2. Anatomy of the Female Breast
Clavicle
Second Rib
Pectorals Major Muscle
Fat
Lactiferous Sinus
Lactiferous Duct
Gland Lobules
Fat
The breast is a modified skin appendages which functions in the females during
lactation.
There are two types of tissue components: Epithelial and Stromal
2
3. Breast Carcinoma
Non-invasive Carcinoma Invasive Carcinoma
a) Invasive Duct Carcinoma: 70% cases.
b) Invasive Lobular Carcinoma: 5% cases.
c) Medullary Carcinoma: 1% cases.
d) Colloid Carcinoma
e) Papillary Carcinoma
f) Tubular Carcinoma:
g) Adenoid Cystic Carcinoma
h) Secretory (Juvenile) Carcinoma
i) Inflammatory Carcinoma
j) Carcinoma with Metaplasia
a) Intraductal carcinoma
b) Lobular carcinoma
3
4. Receptor Overexpression Specific for Breast Cancer
Receptors
Hormone
receptor
(HR)
ER
ER+ve ER-ve
PR
PR+ve PR-ve
Tyrosine
Kinase
Receptor
HER2
HER2+ve HER2-ve
Triple negative breast cancer (TNBC)
Triple-negative breast cancers are ER –ve, PR –ve and HER2-ve, hence called as triple
negative breast cancer (TNBC).
Less number of therapies are available for TNBC. 4
5. Globally, Breast cancer accounts for 23% of the total cancer cases and 14% of the
cancer deaths in females.
The cases are expected to increase by 26% by 2020
In India, premenopausal patients are about 50% of all patients.
A significant proportion of Indian breast cancer patients are younger than 35 years of
age.
More than 80% of Indian patients are younger than 60 years of age.
It constitutes >30% of all cancers in females of Delhi, Mumbai, Ahmadabad, Kolkata,
and Trivandrum.
5
7. Targeted Cancer Therapies
Drugs or other substances that block the growth and spread of cancer by
interfering with specific molecules involved in tumor growth & progression.
Most researchers consider it as new approach to treating breast cancer that
targets the cell signaling pathways of cancer cells.
More selective for cancer cells.
Blocking of signals help to stop cancer progression and may induce cancer cell
death through apoptosis.
The development of targeted therapies requires the identification of good
targets.
7
8. In this seminar, we are going to study breast cancer therapies which are targeted
for following targets:
Tyrosine Kinases Receptors
Steroid Receptor Coactivators (SRC)
Mammalian Target of Rapamycin (mTOR) & Phosphoinositide 3-kinase
(PI3K)
Poly-{adenosine diphosphate (ADP)-ribose} polymerase (PARP)
8
9. Tyrosine Kinases (TKs)
Class of enzymes which are responsible for phosphorylation of tyrosine residue on
targeted proteins.
Stimulate multiple signaling pathways responsible for basic cells functions.
Several oncogenic tyrosine kinases have been detected in human malignancies. There
are two families of tyrosine kinases- Transmembrane receptor kinases & Cytoplasmic non-receptor
kinase
a) Transmembrane kinases receptor :
Human Epidermal Receptor (HER)
Insulin like Growth Receptor (IGFR)
Fibroblast Growth Factor Receptor (FGFR)
Vascular Endothelial Growth Factor Receptor (VEGFR )
Platelet-derived Growth Factor Receptor (PDGFR)
b) Cytoplasmic non-receptor kinase: Steroid Receptor Coactivators (SRC)
9
10. mTOR/PI3K/Akt
Pathway
IP3/DAG Pathway
Ras/MAPK
Pathway
Multiple signaling pathways involved in the development, growth, and survival of breast
cancer cells
10
11. Human Epidermal Receptors (HER)
o ErbB proteins are a four-member family of highly homologous receptor tyrosine kinases
comprised of ErbB1 (EGFR, HER1), ErbB2 (HER2), ErbB3 (HER3), and ErbB4 (HER4).
Epidermal Growth Factor Receptor (EGFR)
o It is also known as ErbB1/HER1, is essential for growth and differentiation of epithelial
cells.
o The expression of EGFR, ligands, and their activating proteases in breast cancers has
been intensively studied.
Epidermal Growth Factor Receptor Targeting Monoclonal Antibodies:
Agent Class of compound Stages
IMC-C225 mAb Phase II
ABX-EGF mAb Phase II
11
12. Human Epidermal Receptor 2(HER2)
The HER2 gene is amplified in approximately 20%-30% of breast cancers.
Overexpression HER2 found in breast cancer cells which has also been associated with
resistance to chemotherapy and hormone therapy.
