1. Pharmacogenomics of phytochemicals from Sudanese medicinal plant in cancer cells
Mohamed E. M. Saeed PhD rer. nat.
Department of Pharmaceutical Biology
Institute of Pharmacy and Biochemistry
April 18th, 2017
05 October 2015 | Mohamed Saeed

2. The global burden estimates in 2013
Cancer worldwide
Complex disease with multiple genetic and epigenetic alterations
Tumor suppressors
Oncogenes
Cancer is considered as one of the leading causes of morbidity and mortality worldwide.
The global burden estimates in 2013
Million new cases
- 8.2 Million deaths

3. Cancer therapy Cancer treatment is composed of:
Surgery, radiation, immunotherapy, chemotherapy
Cancer chemotherapy is challenged worldwide by:
severe side effects.
treatment failure.
Cancer chemotherapy is challenged in developing countries by:
Expensive drugs, which are not affordable by the majority of the population.
We need new and affordable drugs for the Third World
Strategy: Phytotherapeutical drugs based on traditional medicine using cutting-edge technologies.

4. 05 October 2015 | Mohamed Saeed
Prevalence of cancer in Sudan ( )
A total number of cancer patients from the cancer referral hospital (RICK) were included, where almost 80% of patients were treated.
The largest study describing cancer status in Sudan thus far.
The prevalence rates/year were in a range of for adults and for children.
05 October 2015 | Mohamed Saeed

5. 05 October 2015 | Mohamed Saeed
Prevalence of cancer in Sudan ( )
Age-adjusted cancer prevalence:
Cancer prevalence in Sudanese states
Cancer pattern in Kassala state
05 October 2015 | Mohamed Saeed

6. Multidrug resistance of established anticancer drugs
Multidrug resistance (MDR) is defined as the cross-resistance or loss of sensitivity of cancer cells to a broad spectrum of anticancer drugs.
Two factors responsible for MDR:
Individual specificity: Pharmacokinetics (ADME).
Cancer cell specificity: Genetic alterations.
Mechanisms of MDR:

7. Increased drug efflux by ABC transporters
Multifactorial MDR
Three MDR mechanisms have been investigated in my study:
Increased drug efflux by ABC transporters
(P-gp, BCRP and ABCB5)
Impaired apoptosis due to loss of tumor suppressor protein (p53) function
Enhanced cells proliferation (tumor growth) due to mutation-activated EGFR.

8. Collateral Sensitivity
Strategies to overcome MDR
Sensitive phenotypes
Resistant phenotypes
MDR
Collateral Sensitivity
Inhibition
Bypassing

9. Natural compounds in cancer therapy
206 anticancer drugs between 1940‘s – 2010 (Newman and Cragg, J Nat Prod 2012).
Over 60% of approved anticancer agents are naturally inspired.
Due to structure biodiversity, natural products play a major role in the discovery of leads for development of new drugs to combat cancer.
B Biological drugs: peptides or proteins
N Natural product
ND Derived from natural product, semi-synthetic modification
S Totally synthetic drug
S* Synthetic with pharmacophore from natural product
V Vaccine
NM Natural product mimic
NB Natural product “Botanical“

10. Aim of our research Cancer treatment with natural products
Overcoming multidrug resistance (MDR)
Inhibition of ABC-pumps
Bypassing
Collateral sensitivity
Sensitive phenotypes
Resistant phenotypes

11. 05 October 2015 | Mohamed Saeed
Screening of Sudanese medicinal plants
3/65 extracts were cytotoxic
05 October 2015 | Mohamed Saeed

12. Cell Viability (% of Control) Concentrations (µg/ml)
Cytotoxicity of active crude extracts against different MDR cells
P-gp
P-gp
P-gp
p53
EGFR
EGFR
Cell Viability (% of Control)
p53
ABCB5
ABCB5
Concentrations (µg/ml)
Ambrosia maritima L. (Asteraceae) extract was the most active crude extract
05 October 2015 | Mohamed Saeed

13. Strategy 1: Inhibition of ABC-transporters
Apigenin is a flavonoid found in Lawsonia inermis L. and Trigonella foenum-graecum L.
ABC transporter overexpressing cells were not cross-resistant to apigenin.
P-gp
BCRP
Apigenin increased doxorubicin accumulation on P-gp and BCRP overexpressing cells .
Apigenin acts synergistically with established anticancer drugs on killing P-gp and ABCB5 overexpressing cells.

