The American Journal of Chinese Medicine, Vol. 42, No. 6, 1555–1558 © 2014 World Scientific Publishing Company Institute for Advanced Research in Asian Science and Medicine DOI: 10.1142/S0192415X1420002X
Am. J. Chin. Med. 2014.42:1555-1558. Downloaded from www.worldscientific.com by UNIVERSITY OF AUCKLAND LIBRARY - SERIALS UNIT on 02/09/15. For personal use only.
Letter Natural Products and Chemotherapeutic Agents on Cancer: Prevention vs. Treatment Chong-Zhi Wang, Zhiyu Zhang, Samantha Anderson and Chun-Su Yuan Tang Center for Herbal Medicine Research University of Chicago Chicago, IL 60637, USA Published 5 December 2014
Abstract: Natural products play an important role in cancer therapeutics, and lately more attentions have been paid to the prevention of major lethal malignancies, such as colorectal cancer (CRC). After oral ingestion, botanicals’ parent compounds can be converted to their metabolites by the enteric microbiome, and these metabolites may have different bioactivities and variable bioavailability. In this study, we used an active ginseng metabolite, protopanaxadiol (PPD), as an example to assess its colon cancer preventive effect by comparing its effect with the treatment effect of fluorouracil (5-FU). A xenograft tumor nude mouse model with human colon cancer cell inoculation was used. After preventive PPD or treatment 5-FU administration with the same dose (30 mg/kg), tumor growth inhibition was evaluated by both a Xenogen bioluminescence imaging technique and manual tumor size measurement. Our data showed that preventive PPD very significantly inhibited the tumor growth compared to 5-FU ( p < 0:01). Our data suggest that the PPD is a promising cancer prevention agent. More studies are needed to explore the chemopreventive actions of PPD and its potential clinical utility. Keywords: American Ginseng; Enteric Microbiome; Protopanaxadiol; PPD; Metabolite; Colorectal Cancer; Fluorouracil; 5-FU.
Cancer is a group of devastating diseases, all of which involve unregulated cell growth. Colorectal cancer (CRC) is one of the primary lethal cancers in the world, and here we are using the CRC as an example. Since current available therapies for advanced CRC have limited efficacy, increased attention has been focused on its prevention, including the use of botanical compounds, such as American ginseng (Attele et al., 1999).
Correspondence to: Dr. Chong-Zhi Wang, Tang Center for Herbal Medicine Research, University of Chicago, Chicago, IL 60637, USA. E-mail: [email protected]
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Am. J. Chin. Med. 2014.42:1555-1558. Downloaded from www.worldscientific.com by UNIVERSITY OF AUCKLAND LIBRARY - SERIALS UNIT on 02/09/15. For personal use only.
1556
C.-Z. WANG et al.
Nearly all natural products are administered orally in humans. Unlike parenteral administration that has been used in many animal studies, the enteric microbiome plays an important role after oral botanical intake in converting the parent compounds to metabolites. These metabolites may have different bioactivities and variable bioavailability compared to their parent compounds. In this study, we use an active ginseng metabolite, protopanaxadiol (PPD), as an example to discuss its CRC prevention effect. This effect was compared to the treatment effect of a commonly used chemotherapeutic agent, fluorouracil (5-FU). After oral ingestion, the bioavailability of ginseng is low due to incomplete parent compound absorption and conversion to metabolites by the enteric microbiome via the stepwise cleavage of sugar moieties (Hasegawa, 2004; Wan et al., 2013). We recently demonstrated the conversion of ginseng saponins by the human enteric microbiome and detected over 20 metabolites ( Wan et al., 2013). Compound K and PPD are the major reported metabolites that reach systemic circulation (Fig. 1), and the latter has more significant anti-CRC potential compared to the former (Gao et al., 2013).
Figure 1. Biotransformation pathways of major ginseng parent compounds, ginsenosides Rb1, Rc and Rd, to their metabolites by the enteric microbiome. A bioactive ginseng metabolite, compound K, can mainly be further converted to PPD.
