PubMed · 921105
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I Holló, J Szücs, M Boross, F Szalay. 1977. Osteopenia.. https://doi.org/10.7326/0003-4819-87-5-637_1
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Locally secreted growth factors and neuropeptides may play an important role in sustaining the growth of hormone-independent prostate cancer. Our previous studies have shown that calcitonin-like immunoreactive peptide (CTI) is secreted by primary prostate cells in culture, and its secretion from malignant prostate cells is significantly higher than benign cells. Exogenously added calcitonin (CT) induces DNA synthesis in serum-starved prostate cancer LNCaP and PC-3M cells. Present studies extended these findings by cloning cDNAs for CT and CT receptor (CT-R) from prostate cancer cells and studying the expression of CT and CT-R mRNA in prostate cancer cell lines and primary prostate tumor specimens. The results have shown that PC-3 cells expressed CT, and not CT-R, mRNA, whereas CT-R, but not CT, mRNA was expressed by LNCaP cells. Conditioned media from PC-3 cells induced DNA synthesis of LNCaP cells, and this mitogenic response was abolished by anti-CT serum. Highly aggressive PC-3M cells co-expressed CT and CT-R mRNAs. CT also induced a twofold increase in DNA synthesis of primary prostate cells and anti-CT serum caused a 56% decline. In-situ hybridization histochemistry of archival prostate specimens has selectively localized CT and CT-R mRNA in basal epithelium of benign and low grade PC specimens, and these mRNAs were not detected in either luminal epithelium or stroma. In contrast, CT and CT-R mRNA were detected throughout the luminal epithelium of moderate and high-grade PC specimens. Most epithelial cells of low and moderately differentiated tumors expressed either CT or CT-R mRNA, suggesting that CT may serve as a paracrine factor. In contrast, CT and CT-R mRNAs were co-expressed by most tumor cells in advanced PC specimens. The cells expressing CT-R mRNA in primary tumors also co-expressed PCNA. These results, when combined with mitogenic actions of CT on primary prostate cells as well as PC cell lines, strongly support the role for CT in sustaining the growth of cancer cells.
Family physicians will frequently encounter patients with osteoporosis, a condition that is often asymptomatic until a fracture occurs. Treatment of the fracture can be initiated without further diagnostic testing. Thereafter, treatment of osteoporosis includes (1) prevention of further bone loss through weight-bearing exercise, tobacco and alcohol avoidance, hormone replacement therapy in women, and raloxifene and calcium supplementation; (2) treatment of fracture-related pain with analgesics and calcitonin; (3) building bone mass when feasible with alendronate; and (4) modifying behaviors that increase the risk of falls. Patients without fracture who are at risk for osteoporosis can also benefit from these preventive measures. Furthermore, women of all ages should be encouraged to maintain a daily calcium intake of 1,000 to 1,500 mg and to participate in weight-bearing exercise for 30 minutes three times weekly to reduce their risk of falls and fractures. Persons at risk should avoid medications known to compromise bone density, such as glucocorticoids, thyroid hormones and chronic heparin therapy.
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