Anti-tumor and anti-osteolysis effects of the metronomic use of zoledronic acid in primary and metastatic breast cancer mouse models

Immunomodulatory and antitumour bioactive labdane diterpenoids from Leonurus japonicus

OBJECTIVES

Two labdane diterpenoids, leojapone B and heteronone B, were isolated from Leonurus japonicus Houtt., and their biological activity were evaluated in this study.

METHODS

Human and mouse cancer cells, human peripheral blood mononuclear cells (PBMCs) and mouse macrophages (RAW264.7 cells) were used to evaluate the activity of leojapone B and heteronone B, while the in vivo effects of leojapone B were further examined in Lewis Lung Cancer tumour-bearing mice.

KEY FINDINGS

In vitro studies showed that leojapone B selectively inhibited the proliferation of lung cancer cells, and both leojapone B and heteronone B inhibited the production of pro-inflammatory cytokines in activated PBMCs. In tumour-bearing mice model, lung tumours were reduced in size in mice treated with intraperitoneal injections of leojapone B at 20 and 30 mg/kg for 14 days. The population ratio of CD4⁺ /CD8⁺ T cells in mouse spleens was found to be increased, while regulatory T cells were decreased after leojapone B treatment.

CONCLUSIONS

The inhibitory effects of leojapone B in mouse lung tumours were demonstrated for the first time in this study. The immunomodulatory activity of heteronone B were also demonstrated. Our findings indicated that both leojapone B and heteronone B may act as active components in L. japonicus.

Assessment of tumor promoting effects of amniotic and umbilical cord mesenchymal stem cells in vitro and in vivo

Purpose

Human mesenchymal stem cells (hMSCs) have been applied in a variety of therapies recently. However, the role of MSCs in tumor progression remains largely elusive. Some studies demonstrated that MSCs can promote tumor growth, while others had opposite results. Therefore, the lack of evidence about the effect of MSCs on tumor cells impedes its further use.

Methods

In the current study, hMSCs from amniotic membrane (hAMSCs) and umbilical cord (hUCMSCs) were used to evaluate the effects of MSCs on tumor development in vitro and in vivo. Two different animal models based on subcutaneous xenograft bearing nude mice and a murine experimental metastatic model were established for in vivo study. Moreover, cytokines regulated by MSCs co-cultured with cancer cells SPC-A-1 were also analyzed by cytokine array.

Results

Our results indicated that hUCMSCs not only did not promote proliferation in cancer cells, but also inhibited migration. In addition, they inhibited tube formation in human umbilical vein endothelial cells (HUVECs). Although hAMSCs also showed inhibitory effects on cancer cell motility, the proliferation of cancer cells was indeed enhanced. The in vivo data revealed that hUCMSCs did not promote tumor progression in lung adenocarcinoma and gastric carcinoma xenografts. Nevertheless, hAMSCs could do. The results from murine experimental metastatic model also demonstrated that neither hUCMSCs nor hAMSCs significantly enhanced the lung metastasis. The data from cytokine array showed that 11 inflammatory factors, 8 growth factors and 11 chemokines were remarkably secreted and changed.

Conclusions

In view of the data from in vitro and in vivo studies, the exploitation of hUCMSCs in new therapeutic strategies should be safe compared to hAMSCs under malignant conditions. Moreover, this is the first report to systematically elucidate the possible molecular mechanisms involved in UCMSC- and AMSC-affected tumor growth and metastasis.

Electronic supplementary material

The online version of this article (10.1007/s00432-019-02859-6) contains supplementary material, which is available to authorized users.

Anti-angiogenic and anti-tumor effects of metronomic use of novel liposomal zoledronic acid depletes tumor-associated macrophages in triple negative breast cancer

Zoledronic acid (ZOL) has been used as an adjuvant therapy for breast cancer. It is suggested that ZOL might be associated with inhibition of macrophages, which in turn reduces tumor growth, metastasis and tumor angiogenesis. Moreover, metronomic therapy can inhibit tumor angiogenesis and tumor immune cells. Previously we developed ZOL based cationic liposomes that allowed a higher intratumor delivery of drug compared with free ZOL in vivo. Therefore, in this study, Asn-Gly-Arg (NGR) and PEG2000 were used as ligands to modify the surface of liposomes (NGR-PEG-LP-ZOL) in metronomic therapy to clear the tumor-associated macrophages (TAMs) and inhibit the formation of tumor angiogenesis, achieving the purpose of anti-tumor growth.

Our data showed that NGR-PEG-LP-ZOL metronomic therapy has the strongest inhibitory effect on tumor growth. Further, NGR-PEG-LP-ZOL metronomic therapy could significantly impair TAMs by inhibiting the expression of CD206 antibody in tumor tissues, decreasing the expression of cytokine related gene expression of TAMs, as well as reducing the percentage of TAMs in tumor tissues. In addition, NGR-PEG-LP-ZOL metronomic therapy could significantly inhibit the expression of tumor neovascular specific antibody CD31 and reduce the microvessel density. In conclusion, our study demonstrated that NGR-PEG-LP-ZOL metronomic therapy could impair TAMs by inhibiting tumor angiogenesis and enhance the antitumor effect of ZOL.

