Conducting multiple mini-interviews in the midst of COVID-19 pandemic

Multiple mini-interview (MMI) is a 'multiple sample-based' approach comprising multiple focused encounters intended to access and assess a range of attributes in order to gain more objectively multiple impressions of an applicant's interpersonal skills, thoughtfulness and general demeanour. It is designed to focus on four domains that are not considered to be comprehensive, but are considered to be vital for a successful career in the health sciences: critical thinking, ethical decision making, communication and knowledge of the healthcare system. Traditionally, the MMI is conducted face-to-face, but with COVID-19 pandemic and the implementation of social distancing measures, no onsite or campus teaching, banning of mass gatherings and cancellation of face-to-face interviews, Pengiran Anak Puteri Rashidah Sa'adatul Bolkiah Institute of Health Sciences at Universiti Brunei Darussalam explored the feasibility of conducting MMI through virtual means. This report provides an account of our experience in conducting internet-MMI for the selection of new applicants into the August 2020 cohort of the Medicine programme. We also aimed to determine whether the scores derived from internet-MMI were reliable and equivalent to the scores derived from traditional MMI.

Phytochemicals With Anti 5-alpha-reductase Activity: A Prospective For Prostate Cancer Treatment

Prostate cancer (CaP) is one of the leading causes of death in men worldwide. Much attention has been given on its prevention and treatment strategies, including targeting the regulation of 5-alpha-Reductase (5αR) enzyme activity, aimed to limit the progression of CaP by inhibiting the conversion of potent androgen dihydrotestosterone from testosterone that is thought to play a role in pathogenesis of CaP, by using the 5-alpha-Reductase inhibitors (5αRis) such as finasteride and dutasteride. However, 5αRis are reported to exhibit numerous adverse side effects, for instance erectile dysfunction, ejaculatory dysfunction and loss of libido. This has led to a surge of interest on plant-derived alternatives that might offer favourable side effects and less toxic profiles. Phytochemicals from plants are shown to exhibit numerous medicinal properties in various studies targeting many major illnesses including CaP. Therefore, in this review, we aim to discuss the use of phytochemicals namely phytosterols, polyphenols and fatty acids, found in various plants with proven anti-CaP properties, as an alternative herbal CaP medicines as well as to outline their inhibitory activities on 5αRs isozymes based on their structural similarities with current 5αRis as part of CaP treatment approaches.

Overcoming acquired resistance to HSP90 inhibition by targeting JAK-STAT signalling in triple-negative breast cancer

Background

Due to the lack of effective therapies and poor prognosis in TNBC (triple-negative breast cancer) patients, there is a strong need to develop effective novel targeted therapies for this subtype of breast cancer. Inhibition of heat shock protein 90 (HSP90), a conserved molecular chaperone that is involved in the regulation of oncogenic client proteins, has shown to be a promising therapeutic approach for TNBC. However, both intrinsic and acquired resistance to HSP90 inhibitors (HSP90i) limits their effectiveness in cancer patients.

Methods

We developed models of acquired resistance to HSP90i by prolonged exposure of TNBC cells to HSP90i (ganetespib) in vitro. Whole transcriptome profiling and a 328-compound bioactive small molecule screen were performed on these cells to identify the molecular basis of acquired resistance to HSP90i and potential therapeutic approaches to overcome resistance.

Results

Among a panel of seven TNBC cell lines, the most sensitive cell line (Hs578T) to HSP90i was selected as an in vitro model to investigate acquired resistance to HSP90i. Two independent HSP90i-resistant clones were successfully isolated which both showed absence of client proteins degradation, apoptosis induction and G2/M cell cycle arrest after treatment with HSP90i. Gene expression profiling and pathway enrichment analysis demonstrate significant activation of the survival JAK-STAT signalling pathway in both HSP90i-resistant clones, possibly through IL6 autocrine signalling. A bioactive small molecule screen also demonstrated that the HSP90i-resistant clones showed selective sensitivity to JAK2 inhibition. Inhibition of JAK and HSP90 caused higher induction of apoptosis, despite prior acquired resistance to HSP90i.

Conclusions

Acquired resistance to HSP90i in TNBC cells is associated with an upregulated JAK-STAT signalling pathway. A combined inhibition of the JAK-STAT signalling pathway and HSP90 could overcome this resistance. The benefits of the combined therapy could be explored further for the development of effective targeted therapy in TNBC patients.

