Effect of Chemotherapeutics and Tocopherols on MCF-7 Breast Adenocarcinoma and KGN Ovarian Carcinoma Cell Lines In Vitro.

Daniela Figueroa,Mohammad Asaduzzaman,Fiona Young

doi:10.1155/2019/6146972

Abstract

The combination of doxorubicin and cyclophosphamide commonly used to treat breast cancer can cause premature ovarian failure and infertility. α-Tocopherol is a potent antioxidant whereas γ-tocopherol causes apoptosis in a variety of cancer models in vitro including breast cancer. We hypothesised that the combination of doxorubicin (Dox) and 4-hydroperoxycyclophosphamide (4-Cyc) would be more cytotoxic in vitro than each agent alone, and that α-tocopherol would reduce and γ-tocopherol would augment the cytotoxicity of the combined chemotherapeutics. Human MCF-7 breast cancer and KGN ovarian cells were exposed to Dox, 4-Cyc, combined Dox and 4-Cyc, α-tocopherol, γ-tocopherol, or a combination of Dox and 4-Cyc with α-tocopherol or γ–tocopherol. Cell viability was assessed using a crystal violet assay according to four schedules: 24h exposure, 24h exposure + 24h culture in medium, 24h exposure + 48h culture in medium, or 72h continuous exposure. Supernatants from each separate KGN culture experiment (n=3) were examined using an estradiol ELISA. Dox was cytotoxic to both MCF-7 and KGN cells, but 4-Cyc only killed MCF-7 cells. γ-Tocopherol significantly decreased MCF-7 but not KGN cell viability. The combined chemotherapeutics and γ-tocopherol were more cytotoxic to MCF-7 than KGN cells, and α-tocopherol reduced the cytotoxicity of the combined chemotherapeutics towards KGN ovarian cells, but not MCF-7 cells. The addition of both γ-tocopherol and α-tocopherol to the chemotherapeutic combination of Dox and cyclophosphamide has the potential to increase in vitro chemotherapeutic efficacy against breast cancer cells whilst decreasing cytotoxicity towards ovarian granulosa cells.

Highlights

In Asia, approximately 25% of all breast cancer patients are premenopausal and younger than 35 years old [1]
Up to 90% of breast cancer patients can survive for 5 years following diagnosis [2, 3] but it was found that chemotherapyinduced premature ovarian failure and infertility reduce the survivors quality of life [4,5,6,7,8,9,10]
Many types of breast cancer are treated with a combination of chemotherapeutic agents such as doxorubicin and cyclophosphamide [3, 11, 12]

Summary

Introduction

In Asia, approximately 25% of all breast cancer patients are premenopausal and younger than 35 years old [1]. Many types of breast cancer are treated with a combination of chemotherapeutic agents such as doxorubicin (adriamycin) and cyclophosphamide [3, 11, 12]. Cyclophosphamide, an alkylating agent, requires hepatic activation to form 4-hydroxycyclophosphamide and aldophosphamide, which coexist in equilibrium and diffuse freely into cells. Aldophosphamide is metabolised into phosphoramide mustard [17, 18] which causes intraand interstrand crosslinking in DNA. This interferes with DNA replication [19] and stimulates apoptosis [17]. Aldehyde dehydrogenase oxidises aldophosphamide to an inactive metabolite instead of the active phosphoramide mustard, and cells with different levels of aldehyde dehydrogenase respond differently to 4Cyc [18]

Methods

Results

Conclusion