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"Iron-saturated" bovine lactoferrin improves the chemotherapeutic effects of tamoxifen in the treatment of basal-like breast cancer in mice.

Sun X, Jiang R, Przepiorski A, Reddy S, Palmano KP, Krissansen GW - BMC Cancer (2012)

Bottom Line: The combination therapy was significantly (all P < 0.05) more effective than the respective monotherapies.Similar effects of Fe-Lf and tamoxifen on tumor cell viability were seen in the treatment of established tumors.The results indicate that Fe-Lf is a potent natural adjuvant capable of augmenting the chemotherapeutic activity of tamoxifen.

View Article: PubMed Central - HTML - PubMed

Affiliation: Department of Molecular Medicine & Pathology, Faculty of Medical and Health Sciences, University of Auckland, Auckland 1005, New Zealand.

ABSTRACT

Background: Tamoxifen is used in hormone therapy for estrogen-receptor (ER)-positive breast cancer, but also has chemopreventative effects against ER-negative breast cancers. This study sought to investigate whether oral iron-saturated bovine lactoferrin (Fe-Lf), a natural product which enhances chemotherapy, could improve the chemotherapeutic effects of tamoxifen in the treatment of ER-negative breast cancers.

Methods: In a model of breast cancer prevention, female Balb/c mice treated with tamoxifen (5 mg/Kg) were fed an Fe-Lf supplemented diet (5 g/Kg diet) or the base diet. At week 2, 4T1 mammary carcinoma cells were injected into an inguinal mammary fat pad. In a model of breast cancer treatment, tamoxifen treatment was not started until two weeks following tumor cell injection. Tumor growth, metastasis, body weight, and levels of interleukin 18 (IL-18) and interferon γ (IFN-γ) were analyzed.

Results: Tamoxifen weakly (IC(50) ~ 8 μM) inhibited the proliferation of 4T1 cells at pharmacological concentrations in vitro. In the tumor prevention study, a Fe-Lf diet in combination with tamoxifen caused a 4 day delay in tumor formation, and significantly inhibited tumor growth and metastasis to the liver and lung by 48, 58, and 66% (all P < 0.001), respectively, compared to untreated controls. The combination therapy was significantly (all P < 0.05) more effective than the respective monotherapies. Oral Fe-Lf attenuated the loss of body weight caused by tamoxifen and cancer cachexia. It prevented tamoxifen-induced reductions in serum levels of IL-18 and IFN-γ, and intestinal cells expressing IL-18 and IFN-γ. It increased the levels of Lf in leukocytes residing in gut-associated lymphoid tissues. B, T and Natural killer (NK) cells containing high levels of Lf were identified in 4T1 tumors, suggesting they had migrated from the intestine. Similar effects of Fe-Lf and tamoxifen on tumor cell viability were seen in the treatment of established tumors.

Conclusions: The results indicate that Fe-Lf is a potent natural adjuvant capable of augmenting the chemotherapeutic activity of tamoxifen. It could have application in delaying relapse in tamoxifen-treated breast cancer patients who are at risk of developing ER-negative tumors.

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Related in: MedlinePlus

Experimental protocols for prevention and treatment models of breast cancer, and sensitivity of 4T1 cells to tamoxifen. A: Experimental protocols. In the prevention model, mice were placed on the control diet or the Fe-Lf diet, and 4T1 tumor cells were injected into the mammary fat pad 14 days later. Tamoxifen or PBS was administered i.p. on the day the mice were placed on their diets, and on alternate days thereafter. Six mice per group (n = 18) were randomly killed at the indicated time points. In the treatment model, the mice were placed on the diets and 4T1 cells were injected into the mammary fat pad 14 days later. Tamoxifen or PBS was administered 14 days after injection of tumor cells, and on alternate days thereafter. Each group had 6 mice, which were killed at the completion of the experiment. B: Tamoxifen has chemotherapeutic effects against 4T1 cells. 4T1 cells were incubated with increasing concentrations of tamoxifen, and their viability assessed 72 h later by the MTT assay. The cell viability index (% viability) was plotted versus the concentration of tamoxifen.
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Figure 1: Experimental protocols for prevention and treatment models of breast cancer, and sensitivity of 4T1 cells to tamoxifen. A: Experimental protocols. In the prevention model, mice were placed on the control diet or the Fe-Lf diet, and 4T1 tumor cells were injected into the mammary fat pad 14 days later. Tamoxifen or PBS was administered i.p. on the day the mice were placed on their diets, and on alternate days thereafter. Six mice per group (n = 18) were randomly killed at the indicated time points. In the treatment model, the mice were placed on the diets and 4T1 cells were injected into the mammary fat pad 14 days later. Tamoxifen or PBS was administered 14 days after injection of tumor cells, and on alternate days thereafter. Each group had 6 mice, which were killed at the completion of the experiment. B: Tamoxifen has chemotherapeutic effects against 4T1 cells. 4T1 cells were incubated with increasing concentrations of tamoxifen, and their viability assessed 72 h later by the MTT assay. The cell viability index (% viability) was plotted versus the concentration of tamoxifen.

