toposide - chemie – technische universität darmstadt · the medical pathway blocks the enzyme...

Etoposid | Damolces 2013 | Group Y | 1 of 7

ETOPOSIDE by Lasse Oberstraß, Zora Rerop, Robin Riedelsheimer, Paul Saary

CAS-Number: 33419-42-0

IUPAC-Name: 4'-demethyl-pipodophyllotoxin-9-[4,6-O-(R)-ethylidene-beta-D-glucopyranoside], 4' -

(dihydrogen-phosphate)

TABLE OF CONTENTS Etoposide ............................................................................................................................................................................... 1

Introduction .................................................................................................................................................................... 2

History and Discovery ................................................................................................................................................. 2

Extraction and Synthesis ............................................................................................................................................ 2

Extraction of Podophyllotoxin: ........................................................................................................................... 2

1. Pathway (compare “picture 5, path a”) ...................................................................................................... 3

2. Pathway (compare “picture 5, path b”) ...................................................................................................... 3

Mechanism of action .................................................................................................................................................... 4

Topoisomerase II ........................................................................................................................................................... 5

Effect of etoposide ........................................................................................................................................................ 5

Function as drug ............................................................................................................................................................ 6

Medical application: Etoposide ............................................................................................................................... 6

Conclusion ........................................................................................................................................................................ 6


INTRODUCTION Etoposide is a drug uses for some time to

fight various forms of cancer in humans and

animals. In this paper we will shortly

introduce the origin of etoposide, how it can

be synthesized and the mechanism of action.

At the end we will conclude with a

statement regarding the use and actuality of

etoposide.

HISTORY AND DISCOVERY Podophyllotoxins have been used for

medical causes for hundreds of years. Some

cultures used the Wild Chervil since the 9th

century against cancer. The exploration of

the mechanisms and the contained drugs

started in the 1950s. Testing and evaluation

of the components let the researchers to the

contained drug “Etoposide” which proved to

be effective against various kinds of cancer.

Etoposide was first synthesised in 1966 and

soon enough in 1983 the FDA gave its

approval for clinical use, though the

mechanism of the drug was not quite

understood. 1

EXTRACTION AND SYNTHESIS

EXTRACTION OF PODOPHYLLOTOXIN:

1 Podophyllotoxin

Etoposide such as Tensiposide and

Etopophos, are derived from the toxin

podophyllotoxin. Podophyllotoxin is found

in the roots and rhizomes of Podophyllum

emodi, cultivate in Nepal and India, and the

main source of podophyllotoxin. But these

are a threatened species today, because it is

not possible to culture them on fields.

However the leaf blade of the American

Mayappel (Podophyllum peltatum)

(cultivate in the United States) are the

modern alternative. 2

2 Podophylli rhizoma

3

3 Podophyllum peitatum L. 4

A totally new method to produce

Podophyllotoxin is in cell and tissue

cultures. Therefor cell suspensions of white

flax (Linum album) accumulate

Podophyllotoxin and 6-

Mthoxypodophyllotoxin as glucosides. The

crop of this method is 0,2% of the dry solids,

but this is not sufficient for a lucrative

production process. Therefore scientists


apportion the enzymatic pathway to change

the genetic information of the flax, to

improve the crop of the synthesis. 5

Synthesis of Etoposide:

4 Etoposide

Starting at Podophyllotoxin, which is

extracted from the plants, first the phenol

group and the hydroxyl groups must be

protected by protection groups. Then the

podophyllotoxin is coupled with the

protected glucose. But both the phenol and

the hydroxyl protection groups demands

different treatments and multiple steps for

removal. Often these steps involve acidic or

alkaline treatments and the end-product

will decompose. This causes a low crop of

etoposide.

There are two approaches to synthesis

etoposide from podophyllotoxin:

5 Pathway of synthesis 7

1. PATHWAY (COMPARE “PICTURE 5, PATH

A”)

This pathway goes ahead with a

nucleophilic attack from the hydroxy group

of the podophyllotoxin on the non-protected

carbon of the glucose. It starts with a

Königs-Knorr-like coupling of the glucose

derivative, bearing a good leaving group,

with the hydroxyl group. While slitting of

the leaving group of the carbon it couples

with retention of the conformation. The

retention is caused the subgroup effects of

the protection group at the second carbon of

the glucose.

6 Königs-Knorr-Coupling 6

2. PATHWAY (COMPARE “PICTURE 5, PATH

B”)

The synthesis is initiated by a kuhn-

mechanism, which is a stereocontrolled

attack of the free hydroxy group at the

carbon of the podophyllotoxin. The aromatic

rest is a stereogenic anchor, so the attack is

directed to the ß-side of the

Podophyllotoxin. The stereocenter of the

glucopyranose is defined by the initial

condition of itself.