Am. J. Chin. Med. 2014.42:1555-1558. Downloaded from www.worldscientific.com by UNIVERSITY OF AUCKLAND LIBRARY - SERIALS UNIT on 02/09/15. For personal use only.
LETTER — BOTANICALS FOR CHEMOPREVENTION
1557
In this study, we compared the prevention effect of PPD to the treatment effect of 5-FU using a xenograft tumor model with human HCT-116-Luc colon cancer cell inoculation in immunodeficient BALB/c nude mice (Harlan, Indianapolis, IN) (Gao et al., 2013). The cancer cell inoculation was conducted 7 days prior to Day 1. Intraperitoneal PPD 30 mg/kg injection started 7 days prior to Day 1 as chemoprevention. 5-FU (30 mg/kg) was given once per week starting Day 1 as cancer treatment. This 30 mg/kg dose of 5-FU is a fairly commonly used in vivo to treat animal malignancies. Tumor growth inhibition observation started on Day 1 and was monitored by two methods: (1) Xenogen bioluminescence imaging up to 20 days (Gao et al., 2013). Beyond Day 20, this imaging technique is no longer accurate possibly due to the compromised blood circulation within the tumors that affects the image intensity. (2) Manual tumor size measurement was used up to Day 43, and the calculation is as follows: Tumor size in volume ¼ ðWidthÞ 2 ðLengthÞ=2. Data were presented as mean SE and analyzed using analysis of variance (ANOVA) for repeated measures and Student’s t-test. The level of statistical significance was set at p < 0:05. As shown in Fig. 2, compared to the control mice, 5-FU treatment significantly inhibited the tumor growth using both the imaging technique and tumor size measurement. For tumor prevention, PPD was given starting 7 days prior to Day 1, or at time of cancer cell inoculation. Interesting, PPD very significantly inhibited the CRC growth compared to
(A)
(B)
Figure 2. Prevention and treatment effect comparison between PPD and fluorouracil (5-FU) in xenografted athymic mice inoculated with human colon cancer cells. (A) Tumor growth inhibition is monitored by a bioluminescence imaging technique up to 20 days. (B) Tumor size change (in volume) is manually measured up to 43 days. n ¼ 8 per group. 5-FU, 5-FU 30 mg/kg once per week starting Day 1; Pre-PPD, PPD (30 mg/kg) every other day starting 7 days prior to Day 1. þ , p < 0:05 compared to the control group; **p < 0:01 compared to the 5-FU group.
Am. J. Chin. Med. 2014.42:1555-1558. Downloaded from www.worldscientific.com by UNIVERSITY OF AUCKLAND LIBRARY - SERIALS UNIT on 02/09/15. For personal use only.
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C.-Z. WANG et al.
the 5-FU group ( p < 0:01), especially toward the end of the observation. Note that, starting approximately at Day 40, the mice in the control group became very sick due to the terminal stage of the cancer. Natural products may play an important role in cancer chemoprevention (Wang et al., 2012). Attempts have been made to use botanicals for the chemoprevention of major malignancies (Chen et al., 2013; Liu et al., 2013; Wen et al., 2013; Zhang et al., 2013). We are very encouraged by our preliminary data reported here that PPD, an active metabolite of American ginseng after enteric microbiome metabolism, possesses excellent cancer prevention effects. Before moving to the next stage of PPD investigation, more studies are needed to obtain data from additional experimental groups, including the dose-related observations. Nonetheless, our data suggests that PPD is a promising cancer prevention agent. Acknowledgments This work was supported in part by the NIH/ NCCAM grants AT004418 and AT005362. References Attele, A.S., J.A. Wu and C.S. Yuan. Ginseng pharmacology: Multiple constituents and multiple actions. Biochem. Pharmacol. 