calcitonin and Carcinoma--Squamous-Cell

Serum bone Gla protein (BGP) and alkaline phosphatase (AP) activity were compared for the assessment of skeletal status in 11 normal pregnant women, 12 normal women on days 3 and 13 of the menstrual cycle, five postmenopausal women before and after 1 month of treatment with ethinyl estradiol (20 micrograms/day), five patients with cancer and hypercalcemia during treatment with calcitonin, and one patient with Paget disease during treatment with Plicamycin. BGP and AP correlated with each other only in the pregnant women. In all other circumstances, there was no correlation between these two serum osteoblast products. Furthermore, there were conditions in which the two measurements became discordant. These studies demonstrate that BGP and AP commonly are dissociated when used as measurements of skeletal status. Although both are osteoblast products, BGP and AP probably reflect different aspects of osteoblast differentiation and function.

Topics: Adult; Alkaline Phosphatase; Calcitonin; Carcinoma, Squamous Cell; Ethinyl Estradiol; Female; Humans; Hypercalcemia; Lung Neoplasms; Middle Aged; Multiple Myeloma; Osteocalcin; Postmenopause; Pregnancy

Topics: Aged; Bronchial Neoplasms; Calcitonin; Carcinoma, Squamous Cell; Diphosphonates; Drug Therapy, Combination; Humans; Hypercalcemia; Male

The osteoclast is the unique multinucleated cell that is responsible for bone degradation in both physiological and pathological circumstances. However, knowledge of the lineage of this inaccessible cell, the nature of its precursors, and the regulation of its formation and activation is limited and controversial. Here we show that the human promyelocytic cell line HL-60 has the potential, under the appropriate culture conditions, to differentiate into cells that have morphological and functional characteristics of osteoclasts, including multinucleation, presence of tartrate-resistant acid phosphatase activity, cross-reactivity with monoclonal antibodies that preferentially recognize osteoclasts, and capacity to resorb bone and respond to calcitonin. The multinucleated cells also contain high affinity receptors to calcitonin, in contrast to wild-type undifferentiated HL-60 cells. These data suggest that osteoclasts share a common precursor with hematopoietic cells. These undifferentiated and differentiated HL-60 cells should provide a unique model for study of the cell biology of human osteoclast differentiation, allowing molecular biological and biochemical studies heretofore not possible.

Topics: Bone Resorption; Calcitonin; Calcitriol; Carcinoma, Squamous Cell; Cell Differentiation; Cell Nucleus; Hematopoietic Stem Cells; Humans; Immunoenzyme Techniques; Leukemia, Promyelocytic, Acute; Osteoclasts; Phenotype; Receptors, Calcitonin; Receptors, Cell Surface; Tumor Cells, Cultured