calcipotriene and Adenomatous-Polyposis-Coli

Multiple genetic and environmental steps may underpin the development of human colorectal neoplasia, and experimental evidence suggests that promoters of colorectal cancer also induce colorectal epithelial cell hyperplasia. In vitro crypt cell production rate (CCPR) was measured to determine the effect of calcium, epidermal growth factor (EGF), vitamin D3 metabolites and synthetic analogues on human rectal epithelial cell proliferation. In a double-blind trial of oral calcium supplementation, CCPR was reduced by 49% in patients with familial adenomatous polyposis (FAP), but there was no effect on established neoplasia. In control tissue, the active form of vitamin D3 (1,25(OH)2D3) reduced rectal CCPR by 57% at 1 microM, 55% at 10 nM and 45% at 100 pM. Likewise, in tissue taken from patients with FAP, 1,25(OH)2D3 reduced CCPR by 52%. Vitamin D3 has profound effects on calcium metabolism, but synthetic analogues can avoid these. The effects of a synthetic analogue (MC-903) on human rectal CCPR were therefore studied. MC-903 (10(-7) M) reduced CCPR in control tissue by 51%, and in FAP tissue by 52% at 10(-6) M and 51% at 10(-7) M. In addition, MC-903 and a related analogue, EB 1089, produced a clear-cut dose-dependent inhibition of both HT-29 and Caco2 colorectal cancer cells maintained in culture. Hence, vitamin D3 and its analogues can reduce the rate of cell proliferation in normal, premalignant and malignant colorectal epithelial cells and might therefore have future therapeutic uses as chemoprotective or chemotherapeutic agents. Lastly, EGF increases CCPR by 102% in FAP tissue that expresses the EGF receptor. Thus, human colorectal cell proliferation is influenced by a variety of luminal and humoral agents and a greater understanding of these actions should help plan future treatments.

Topics: Adenomatous Polyposis Coli; Adolescent; Adult; Aged; Antineoplastic Agents; Calcitriol; Calcium; Cell Division; Double-Blind Method; Epithelium; Female; Humans; In Vitro Techniques; Male; Middle Aged; Rectum; Vitamin D

Vitamin D may protect against colorectal cancer by reducing cell proliferation and inducing differentiation. By contrast, epidermal growth factor (EGF) stimulates cell proliferation and may encourage gastrointestinal mucosal healing. This study investigated the effect of a synthetic vitamin D analogue, calcipotriol, and EGF on human rectal epithelial cell proliferation in patients with familial adenomatous polyposis (FAP). In addition, a new technique to measure the cell cycle time is described. Sigmoidoscopic biopsy specimens were obtained from 14 patients with FAP. Tissue was established in organ culture, with or without the addition of EGF (n = 8), or calcipotriol (n = 6). Proliferation was determined using (a) metaphase arrest to measure the crypt cell production rate, (b) native mitotic index, and (c) the growth fraction using PC10 antibody. EGF receptor expression was shown using a polyclonal antibody AP12E. Calcipotriol reduced crypt cell production rate by 52% from mean (SEM) 5.29 (1.18) to 2.56 (0.80) cells/crypt/hour (p < 0.01) and EGF increased crypt cell production rate by 102% from 3.62 (0.59) to 7.33 (0.90) cells/crypt/hour (p < 0.05), and this tissue expressed the EGF receptor. The growth fraction was 48.40 (4.0)%, and the native mitotic index 1.08 (0.14)%. The cell cycle time was estimated as 94.5 hours and the time for mitosis as one hour. Thus, calcipotriol and EGF have divergent effects on human rectal mucosal proliferation.

Topics: Adenomatous Polyposis Coli; Adult; Aged; Calcitriol; Cell Cycle; Epidermal Growth Factor; ErbB Receptors; Humans; In Vitro Techniques; Intestinal Mucosa; Middle Aged; Mitotic Index; Proliferating Cell Nuclear Antigen; Rectum; Stimulation, Chemical; Time Factors

Like calcium, vitamin D may protect against colorectal neoplasia as it reduces epithelial cell proliferation and induces differentiation. Although its therapeutic use is limited by its effects on calcium metabolism, analogues such as calcipotriol produce little hypercalcaemia. Stathmokinetic and immunohistochemical techniques were used to study the effect of 1,25 (OH)2 D3 and its analogues on cell proliferation in human rectal mucosa and a colon cancer cell line. Paired sigmoidoscopic biopsy specimens were obtained from 17 control patients and five patients with familial adenomatous polyposis. Explants were established in organ culture, with or without the addition of vitamin D. Proliferation was assessed using (1) metaphase arrest to determine the crypt cell production rate (CCPR) and (2) Ki-67 monoclonal antibody directed against an antigen present in proliferating cells. 1,25 (OH)2 D3 in concentrations of 1 microM-100 pM (10(-6)-10(-10) M) reduced the CCPR (cells/crypt/hour) from 4.74 to 2.15-2.67 (p < 0.001), and the Ki-67 labelling index from 7.28-3.74 (p < 0.01). Likewise, vitamin D2, 10 nM (10(-8) M) reduced the CCPR from 4.74-2.74 (p < 0.05) and calcipotriol from 4.86-2.38 (p < 0.05). In familial adenomatous polyposis patients 1,25 (OH)2 D3 100 pM (10(-10) M) halved the CCPR from 8.75-4.22. Calcipotriol (10(-5) M to 10(-9) M) produced a clearcut dose response inhibition of HT-29 cell growth. Thus, vitamin D and its metabolites inhibit proliferation in normal and premalignant rectal epithelium and suppress growth in a colorectal cancer cell line.

Topics: Adenomatous Polyposis Coli; Adult; Calcitriol; Cell Division; Colonic Neoplasms; Ergocalciferols; Humans; Immunohistochemistry; Intestinal Mucosa; Rectum; Tumor Cells, Cultured; Vitamin D