58: 1685–1693, 1999. Chen, Y.C., H.Y. Chang, J.S. Deng, J.J. Chen, S.S. Huang, I.H. Lin, W.L. Kuo, W. Chao and G.J. Huang. Hispolon from Phellinus linteus induces G0/G1 cell cycle arrest and apoptosis in NB4 human leukaemia cells. Am. J. Chin. Med. 41: 1439–1457, 2013. Gao, J.L., G.Y. Lv, B.C. He, B.Q. Zhang, H. Zhang, N. Wang, C.Z. Wang, W. Du, C.S. Yuan and T.C. He. Ginseng saponin metabolite 20(S)-protopanaxadiol inhibits tumor growth by targeting multiple cancer signaling pathways. Oncol. Rep. 30: 292–298, 2013. Hasegawa, H. Proof of the mysterious efficacy of ginseng: Basic and clinical trials: Metabolic activation of ginsenoside: Deglycosylation by intestinal bacteria and esterification with fatty acid. J. Pharmacol. Sci. 95: 153–157, 2004. Liu, S., X.J. Wang, Y. Liu and Y.F. Cui. PI3K/AKT/mTOR signaling is involved in (-)-epigallocatechin-3-gallate-induced apoptosis of human pancreatic carcinoma cells. Am. J. Chin. Med. 41: 629–642, 2013. Wan, J.Y., P. Liu, H.Y. Wang, L.W. Qi, C.Z. Wang, P. Li and C.S. Yuan. Biotransformation and metabolic profile of American ginseng saponins with human intestinal microflora by liquid chromatography quadrupole time-of-flight mass spectrometry. J. Chromatogr. A 1286: 83–92, 2013. Wang, C.Z., T. Calway and C.S. Yuan. Herbal medicines as adjuvants for cancer therapeutics. Am. J. Chin. Med. 40: 657–669, 2012. Wen, X.D., C.Z. Wang, C. Yu, Z. Zhang, T. Calway, Y. Wang, P. Li and C.S. Yuan. Salvia miltiorrhiza (dan shen) significantly ameliorates colon inflammation in dextran sulfate sodium induced colitis. Am. J. Chin. Med. 41: 1097–1108, 2013. Zhang, Y.L., R. Zhang, H.L. Xu, X.F. Yu, S.C. Qu and D.Y. Sui. 20(S)-protopanaxadiol triggers mitochondrial-mediated apoptosis in human lung adenocarcinoma A549 cells via inhibiting the PI3K/Akt signaling pathway. Am. J. Chin. Med. 41: 1137–1152, 2013.
Am. J. Chin. Med. 2014.42:1555-1558. Downloaded from www.worldscientific.com by UNIVERSITY OF AUCKLAND LIBRARY - SERIALS UNIT on 02/09/15. For personal use only.
Letter Natural Products and Chemotherapeutic Agents on Cancer: Prevention vs. Treatment Chong-Zhi Wang, Zhiyu Zhang, Samantha Anderson and Chun-Su Yuan Tang Center for Herbal Medicine Research University of Chicago Chicago, IL 60637, USA Published 5 December 2014
Abstract: Natural products play an important role in cancer therapeutics, and lately more attentions have been paid to the prevention of major lethal malignancies, such as colorectal cancer (CRC). After oral ingestion, botanicals’ parent compounds can be converted to their metabolites by the enteric microbiome, and these metabolites may have different bioactivities and variable bioavailability. In this study, we used an active ginseng metabolite, protopanaxadiol (PPD), as an example to assess its colon cancer preventive effect by comparing its effect with the treatment effect of fluorouracil (5-FU). A xenograft tumor nude mouse model with human colon cancer cell inoculation was used. After preventive PPD or treatment 5-FU administration with the same dose (30 mg/kg), tumor growth inhibition was evaluated by both a Xenogen bioluminescence imaging technique and manual tumor size measurement. Our data showed that preventive PPD very significantly inhibited the tumor growth compared to 5-FU ( p < 0:01). Our data suggest that the PPD is a promising cancer prevention agent. More studies are needed to explore the chemopreventive actions of PPD and its potential clinical utility. Keywords: American Ginseng; Enteric Microbiome; Protopanaxadiol; PPD; Metabolite; Colorectal Cancer; Fluorouracil; 5-FU.
Cancer is a group of devastating diseases, all of which involve unregulated cell growth. Colorectal cancer (CRC) is one of the primary lethal cancers in the world, and here we are using the CRC as an example. Since current available therapies for advanced CRC have limited efficacy, increased attention has been focused on its prevention, including the use of botanical compounds, such as American ginseng (Attele et al., 1999).