The second is the prefered way, because the

ß-side configuration of both the benzylic

and the anomeric carbon is favored and the

crop is maximised. 7

Synthesis of Etoposide-Phosphate:


7 Etoposide-phosphate

Etoposide is poorly water soluble, therefore

the pharmaceutical formulation is very

complicated.

To solve this problem first etoposide is

transferred to etoposide-phosphate, this can

better be applied to the patient. Inside the

body etoposide-phosphate is metabolized to

etoposide, which can function as anti cancer

drug.

There are two common possibilities to

synthesis etoposide-phosphate:

1. Etoposide is first converted with

Phosphoroxychloride and then hydrolysed.

2. It reacts first with Diphenylchlorphosphate

and is also hydrolysed after that. 8

8 Phosphoroxychloride 9 9 Diphenylchlorphosphate10

MECHANISM OF ACTION Every eukaryotic cell has a so called cell-

division cycle. During its life it can divide

itself into two cells. Although not all cell

keep this capability the mechanism of cell

division is essential to understand cancer

and how it can be fought.

A healthy cell cycle begins at the G0-Phase in

which the cell is not dividing. Starting in G1-

Phase the cell grows and soon will be

replicating its entire genetic material in the

so called S-Phase. Thus the following phase,

the G2-phase, is critical for the cell-cycle. If

the cell detects an error in the replicated

DNA the cell will not proceed to the next and

most important M-phase.

The Mitosis is now the actual dividing of the

cell, and can be described as eight steps

leading to a full cell-division. But as it is not

important for the mechanism of action

regarding etoposides, we will skip ahead.

10 The Cell Cycle 11

By nature cancer cells have a higher cell-

division rate than healthy cells. So the idea

is to use this fact and interact with the cells

in a manner that would suppress cell-


division and in that way stop the cancer

growth.

TOPOISOMERASE II Unwinding the DNA while replication in S-

Phase twists the rest of the coil, this causes

tension. This leads to supercoiled DNA. To

release the tension enzymes called

topoisomerase first cut the DNA-strand,

release the tension trough moving the DNA-

strands and then reseal it.

11 Type II Triopoisomerase

12 Cellular roles of DNA topoisomerases: a

molecular perspective.12

Etoposide inhibits type II topoisomerase so

it is necessary to take a closer look at the

function. A DNA-binding gate of

topoisomerase II binds a DNA strand, called

G segment. Binding two ATP induces a

conformational change and a second DNA

strand, called T segment, binds to the

enzyme. Hydrolysis of ATP leads to the

cleavage of the G segments phosphodiester

backbone. This causes a double-stranded

break in the G segment. The DNA-binding

gate separates and the T segment is

transferred to the newly formed gap. The G

segment will be resealed which leads to the

release of the T segment. Releasing ADP

resets the system and another T segment

can be bound. 13

In conclusion this means in a supercoil type

II topoisomerase cuts a double-strand

transfer another DNA-strand throw the gap

and decrease linking. In fact of that the

twisting tension is released.

EFFECT OF ETOPOSIDE Etoposide inhibits the ability of

topoisomerase II to ligate the G segments


nucleic acids that it cleaves during the T

segment passage reaction. A covalent

topoisomerase II−drug−nucleic acid

complex is formed.

It is not yet clear which part of etoposide

binds to the DNA but 1H NMR analytic

shows drug−enzyme interactions at the

proton level. In the figure shown red

protons are in close contact with

topoisomerase II binary drug−enzyme

complex. 14

Etoposide acts specifically when DNA

tracking enzymes (polymerases or

helicases) collide with the complexes. They

convert them to permanent enzyme-linked

double-stranded breaks in the genetic

material. As a result the genome is

destabilized. If the amount of breaks is

significant the programmed cell death

triggered.

FUNCTION AS DRUG In cancer cells the replication rate is higher

than in normal cells. This causes more

tension in the DNA helix, which leads to

higher topoisomerase activity. Finally more

DNA breaks happen in cancer cells than in

normal cells which means cancer cells dies

quicker than normal cells.

MEDICAL APPLICATION: ETOPOSIDE Etoposide is a cytostatic drug which is used

with Cisplatin and Bleomycin as a

polychemotherapy in modern medicine.

Etoposide Sandoz® is against malign tumors

and the pattern is named the PEB-pattern.

