidney, or lung cells at the above concentrations. CONCLUSION: Four cardiac hormones cause death of pancreatic and prostate cancer cells but not of normal prostate, lung, or kidney cells.

Cardiac Hormones Target the Ras-MEK 1/2-ERK 1/2 Kinase Cancer Signaling Pathways.

The heart is a sophisticated endocrine gland synthesizing the atrial natriuretic peptide prohormone which contains four peptide hormones, i.e., atrial natriuretic peptide, vessel dilator, kaliuretic peptide and long-acting natriuretic peptide, which decrease up to 97% of human pancreatic, breast, colon, prostate, kidney and ovarian carcinomas as well as small-cell and squamous cell lung cancer cells in cell culture. In vivo, these four cardiac hormones eliminate up to 80% of human pancreatic adenocarcinomas, two-thirds of human breast cancers, and up to 86% of human small-cell lung cancers growing in athymic mice. Their signaling in cancer cells includes inhibition of up to 95% of the basal activity of Ras, 98% inhibition of the phosphorylation of the MEK 1/2 kinases and 97% inhibition of the activation of basal activity of the ERK 1/2 kinases mediated via the intracellular messenger cyclic GMP. They also completely block the activity of mitogens such as epidermal growth factor's ability to stimulate ERK and Ras. They do not inhibit the activity of ERK in healthy cells such as human fibroblasts. The final step in their anticancer mechanism of action is that they enter the nucleus as demonstrated by immunocytochemical studies to inhibit DNA synthesis within cancer cells.

Vessel dilator and C-type natriuretic peptide enhance the proliferation of human osteoblasts.

C-natriuretic peptide (CNP) has been shown to regulate proliferation of mouse and rat osteoblasts. Genetic deletion of CNP results in dwarfism. Overexposure of CNP has been associated with arachnodactyly of hands and feet with a very long hallux bilaterally in a 14-y-old girl. CNP effects on bone growth involve inhibition of MEK 1 and ERK 1/2 kinases mediated via the intracellular messenger cGMP. Vessel dilator is another natriuretic peptide synthesized by the atrial natriuretic peptide gene whose biologic half-life is 12 times longer than CNP. Vessel dilator's biologic effects on proliferating cells are mediated via inhibiting MEK 1/2 and ERK 1/2 kinases via cGMP. Vessel dilator has never been studied on osteoblasts. CNP at 10 (nanomolar) nM (p = 0.02) and vessel dilator at 10 nM, 1 nM, 100 (picomolar) pM, and 10 pM (p ≤ 0.01) in dose-response studies enhanced human osteoblasts' proliferation. This first study of human osteoblasts would suggest that vessel dilator with a much longer biologic half-life and with osteoblast-stimulatory effects at lower concentrations than CNP may have therapeutic potential in human achondroplasia, short stature, and osteoporosis. Vessel dilator stimulates osteoblast proliferation whereas most current therapies of osteoporosis target osteoclasts.

Cardiac hormones inhibit proliferation of pancreatic cancer but not normal cells.

BACKGROUND: Four cardiac hormones, i.e. atrial natriuretic peptide (ANP), vessel dilator, long-acting natriuretic peptide (LANP) and kaliuretic peptide (KP), have anticancer effects both in vitro and in vivo. The sustained decrease in number of human pancreatic adenocarcinoma cells for 3 days secondary to the four hormones noted previously suggests a decrease in proliferation of pancreatic cancer cells not eliminated after initial treatment. MATERIALS AND METHODS: Four cardiac hormones were evaluated for their ability to directly decrease proliferation of human pancreatic cancer cells with comparison of their effects on proliferation on normal human lung, kidney, prostate and endothelial cells. RESULTS: ANP, LANP, vessel dilator and KP decreased the proliferation of viable human pancreatic adenocarcinoma cells by 39%, 73%, 26% and 32% respectively at their 0.01 microM concentrations compared with the proliferation of untreated pancreatic cancer cells. Maximal inhibition of proliferation (81%) occurred with LANP at its 0.1 microM concentration in dose-response studies. At these same concentrations, there was no decrease in proliferation of human kidney, lung, prostate or endothelial cells compared with untreated kidney, lung, prostate or endothelial cells. CONCLUSION: Four cardiac hormones have strong anti-proliferative effects on human pancreatic adenocarcinoma cells while sparing human kidney, lung, prostate and endothelial cells from a similar strong anti-proliferative effect. This anti-proliferative effect on pancreatic cancer cells helps to explain why human pancreatic cancers in vivo treated with the cardiac hormones decrease to less than 10% of the volume of untreated pancreatic cancers as they proliferate less.

Epidermal growth factor's activation of Ras is inhibited by four cardiac hormones.

BACKGROUND: Four cardiac hormones synthesized by the same gene, i.e. atrial natriuretic peptide, vessel dilator, kaliuretic peptide and long-acting natriuretic peptide, have anticancer effects in vitro and in vivo. Epidermal growth factor's mechanism of cancer formation involves the activation of Ras. MATERIALS AND METHODS: These four cardiac hormones were evaluated for their ability to inhibit mitogen (epidermal growth factor) activation of Ras. RESULTS: Epidermal growth factor increased the activation of Ras by 68%, 85% and 90% at its 1, 2 and 5 ng mL(-1) concentrations. Vessel dilator, long-acting natriuretic peptide, atrial natriuretic peptide and kaliuretic peptide inhibited 5 ng mL(-1) epidermal growth factor's stimulation of Ras by 73%, 79%, 33% and 45%, respectively, at their 1 microM concentrations. Their effects on epidermal growth factor's activation of Ras were specific with addition of the cardiac hormones' respective antibodies (5 microM) blocking 95%, 93%, 100% and 100% (P < 0.001 for each) of their ability to inhibit epidermal growth factor's stimulation of Ras. CONCLUSIONS: Four cardiac hormones specifically inhibit epidermal growth factor's activation of Ras. This investigation would suggest that these cardiac hormones' anticancer effects involve the inhibition of mitogens such as epidermal growth factor's ability to activate Ras as well as inhibiting unstimulated basal activity of Ras.