Correspondence to: Dr. Chong-Zhi Wang, Tang Center for Herbal Medicine Research, University of Chicago, Chicago, IL 60637, USA. E-mail: [email protected]
1555
Am. J. Chin. Med. 2014.42:1555-1558. Downloaded from www.worldscientific.com by UNIVERSITY OF AUCKLAND LIBRARY - SERIALS UNIT on 02/09/15. For personal use only.
1556
C.-Z. WANG et al.
Nearly all natural products are administered orally in humans. Unlike parenteral administration that has been used in many animal studies, the enteric microbiome plays an important role after oral botanical intake in converting the parent compounds to metabolites. These metabolites may have different bioactivities and variable bioavailability compared to their parent compounds. In this study, we use an active ginseng metabolite, protopanaxadiol (PPD), as an example to discuss its CRC prevention effect. This effect was compared to the treatment effect of a commonly used chemotherapeutic agent, fluorouracil (5-FU). After oral ingestion, the bioavailability of ginseng is low due to incomplete parent compound absorption and conversion to metabolites by the enteric microbiome via the stepwise cleavage of sugar moieties (Hasegawa, 2004; Wan et al., 2013). We recently demonstrated the conversion of ginseng saponins by the human enteric microbiome and detected over 20 metabolites ( Wan et al., 2013). Compound K and PPD are the major reported metabolites that reach systemic circulation (Fig. 1), and the latter has more significant anti-CRC potential compared to the former (Gao et al., 2013).
Figure 1. Biotransformation pathways of major ginseng parent compounds, ginsenosides Rb1, Rc and Rd, to their metabolites by the enteric microbiome. A bioactive ginseng metabolite, compound K, can mainly be further converted to PPD.
Am. J. Chin. Med. 2014.42:1555-1558. Downloaded from www.worldscientific.com by UNIVERSITY OF AUCKLAND LIBRARY - SERIALS UNIT on 02/09/15. For personal use only.
LETTER — BOTANICALS FOR CHEMOPREVENTION
1557
In this study, we compared the prevention effect of PPD to the treatment effect of 5-FU using a xenograft tumor model with human HCT-116-Luc colon cancer cell inoculation in immunodeficient BALB/c nude mice (Harlan, Indianapolis, IN) (Gao et al., 2013). The cancer cell inoculation was conducted 7 days prior to Day 1. Intraperitoneal PPD 30 mg/kg injection started 7 days prior to Day 1 as chemoprevention. 5-FU (30 mg/kg) was given once per week starting Day 1 as cancer treatment. This 30 mg/kg dose of 5-FU is a fairly commonly used in vivo to treat animal malignancies. Tumor growth inhibition observation started on Day 1 and was monitored by two methods: (1) Xenogen bioluminescence imaging up to 20 days (Gao et al., 2013). Beyond Day 20, this imaging technique is no longer accurate possibly due to the compromised blood circulation within the tumors that affects the image intensity. (2) Manual tumor size measurement was used up to Day 43, and the calculation is as follows: Tumor size in volume ¼ ðWidthÞ 2 ðLengthÞ=2. Data were presented as mean SE and analyzed using analysis of variance (ANOVA) for repeated measures and Student’s t-test. The level of statistical significance was set at p < 0:05. As shown in Fig. 2, compared to the control mice, 5-FU treatment significantly inhibited the tumor growth using both the imaging technique and tumor size measurement. For tumor prevention, PPD was given starting 7 days prior to Day 1, or at time of cancer cell inoculation. Interesting, PPD very significantly inhibited the CRC growth compared to
(A)
(B)
Figure 2. Prevention and treatment effect comparison between PPD and fluorouracil (5-FU) in xenografted athymic mice inoculated with human colon cancer cells. (A) Tumor growth inhibition is monitored by a bioluminescence imaging technique up to 20 days. (B) Tumor size change (in volume) is manually measured up to 43 days. n ¼ 8 per group. 5-FU, 5-FU 30 mg/kg once per week starting Day 1; Pre-PPD, PPD (30 mg/kg) every other day starting 7 days prior to Day 1. þ , p < 0:05 compared to the control group; **p < 0:01 compared to the 5-FU group.
