P2 Script (Matt) Preparation Flashcards
Slide 1: Project Title
- Greetings
- Acknowledge review panel (if possible)
- Introduction
- Understanding the mechanisms of alpha-mangostin, curcumin & lycopene in the in vitro protection against cisplatin-induced nephrotoxicity (CIN)
Slide 2: Impetus of Study
- Let’s start by explaining the impetus behind our research project.
- Why are we exploring natural antioxidants, specifically alpha-mangostin, curcumin & lycopene, as potential prophylactic options in the protection against CIN?
Slide 3: Hydration Protocols
- Aggressive hydration protocols are administered pre-emptively in chemotherapy regimes to reduce CIN
- Discontinuation rate remains high, with acute kidney injury observed in 20-30% of patients receiving cisplatin
- While hydration and diuresis did help to taper incidence of CIN, they offer limited protection
- Since degree of cisplatin-induced necrosis in kidney cells is not subsequently attenuated
- Growing need for more effective nephroprotective strategies to minimise CIN
Slide 4: Outline
- Leads into the outline of our presentation today
- Go through introduction, objectives, materials and methods, results, discussion and conclusions of our study conducted
Slide 5: Introduction
To start off,…
Slide 6: Uses of Cisplatin
- Highly sought-after chemotherapeutic agent
- Treatment of a plethora of solid tumour cancers and haematological cancers
- Despite being in the market for more than 40 years, challenging to repeatedly administer as first-line therapy
- Due to primary association to nephrotoxicity
- Consequently, many have delved into understanding the mechanisms of CIN.
- To comprehend available therapeutic targets to circumvent nephrotoxicity
- Hopefully allow its use across a broader range of patients benefiting from cisplatin administration
Slide 6: CIN
So, how does cisplatin result in renal toxicity?
Slide 7: MOA of CIN
1st: Renal uptake mediated by organic cation transporter 2 (OCT2)
- Predominantly found along basolateral membrane of proximal renal tubular epithelia
2nd: Undergoes a series of enzymatic reactions leading to eventual generation of reactive oxygen species (ROS)
- Thus causing oxidative stress to renal tubular cells
Slide 8: in vivo Animal Strategies
Now that we have a general idea of the mechanisms of CIN, what are the strategies currently employed and explored to combat CIN?
- Introduced earlier that the most commonly employed strategy is the use of aggressive hydration protocols involving the administration of 1-2 litres of normal saline, accompanied with diuretics such as mannitol and furosemide.
Other proposed strategies involve in vivo animal studies:
1st: OCT2 inhibitors (cimetidine)
- Able to reduce uptake of cisplatin into renal tubular cells, therefore reducing CIN
- However, animal models co-treated with cimetidine and cisplatin still displayed signs of nephrotoxicity, such as apoptosis and proteinuria
- Potential of using cimetidine as CIN prophylaxis may be limited
2nd: Downregulation of tumour necrosis factor-alpha (TNF-alpha)
- Can limit the inflammatory reaction in response to cisplatin, hence attenuating CIN
- Process of reducing these inflammatory markers will be subsequently discussed in a later section
3rd: Chronic administration of Vitamin C
- Helpful in ameliorating CIN in rats
- By scavenging circulating ROS and/or reactive nitrogen species
Slide 9: Natural Antioxidants
So, why is our attention focused on exploring the use of antioxidants as prophylaxis against CIN?
Greater potential to become clinically relevant, as compared to the other two strategies discussed earlier
Slide 11: Alpha-mangostin
Brief Introduction of NAO:
- Recently explored as an alternative means to dampen the effects of CIN
- Attractiveness as naturally available food-derived compounds
- Potential to be tested in clinical trials
1st NAO of interest: Alpha-mangostin
- Naturally available xanthone harvested from mangosteen
- Can mitigate cisplatin-induced cytotoxicity (CIC) within HEK293 cells
- By reducing ROS production & suppressing activation of caspase-3 signalling cascade, which is highly involved in apoptosis
- Able to mitigate CIN by completely preventing the increase in TNF-alpha mRNA levels, thus reducing inflammation and cell death
Slide 12: Curcumin
2nd NAO of interest: Curcumin
- Polyphenol derived from turmeric
- Shown in a study with rats to reduce CIN by scavenging ROS in a concentration-dependent manner
- Another study: Mitigate CIN by reduction in lipid peroxidation
Slide 13: Lycopene
3rd NAO of interest: Lycopene
- Carotenoid found in tomatoes and other red fruits
- Attenuate CIN by decreasing lipid peroxidation, reducing glutathione peroxidase levels
- Also cushioning the decrease in essential antioxidative substances, such as glutathione and catalase in rats
Slide 14: Research Objectives & Hypothesis
Link: As such, NAOs can indeed mitigate the effects of CIN.
Study Objective:
To investigate the mechanisms of actions of these three NAOs in the in vitro protection against CIN.
Hypothesis:
Alpha-mangostin, curcumin and lycopene protect against CIN through
1) the minimisation of cell cycle arrest,
2) the reduction in caspase-3 levels, and
3) the reduction of intracellular TNF-alpha production.
Slide 25: Conclusion & Future Work
In summary,…
Slide 27: Evaluation of MOA of NAOs against CIN
- Based on our results, when we treated the cells with 70 μM cisplatin, we evaluated that all three NAOs pre-treated at 1 μM can reduce cell cycle arrest at the sub-G0/G1 apoptotic phase
- However, only 1 μM of α-mangostin and curcumin pre-treatment was able to reduce caspase-3 activation, BUT NOT 1 μM of lycopene pre-treatment.
- Unable to conclusively determine if α-mangostin, curcumin, and lycopene play a dominant role in the downregulation of TNF-alpha to ameliorate CIN
Slide 28: Future Work
- Next step forward would be to delve deeper into the specifics of these MOAs.
- Future work can include conducting in vivo animal studies with closely related pharmacokinetics and/or pharmacodynamic profiles, such as zebrafish
- Extending the duration of NAO pre-treatment is another possible thrust to explore to determine if there are any time-dependent effects with NAO pre-treatment
- As various cytokines are released together upon inflammation, further studies can explore if other key inflammatory cytokines responsible for inflammation caused by cisplatin, such as IL-10, are downregulated by NAO pre-treatment.
- Combination therapy of these three NAOs can be investigated to explore if there are any synergistic activities to aid in attenuating CIN
Slide 29: Thank You!
We hope that through our study, drugs with the same mechanisms can be screened for and could potentially take the place of the NAOs to mitigate the effects brought about by CIN. Thank you.
