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Dive into the research topics where Si Gao is active.

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Featured researches published by Si Gao.


Phytotherapy Research | 2013

The effects of an antiosteoporosis herbal formula containing epimedii herba, ligustri lucidi fructus and psoraleae fructus on density and structure of rat long bones under tail-suspension, and its mechanisms of action.

Wing-Sum Siu; Hing-Lok Wong; Ching-Po Lau; Wai-Ting Shum; Chun-Wai Wong; Si Gao; Kwok-Pui Fung; Clara Bik-San Lau; Leung-Kim Hung; Chun-Hay Ko; Ping Chung Leung

An innovative anti‐osteoporosis herbal formula containing Epimedii Herba, Ligustri Lucidi Fructus and Psoraleae Fructus (ELP) has been previously shown its bone protecting effects in ovariectomized osteoporotic rats and also in post‐menopausal osteopenic women. This study aimed to investigate the efficacy of ELP against bone loss during physical inactivity or weightlessness. A hindlimb unloading tail‐suspended rat model was used for studying the effects of ELP on bone mineral density (BMD) and bone micro‐architecture. For in vitro mechanistic studies, rat mesenchymal stem cells (MSCs) and mouse macrophage cells (RAW264.7) were used for studying the effects of ELP on osteogenic/adipogenic differentiations and osteoclastogenesis, respectively. Our data illustrated that ELP had a significant preventive effect against bone loss induced by tail‐suspension (TS) at day 28 (p < 0.01) as indicated in the reduction in BMD loss and the preservation of bone micro‐architecture. ELP could significantly promote the osteogenesis and suppress the adipogenesis (p < 0.05) in MSCs. Besides, significant inhibition of osteoclast formation (p < 0.01) was found in ELP‐treated RAW264.7 cells upon receptor activator of nuclear factor kappa‐B ligand induction. Our study presents the first scientific evidence that ELP had a significant preventive effect against bone loss induced by TS through the actions of enhancing osteogenesis, suppressing adipogenesis and osteoclastogenesis. Copyright


Phytomedicine | 2014

In vivo and in vitro anti-tumor and anti-metastasis effects of Coriolus versicolor aqueous extract on mouse mammary 4T1 carcinoma.

Ke-Wang Luo; Grace Gar-Lee Yue; Chun-Hay Ko; Julia Kin-Ming Lee; Si Gao; Long-Fei Li; Gang Li; Kwok-Pui Fung; Ping Chung Leung; Clara Bik-San Lau

Coriolus versicolor (CV), a medicinal mushroom widely consumed in Asian countries, has been demonstrated to be effective in stimulation of immune system and inhibition of tumor growth. The present study aimed to investigate the anti-tumor and anti-metastasis effects of CV aqueous extract in mouse mammary carcinoma 4T1 cells and in 4T1-tumor bearing mouse model. Our results showed that CV aqueous extract (0.125-2 mg/ml) did not inhibit 4T1 cell proliferation while the non-cytotoxic dose of CV extract (1-2 mg/ml) significantly inhibited cell migration and invasion (p<0.05). Besides, the enzyme activities and protein levels of MMP-9 were suppressed by CV extract significantly. Animal studies showed that CV aqueous extract (1 g/kg, orally-fed daily for 4 weeks) was effective in decreasing the tumor weight by 36%, and decreased the lung metastasis by 70.8% against untreated control. Besides, micro-CT analysis of the tumor-bearing mice tibias indicated that CV extract was effective in bone protection against breast cancer-induced bone destruction as the bone volume was significantly increased. On the other hand, CV aqueous extract treatments resulted in remarkable immunomodulatory effects, which was reflected by the augmentation of IL-2, 6, 12, TNF-α and IFN-γ productions from the spleen lymphocytes of CV-treated tumor-bearing mice. In conclusion, our results demonstrated for the first time that the CV aqueous extract exhibited anti-tumor, anti-metastasis and immunomodulation effects in metastatic breast cancer mouse model, and could protect the bone from breast cancer-induced bone destruction. These findings provided scientific evidences for the clinical application of CV aqueous extract in breast cancer patients.


