Agranulocytosis Induced by Tamoxifen in a Breast Cancer Patient

Protective role of olive oil extract of propolis on short and long-term administration of tamoxifen in rats

Tamoxifen (TAM) is an antiestrogenic agent used for adjuvant treatment in estrogen receptor-positive breast cancers in the pre/post-menopausal period. This study, it was aimed to determine the effect of olive oil extract of propolis (OEP) on short and long-term administration of TAM in rats. Wistar albino rats were divided into groups with eight animals in each. Groups: control, OEP, TAM, and OEP + TAM. At the end of the experiment, oxidative stress tests were performed with Enzyme-Linked ImmunoSorbent Assay (ELISA) on blood and tissue samples (liver, kidney, and ovary) taken from rats. After single-dose TAM administration, there was a significant increase in red blood cell, hematocrit, mean corpuscular hemoglobin, and mean corpuscular hemoglobin concentration levels compared to the control group, a decrease in low-density lipoprotein (LDL) value, a significant increase in liver enzymes and fasting glucose values was detected compared with the control and propolis groups. A normalizing effect was observed in the group given OEP and TAM combined. The increase in Malondialdehyde (MDA) and the decrease in enzyme activities in tissues are also noteworthy. Propolis application reduced the tissue damage caused by TAM. In addition, improved cytokine levels, which increased with TAM administration. It has been concluded that OEP can be given in supportive treatment, as it improves hematological and antioxidant parameters in TAM treatment.

The Optimized Formulation of Tamoxifen-Loaded Niosomes Efficiently Induced Apoptosis and Cell Cycle Arrest in Breast Cancer Cells

The aim, as proof of concept, was to optimize niosomal formulations of tamoxifen in terms of size, morphology, encapsulation efficiency, and release kinetics for further treatment of the breast cancer (BC). Different assays were carried out to evaluate the pro-apoptotic and cytotoxicity impact of tamoxifen-loaded niosomes in two BC cells, MDA-MB-231 and SKBR3. In this study, tamoxifen was loaded in niosomes after optimization in the formulation. The formulation of niosomes supported maximized drug entrapment and minimized their size. The novel formulation showed improvement in storage stability, and after 60 days only, small changes in size, polydispersity index, and drug entrapment were observed. Besides, a pH-dependent release pattern of formulated niosomes displayed slow release at physiological pH (7.4) and a considerable increase of release at acidic pH (5.4), making them a promising candidate for drug delivery in the BC treatment. The cytotoxicity study exhibited high biocompatibility with MCF10A healthy cells, while remarkable inhibitory effects were observed after treatment of cancerous lines, MDA-MB-231, and SKBR3 cells. The IC50 values for the tamoxifen-loaded niosomes were significantly less than other groups. Moreover, treatment with drug-loaded niosomes significantly changed the gene expression pattern of BC cells. Statistically significant down-regulation of cyclin D, cyclin E, VEGFR-1, MMP-2, and MMP-9 genes and up-regulation of caspase-3 and caspase-9 were observed. These results were in correlation with cell cycle arrest, lessoned migration capacity, and increased caspase activity and apoptosis induction in cancerous cells. Optimization in the formulation of tamoxifen-loaded niosomes can make them a novel candidate for drug delivery in BC treatment.

Estrogen markedly reduces circulating low-density neutrophils and enhances pro-tumoral gene expression in neutrophil of tumour-bearing mice

Background

Neutrophils are important for immune surveillance of tumour cells. Neutrophils may also be epigenetically programmed in the tumour microenvironment to promote tumour progression. In addition to the commonly known high-density neutrophils (HDN) based on their separation on density gradient, recent studies have reported the presence of high levels of low-density neutrophils (LDN) in tumour-bearing mice and cancer patients. We reported previously that estrogen promotes the growth of estrogen receptor α-negative mammary tumours in mice undergoing mammary involution through stimulating pro-tumoral activities of neutrophils in the mammary tissue.

Methods

Female BALB/cAnNTac mice at 7–8 weeks old were mated and bilateral ovariectomy was performed 2 days post-partum. At 24 h after forced-weaning of pups to induce mammary involution, post-partum female mice were injected with either E2V, or vehicle control on alternative days for 2-weeks. On 48 h post-weaning, treated female mice were inoculated subcutaneously with 4 T1-Luc2 cells into the 9th abdominal mammary gland. Age-matched nulliparous female was treated similarly. Animals were euthanized on day 14 post-tumour inoculation for analysis. To evaluate the short-term effect of estrogen, post-partum females were treated with only one dose of E2V on day 12 post-tumour inoculation.

Results

Estrogen treatment for 2-weeks reduces the number of blood LDN by more than 10-fold in tumour-bearing nulliparous and involuting mice, whilst it had no significant effect on blood HDN. The effect on tumour-bearing mice is associated with reduced number of mitotic neutrophils in the bone marrow and increased apoptosis in blood neutrophils. Since estrogen enhanced tumour growth in involuting mice, but not in nulliparous mice, we assessed the effect of estrogen on the gene expression associated with pro-tumoral activities of neutrophils. Whilst 48 h treatment with estrogen had no effect, 2-weeks treatment significantly increased the expression of Arg1, Il1b and Tgfb1 in both HDN and LDN of involuting mice. In contrast, estrogen increased the expression of Arg1 and Ccl5 in HDN and LDN of nulliparous mice.

Conclusions

Prolonged estrogenic stimulation in tumour-bearing mice markedly hampered tumour-associated increase of LDN plausibly by inhibiting their output from the bone marrow and by shortening their life span. Estrogen also alters the gene expression in neutrophils that is not seen in tumour-free mice. The results imply that estrogen may significantly influence the tumour-modulating activity of blood neutrophils.

Supplementary Information

The online version contains supplementary material available at 10.1186/s12885-021-08751-2.