HER2 target is present in a very high proportion of tumor cells
Human Epidermal Receptor 2 Targeting Monoclonal Antibodies:
Agent Class of compound Stages
Trastuzumab mAb Approved
Trastuzumab–DM-1 mAb-toxin conjugate Approved
12
14. Selected HER Family Tyrosine Kinase Inhibitors:
Compound Selectivity invitro IC(Nm) Stages
EGFR HER2
ZD1839, Gefitinib 27 3700 Marketed
OSI-774, Erlotinib 2 350 Marketed
GW572016, Lapatinib 11 9 Marketed
CP-724714 4300 8 Phase II
Arry-334543 7 2 Phase II
CI-1033, PD183805,
0.8 19 Phase II
Canertinib
BIBW-2992 0.5 14 Phase II
AV-412, MP-412 1 18 Phase I
AEE788 6 6 Phase II
EKB-569, Pelitinib 39 1200 Phase II
HKI-272, Neratinib 92 59 Phase II
BMS-599626 22 32 Phase I
14
15. Insulin-like Growth Factor Receptor (IGFR)
IGF system is composed of
IGF
system
Ligands
IGF1 IGF2
Receptors
IGF1R IGF2R
Binding
Proteins
6 IGFBPs
↑ circulating levels of IGF-I are associated with a greater risk of breast cancer
in premenopausal women, with an especially high risk among those younger than
50 years.
↑ IGFs resists apoptosis in response to chemotherapy and radiation.
IGFBPs is activated by the estrogen, which itself activates expression of IGF-15
I.
16. Insulin-like growth factor 1 receptor (IGF-1R) Targeting Agents:
Agents Regimen Stages
IGF-1R Antibodies
CP-751,871 Docetaxel Phase II
Exemestane Phase II
Single agent Phase I
AVE1642 / EM164 Faslodex Phase II
IMC-A12 (Cixutumumab) Temsirolimus Phase I/ II
Capecitabine and Lapatinib Phase II
AMG 479 Exemestane or fulvestrant Phase II
MK-0646/h7C10
(Dalotuzumab)
Single Regimen Phase II
Ridaforolimus Phase II
Ridaforolimus and exemestane Phase II
Dual IGF-1R–insulin receptor inhibitor
BMS-754807 Trastuzumab Phase I/ II
Letrozole Phase II
16
17. Fibroblast Growth Factor Receptor (FGFR)
The fibroblast growth factor (FGF) consist of 18 ligands.
FGF1 & FGF23 signal through four high affinity fibroblast growth factor
receptor (FGFR1 to FGFR4).
Under physiological conditions, the highly complex FGF signaling pathway is
tightly regulated.
The deregulation of FGF signaling to development of cancer, promoting
cancer cell proliferation, survival and migration.
17
18. Drug class Drug name Target Stages
1st generation
TKI258 (Dovitinib) FGFR, PDGFR &
TKIs
VEGFR
Phase III
BMS54021 (Brivanib) FGFR & VEGFR Phase II
BIBF 1120 FGFR, PDGFR &
VEGFR
Phase III
Ponatinib ABL, FGFR,
PDGFRα, FLT3 &
VEGFR2
Phase II
E7080 FGFR, PDGFR,
VEGFR, KIT, RET
Phase I
E3810 FGFR1& VEGFR1
to VEGHR3
inhibitor
Phase I
Sulfatinib FGFR & VEGFR
inhibitor
Phase I
Fibroblast Growth Factor Receptor Targeting Agents:
18
19. Drug class Drug name Target Stages
2nd generation
AZD 4547 Selective FGFR1,
TKIs
FGFR2 & FGFR3
inhibitor
Phase II
BGJ398 Selective pan- FGFR
inhibitor
Phase I
FGFR antibodies IMC-A1 FGFR1-IIIc-specific
antibody
Preclinical
GP369 FGFR2 blocking
antibody
Preclinical
PRO-001 FGFR3-specific
blocking antibody
Preclinical
R3Mab FGFR3-specific
antibody
Preclinical
FGFR ligand
traps
FP-1039 FGF ligand traps
(blocks multiple FGFs)
Phase I
Fibroblast Growth Factor Receptor Targeting Agents:
19
20. Vascular Endothelial Growth Factor (VEGF)
VEGF overexpression is common in breast cancer.
Bevacizumab (Avastin; Genentech), a humanized monoclonal antibody against VEGF,
was granted accelerated approval in the US for the first-line treatment of MBC in
combination with Paclitaxel in 2008.
1st generation tyrosine kinase inhibitor; which also targets VEGFR are shown in
previous table.
Selected additional VEGF-targeted therapies:
Aflibercept or VEGF Trap is an antiangiogenic peptide-antibody fusion containing
portions of human VEGF receptor 1 and 2.
Vascular disrupting agents (eg, Ombrabulin; Sanofi-Aventis) another class of
antiangiogenic therapy, are under clinical trials for MBC.
20
21. Platelet Derived Growth Factor (PDGFR)
PDGFR is expressed in most breast tumors.