Pharmacological Research | 2016

Combined therapy using bevacizumab and turmeric ethanolic extract (with absorbable curcumin) exhibited beneficial efficacy in colon cancer mice.

Grace Gar-Lee Yue; Hin-Fai Kwok; Julia Kin-Ming Lee; Lei Jiang; Eric Chun-Wai Wong; Si Gao; Hing-Lok Wong; Lin Li; Kar-Man Chan; Ping Chung Leung; Kwok-Pui Fung; Zhong Zuo; Clara Bik-San Lau

Turmeric is commonly used as a medicinal herb and dietary supplement. Its active ingredient, curcumin, has been shown to possess antitumor effects in colorectal cancer patients. However, poor absorption of curcumin in intestine impedes its wide clinical application. Our previous findings showed that the presence of turmerones increased the accumulation of curcumin inside colonic cells. Hence, we hypothesized that curcumin with turmerones or present in turmeric ethanolic extract would augment its anti-tumor activities in tumor-bearing mice. The pharmacokinetics of curcumin in different preparations (containing same amount of curcumin) were studied in mice. The anti-tumor efficacies of curcumin or turmeric extract (with absorbable curcumin) in combination with bevacizumab were further investigated in HT29 colon tumor-bearing mice. Pharmacokinetic results showed that the plasma curcumin level of turmeric extract-fed mice was the highest, suggesting turmeric extract had the best bioavailability of curcumin. Besides, combined turmeric extract plus bevacizumab treatment significantly inhibited the tumor growth. Such inhibitory effects were stronger than those of curcumin plus bevacizumab or bevacizumab alone and were comparable with those of 5-fluorouracil+leucovorin+oxaliplatin (FOLFOX) plus bevacizumab. Notably, there was no observable side effect induced by turmeric extract treatment while significant side effects were found in FOLFOX-treated mice. In conclusion, combination of turmeric extract with bevacizumab possessed potent anti-tumor effects without observable side effects, strongly suggesting the adjuvant use of turmeric extract in colorectal cancer therapy. Our current findings warrant the confirmation regarding the benefits arising from the combined use of bevacizumab and turmeric in colorectal cancer patients in the near future.


Evidence-based Complementary and Alternative Medicine | 2013

Effect of Dietary Cocoa Tea (Camellia ptilophylla) Supplementation on High-Fat Diet-Induced Obesity, Hepatic Steatosis, and Hyperlipidemia in Mice

Xiao rong Yang; Elaine Wat; Yan Ping Wang; Chun-Hay Ko; Chi Man Koon; Wing Sum Siu; Si Gao; David Wing-Shing Cheung; Clara Bik-San Lau; Chuang Xing Ye; Ping Chung Leung

Recent studies suggested that green tea has the potential to protect against diet-induced obesity. The presence of caffeine within green tea has caused limitations. Cocoa tea (Camellia ptilophylla) is a naturally decaffeinated tea plant. To determine whether cocoa tea supplementation results in an improvement in high-fat diet-induced obesity, hyperlipidemia and hepatic steatosis, and whether such effects would be comparable to those of green tea extract, we studied six groups (n = 10) of C57BL/6 mice that were fed with (1) normal chow (N); (2) high-fat diet (21% butterfat + 0.15% cholesterol, wt/wt) (HF); (3) a high-fat diet supplemented with 2% green tea extract (HFLG); (4) a high-fat diet supplemented with 4% green tea extract (HFHG); (5) a high-fat diet supplemented with 2% cocoa tea extract (HFLC); and (6) a high-fat diet supplemented with 4% cocoa tea extract (HFHC). From the results, 2% and 4% dietary cocoa tea supplementation caused a dose-dependent decrease in (a) body weight, (b) fat pad mass, (c) liver weight, (d) total liver lipid, (e) liver triglyceride and cholesterol, and (f) plasma lipids (triglyceride and cholesterol). These data indicate that dietary cocoa tea, being naturally decaffeinated, has a beneficial effect on high-fat diet-induced obesity, hepatomegaly, hepatic steatosis, and elevated plasma lipid levels in mice, which are comparable to green tea. The present findings have provided the proof of concept that dietary cocoa tea might be of therapeutic value and could therefore provide a safer and cost effective option for patients with diet-induced metabolic syndrome.


