The human prostatic carcinoma cell line LNCaP expresses biologically active, specific receptors for 1 alpha,25-dihydroxyvitamin D3.

The LNCaP prostatic carcinoma cell line was examined for the presence of specific receptors for 1 alpha,25-dihydroxyvitamin D3 [1 alpha,25-(OH)2D3]. Whole cell binding studies identified approximately 2500 high-affinity (Kd = 1.4 x 10(-9) binding sites per cell. Competition studies revealed that these receptors are specific for the 1 alpha,25(OH)2 metabolite. Binding studies using the synthetic androgen R1881 indicate that separate androgen and vitamin D3 receptors exist in LNCaP cells. The vitamin D3 receptors sediment at approximately 3.5S on linear sucrose gradients. The sedimentation coefficient could be shifted with a monoclonal anti-vitamin D3 receptor antibody (9A7 gamma) but not with a monoclonal antibody to the androgen receptor (AN1-15). The receptor/ligand complex elutes from native DNA cellulose at 0.2 M KCl. Northern blot analysis identified an mRNA of approximately 4.6 kilobases which hybridized with a specific vitamin D3 receptor complementary DNA probe (hVDR). In the absence of androgens, 1 alpha,25(OH)2D3 stimulated growth and prostate-specific antigen production by LNCaP cells in a dose-dependent fashion. Dose-response curves indicated that at physiological concentrations (10(-9) M) 1 alpha,25(OH)2D3 was mitogenic, whereas at higher concentrations (10(-8) M) it promotes differentiation. These studies suggest that 1 alpha,25(OH)2D3 could play an important role in the natural history of and response to hormone therapy by prostatic cancer.

Preoperative versus postoperative irradiation in the prophylaxis of heterotopic bone formation in rats.

Irradiation treatment, commenced within 1-5 days post-surgery, reliably prophylaxes heterotopic bone formation but is painful and impairs desirable postop immobilization. To compare pre- versus post-op radiation, we bilaterally implanted bone matrix pellets into the thighs of 111 30-day-old Long Evans rats. Rats were randomized to time of radiation initiation (2 days pre-op, 1 hr pre-op, or 2 days post-op) and dose (300, 800, 1800, 2400, or 3000 cGy in 1 fraction). Pellets were removed on post-op day 16 or 48 and evaluated histologically and radiologically. Histologic analysis showed dose-related suppression in bone formation, that is, 40%, 27%, 6.8%, 2.5%, 6.4%, and 0.0% bone formed among sites receiving 0, 300, 800, 1800, 2400, and 3000 cGy, respectively. The difference in bone formation between control and irradiated implant sites was significant at every dose level in all treatment groups (p less than or equal to .03). There was no statistically significant difference in overall bone formation between post-op (7.1%) and 1 hr pre-op (5.3%) groups, whereas 2 day pre-op rats formed significantly more bone (12.6%). Stratified by dose, however, there were no significant differences between treatment groups except at 800 cGy. At this dose, 2 day pre-op rats formed more bone (10.6%) than 1 hr pre-op (6.6%) or post-op (3.3%) groups. Results suggest that a) radiation given shortly prior to a stimulus inducing proliferation among multipotential cells may inhibit subsequent proliferation and/or differentiation, and b) clinical formation of heterotopic bone may be preventable via modest doses of irradiation delivered shortly prior to surgery.

Identification of normal or neoplastic murine mesenchymal cells in chimeric tissues or heterotransplants.

An improved method for identifying murine mesenchymal cells in chimeric tissues or heterotransplants using Hoechst dye 33258 is described. Following fixation in formalin-saline, tissues are embedded in JB-4 plastic. Sections 3 micron thick are then stained in a 10 microgram/ml solution of Hoechst 33258 in Hanks' balanced salt solution for 5-10 min at 4 C. After rising, the sections are coverslipped using a modified polyvinyl alcohol mounting medium. This approach offers several advantages over existing techniques: 1) uniform section thickness is more easily obtained than with paraffin or cryostat microtomy, thereby allowing improved resolution and more reliable identification of mesenchymal cells with small nuclei such as skeletal muscle myocytes or fibroblasts, 2) the preparations are stable over long periods and can be repeatedly viewed or photographed, and 3) calcified tissues can be examined without prior decalcification. An example is shown of species identification using rat chondrosarcoma cells grown in nude mice.

Phenotypic modulation of the swarm rat chondrosarcoma induced by morphogenetic bone matrix.

The recognized similarities between developing embryonic tissues and neoplastic cells have led to a number of experimental demonstrations which indicate that inductive microenvironments can alter the malignant phenotype. In postnatal life a morphogenetic cascade resembling endochondral bone development can be induced by s.c. implantation of demineralized diaphyseal bone matrix. We have examined the ability of this microenvironment to alter the phenotype of the transplantable Swarm rat chondrosarcoma in mixed implants. Neoplastic chondrocytes could be distinguished from host cells by nuclear morphometry since the nuclear area of the neoplastic chondrocytes was 2 to 3 times larger than that of comparable host-derived chondrocytes. Through the first 7 days post-implantation tumor cells in the presence of morphogenetically active matrix are morphologically indistinguishable from those implanted with morphogenetically inactivated matrix or implanted by themselves. With the advent of host cell chondrogenesis, however, adjacent neoplastic cells begin to undergo chondrolysis and calcification. Only those cells in the immediate proximity of host morphogenetic foci appear affected. An average of 26.7 +/- 7.0% (SD) of the implant surface areas examined revealed such changes. Chondrosarcoma cells implanted by themselves or in the presence of morphogenetically inactivated bone matrix underwent no such changes. These results suggest that factors released from host cells induced to undergo bone morphogenesis are capable of altering the differentiated phenotype of neoplastic cells.

Epithelioma cuniculatum plantare.

Epithelioma cuniculatum plantare is a tumor of epithelial origin occurring on the plantar aspect of the foot. It is an uncommon, locally aggressive neoplasm, not limited to this area, and in other body sites is referred to as verrucous carcinoma. The history and treatment of a patient with plantar verrucous carcinoma is presented; a survey of the literature reflects difficulty in establishing an early diagnosis. This, however, can be facilitated when the gross appearance and a history of prior surgical attempts to excise the lesion are known to the surgeon and the pathologist, and the surgical specimen ideally encompasses the deeper portions of the lesion.