Am. J. Chin. Med. 2014.42:1555-1558. Downloaded from www.worldscientific.com by UNIVERSITY OF AUCKLAND LIBRARY - SERIALS UNIT on 02/09/15. For personal use only.
1558
C.-Z. WANG et al.
the 5-FU group ( p < 0:01), especially toward the end of the observation. Note that, starting approximately at Day 40, the mice in the control group became very sick due to the terminal stage of the cancer. Natural products may play an important role in cancer chemoprevention (Wang et al., 2012). Attempts have been made to use botanicals for the chemoprevention of major malignancies (Chen et al., 2013; Liu et al., 2013; Wen et al., 2013; Zhang et al., 2013). We are very encouraged by our preliminary data reported here that PPD, an active metabolite of American ginseng after enteric microbiome metabolism, possesses excellent cancer prevention effects. Before moving to the next stage of PPD investigation, more studies are needed to obtain data from additional experimental groups, including the dose-related observations. Nonetheless, our data suggests that PPD is a promising cancer prevention agent. Acknowledgments This work was supported in part by the NIH/ NCCAM grants AT004418 and AT005362. References Attele, A.S., J.A. Wu and C.S. Yuan. Ginseng pharmacology: Multiple constituents and multiple actions. Biochem. Pharmacol. 58: 1685–1693, 1999. Chen, Y.C., H.Y. Chang, J.S. Deng, J.J. Chen, S.S. Huang, I.H. Lin, W.L. Kuo, W. Chao and G.J. Huang. Hispolon from Phellinus linteus induces G0/G1 cell cycle arrest and apoptosis in NB4 human leukaemia cells. Am. J. Chin. Med. 41: 1439–1457, 2013. Gao, J.L., G.Y. Lv, B.C. He, B.Q. Zhang, H. Zhang, N. Wang, C.Z. Wang, W. Du, C.S. Yuan and T.C. He. Ginseng saponin metabolite 20(S)-protopanaxadiol inhibits tumor growth by targeting multiple cancer signaling pathways. Oncol. Rep. 30: 292–298, 2013. Hasegawa, H. Proof of the mysterious efficacy of ginseng: Basic and clinical trials: Metabolic activation of ginsenoside: Deglycosylation by intestinal bacteria and esterification with fatty acid. J. Pharmacol. Sci. 95: 153–157, 2004. Liu, S., X.J. Wang, Y. Liu and Y.F. Cui. PI3K/AKT/mTOR signaling is involved in (-)-epigallocatechin-3-gallate-induced apoptosis of human pancreatic carcinoma cells. Am. J. Chin. Med. 41: 629–642, 2013. Wan, J.Y., P. Liu, H.Y. Wang, L.W. Qi, C.Z. Wang, P. Li and C.S. Yuan. Biotransformation and metabolic profile of American ginseng saponins with human intestinal microflora by liquid chromatography quadrupole time-of-flight mass spectrometry. J. Chromatogr. A 1286: 83–92, 2013. Wang, C.Z., T. Calway and C.S. Yuan. Herbal medicines as adjuvants for cancer therapeutics. Am. J. Chin. Med. 40: 657–669, 2012. Wen, X.D., C.Z. Wang, C. Yu, Z. Zhang, T. Calway, Y. Wang, P. Li and C.S. Yuan. Salvia miltiorrhiza (dan shen) significantly ameliorates colon inflammation in dextran sulfate sodium induced colitis. Am. J. Chin. Med. 41: 1097–1108, 2013. Zhang, Y.L., R. Zhang, H.L. Xu, X.F. Yu, S.C. Qu and D.Y. Sui. 20(S)-protopanaxadiol triggers mitochondrial-mediated apoptosis in human lung adenocarcinoma A549 cells via inhibiting the PI3K/Akt signaling pathway. Am. J. Chin. Med. 41: 1137–1152, 2013.
