Lam Wing, Jiang Zaoli, Guan Fulan, Hu Rong, Liu Shwu-Huey, Chu Edward, Cheng Yung-Chi
Department of Pharmacology, Yale University School of Medicine, New Haven, CT 06510, USA.
BMC Complement Altern Med. 2014 Dec 15;14:490. doi: 10.1186/1472-6882-14-490.
The four-herb Chinese medicine PHY906(KD018) has been shown to both enhance the in vivo antitumor activity of irinotecan (CPT-11) against colon cancer tumor allografts and alleviate intestinal toxicity caused by CPT-11.
Since intestinal bacteria can metabolize CPT-11 and PHY906, we investigated whether intestinal bacteria play a critical role in the in vivo activity of PHY906 in murine Colon-38 tumor-bearing mice. Intestinal bacteria were depleted using streptomycin/neomycin for 10 days before and during treatment with PHY906 and/or CPT-11. qPCR using 16S DNA group-specific primers was used to quantify the levels of the major intestinal bacteria.
Both PHY906 and antibiotic treatment changed the profile of intestinal bacteria species: Lactobacillus/Enterococcus, Bacteroides, Clostridium leptum, and E. rectale/C. coccoides. Antibiotic treatment did not alter the ability of PHY906 to enhance the antitumor activity of CPT-11. Antibiotic treatment alone partially reduced animal body weight loss in CPT-11-treated mice. However, PHY906 treatment was able to protect against the body weight loss in the CPT-11/antibiotic treatment group. H&E and PCNA staining of intestine showed that antibiotic treatment partially reduced the intestinal damage caused by CPT-11 but not as effectively as PHY906 treatment. Antibiotic treatment plus PHY906 conferred the most effective protection of intestine histological structure against damage by CPT-11. Both PHY906 and antibiotic treatment inhibited CPT-11-associated inflammatory processes, including infiltration of the intestine by neutrophils, MCP1 and TNF-alpha mRNA expression in the intestine, and expression of pro-inflammatory cytokines G-CSF and MCP1 proteins in the plasma. However, whereas antibiotic treatment suppressed the mRNA expression of two important intestinal progenitor/stem cell markers, Olfm4 and Lgr5, PHY906 treatment resulted in enhanced expression of these two stem cell markers.
Alterations in the population of intestinal bacteria did not affect the abilities of PHY906 to enhance CPT-11 antitumor activity or reduce the intestinal toxicity associated with CPT-11 treatment. The major species of intestinal bacteria do not appear to play a role in PHY906's enhancement of the therapeutic index of CPT-11 in tumor-bearing mice. Thus, patients with different intestinal bacterial profiles may still benefit from PHY906 treatment alongside CPT-11.
中药复方PHY906（KD018）已被证明既能增强伊立替康（CPT-11）对结肠癌移植瘤的体内抗肿瘤活性，又能减轻CPT-11引起的肠道毒性。
由于肠道细菌可代谢CPT-11和PHY906，我们研究了肠道细菌在荷Colon-38肿瘤小鼠体内PHY906活性中是否起关键作用。在使用PHY906和/或CPT-11治疗前及治疗期间，用链霉素/新霉素清除肠道细菌10天。使用16S DNA组特异性引物的qPCR用于定量主要肠道细菌的水平。
PHY906和抗生素治疗均改变了肠道细菌种类的分布：乳酸杆菌/肠球菌、拟杆菌、纤细梭菌和直肠真杆菌/球形梭菌。抗生素治疗并未改变PHY906增强CPT-11抗肿瘤活性的能力。单独使用抗生素治疗可部分减轻CPT-11治疗小鼠的体重减轻。然而，PHY906治疗能够防止CPT-11/抗生素治疗组的体重减轻。肠道的苏木精-伊红（H&E）染色和增殖细胞核抗原（PCNA）染色显示，抗生素治疗可部分减轻CPT-11引起的肠道损伤，但效果不如PHY906治疗。抗生素治疗加PHY906对肠道组织结构提供了最有效的保护，使其免受CPT-11的损伤。PHY906和抗生素治疗均抑制了与CPT-11相关的炎症过程，包括中性粒细胞浸润肠道、肠道中MCP1和TNF-α mRNA表达以及血浆中促炎细胞因子G-CSF和MCP1蛋白的表达。然而，抗生素治疗抑制了两种重要的肠道祖细胞/干细胞标志物Olfm4和Lgr5的mRNA表达，而PHY906治疗则导致这两种干细胞标志物的表达增强。
肠道细菌群体的改变并不影响PHY906增强CPT-11抗肿瘤活性或降低与CPT-11治疗相关的肠道毒性的能力。主要的肠道细菌种类似乎在PHY906提高荷瘤小鼠CPT-11治疗指数方面不起作用。因此，具有不同肠道细菌谱的患者在接受CPT-11治疗的同时仍可能从PHY906治疗中获益。