Scientific Reports | 2016

New potential beneficial effects of actein, a triterpene glycoside isolated from Cimicifuga species, in breast cancer treatment.

Grace Gar-Lee Yue; Sida Xie; Julia Kin-Ming Lee; Hin-Fai Kwok; Si Gao; Yin Nian; Xiao-Xiao Wu; Chun-Kwok Wong; Ming-Hua Qiu; Clara Bik-San Lau

Actein is a triterpene glycoside isolated from the rhizomes of Cimicifuga foetida (Chinese herb “shengma”) which could inhibit the growth of breast cancer cells. Nevertheless, the effect of actein on angiogenesis, which is an essential step for tumor growth and metastasis, has never been reported. Hence, this study aimed to investigate the in vitro and in vivo effects of actein on angiogenesis using human microvascular endothelial cells (HMEC-1), matrigel plug and tumor-bearing mouse models. Our results showed that actein significantly inhibited the proliferation, reduced the migration and motility of endothelial cells, and it could suppress the protein expressions of VEGFR1, pJNK and pERK, suggesting that JNK/ERK pathways were involved. In vivo results showed that oral administration of actein at 10 mg/kg for 7 days inhibited blood vessel formation in the growth factor-containing matrigel plugs. Oral actein treatments (10–15 mg/kg) for 28 days resulted in decreasing mouse 4T1 breast tumor sizes and metastasis to lungs and livers. The apparent reduced angiogenic proteins (CD34 and Factor VIII) expressions and down-regulated metastasis-related VEGFR1 and CXCR4 gene expressions were observed in breast tumors. Our novel findings provide insights into the use of actein for development of anti-angiogenic agents for breast cancer.


Chinese Journal of Integrative Medicine | 2012

Application of Chinese herbal medicines to revitalize adult stem cells for tissue regeneration.

Hing-Lok Wong; Wing-Sum Siu; Wai-Ting Shum; Si Gao; Ping Chung Leung; Chun-Hay Ko

It has been established in the recent several decades that adult stem cells play a crucial role in tissue renewal and regeneration. Adult stem cells locate in certain organs can differentiate into functional entities such as macrophages and bone cells. Hematopoietic stem cells (HSCs) and mesenchymal stem cells (MSCs) are two of the most important populations of adult stem cells. The application of these stem cells offers a new insight in treating various pathological conditions, through replenishing cells of specific functions by turning on or off the differentiating program within quiescent stem cell niches. Apart from that, they are also capable to travel through the circulation, migrate to injury sites and differentiate to enhance regeneration process. Recently, Chinese medicine (CM) has shown to be potential candidates to activate adult stem cells for tissue regeneration. This review summarizes our own, as well as others’ findings concerning the use of Chinese herbal medicine in the regulation processes of adult stem cells differentiation and their movement in tissue repair and rejuvenation. A number of Chinese herbs are used as therapeutic agents and presumably preventive agents on metabolic disorders. In our opinion, the activation of adult stem cells self-regeneration not only provides a novel way to repair tissue damage, but also reduces the use of targeted drug that adversely altering the normal metabolism of human subjects.