It´s adminis as a solution and the application

rate depends on the body surface (between

50-100 mg/m²). The administering rate is

between 0.5 and 2 hours.

The application of Etoposide Sandoz®,

Cisplatin and Bleomycin is in case of:

bronchial carcinoma, testis tumor, chorion

carcinoma (maleficent regrowing of the

placenta) and ovarian carcinomas.

The therapy is cyclic, six times á 21 days. At

the first day Etoposide Sandoz®, Bleomycin

and Cisplatin are given. At day two and

three there is only given Etoposide and at

the days eight and fifteen Bleomycin is given

again. The free days in the cycles are

important for the healthy cells to repair the

damage of the DNA because their cell

division is not as fast as the cell division of

cancer cells. So the cancer cells die and the

healthy normal cells repair themselves.

Because of the DNA damage you shouldn't

become pregnant or donate sperm.

The most spillover effects that affect to the

patient are hair loss, vomiting, dizziness and

tiredness. Furthermore the is a reduced

number of leucocytes and hämoglobin,

hypersensitivity reactions (fever, reduced

blood pressure, shivering). Against the side

effects medicament can be given.

It´s forbidden to give Etoposide to people

with kidney- or liver damages.

If the patient does not bear the PEB-pattern

Bleomycin can be changed with Ifosfamid

and Cisplatin with Carboplatin.15

CONCLUSION In conclusion one can see, that etoposide is an interesting medicin for the never ending cause

against cancer. Today we synthesise this drug using organic chemistry in a very complex and

innovative mechanism while once it was won using plants. The medical pathway blocks the

enzyme calles topoisomerase II and because this enzyme is manly activ trought cell division its

malfunction, caused by etoposide, will hit cancer cells, which divide more rapidly than other

cells, the hardest and by this will inhibit the growth or at the end kill all cancer cells.


1 K.R. Hande, “Etoposide: Four Decades of Development of a Topoisomerase II Inhibitor”, 1 Apr. 1998

2 Rita M. Moraes, Hemant Lata, Ebru Bedir, Muhammad Maqbool, and Kent Cushman: “The American

Mayapple and its Potential for Podophyllotoxin Production” 2002,

<http://www.hort.purdue.edu/newcrop/ncnu02/v5-527.html> (Mai 2013)

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4<http://www.medizinalpflanzen.de/allgemei/koehler/koeh-246.jpg> (June 2013)

5 Heinrich-Heine-Universität Düsseldorf, 2010-2013: “Lignane in Leinkulturen: Vorkommen und

Biosynthese”, <http://www.biologie.hhu.de/institute-und-abteilungen/prof-dr-a-alfermann-i-

r/forschung.html> (Juli 2013)

6 http://de.wikipedia.org/wiki/Glycoside (June 2013)

7 Pietro Allevi, Mario Anastasia, Pierangela Ciuffreda, Ettore Bigatti and Peter MacDonaldt; Department of

Chemistry and Biochemistry, University of Milan, Via Saldini 50, I-20133 Milan, Italy, and Sicor S.p.A. Via

Terrazzano 77, 2001 7 Rho, Italy Received January 5, 1993: “Stereoselective Glucosidationl of

Podophyllum Limans. A New Simple Synthesis of Etoposide.”

8 Silverberg, Lee J., Fayetteville, New York, US; Vemishetti, Purushotham, East Syracuse, New York, US;

Dillon, Jr., John L., Clay, New York, US; Usher, John J., East Syracuse, New York, US: “Verfahren zur

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9<http://upload.wikimedia.org/wikipedia/commons/thumb/e/e0/Phosphorus_oxytrichloride.PNG/175p

x-Phosphorus_oxytrichloride.PNG> (June 2013)

10<http://en.wikipedia.org/wiki/File:Ph2PCl.png> (June 2013)

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12 James C. Wang. Nature Reviews Molecular Cell Biology 3, 430-440 (June 2002)

13 Nitiss, John L. Targeting DNA topoisomerase II in cancer chemotherapy. Nat Rev Cancer 9, 338-350 (May

2009)

14 Amy M. Wilstermann, Ryan P. Bender, Murrell Godfrey, Sungjo Choi, Clemens Anklin, David B.

Berkowitz, Neil Osheroff, and David E. Graves, Topoisomerase II−Drug Interaction Domains: Identification

of Substituents on Etoposide That Interact with the Enzyme, Biochemistry 2007 46 (28), 8217-8225

15 of Substituents on Etoposide That Interact with the Enzyme, Biochemistry 2007 46 (28), 8217-8225

toposide - chemie – technische universität darmstadt · the medical pathway blocks the enzyme...

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