Unravelling the cellular and molecular mechanisms underlying chemoresistance in cancer


Background: Failure to execute apoptosis is a hallmark of cancer. Most chemotherapeutic agents kill cancer cells by inducing apoptosis, however resistance is often acquired over time, resulting in tumour relapse. This is particularly evident when cancer cells are exposed to increasing concentrations of an effective chemotherapeutic agent, such as the BH3 mimetic, ABT-199 and ABT-263. Our recent paper demonstrated a way to modulate intermediary metabolism to overcome this resistance and potentially improve therapy in patients [Al-Zebeeby et al 2019]. Although the pathways and primary players responsible for executing apoptosis have been extensively characterised in the last few decades, how intermediary metabolism plays a role in modulating apoptosis is largely unknown. Moreover, recent studies have highlighted the importance of a crosstalk between mitochondria and the endoplasmic reticulum (ER) in the execution of apoptosis. It is likely that intermediary metabolism could impact upon this. The mitochondrion is a dynamic organelle that undergoes extensive fission (mediated by DRP-1 GTPase) and fusion (mediated by OPA1 and mitofusins). More importantly, these fission/fusion enzymes have been shown to play a role in the induction of apoptosis, thus linking mitochondrial membrane dynamics and apoptosis. Similarly, the reticular and sheet-like structure of the ER is maintained by several ER-shaping proteins. Our preliminary studies using several cancer cell lines reveal that downregulation of these proteins results in extensive mitochondrial fusion, reduced ER-mitochondria contacts, decreased mitochondrial bioenergetics, and most importantly, reduced apoptosis [Milani et al 2018].

Project Aims: The proposed project is aimed at: (1) identifying the extent of ER-mitochondria contact sites, membrane dynamics and functions in chemosensitive and resistant cancers, as well as (2) characterising the role of intermediary metabolism in ER-mitochondrial dynamics, which will then be correlated with the ability of specific metabolic pathway inhibitors to overcome chemoresistance.
Techniques involved: We have access to several sensitive and chemoresistant cancer cell lines, as well as primary samples from chronic lymphocytic leukaemia and squamous carcinoma of the head and neck. Techniques utilised will include microscopy (confocal/ EM/ 3view rendering), biochemical assays (western blotting, protein expression, enzyme assays, immunocytochemistry, immunohistochemistry, flow cytometry, mitochondrial functional assays) as well as molecular assays (cloning, gene editing, RNA interference).

Further Training and Support: In addition to extensive training in various cell/molecular biology and biochemical techniques, the student will be encouraged to complete a range of modules, including time and project management, statistics, research ethics, as well as written and oral communication, catered to the postgraduate students. The student will be trained on experimental design and execution by the primary supervisor and mentored by all staff in the supervisory panel. The student will actively participate in journal clubs, weekly departmental seminars and weekly lab meetings.

Project Timescale: 3 years of laboratory work, followed by 1 year (optional) for thesis writing and submission.

Working environment: The prospective student will join a highly dynamic and motivated team of researchers in the Varadarajan Lab (https://www.varadarajanlab.org) in the Institute of Systems, Molecular and Integrative Biology at the University of Liverpool. Five PhD students have graduated with at least one first authored publication from the group. Our current group members include – a postdoctoral fellow, three PhD students, and several masters and undergraduate students.

Requirements: Candidates should be self-motivated, hard-working and have an undergraduate and/or Masters degree in biology, biochemistry, pharmacy or related areas. They are strongly advised to read the recommended references prior to contacting the supervisor regarding this position.

If you are interested in applying for the opportunity, please contact Dr Varadarajan on .


Open to students worldwide

Funding information

Self-funded project

We are looking for self-funded students or students who have secured funding from an independent body. There is no financial support available from Liverpool for this study.

The successful applicant will be expected to have funding in place for the tuition fees (check University of Liverpool website), consumables/bench fee (£ 15000 per annum) and living expenses during their stay in Liverpool.



1. Al-Zebeeby A., Vogler M., Milani M., Richards C., Alotibi A., Greaves G., Dyer MJS., Cohen GM & Varadarajan S (2018). Targeting intermediary metabolism enhances the efficacy of BH3 mimetic therapy in haematological malignancies. Haematologica. Epub. doi:10.3324/haematol. 2018.204701.
2. Lucas CM, Milani M, Butterworth M, Carmell N, Clark RE, Cohen GM & Varadarajan S (2016). High CIP2A levels correlate with an antiapoptotic phenotype that can be overcome by targeting BCL-XL in chronic myeloid leukemia. Leukemia 30, 1273–1281.
3. Milani M, Byrne DP, Greaves G, Butterworth M, Cohen GM, Eyers PA & Varadarajan S (2017). DRP-1 is required for BH3 mimetic-mediated mitochondrial fragmentation and apoptosis. Cell Death and Disease 8 (1), e2552.
4. Milani M, Cohen GM & Varadarajan S (2018). ER shaping proteins regulate mitochondrial fission, outer membrane permeabilization and apoptosis. Bioarchives: doi: https://doi.org/10.1101/340448