We can acquire the basic knowledge about canine oncoprotein targets specifically for Melanoma, Osteosarcoma and Breast cancer. I haven't mentioned all the proteins and their targets involved, but just a general overview of these targets with the drugs involved in their treatment/clinical trials.

1. CANINE ONCOPROTEIN TARGETS
FOR BREAST CANCER,
MELANOMA AND
OSTEOSARCOMA
Made By: Snehal Krishnat Salunkhe
Principal Investigator: Dr. Pradip Chaudhari
Department/lab: Small Animal Imaging Facility
(Advanced Centre for Training, Education and Research in Cancer,
Navi Mumbai)

2. INTRODUCTION
• Target proteins are functional biomolecules that are
addressed and controlled by biologically active compounds.
• The identification of target proteins, the investigation of signal
transduction processes and the understanding of their
interaction with ligands are key elements of modern
biomedical research.
• Target proteins control the action and the kinetic behavior of
drugs within the organism. The elucidation of structure,
conformational signaling and catalytic properties of particular
target proteins facilitates a rational design of drugs and
biotechnological processes.
• Known as biologicals, target proteins can also be drugs by
themselves when their modification and formulation is
emphasized within the pharmaceutical sciences.

3. FIGURE 1: Mechanism of target protein function

4. CANINE BREAST CANCER
• Mammary tumors, at least in dogs and to a certain extent in cats,
have many similarities to breast neoplasms in women.
• The mean onset age for mammary tumors is between 10 and 11
years.
• Incidence is higher in certain breeds, such as: Poodle, English
Spaniel, Brittany Spaniel, English Setter, Pointer, Fox Terrier,
Boston Terrier and Cocker Spaniel; incidence is lower in
Chihuahua and Boxer breeds .
• In dogs, approximately 40% of all mammary tumors are located in
the inguinal mammary glands and appear shortly after estrus.
• Chemotherapy in mammary neoplasms can be applied under the
form of drug combinations, such as cyclophosphamide,
vincristine and methotrexate or as postoperative adjuvant
treatment.

5. ONCOPROTEIN TARGETS
• In human breast neoplasms, a highly invasive and treatment-
resistant protein, responsible for malignant evolution, has
been identified.
• This protein, called stromelysin-3 (ST3) appears in the case of
malignant tumors, having extremely high levels, and is not
found in cultured malignant tumor cells, but is detected
around the tumor.
• Stromelysin-3 (MMP-11) in particular, has been originally
described and isolated from fibroblastic cells surrounding
invasive breast carcinoma
• Its predicted structure shares common features with that of
other stromelysins and collagenases.

6. FIGURE 2: (1HV5) Crystal Structure Of The Stromelysin-3 (Mmp-11) Catalytic
Domain complexed With A Phosphinic Inhibitor
•Since Stromelysin-3 falls under the category of Matrix Metalloproteinase, it
has Zinc and Calcium as metal ions

7. •Stromelysin-3′s gene, located on chromosome 22q11.2 is being
expressed at high levels, predominantly by peritumoral fibroblasts,
in almost all invasive breast carcinomas and in a number of breast
cancer metastases.
•Malignant cancer cells subvert ST3 function in order to circumvent
homeostasis and survive in connective host tissues.
•Inhibition of apoptosis is an important feature of human
neoplasia, which potentially contributes to tumor progression and
resistance to therapy
•Anti ST3 treatments which uses MMP inhibitors such as
Rebimastat, Phosphinic MMP inhibitors, etc may restore the
ability to properly regulate cancer cells to undergo apoptosis, which
could be considered as a benefit to the treatment of malignancies.

