Vol 12, Issue 3, 2019 Online - 2455-3891 Print - 0974-2441 HYPERTHERMIA EFFECT ON HUMAN NORMAL BREAST (MCF-10A) AND CANCER (MDA-MB 231 AND MCF-7) CELLS ASITA ELENGOE 1 , NOOR JAHAN BANU MOHAMMED ALITHEEN 2 , SALEHHUDDIN HAMDAN 3 * 1 Department of Biotechnology, Faculty of Science, Lincoln University College, 47301 Petaling Jaya, Selangor, Malaysia, 2 Department of Cell and Molecular Biology, Faculty of Biotechnology and Biomolecular Sciences, Universiti Putra Malaysia, Serdang, Selangor, Malaysia, 3 Department of Biosciences and Health Sciences, Faculty of Science, Universiti Teknologi Malaysia, 81310 Skudai, Johor, Malaysia. Email: saleh65@utm.my Received: 27 November 2018, Revised and Accepted: 14 January 2019 ABSTRACT Objective: In this study, the hyperthermia effect on the viability of human normal breast (MCF-10A) and cancer (MDA-MB 231 and MCF-7) cells was evaluated by MTT assay. Methods: Cells were exposed to heat at 38ºC, 39ºC, 40ºC, 41ºC, 42ºC, 43ºC, and 44ºC for five different durations of heat exposure (0.5, 1, 2, 3, and 4 h). Breakpoint temperatures of MCF-10A, MDA-MB 231, and MCF-7 were determined using cumulative equivalent 43°C (CEM 43 ) model. This model was first time used to calculate thermal isoeffect dose (TID) for MCF-10A, MDA-MB 231, and MCF-7. Results: MCF-10A started to die at 42°C for 3 h while MDA-MB 231 and MCF-7 need a temperature of 38°C for 0.5 h; thus, they were identified as the threshold temperatures in CEM 43 model. Furthermore, the effect of “43°C incubator 2 h” had similar total thermal dose as “44°C incubator 0.5 h” for MDA-MB 231 and MCF-7. In addition, “43°C incubator 3 h” effect had also almost the same thermal dose as “44°C incubator 1 h” for MDA-MB 231 and MCF-7. Conclusion: A better understanding of the significant correlations between CEM 43 and response parameters in clinical trials could be useful to treat breast cancer patients. Keywords: Hyperthermia, MCF-10A, MDA-MB 231, MCF-7, cumulative equivalent 43°C model, Thermal isoeffect dose INTRODUCTION Breast cancer is a major global health problem and the most common invasive cancer in women of all ethnic backgrounds. Worldwide, estimated 1.6 million new cases are diagnosed for each year [1, 2]. There are many attempts with a multitude of novel therapeutic concepts although the conventional methods based on surgery, chemotherapy, radiotherapy, or their combinations steadily develop [3]. Hyperthermia among them has attracted significant attention and already entered clinical practice as an adjuvant to chemotherapy and radiotherapy [4]. It is used to raise the temperature of a region of the body affected by cancer with minimal or no damaging healthy tissues [5]. Thermal chemosensitization and thermal radiosensitization effects have been observed both in vivo and in in vitro cell culture experiments [6]. At least 18 randomized studies have demonstrated that the synergistic effects of combining hyperthermia with either chemotherapy or radiotherapy or both to achieve better therapeutic effects [5]. This was demonstrated for the breast, cervix, head and neck, pancreas, bladder, esophagus, prostate, lung, vulva/vagina cancers, and for melanoma. Hyperthermia has shown great potential in overcoming multidrug resistant (e.g. doxorubicin) which may result in the accumulation of chemotherapy agents within the target cells [6]. Rolf (2008) observed that synergism as a continuous change with increasing the rate temperatures at which cells are killed by the drug [7]. It is generally accepted that when temperatures are raised from 37ºC to over 40ºC, most alkylating agents (e.g., cyclophosphamide and ifosfamide), platinum compounds, and nitrosoureas (bis-chloroethylnitrosourea, and 1-2-chloroethyl-3-cyclohexyl-1-nitrosourea) are linearly enhanced in their cytotoxic effect. On other the hand, threshold temperatures for the interaction with heat at or near 42.5ºC have a synergistic effect with doxorubicin or bleomycin meanwhile most antimetabolites (e.g. 5-fluorodeoxyuridine and methotrexate), vinca alkaloids, or taxanes show independent action [7, 8]. Thus, thermal isoeffect dose (TID) is important because it helps to predict the outcome in vitro for a given heat dose. It can be applied to sensitize phenomena with cytostatic drugs, anticancer agents, and radiation therapy to improve better outcome in breast cancer treatment. The TID for induction of cell death was found to be closely related to the amount of energy required to inactivate proteins and enzymes [9]. Although the Arrhenius analysis could be used to calculate the inactivation energy, it is hard to compare two different time-temperature combinations in that plot. Therefore, Sapareto and Dewey [10] described the term “TID” (meaning two different time-temperature combinations produced the same cell killing effect) for comparing different time-temperature combinations. Calculation of the thermal dose applied in hyperthermia has been successfully integrated into the concept of a TID during a certain duration exposure at a given temperature. Treatment outcome varied greatly between different types of cell lines although the same or different settings of hyperthermia used. For example, the proliferation of human osteosarcoma cells was inhibited by hyperthermia treatment at 42°C whereas heat shock at 44°C inhibited proliferation significantly in normal fibroblasts cells [9]. Therefore, different mechanisms were involved in heat shock-induced cell death among normal cell and cancer cell [5]. According to Omar and Lanks [11] investigated that cancer cells are more susceptible to killing by heat than normal cells after the hyperthermia treatment (43°C–45°C). © 2019 The Authors. Published by Innovare Academic Sciences Pvt Ltd. This is an open access article under the CC BY license (http://creativecommons. org/licenses/by/4. 0/) DOI: http://dx.doi.org/10.22159/ajpcr.2019.v12i3.30956 Research Article