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Hi everyone my name is camille pegg in tow and today i will be talking about a chemotherapeutic drug known as tamoxifen so a little bit of background tamoxifen is used in the prevention or the treatment of breast cancer it is a drug that binds to the estrogen receptor and this causes a conformational change in the receptor and it is also able to block any estrogen

Signal activity in mammalian tissues such as in the breast or in the uterus so over here i have an example of an estrogen that is being blocked by a tamoxifen that is bound to an estrogen receptor so this blocking can actually prevent any cell growth it shrinks any tumors and the cell is able to die in addition it can also reduce the dna polymerase activity it

Can impair thymidine utilization it can block the estradiol uptake and of course it decreases estrogen up here is a picture that i got from the textbook so this is an example of two of the four different types of breast cancers so here we have luminal a and luminal b and basically this is showing the estrogen receptors right here in the red that is present as

Well as any pr receptors and her2 which is a growth factor receptor so tamoxifen interferes with the estrogen estrogen signal pathway over here we have an example of estrogen in the breast cancer cell so estrogen binds to the estrogen receptor and thus it binds to a short dna sequence known as estrogen receptor element this activated estrogen receptor binds to a

Co-activator protein and it can induce cell proliferation on the other hand we have tamoxifen that by to the estrogen receptor and thus estrogen is being blocked and so when tamoxifen binds to this receptor it it blocks the coactivator protein and the signal pathway is interrupted and there is no cell proliferation on the other hand we have here estrogen receptors

In a normal cell so the estrogen still is able to bind to the estrogen receptor it binds to the dna sequence and this triggers cell proliferation so tamoxifen can have many major side effects some good side effects includes the reduced risk of estrogen receptor breast cancer and it can lower an ldl cholesterol on the other hand some bad side effects includes the

Development of uterine cancer an increased risk of blood clots or venous thromboembolism it causes menopause like symptoms such as hot flashes fatigue and headaches this is because tamoxifen can act as an estrogen in other parts of the body but so although it it blocks estrogen activity in the breast it can act as an estrogen in other parts such as in the uterus

So because it is an estrogen in the uterine acts as an estrogen in the uterus it can cause the uterine lining to grow and this can increase endometrial cancer as for the venous thromboembolism same thing here tamoxifen can act as an estrogen this can increase blood clots and also if you take tamoxifen it can decrease any antithrombin and also decrease protein see

Ask for the menopause like symptoms such as hot flashes the hot flashes is due to hormone levels that are fluctuating estrogen is a hormone so the therefore it directly relates to the hypothalamus meaning that if there’s a change in the estrogen level this can confuse the hypothalamus and can signal to the nervous system to increase your heart rate it can cause

The sweat glands to produce more sweat in order to cool the body temperature and thus your body experiences hot flashes so my question is why is it that tamoxifen can be used in the treatment for er or estrogen receptor positive breast cancers however it cannot be used in er negative breast cancers

Transcribed from video
Tamoxifen By c pag