The individual PDGF chains have different affinities for the two receptors- PDGFR α &
PDGFR β.
PDGFR α has high affinity for PDGF -A, -B, and -C, whereas PDGFR β has high
affinity for PDGF -B and –D.
Induces angiogenesis by up-regulating VEGF production.
1st generation TKs; which also targets PDGFR are shown in previous table.
21
22. Steroid Receptor Coactivators (SRCs)
SRCs are small proteins of 160 kDa non-receptor tyrosine kinase and include SRC-1,
SRC-2/transcription intermediary factor-2 (TIF-2) and SRC-3.
SRC may play a significant role in tumor progression and spread.
SRC interact receptor tyrosine kinases (e.g. HER family), integrins, steroid hormone
receptors, including the estrogen receptor.
Steroid Receptor Coactivators (SRC) Inhibitors:
Agents Stages Regimen
Dasatinib Phase I/II Fulvestrant and MK-0646
Bosutinib Phase II Single Agent
Saracatinib Phase II Vs Zoledronic
22
23. Mammalian Target of Rapamycin (mTOR)
mTOR is a member of the cellular mTOR/PI3K/Akt pathway. A high proportion of breast
tumors exhibit constitutive activation of the mTOR pathway.
Rapamycin is a macrolytic lactone produced by Streptomyces hygroscopicus, which has
immunosuppressive, antimicrobial, and antitumor properties. Rapamycin targets a
principal protein that was named mTOR.
Two mTOR complexes have been identified: mTORC1 and mTORC2 of cell growth and
proliferation, cell metabolism, angiogenesis, and apoptosis.
New agents are being developed that can inhibit both mTORC1 and mTORC2.
Phosphoinositide 3-kinase (PI3K)
Three classes of PI3K enzymes, designated I to III, have been identified; members of
PI3K class I have been implicated in the mTOR pathway
PI3K can be key target that, if effectively inhibited, could improve outcomes.
23
25. mTOR inhibitors:
Drug Drug class Stage of development
Sirolimus
(Rapamycin)
mTOR inhibitor Approved
Everolimus
(RAD001)
mTOR inhibitor Approved in 2012 for postmenopausal
women with advanced HR+/HER2- breast
cancer in combination with exemestane
after failure of treatment with letrozole or
anastrozole
Ridaforolimus
(deforolimus)
(AP23573)
mTOR inhibitor Phase III clinical trials
PP242 mTOR inhibitor Preclinical
BN107 mTOR inhibitor Preclinical
25
27. PI3K selective inhibitors:
Agents Company Stage
PX-866 Oncothyreon Inc Phase I
GDC-0941 Genentech Inc Phase II
XL-147 Exelixis Phase I/II
BKM-120 Novartis Phase I
27
28. Dual kinase (mTOR &PI3K) inhibitors:
Drug Drug class Stage of development
PI-103 Dual kinase inhibitor Preclinical
LY294002 Dual kinase inhibitor Preclinical
NVP-BEZ235 Dual kinase inhibitor Phase I/II clinical trials
SF1126 Dual kinase inhibitor Phase I/II
XL765 Dual kinase inhibitor Phase I
BGT226 Dual kinase inhibitor Phase I/II
28
29. Poly-{Adenosine diphosphate (ADP)-Ribose} Polymerase (PARP)
DNA damage, double strand breaks are highly toxic to cells
Homologous recombination is DNA repair mechanism.
Homologous recombination is dependent on functional BRCA 1 and 2 pathways.
Germline mutations in either the BRCA1 or BRCA2 genes are associated with a high
risk of developing a number of breast cancers.
When the BRCA-associated DNA repair pathway (homologous recombination) – is lost
or dysfunctional, repair shifts toward alternate DNA repair mechanisms dependent on a
unique class of enzymes, Poly-(adenosine diphosphate [ADP]-ribose) polymerase (PARP).
29
30. PARP-inhibitors in clinical development:
Agent Company Stages
Olaparib (AZD2281) AstraZeneca/KuDOS Phase I/II
Veliparib Abbott Phase I/II
BS1-201 BiPar/SanofiAventis Phase II/III
AG014699 Pfizer Phase I/II
MK482 Merck Phase I
INO-1001 Inotek Phase I
CEP9272 Cephalon Phase I
30
31. Conclusion
Targeted cancer therapies hold the promise of being more selective, reducing side
effects, and improving quality of life.
Targeted therapies may work best in combination, either with other targeted therapies
or with more traditional therapies. Researchers are working to find new ways to target
cancer cells as part of treatment.
Various targeted therapies are being studied in clinical trials to see how well they
work in treating breast cancer.
As more targets are identified and therapies are developed, doctors will be able to
offer patients treatment that works best for their type of breast cancer.
In future, metastatic breast cancer, triple negative breast cancer can be well treated.
31
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34