Cell kinetics and gene expression changes in colorectal cancer patients given resistant starch: a randomised controlled trial.
OBJECTIVE
This study investigated the effects of oral supplementation of resistant starch (RS) on tumour cell and colonic mucosal cell kinetics and on gene expression in patients with colorectal cancer (CRC), and its potential role in colon cancer prevention.


METHODS
65 patients with CRC were randomised to treatment with RS or ordinary starch (OS) and were given starch treatment for up to 4 weeks. Pretreatment and post-treatment biopsies were obtained from the tumour and colonic mucosa, and the effects of the starch treatment on cell proliferation and expression of the cell cycle regulatory genes CDK4 (cyclin-dependent kinase 4) and GADD45A (growth arrest and DNA damage-inducible, alpha) were investigated.


RESULTS
The proportion of mitotic cells in the top half of the colonic crypt was significantly lower following RS treatment (3.1 (1.5), mean (SEM)) as compared with OS treatment (13.7 (3.2)) (p = 0.028). However, there was no effect of RS treatment on crypt dimensions and tumour cell proliferation index. There was significant upregulation in expression of CDK4 (p<0.01) and downregulation in expression of GADD45A (p<0.001) in the tumour tissue when compared with macroscopically normal mucosa. Following RS treatment, CDK4 expression in tumours (0.88 (0.15)) was twofold higher than that in the OS group (0.37 (0.16)) (p = 0.02). The expression of GADD45A, which was downregulated in the presence of cancer, was significantly upregulated (p = 0.048) following RS treatment (1.41 (0.26)) as compared with OS treatment (0.56 (0.3)). However, there were no significant differences in the expression of these genes in the normal mucosa following starch treatment.


CONCLUSIONS
Cell proliferation in the upper part of colonic crypts is a premalignant marker and its reduction by RS supplementation is consistent with an antineoplastic action of this food component. Differential expression of the key cell cycle regulatory genes may contribute to the molecular mechanisms underlying these antineoplastic effects of RS.
Dronamraju
S S
SS
Department of General Surgery, North Tyneside General Hospital, Rake Lane, North Shields NE29 8NH, UK. mailshridhar@yahoo.com
Coxhead
J M
JM
Kelly
S B
SB
Burn
J
J
Mathers
J C
JC
D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D018797:Cell Cycle Proteins / Q000187:drug effects / Q000235:genetics / Q000378:metabolism*; D015179:Colorectal Neoplasms / Q000188:drug therapy / Q000378:metabolism* / Q000473:pathology; D051358:Cyclin-Dependent Kinase 4 / Q000187:drug effects / Q000235:genetics / Q000378:metabolism*; D004063:Digestion; D005260:Female; D015870:Gene Expression / Q000187:drug effects; D006801:Humans; D007413:Intestinal Mucosa / Q000187:drug effects / Q000378:metabolism* / Q000473:pathology; D008297:Male; D008875:Middle Aged; D009687:Nuclear Proteins / Q000187:drug effects / Q000235:genetics / Q000378:metabolism*; D013213:Starch / Q000378:metabolism / Q000494:pharmacology*; D000097642:GADD45 Proteins
D018797:Cell Cycle Proteins; D051358:Cyclin-Dependent Kinase 4; D009687:Nuclear Proteins; D013213:Starch; C439070:GADD45A protein, human; D000097642:GADD45 Proteins