Oncology Reports | 2015

The combined use of Camellia sinensis and metronomic zoledronate in 4T1 mouse carcinoma against tumor growth and metastasis

Ke-Wang Luo; Grace Gar-Lee Yue; Chun-Hay Ko; Si Gao; Julia Kin-Ming Lee; Gang Li; Kwok-Pui Fung; Ping Chung Leung; Clara Bik-San Lau

In previous studies, we demonstrated that the green tea Camellia sinensis (CS) water extract had potent antitumor and antimetastatic effects on 4T1 breast cancer. The metronomic regimen (0.0125 mg/kg twice a week for 4 weeks) of zoledronate (ZOL) was found to be effective in decreasing tumor burden and metastasis as compared with conventional regimen. The aim of the present study was to investigate the antitumor, antimetastatic and anti-osteolytic effects of the combined use of CS water extract and metronomic ZOL against 4T1 breast carcinoma in vitro and in vivo. The results demonstrated that the combination of CS+ZOL exerted a more potent effect on lung and liver by decreasing tumor burden and metastasis, when compared to CS or metronomic ZOL as monotherapies. The combination of CS+ZOL demonstrated optimal bone protection against breast cancer-induced osteolysis for the three groups of CS, ZOL and CS+ZOL. The in vitro results further demonstrated that ZOL enhanced CS-induced apoptosis in 4T1 cells as assessed by the Annexin V-FITC/PI staining and caspase-3 activity assays. In addition, the combined use of CS+ZOL significantly inhibited 4T1 cell migration. Mechanistic studies showed that the enzyme levels of matrix metalloproteinases (MMP)-2 and MMP-9 were suppressed significantly by CS+ZOL. In conclusion, to the best of our knowledge, this is the first study to investigate the novel combined application of herbal extract CS and chemotherapy ZOL in 4T1 breast cancer. The combination of CS plus metronomic ZOL demonstrated significant antitumor, antimetastatic and anti-osteolytic effects against breast cancer, and suggested potential clinical application for breast cancer patients.


Evidence-based Complementary and Alternative Medicine | 2012

In vivo study on the pharmacological interactions between a chinese herbal formula ELP and antiresorptive drugs to counteract osteoporosis

Chun-Hay Ko; Wing-Sum Siu; Hing-Lok Wong; Si Gao; Wai-Ting Shum; Ching-Po Lau; Sau-Wan Cheng; Jacqueline Chor Wing Tam; Leung-Kim Hung; Kwok-Pui Fung; Clara Bik-San Lau; Quan-Bin Han; Ping Chung Leung

Antiresorptive drugs, alendronate and raloxifene, are effective in lowering bone mineral density (BMD) loss in postmenopausal women. However, long-term treatment may be associated with serious side effects. Our research group has recently discovered that a Chinese herbal formula, ELP, could significantly reduce BMD loss in animal and human studies. Therefore, the present study aimed to investigate the potential synergistic bone-protective effects of different herb-drug combinations using ovariectomized rats. To assess the efficacy of different combinations, the total BMD was monitored biweekly in the 8-week course of daily oral treatment. Bone microarchitecture, bone strength, and deoxypyridinoline level were also determined after 8 weeks. From our results, coadministration of ELP and raloxifene increased the total tibial BMD by 5.26% (2.5 mg/kg/day of raloxifene; P = 0.014) and 5.94% (0.25 mg/kg/day of raloxifene; P = 0.026) when compared with the respective dosage groups with raloxifene alone. Similar synergistic effects were also observed in BMD increase at distal femur (0.25 mg/kg/day; P = 0.001) and reduction in urinary deoxypyridinoline crosslink excretion (2.5 and 0.25 mg/kg/day; both P = 0.02). However, such interactions could not be observed in all alendronate-treated groups. Our data provide first evidence that ELP could synergistically enhance the therapeutic effects of raloxifene, so that the clinical dosage of raloxifene could be reduced.


