The cytotoxic effect of Bowman-Birk isoinhibitors, IBB1 and IBBD2, from soybean (Glycine max) on HT29 human colorectal cancer cells is related to their intrinsic ability to inhibit serine proteases.
Bowman-Birk inhibitors (BBI) from soybean and related proteins are naturally occurring protease inhibitors with potential health-promoting properties within the gastrointestinal tract. In this work, we have investigated the effects of soybean BBI proteins on HT29 colon adenocarcinoma cells, compared with non-malignant colonic fibroblast CCD-18Co cells. Two major soybean isoinhibitors, IBB1 and IBBD2, showing considerable amino acid sequence divergence within their inhibitory domains, were purified in order to examine their functional properties, including their individual effects on the proliferation of HT29 colon cancer cells. IBB1 inhibited both trypsin and chymotrypsin whereas IBBD2 inhibited trypsin only. Despite showing significant differences in their enzyme inhibitory properties, the median inhibitory concentration values determined for IBB1 and IBBD2 on HT29 cell growth were not significantly different (39.9+/-2.3 and 48.3+/-3.5 microM, respectively). The cell cycle distribution pattern of HT29 colon cancer cells was affected by BBI treatment in a dose-dependent manner, with cells becoming blocked in the G0-G1 phase. Chemically inactive soybean BBI had a weak but non-significant effect on the proliferation of HT29 cells. The anti-proliferative properties of BBI isoinhibitors from soybean reveal that both trypsin- and chymotrypsin-like proteases involved in carcinogenesis should be considered as potential targets of BBI-like proteins.
Clemente
Alfonso
A
Department of Physiology and Biochemistry of Nutrition, Estación Experimental del Zaidín (CSIC), Granada, Spain. alfonso.clemente@eez.csic.es
Moreno
Francisco Javier
FJ
Marín-Manzano
Maria del Carmen
Mdel C
Jiménez
Elisabeth
E
Domoney
Claire
C
D000230:Adenocarcinoma / Q000473:pathology / Q000517:prevention & control*; D000478:Alkylation; D016588:Anticarcinogenic Agents / Q000737:chemistry / Q000302:isolation & purification / Q000494:pharmacology*; D049109:Cell Proliferation / Q000187:drug effects*; D002470:Cell Survival / Q000187:drug effects; D002918:Chymotrypsin / Q000037:antagonists & inhibitors; D015179:Colorectal Neoplasms / Q000473:pathology / Q000517:prevention & control*; D004305:Dose-Response Relationship, Drug; D019073:HT29 Cells; D006801:Humans; D020128:Inhibitory Concentration 50; D010449:Peptide Mapping; D054730:Protein Interaction Domains and Motifs; D020033:Protein Isoforms / Q000737:chemistry / Q000302:isolation & purification / Q000494:pharmacology; D016192:Resting Phase, Cell Cycle / Q000187:drug effects; D016415:Sequence Alignment; D015842:Serine Proteinase Inhibitors / Q000737:chemistry / Q000302:isolation & purification / Q000494:pharmacology*; D013997:Time Factors; D014358:Trypsin Inhibitor, Bowman-Birk Soybean / Q000737:chemistry / Q000302:isolation & purification / Q000494:pharmacology*; D014361:Trypsin Inhibitors / Q000737:chemistry / Q000302:isolation & purification / Q000494:pharmacology
D016588:Anticarcinogenic Agents; D020033:Protein Isoforms; D015842:Serine Proteinase Inhibitors; D014358:Trypsin Inhibitor, Bowman-Birk Soybean; D014361:Trypsin Inhibitors; D002918:Chymotrypsin