Mentions: In the prevention experiment, 72 six-week-old Balb/c female mice were randomized into four groups of 18 animals each, to receive either the control diet, control diet + tamoxifen, Fe-Lf diet, or Fe-Lf diet + tamoxifen. The feeding schedules are shown in Figure 1A. In the control diet and Fe-Lf diet groups, the mice were fed with control or Fe-Lf diets, respectively, and received an i.p. injection of 100 μL of PBS every two days. In the control diet + tamoxifen and Fe-Lf diet + tamoxifen groups, the mice were fed with control and Fe-Lf diets, respectively, and received an injection of 100 μL of tamoxifen (Sigma, MO) suspension at a dose of 5 mg/Kg body weight every two days. The tamoxifen powder was initially dissolved in 100% ethanol, and then diluted in PBS to prepare a tamoxifen injectable suspension. Tamoxifen was injected subcutaneously on the inside of either thigh with the sites of injection being rotated. Fourteen days later, 50 μl of a mixture of BD Matrigel™ Basement Membrane Matrix (BD Biosciences) and PBS (phosphate buffered saline) (1:1, v/v) containing 2 × 104 4T1 cells was injected into the right inguinal mammary fat pad of mice. The mice were monitored and weighed, and the sizes of the tumors were recorded by measuring tumor diameters. Six mice in each group were killed at the indicated time points (Figure 1A), bled by cardiac puncture and sera isolated. Tumors, lungs, livers, small intestines, gastrocnemius muscles and ovarian adipose tissues were excised and weighed.


"Iron-saturated" bovine lactoferrin improves the chemotherapeutic effects of tamoxifen in the treatment of basal-like breast cancer in mice.

Sun X, Jiang R, Przepiorski A, Reddy S, Palmano KP, Krissansen GW - BMC Cancer (2012)

Experimental protocols for prevention and treatment models of breast cancer, and sensitivity of 4T1 cells to tamoxifen. A: Experimental protocols. In the prevention model, mice were placed on the control diet or the Fe-Lf diet, and 4T1 tumor cells were injected into the mammary fat pad 14 days later. Tamoxifen or PBS was administered i.p. on the day the mice were placed on their diets, and on alternate days thereafter. Six mice per group (n = 18) were randomly killed at the indicated time points. In the treatment model, the mice were placed on the diets and 4T1 cells were injected into the mammary fat pad 14 days later. Tamoxifen or PBS was administered 14 days after injection of tumor cells, and on alternate days thereafter. Each group had 6 mice, which were killed at the completion of the experiment. B: Tamoxifen has chemotherapeutic effects against 4T1 cells. 4T1 cells were incubated with increasing concentrations of tamoxifen, and their viability assessed 72 h later by the MTT assay. The cell viability index (% viability) was plotted versus the concentration of tamoxifen.
© Copyright Policy - open-access
Related In: Results  -  Collection

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getmorefigures.php?uid=PMC3539967&req=5