Journal of Ethnopharmacology | 2017

Evaluation of the combined use of metronomic zoledronic acid and Coriolus versicolor in intratibial breast cancer mouse model

Chun-Hay Ko; Grace Gar-Lee Yue; Si Gao; Ke-Wang Luo; Wing-Sum Siu; Wai-Ting Shum; Hoi-Ting Shiu; Julia Kin-Ming Lee; Gang Li; Ping Chung Leung; Andreas Evdokiou; Clara Bik-San Lau

ETHNOPHARMACOLOGICAL RELEVANCE Coriolus versicolor (CV) is a mushroom traditionally used for strengthening the immune system and nowadays used as immunomodulatory adjuvant in anticancer therapy. Breast cancer usually metastasizes to the skeleton, interrupts the normal bone remodeling process and causes osteolytic bone lesions. The aims of the present study were to evaluate its herb-drug interaction with metronomic zoledronate in preventing cancer propagation, metastasis and bone destruction. MATERIALS AND METHODS Mice inoculated with human breast cancer cells tagged with a luciferase (MDA-MB-231-TXSA) in tibia were treated with CV aqueous extract, mZOL, or the combination of both for 4 weeks. Alteration of the luciferase signals in tibia, liver and lung were quantified using the IVIS imaging system. The skeletal response was evaluated using micro-computed tomography (micro-CT). In vitro experiments were carried out to confirm the in vivo findings. RESULTS Results showed that combination of CV and mZOL diminished tumor growth without increasing the incidence of lung and liver metastasis in intratibial breast tumor model. The combination therapy also reserved the integrity of bones. In vitro studies demonstrated that combined use of CV and mZOL inhibited cancer cell proliferation and osteoclastogenesis. CONCLUSIONS These findings suggested that combination treatment of CV and mZOL attenuated breast tumor propagation, protected against osteolytic bone lesion without significant metastases. This study provides scientific evidences on the beneficial outcome of using CV together with mZOL in the management of breast cancer and metastasis, which may lead to the development of CV as adjuvant health supplement for the control of breast cancer.


Scientific Reports | 2017

The adjuvant value of Herba Cistanches when used in combination with statin in murine models

Elaine Wat; Chun Fai Ng; Chi Man Koon; Cheng Zhang; Si Gao; Brian Tomlinson; Clara Bik-San Lau

Statins are well known to have muscle toxicity problem. Herba Cistanches (HC) is a Chinese herb traditionally used for pain in the loins and knees. Our previous in vitro study suggested that it could protect against statin-induced muscle toxicity. However, its in vivo protective effect has never been investigated. The objective of this study was to determine if the aqueous extract of HC (HCE) could prevent simvastatin-induced muscle toxicity in rats, and whether HCE could also exert beneficial effects on reducing high-fat diet-induced hypercholesterolemia and elevated liver cholesterol, thereby reducing the dose of simvastatin when used in combined therapy. From our results, HCE significantly restored simvastatin-induced reduction in muscle weights and reduced elevated plasma creatine kinase in rats. HCE also improved simvastatin-induced reduction in muscle glutathione levels, muscle mitochondrial membrane potential, and reduced simvastatin-induced muscle inflammation. Furthermore, HCE could exert reduction on liver weight, total liver lipid levels and plasma lipid levels in high-fat-fed mice. In conclusion, our study provided in vivo evidence that HCE has potential protective effect on simvastatin-induced toxicity in muscles, and also beneficial effects on diet-induced non-alcoholic fatty liver and hyperlipidemia when being used alone or in combination with simvastatin at a reduced dose.

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Clara Bik-San Lau

The Chinese University of Hong Kong

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Ping Chung Leung

The Chinese University of Hong Kong

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Chun-Hay Ko

The Chinese University of Hong Kong

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Grace Gar-Lee Yue

The Chinese University of Hong Kong

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Kwok-Pui Fung

The Chinese University of Hong Kong

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Julia Kin-Ming Lee

The Chinese University of Hong Kong

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Wai-Ting Shum

The Chinese University of Hong Kong

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Wing-Sum Siu

The Chinese University of Hong Kong

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Gang Li

The Chinese University of Hong Kong

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Hing-Lok Wong

The Chinese University of Hong Kong

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