Effects of Ruxolitinib and Calcitriol Combination Treatment on Various Molecular Subtypes of Breast Cancer.

Jean Schneider,Ye Won Jeon,Young Jin Suh,Seung Taek Lim

doi:10.3390/ijms23052535

Abstract

The anticancer effects of ruxolitinib and calcitriol against breast cancer were reported previously. However, the effect of ruxolitinib and calcitriol combination treatment on various molecular subtypes of breast cancer remains unexplored. In this study, we used MCF-7, SKBR3, and MDA-MB-468 cells to investigate the effect of ruxolitinib and calcitriol combination treatment on cell proliferation, apoptosis, cell cycle, and cell signaling markers, in vitro and in vivo. Our results revealed the synergistic anticancer effect of ruxolitinib and calcitriol combination treatment in SKBR3 and MDA-MB-468 cells, but not in MCF-7 cells in vitro, via cell proliferation inhibition, apoptosis induction, cell cycle arrest, and the alteration of cell signaling protein expression, including cell cycle-related (cyclin D1, CDK1, CDK4, p21, and p27), apoptosis-related (c-caspase and c-PARP), and cell proliferation-related (c-Myc, p-p53, and p-JAK2) proteins. Furthermore, in the MDA-MB-468 xenograft mouse model, we demonstrated the synergistic antitumor effect of ruxolitinib and calcitriol combination treatment, including the alteration of c-PARP, cyclin D1, and c-Myc expression, without significant drug toxicity. The combination exhibited a synergistic effect in HER2-enriched and triple-negative breast cancer subtypes. In conclusion, our results suggest different effects of the combination treatment of ruxolitinib and calcitriol depending on the molecular subtype of breast cancer.

Highlights

Breast cancer is the most frequently diagnosed cancer and was the most common cause of cancer-specific mortality among women worldwide in 2020 [1]
In SKBR3 and MDA-MB-468 cells, combination index (CI) at all combinations showed a synergistic effect between ruxolitinib and calcitriol (SKBR3: CI 0.759–0.836, MDA-MB-468: CI 0.676–0.787). These results indicate that the combination treatment with ruxolitinib and calcitriol had a synergistic antiproliferative effect in SKBR3 and MDA-MB-468 cells but not in MCF-7 cells
5.22 ± 2.52%, G2/M 32.86 ± 5.02%, Sub G1 4.86 ± 0.88%) compared to those in the control group. These results suggest that while the G2/M arrest effect of ruxolitinib and G0/G1 arrest effect of calcitriol were consistent in all the cell lines tested, the combined effect of ruxolitinib and calcitriol in the cell cycle was different among cell lines depending on their molecular subtypes

Summary

Introduction

Breast cancer is the most frequently diagnosed cancer and was the most common cause of cancer-specific mortality among women worldwide in 2020 [1]. It is estimated that in the United States, approximately 281,550 cases and 43,600 deaths will occur due to breast cancer in 2021 [2]. Despite recent advances in the therapeutic strategies for breast cancer, including surgical techniques and chemotherapy regimens, the prognosis in patients with breast cancer remains unsatisfactory [3]. One of the reasons that worsen a patient’s prognosis is the resistance to anticancer agents [4], which inevitably necessitates a novel therapeutic strategy, including the combination of anticancer agents that were previously used as a single agent. The determination of relevant combinations of anticancer drugs allows for a synergistic treatment effect compared with monotherapy [5]. Ruxolitinib is an oral selective inhibitor of Janus kinase (JAK) 1 and JAK2 [6] and was initially approved for use in the treatment of myelofibrosis and polycythemia vera [7,8]

Methods

Results

Discussion

Conclusion