Figure 1: Experimental protocols for prevention and treatment models of breast cancer, and sensitivity of 4T1 cells to tamoxifen. A: Experimental protocols. In the prevention model, mice were placed on the control diet or the Fe-Lf diet, and 4T1 tumor cells were injected into the mammary fat pad 14 days later. Tamoxifen or PBS was administered i.p. on the day the mice were placed on their diets, and on alternate days thereafter. Six mice per group (n = 18) were randomly killed at the indicated time points. In the treatment model, the mice were placed on the diets and 4T1 cells were injected into the mammary fat pad 14 days later. Tamoxifen or PBS was administered 14 days after injection of tumor cells, and on alternate days thereafter. Each group had 6 mice, which were killed at the completion of the experiment. B: Tamoxifen has chemotherapeutic effects against 4T1 cells. 4T1 cells were incubated with increasing concentrations of tamoxifen, and their viability assessed 72 h later by the MTT assay. The cell viability index (% viability) was plotted versus the concentration of tamoxifen.
Mentions: In the prevention experiment, 72 six-week-old Balb/c female mice were randomized into four groups of 18 animals each, to receive either the control diet, control diet + tamoxifen, Fe-Lf diet, or Fe-Lf diet + tamoxifen. The feeding schedules are shown in Figure 1A. In the control diet and Fe-Lf diet groups, the mice were fed with control or Fe-Lf diets, respectively, and received an i.p. injection of 100 μL of PBS every two days. In the control diet + tamoxifen and Fe-Lf diet + tamoxifen groups, the mice were fed with control and Fe-Lf diets, respectively, and received an injection of 100 μL of tamoxifen (Sigma, MO) suspension at a dose of 5 mg/Kg body weight every two days. The tamoxifen powder was initially dissolved in 100% ethanol, and then diluted in PBS to prepare a tamoxifen injectable suspension. Tamoxifen was injected subcutaneously on the inside of either thigh with the sites of injection being rotated. Fourteen days later, 50 μl of a mixture of BD Matrigel™ Basement Membrane Matrix (BD Biosciences) and PBS (phosphate buffered saline) (1:1, v/v) containing 2 × 104 4T1 cells was injected into the right inguinal mammary fat pad of mice. The mice were monitored and weighed, and the sizes of the tumors were recorded by measuring tumor diameters. Six mice in each group were killed at the indicated time points (Figure 1A), bled by cardiac puncture and sera isolated. Tumors, lungs, livers, small intestines, gastrocnemius muscles and ovarian adipose tissues were excised and weighed.

Bottom Line: The combination therapy was significantly (all P < 0.05) more effective than the respective monotherapies.Similar effects of Fe-Lf and tamoxifen on tumor cell viability were seen in the treatment of established tumors.The results indicate that Fe-Lf is a potent natural adjuvant capable of augmenting the chemotherapeutic activity of tamoxifen.

View Article: PubMed Central - HTML - PubMed

Affiliation: Department of Molecular Medicine & Pathology, Faculty of Medical and Health Sciences, University of Auckland, Auckland 1005, New Zealand.

ABSTRACT

Background: Tamoxifen is used in hormone therapy for estrogen-receptor (ER)-positive breast cancer, but also has chemopreventative effects against ER-negative breast cancers. This study sought to investigate whether oral iron-saturated bovine lactoferrin (Fe-Lf), a natural product which enhances chemotherapy, could improve the chemotherapeutic effects of tamoxifen in the treatment of ER-negative breast cancers.

Methods: In a model of breast cancer prevention, female Balb/c mice treated with tamoxifen (5 mg/Kg) were fed an Fe-Lf supplemented diet (5 g/Kg diet) or the base diet. At week 2, 4T1 mammary carcinoma cells were injected into an inguinal mammary fat pad. In a model of breast cancer treatment, tamoxifen treatment was not started until two weeks following tumor cell injection. Tumor growth, metastasis, body weight, and levels of interleukin 18 (IL-18) and interferon γ (IFN-γ) were analyzed.

Results: Tamoxifen weakly (IC(50) ~ 8 μM) inhibited the proliferation of 4T1 cells at pharmacological concentrations in vitro. In the tumor prevention study, a Fe-Lf diet in combination with tamoxifen caused a 4 day delay in tumor formation, and significantly inhibited tumor growth and metastasis to the liver and lung by 48, 58, and 66% (all P < 0.001), respectively, compared to untreated controls. The combination therapy was significantly (all P < 0.05) more effective than the respective monotherapies. Oral Fe-Lf attenuated the loss of body weight caused by tamoxifen and cancer cachexia. It prevented tamoxifen-induced reductions in serum levels of IL-18 and IFN-γ, and intestinal cells expressing IL-18 and IFN-γ. It increased the levels of Lf in leukocytes residing in gut-associated lymphoid tissues. B, T and Natural killer (NK) cells containing high levels of Lf were identified in 4T1 tumors, suggesting they had migrated from the intestine. Similar effects of Fe-Lf and tamoxifen on tumor cell viability were seen in the treatment of established tumors.

Conclusions: The results indicate that Fe-Lf is a potent natural adjuvant capable of augmenting the chemotherapeutic activity of tamoxifen. It could have application in delaying relapse in tamoxifen-treated breast cancer patients who are at risk of developing ER-negative tumors.

Show MeSH
Related in: MedlinePlus