14. Molecular docking on human P-gp and ABCB5
Homology modelling of P-gp and ABCB5
Molecular docking on human P-gp and ABCB5
Apigenin binds at NBD. Thereby, interferes with ATP binding leading to deplete energy for efflux function of these transporters.
Apigenin may be a multi-specific inhibitor for several ABC-transporters mediating MDR

15. Strategy II: Bypassing
(-)-Sesamin is a lignan found in sesame oil.
P-gp
ABCB5
(-)-Sesamin is neither P-gp nor ABCB5 substrate and has the ability to bypass chemo-resistance of refractory tumors.

16. Pharmacogenomics of (-)-Sesamin
Hypothesis: missing cross-resistance in MDR cells is due to different mechanisms.
Bioinformatics to predict these mechanisms from microarray-based mRNA expression.
Several candidate genes have been identified.
COMPARE analysis for correlation between gene expressions and sesamin’s activity against NCI cell lines.
Hierarchical cluster analysis for cell lines according to their mRNA expression of genes identified by COMPARE analysis.

17. Strategy III: Collateral sensitivity
Neoambrosin and damsin
Neoambrosin and damsin are sesquiterpene lactones isolated from Ambrosia maritima L.
Both compounds exerted hypersensitivity (collateral sensitivity) towards ΔEGFR expressing cells.
Resistance ratio
Neoambrosin
0.18
Damsin
0.15

18. Mechanism of collateral sensitivity of both SLs
Immunoblotting analyses of EGFR and its downstream signal transducers, to further explore collateral sensitivity.
Inhibition of phosphoryled c-Src in different GBM cell lines.

19. Neoambrosin and damsin target c-Src and silence its kinase activity
Mechanism of collateral sensitivity of both SLs
Molecular docking on c-Src kinase domain.
c-Src downstream signaling pathways.
-7.23 kcal/mol
-9.85 kcal/mol
-7.25 kcal/mol
The catalytic ATP binding site lies in a cleft between the two lobes. Any molecule able to interrupt open/closed c-Src form is considered as inhibitory.
Neoambrosin and damsin target c-Src and silence its kinase activity

20. Top 10 out of 25 deregulated networks of CCRF-CEM leukemia cells treated with neoambrosin or damsin

21. 05 October 2015 | Mohamed Saeed
Molecular docking and QSAR (in silico) of artemisinin derivatives to VEGFR1
Artemisia annua and artemisinins are widely used in Africa.
Artemisinins inhibit angiogenesis (Dell’Eva et al., Biochem. Pharmacol 2004).
Vascular endothelial growth factors and their receptors are major angiogenic players.
Correlation of binding energies of synthetic artemisinins to in vivo anti-angiogenic activity.
3 of 52 artemisinin derivatives reveal high affinity to VEGFR1 kinase domain.
kcal\mol
kcal\mol
R =
P = 0.035
-8.12 kcal\mol
kcal\mol
05 October 2015 | Mohamed Saeed

22. QSAR analysis Training set Test set Predictive power of QSAR model
Versus
Artemisinin dimer
10-dihydroartemisinylbutyrate
Artemisinin B
Artemisic acid
Highest predicted activity
Lowest predicted activity
05 October 2015 | Mohamed Saeed

23. Conclusions and future perspectives
Cancer treatment with natural products
Screening for cytotoxic medicinal plants against MDR cancer cells
Isolation and identification of phytochemicals from the cytotoxic plants
Inhibition of ABC-pumps:
Apigenin
Bypassing:
Sesamin
Collateral sensitivity:
Neoambrosin, Damsin, Honokiol
Initiate animal studies and clinical trials to prove efficacy and safety in cancer patients
05 October 2015 | Mohamed Saeed

24. Department of Pharmaceutical Biology University of Mainz
Acknowledgement
Department of Pharmaceutical Biology University of Mainz
Prof. Dr. Thomas Efferth
Department of Pharmacognosy, University of Khartoum, Sudan
Prof. Hassan Khalid
Institute of Biotechnology and Drug Research, University of Mainz
Prof Dr. Eckhard Thines
Dr. Stefan Jacob
Institute of Organic Chemistry, University of Mainz
Prof Dr Till Opatz
Dr. Louis Sandjo
Department of Pharmaceutical/Medicinal Chemistry, University of Mainz
AK Brenk
05 October 2015 | Mohamed Saeed

25. 05 October 2015 | Mohamed Saeed
Thank you for your attention!
05 October 2015 | Mohamed Saeed