No abstract

Abstract. Nasopharyngeal carcinoma (NPC) is a type of cancer endemic in Asia, including Malaysia, Southern China, Hong Kong and Taiwan. Treatment resistance, particularly in recurring cases, remains a challenge. Thus, studies to develop novel therapeutic agents are important. Potential therapeutic compounds may be effectively examined using two-dimensional (2D) cell culture models, three-dimensional (3D) spheroid models or in vivo animal models. The majority of drug assessments for cancers, including for NPC, are currently performed with 2D cell culture models. This model offers economical and high-throughput screening advantages. However, 2D cell culture models cannot recapitulate the architecture and the microenvironment of a tumor. In vivo models may recapitulate certain architectural and microenvironmental conditions of a tumor, however, these are not feasible for the screening of large numbers of compounds. By contrast, 3D spheroid models may be able to recapitulate a physiological microenvironment not observed in 2D cell culture models, in addition to avoiding the impediments of in vivo animal models. Thus, the 3D spheroid model offers a more representative model for the study of NPC growth, invasion and drug response, which may be cost-effective without forgoing quality. Contents1. Introduction 2. 2D cell culture models 3. In vivo animal models 4. 3D spheroid models 5. 3D spheroid models for high-throughput drug screening 6. NPC 3D spheroids 7. Conclusion IntroductionNasopharyngeal carcinoma (NPC) is a type of cancer that affects the nasopharynx, commonly at the posterior and superior region in the fossa of Rosenmüller (1). It is a geographically distinct cancer, which is prevalent in south-east Asia, southern China and southern Africa (2). Viral, dietary, hereditary and lifestyle factors have been identified as risk factors for NPC (2). Current NPC treatment consists of radiotherapy, chemotherapy or chemo-radiotherapy; treatment resistance, particularly in advanced and recurrent cases of NPC, remains a challenge (2). NPC is staged according to the TNM system, whereby T describes the primary tumor invasion to the tissue or organs near the nasopharynx, N describes the spread to the lymph nodes and M indicates the metastasis of the tumor. NPC is usually detected at a late stage (III or IV) (2). Early-stage NPC has unspecific and ambiguous clinical symptoms such as neck lumps, bloodstained sputum, mild hearing loss and a unilateral headache which may be ignored by its sufferer or misdiagnosed by a doctor (3). Ultimately, this leads to a late disease presentation as well as detection. The pathogenesis of NPC involves genetic and epigenetic changes in the nasopharyngeal epithelium (4). Previous studies have improved current understanding of the potential molecular targets and signaling pathways involved in NPC pathogenesis, which has assisted the development of targeted therapies for the treatment of NPC, including cetuximab (Erbitux

ObjectiveThere are number of studies which report that BCL-2 anti-apoptotic proteins (e.g. BCL-2, BCL-XL, and MCL-1) are highly expressed in cervical cancer tissues compared to the normal cervical epithelia. Despite these reports, targeting these proteins for cervical cancer treatment has not been explored extensively. BH3-mimetics that inhibit specific BCL-2 anti-apoptotic proteins may hold encouraging treatment outcomes for cervical cancer management. Hence, the aim of this pilot study is to investigate the sensitivity of cervical cancer cell lines to combination of two BH3-mimetics namely ABT-263 which selectively inhibits BCL-2, BCL-XL and BCL-w and A-1210477, a selective MCL-1 inhibitor.ResultsWe report that combination of A-1210477 and ABT-263 exhibited synergistic effects on all cervical cancer cell lines tested. Drug sensitization studies revealed that A-1210477 sensitised the cervical cancer cell lines SiHa and CaSki to ABT-263 by 11- and fivefold, respectively. Sensitization also occurred in the opposite direction whereby ABT-263 sensitised SiHa and CaSki to A-1210477 by eightfold. This report shows that combination of ABT-263 and A-1210477 could be a potential treatment strategy for cervical cancer. Extensive drug mechanistic studies and drug sensitivity studies in physiological models are necessary to unleash the prospect of this combination for cervical cancer therapy.Electronic supplementary materialThe online version of this article (10.1186/s13104-018-3302-0) contains supplementary material, which is available to authorized users.

Spheroids are generally self-assembled cells with the ability to generate their extracellular matrix, including the complex cell-matrix and the cell-cell interactions that resemble the functional characteristics of the corresponding tissue in vivo. The study aimed to develop a three-dimensional (3D) spheroid system for the cervical cancer cell lines, HeLa (HPV18), CaSki (HPV16), SiHa (HPV16), C33A (non-HPV), HT3 (non-HPV) as well as to identify its biological activity in the extracellular form. For the formation of the cervical cancer spheroids, the liquid overlay approach was applied, followed by embedding to the bovine collagen I matrix. Spheroid formation using the liquid overlay approach is achieved by growing the cells on a non-adhesive surface to prevent cellular adhesion, resulting in the cells forming aggregates and, subsequently, the spheroids. The obtained data shows the definite biological behavior of each of the particular cervical cancer cell lines, indicating that cells adapt their natural phenotype in a three-dimensional microenvironment.

34A combination of the BCL-2 inhibitors ABT-263 and A-1210477 inhibited cell proliferation 35 in the HeLa, C33A, SiHa and CaSki human cervical cancer cell lines. Drug sensitivity was 36 initially tested using 2-dimensional (2D) cell culture models. As ABT-263 binds to both BCL-37 2 and BCL-XL at high affinity, it was unclear whether the synergism of the drug combination 38 was driven either by singly inhibiting BCL-2 or BCL-XL, or inhibition of both. Therefore, we 39 used the BCL-2 selective inhibitor ABT-199 and the BCL-XL selective inhibitor A1331852 to 40 resolved the individual antitumor activities of ABT-263 into BCL-2 and BCL-XL dependent 41 mechanisms. A-1210477 was substituted with the orally bioavailable S63845. The SiHa, C33A 42 and CaSki cell lines were resistant to single agent treatment of all three drugs, suggesting that 43 none of these anti-apoptotic proteins singly mediate survival of the cells. HeLa cells were 44 resistant to single agent treatment of ABT-199 and A1331852 but were sensitive to S63845 45 indicating that they depend on MCL-1 for survival. Co-inhibition of BCL-XL and MCL-1 with 46 A1331852 and S63845 significantly inhibited cell proliferation of all four cell lines. Similar 47 data were obtained with 3-dimensional spheroid cell culture models generated from two 48 cervical cancer cell lines in vitro. Treatment with a combination of A1331852 and S63845 49 resulted in inhibition of growth and invasion of the 3D spheroids. Co-inhibition of BCL-2 and 50 MCL-1 with ABT-199 and S63845, also inhibited cell proliferation of all cancer cell lines, 51 except SiHa. However, the effect of the combination was not as pronounced as combination of 52 A1331852 and S63845. Collectively, our data demonstrate that the combination of MCL-1-53 selective inhibitors with either selective inhibitors of either BCL-XL or BCL-2 may be 54 potentially useful as treatment strategies for the management of cervical cancer. 55 56