Department of Molecular Medicine, Faculty of Medicine, University of Malaya, Kuala Lumpur, Malaysia.
Parasitol Res. 2012 Jun;110(6):2475-80. doi: 10.1007/s00436-011-2788-3. Epub 2012 Jan 26.
The pathogenesis of Blastocystis hominis in human hosts has always been a matter of debate as it is present in both symptomatic and asymptomatic individuals. A recent report showed that B. hominis isolated from an asymptomatic individual could facilitate the proliferation and growth of existing cancer cells while having the potential to downregulate the host immune response. The present study investigated the differences between the effects of symptomatic and asymptomatic derived solubilized antigen of B. hominis (Blasto-Ag) on the cell viability and proliferation of colorectal cancer cells. Besides that, the gene expression of cytokine and nuclear transcriptional factors in response to the symptomatic and asymptomatic B. hominis antigen in HCT116 was also compared. In the current study, an increase in cell proliferation was observed in HCT116 cells which led to the speculation that B. hominis infection could facilitate the growth of colorectal cancer cells. In addition, a more significant upregulation of Th2 cytokines observed in HCT116 may lead to the postulation that symptomatic Blasto-Ag may have the potential in weakening the cellular immune response, allowing the progression of existing tumor cells. The upregulation of nuclear factor kappa light chain enhancer of activated B cells (NF-κB) was observed in HCT116 exposed to symptomatic Blasto-Ag, while asymptomatic Blasto-Ag exhibited an insignificant effect on NF-κB gene expression in HCT116. HCT116 cells exposed to symptomatic and asymptomatic Blasto-Ag caused a significant upregulation of CTSB which lead to the postulation that the Blasto-Ag may enhance the invasive and metastasis properties of colorectal cancer. In conclusion, antigen isolated from a symptomatic individual is more pathogenic as compared to asymptomatic isolates as it caused a more extensive inflammatory reaction as well as more enhanced proliferation of cancer cells.
人源芽囊原虫的发病机制一直存在争议，因为它存在于有症状和无症状个体中。最近的一份报告显示，从无症状个体中分离出的芽囊原虫能够促进现有癌细胞的增殖和生长，同时有可能下调宿主免疫反应。本研究旨在探讨有症状和无症状来源的可溶性芽囊原虫抗原（Blasto-Ag）对结直肠癌细胞活力和增殖的影响差异。此外，还比较了 HCT116 对有症状和无症状芽囊原虫抗原的细胞因子和核转录因子的基因表达。在本研究中，观察到 HCT116 细胞的增殖增加，这使得人们推测芽囊原虫感染可能促进结直肠癌细胞的生长。此外，在 HCT116 中观察到 Th2 细胞因子的上调更为显著，这可能导致有症状的 Blast-Ag 可能具有削弱细胞免疫反应的潜力，从而允许现有肿瘤细胞的进展。在暴露于有症状的 Blast-Ag 的 HCT116 中观察到核因子 kappa 轻链增强子的激活 B 细胞（NF-κB）的上调，而无症状的 Blast-Ag 对 HCT116 中 NF-κB 基因表达没有显著影响。暴露于有症状和无症状的 Blast-Ag 的 HCT116 导致 CTSB 的显著上调，这使得人们推测 Blast-Ag 可能增强结直肠癌细胞的侵袭和转移特性。总之，与无症状分离株相比，来自有症状个体的抗原更具致病性，因为它引起了更广泛的炎症反应以及更增强的癌细胞增殖。