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

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.

The adjuvant value of Andrographis paniculata in metastatic esophageal cancer treatment - from preclinical perspectives

Esophageal cancer (EC) is the fourth and sixth leading cause of cancer-related deaths in China and United States, respectively. The dismal prognosis of EC is mainly attributed to distant metastases, which may not be overcome by chemotherapy alone. Hence, the use of alternative adjuvant treatments, such as herbal medicines, for metastatic EC remains a great desire of patients. Our previous study demonstrated the in vivo anti-tumor and in vitro anti-invasion activities of Andrographis paniculata (AP) in esophageal cancer. In the present study, the chemical constituents of absorbed AP components through human intestinal Caco-2 cell monolayer were verified for the first time. The anti-migratory activities and suppressive effects on metastasis-related factors such as HER2, MMP2, MMP9, TM4SF3, CXCR4 of the absorbed AP components were revealed in esophageal cancer cells EC-109. The anti-tumor and anti-metastatic effects of AP water extract (1600 mg/kg) were further confirmed in metastatic esophageal xenograft-bearing mice. Besides, AP water extract acted synergistically with cisplatin plus 5-fluorouracil on inhibiting tumor nodule growth (with combination index <0.7). Meanwhile, chemotherapeutics-induced side-effects could also be reduced by AP water extract. The present findings provide evidence on safety and advantages of the combined use of AP with chemotherapeutics in pre-clinical setting.

Intra-tumor delivery of zoledronate mitigates metastasis-induced osteolysis superior to systemic administration

Bisphosphonates (BPs) have recently been shown to have direct anti-tumor properties. Systemic treatment with BPs can have multiple adverse effects such as osteonecrosis of the jaw and BP induced bone fracturing and spine instability. While benefits of systemic BP treatments may outweigh risks, local treatment with BPs has been explored as an alternate strategy to reduce unwarranted risk. In the present study, we examined whether local delivery of BPs inhibits tumor-induced osteolysis and tumor growth more effectively than systemic treatment in an animal model of tumor-induced bone disease. Following establishment of an intra-tibial model of bone metastases in athymic mice, the experimental group was treated by local administration of zoledronate into the tibial lesion. A comparison of the effect of local versus systemic delivery of zoledronate on the formation of tumor-induced osteolysis was also carried out. A significant increase in mean bone volume/tissue volume % (BV/TV) of the locally treated group (12.30±2.80%) compared to the control group (7.13±1.22%) (P<0.001). Additionally, there was a significant increase in the BV/TV (10.90±1.25%) in the locally treated group compared to the systemically treated group (7.53±0.75%) (P=0.005). These preliminary results suggest that local delivery of BPs outperforms both systemic and control treatments to inhibit tumor-induced osteolysis.

Adoptive transfer of ex vivo expanded Vγ9Vδ2 T cells in combination with zoledronic acid inhibits cancer growth and limits osteolysis in a murine model of osteolytic breast cancer

Bone metastases occur in over 75% of patients with advanced breast cancer and are responsible for high levels of morbidity and mortality. In this study, ex vivo expanded cytotoxic Vγ9Vδ2 T cells isolated from human peripheral blood were tested for their anti-cancer efficacy in combination with zoledronic acid (ZOL), using a mouse model of osteolytic breast cancer. In vitro, expanded Vγ9Vδ2 T cells were cytotoxic against a panel of human breast cancer cell lines, and ZOL pre-treatment further sensitised breast cancer cells to killing by Vγ9Vδ2 T cells. Vγ9Vδ2 T cells adoptively transferred into NOD/SCID mice localised to osteolytic breast cancer lesions in the bone, and multiple infusions of Vγ9Vδ2 T cells reduced tumour growth in the bone. ZOL pre-treatment potentiated the anti-cancer efficacy of Vγ9Vδ2 T cells, with mice showing further reductions in tumour burden. Mice treated with the combination also had reduced tumour burden of secondary pulmonary metastases, and decreased bone degradation. Our data suggests that adoptive transfer of Vγ9Vδ2 T cell in combination with ZOL may prove an effective immunotherapeutic approach for the treatment of breast cancer bone metastases.

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

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.