Electronic supplementary material

The online version of this article (10.1186/s12885-019-5295-z) contains supplementary material, which is available to authorized users.

Abstract B88: Mechanisms of resistance to the Hsp90 inhibitor ganetespib in triple negative breast cancer

Background: Triple negative breast cancer (TNBC), which accounts for 10-17% of all breast cancers, is challenging to treat due to its heterogeneity and the absence of identified targeted therapies. Heat shock protein 90 kDa (Hsp90) is a molecular chaperone protein essential for regulating the stability and activity of several client proteins required for oncogenesis, and selective Hsp90 inhibitors have shown anti-cancer activity in multiple cancer models including TNBC. Ganetespib, a second generation Hsp90 inhibitor, has shown promising clinical activity in TNBC patients but responders develop acquired resistance. Here, we generated an in vitro model of ganetespib-resistant TNBC cells and investigated the mechanisms of resistance to ganetespib in TNBC using a 96-well based small molecule screen.

Methods: Ganetespib treatment sensitivity in a panel of seven TNBC cell lines (HS578T, HCC1143, HCC1937, MDA-MB-468, MDA-MB-231, MDA-MB-453 and BT20) was assessed using a resazurin-based cell proliferation assay. HS578T cells were incubated in a high concentration of ganetespib (>IC50) to generate ganetespib-resistant clones. The effects on Hsp90 oncogenic client proteins (AKT and EGFR) and Hsp70 were determined by western blotting. Cross resistance to other Hsp90 inhibitors was also assessed. 96-well based small molecule screen with a library of 326 bioactive small molecule inhibitors was performed on parental HS578T and ganetespib-resistant clones in the absence and presence of ganetespib. Resazurin-based cell proliferation assay was used as an end point. Positive hits were identified as log10(percentage of proliferation in parental/resistant) ≥ 2SD.

Results: TNBC cell lines showed differential sensitivity to ganetespib (IC50 range: 4.75 to 20.16 nM), with HS578T being the most sensitive and HCC1143 the most resistant. Independent ganetespib-resistant HS578T clones (CR2 and CR3) were successfully generated by incubating parental HS578T cells in ganetespib (30 nM) for 42 days. IC50 values for the ganetespib-resistant clones (CR2: 15.57 ± 1.90 nM and CR3: 20.28 ± 2.75 nM) were 3 to 4-fold higher than the parental HS578T cells (IC50: 4.79 ± 0.32 nM). The client proteins were not further down-regulated after ganetespib treatment in the ganetespib-resistant clones compared to the parental HS578T cells. Resistant clones also showed cross resistance to 1st generation (17-AAG) and 2nd generation (NVP-AUY922) Hsp90 inhibitors. The small molecule screen was reproducible as the independent runs and duplicates strongly correlated (R2 >0.7). The ganetespib-resistant CR3 clones showed selective sensitivity to 11/326 compounds (Z score ≥ 2), only in the presence of ganetespib when compared to the parental HS578T cells, most notable being LY2784544, a JAK2 inhibitor.

Conclusion: Ganetespib-resistant HS578T cells provide a promising model to study the resistance mechanisms to ganetespib in TNBC. Our current data suggest that TNBC cells are responsive to JAK2 inhibition in the presence of ganetespib despite prior acquisition of resistant to ganetespib. Activation of a JAK2/STAT3 survival pathway may be a potential resistance mechanism to Hsp90 inhibition and combined Hsp90 and JAK2 inhibition could potentially be a useful therapeutic strategy for TNBC.

Citation Format: Nuramalina H. Mumin, Sivan Bokobza, Fiona Cahill, Neele Drobnitzky, Yanyan Jiang, Luiza Madia Lourenco, Aoife Vaughan, Anika Weber, Anthony Kong, Anderson Ryan. Mechanisms of resistance to the Hsp90 inhibitor ganetespib in triple negative breast cancer. [abstract]. In: Proceedings of the AACR-NCI-EORTC International Conference: Molecular Targets and Cancer Therapeutics; 2015 Nov 5-9; Boston, MA. Philadelphia (PA): AACR; Mol Cancer Ther 2015;14(12 Suppl 2):Abstract nr B88.