15-deoxy-δ12,14-prostaglandin j2 inhibits osteolytic breast cancer bone metastasis and estrogen deficiency-induced bone loss

Breast cancer is the major cause of cancer death in women worldwide. The most common site of metastasis is bone. Bone metastases obstruct the normal bone remodeling process and aberrantly enhance osteoclast-mediated bone resorption, which results in osteolytic lesions. 15-deoxy-Δ^12,14-prostaglandin J₂ (15d-PGJ₂) is an endogenous ligand of peroxisome proliferator-activated receptor gamma (PPARγ) that has anti-inflammatory and antitumor activity at micromolar concentrations through PPARγ-dependent and/or PPARγ-independent pathways. We investigated the inhibitory activity of 15d-PGJ₂ on the bone loss that is associated with breast cancer bone metastasis and estrogen deficiency caused by cancer treatment. 15d-PGJ₂ dose-dependently inhibited viability, migration, invasion, and parathyroid hormone-related protein (PTHrP) production in MDA-MB-231 breast cancer cells. 15d-PGJ₂ suppressed receptor activator of nuclear factor kappa-B ligand (RANKL) mRNA levels and normalized osteoprotegerin (OPG) mRNA levels in hFOB1.19 osteoblastic cells treated with culture medium from MDA-MB-231 cells or PTHrP, which decreased the RANKL/OPG ratio. 15d-PGJ₂ blocked RANKL-induced osteoclastogenesis and inhibited the formation of resorption pits by decreasing the activities of cathepsin K and matrix metalloproteinases, which are secreted by mature osteoclasts. 15d-PGJ₂ exerted its effects on breast cancer and bone cells via PPARγ-independent pathways. In Balb/c nu/nu mice that received an intracardiac injection of MDA-MB-231 cells, subcutaneously injected 15d-PGJ₂ substantially decreased metastatic progression, cancer cell-mediated bone destruction in femora, tibiae, and mandibles, and serum PTHrP levels. 15d-PGJ₂ prevented the destruction of femoral trabecular structures in estrogen-deprived ICR mice as measured by bone morphometric parameters and serum biochemical data. Therefore, 15d-PGJ₂ may be beneficial for the prevention and treatment of breast cancer-associated bone diseases.

The combined use of Camellia sinensis and metronomic zoledronic acid in a breast cancer-induced osteolysis mouse model

PURPOSE

In previous studies, we demonstrated that green tea (Camellia sinensis, CS) water extract had potent anti-tumor and anti-metastasis effects in the 4T1 mouse breast cancer xenograft model, and the metronomic regimen (0.0125 mg/kg twice a week for 4 weeks) of zoledronic acid (ZOL) was also effective in decreasing tumor burden and metastasis when compared with the conventional regimen. This study aimed to investigate the combined use of CS water extract and metronomic ZOL against tumor metastasis and bone destruction in MDA-MB-231-TXSA human breast cancer.

METHODS

Female nude mice were injected with MDA-MB-231-TXSA cells into the marrow space of tibia and were treated with CS water extract and/or metronomic ZOL for 4 weeks. Tumor growth and metastasis to lungs and livers were assessed by in vivo bioluminescence imaging. Abilities of migration and invasion of MDA-MB-231-TXSA cells were also evaluated in vitro.

RESULTS

Our results demonstrated that combination of CS and ZOL had the most potent effects on tumor burden and metastasis to bone, lung and liver, while treatment with CS or ZOL alone significantly protected the bone from cancer-induced osteolysis. In vitro, the combined use of CS + ZOL significantly inhibited MDA-MB-231-TXSA cell migration and invasion. Mechanistic zymography studies showed that the enzyme activities of MMP-9 and MMP-2 were significantly suppressed by CS and CS + ZOL.

CONCLUSIONS

The combination of CS plus metronomic ZOL demonstrated potent anti-tumor, anti-metastasis and anti-osteolysis effects against breast cancer, suggesting the potential clinical application against breast cancer patients.

Pharmacologic inhibition of bone resorption prevents cancer-induced osteolysis but enhances soft tissue metastasis in a mouse model of osteolytic breast cancer

Osteoprotegerin (OPG) is a secreted member of the TNF receptor superfamily, which binds to the receptor activator of nuclear factor κB ligand (RANKL) and inhibits osteoclast activity and bone resorption. Systemic administration of recombinant OPG was previously shown to inhibit tumor growth in bone and to prevent cancer-induced osteolysis. In this study, we examined the effect of OPG, when produced locally by breast cancer cells located within bone, using a mouse model of osteolytic breast cancer. MDA-MB-231-TXSA breast cancer cells, tagged with a luciferase reporter gene construct and engineered to overexpress full-length human OPG, were transplanted directly into the tibial marrow cavity of nude mice. Overexpression of OPG by breast cancer cells protected the bone from breast cancer-induced osteolysis and diminished intra-osseous tumor growth but had no effect on extra-skeletal tumor growth. This effect was associated with a significant reduction in the number of osteoclasts that lined the bone surface, resulting in a net increase in bone volume. Despite limiting breast cancer-mediated bone loss, OPG overexpression resulted in a significant increase in the incidence of pulmonary metastasis. Our results demonstrate that inhibition of osteoclastic bone resorption by OPG when secreted locally by tumors in bone may affect the behaviour of cancer cells within the bone microenvironment and their likelihood of spreading and establishing metastasis elsewhere in the body.