8. •Tumorigenic processes activated by MMPs in breast cancer, suggest
that these molecules should offer promising targets for therapy.
However, intensive efforts to develop and translate pharmacological
MMP inhibitors for cancer treatment culminated a decade ago in
disappointing results in multiple clinical trials .
•Of relevance to breast cancer, a phase III trial of the broad
spectrum MMP inhibitor marimastat in metastatic breast cancer
found no therapeutic benefit .
•Phase II pilot trials of adjuvant marimastat and rebimastat in early
stage breast cancer concluded that large scale studies were not
feasible in this setting given the high incidence of musculoskeletal
toxicity and failure of chronic dose levels to maintain plasma levels
within the target range for these drugs

9. CANINE MELANOMA
• Melanomas are malignant neoplasms originating from
melanocytes. They occur in most animal species, but the dog is
considered the best animal model for the disease.
• Melanomas in dogs are most frequently found in the buccal
cavity, but the skin, eyes, and digits are other common locations
for these neoplasms.
• Malignant melanomas typically occur in middle-aged to older
dogs
• In a survey of 384 melanocytic canine tumors, oral, cutaneous,
lips/feet, and eye sites comprised 19%, 59%, 19%, and 3%,
respectively

10. ONCOPROTEIN TARGETS
• These dendritic cells in melanoma development have demonstrated
altered expression of cell–cell adhesion molecules, such as
decreased expression of E-cadherin and V-CAM 1 and increased
expression of N-cadherin, Mel-CAM 1, ICAM 1, and α β integrins
• In addition, malignant melanomas are positive for vimentin and
variably positive for S-100 protein and neuron-specific enolase
(NSE)
• Several genes/genetic pathways were identified in human
melanomas, and these are important for the diagnosis,
establishment of prognosis, and drug targeting . Some of these
genes are described below:
1. CDKN2A Locus—about 70% of melanomas harbor mutations or
deletions in this locus on chromosome 9p21.
2. Genes that are altered when normal melanocytes generate a
nevus: BRAF, NRAS, and INK4a/ARF.
3. Genes that are mutated or deregulated when a nevus is
transformed to a melanoma: BRAF, NRAS, INK4a/ARF, PTEN, c-kit,
NEDD9, and MITF.

11. •BRAF is a key serine–threonine kinase from the mitogen-activated protein
kinase (MAPK) signaling pathway and 50% of cutaneous melanomas without
association with chronic sun damage harbor a BRAF mutation.
•Dabrafenib is a selective BRAF-mutant inhibitor approved (2013) by the FDA for
the treatment of unresectable or metastatic melanomas harboring BRAF
mutations. Several clinical trials are ongoing with dabrafenib in monotherapy
and in combination with radiotherapy, immunotherapies, and other targeted
therapies.
•Targeting the tyrosine kinases has led to remarkable response rates with better
OS rates in melanoma clinical trials.
FIGURE 3: Structure of BRAF gene

12. CANINE OSTEOSARCOMA
• Osteosarcomas represent the most frequent histological type of
primary bone tumors, over 80% in dogs, and over 50% in cats.
Osteosarcoma is the most common bone tumor, representing 5–
6% of all tumors of the canine species.
• Osteosarcomas in dogs develop in the metaphyseal region of
long bones, followed in decreasing order by the radius and
humerus bones (especially in Boxer dogs), while other locations
are sporadic.
• The mean onset age of osteosarcoma in dogs is 7.6 years, with
age ranges between 1 and 15 years. Rib tumors occur more
frequently in adult-young dogs, while cranial location appears at
a more advanced age.

13. ONCOPROTEIN TARGETS
•The cause of OS is unknown, but it has been speculated that
genetic factors such as the TP53 suppressor gene may play a role.
The TP53 gene encodes for a protein that serves as a regulator in
cellular proliferation, DNA repair, and programmed cell death.
•The incidence of TP53 mutations in canine OS varies from 24% to
47%.
•The p53 protein is located in the nucleus of cells throughout the
body, where it attaches (binds) directly to DNA. When the DNA in a
cell becomes damaged by agents such as toxic chemicals, radiation,
or ultraviolet (UV) rays from sunlight, this protein plays a critical role
in determining whether the DNA will be repaired or the damaged
cell will self-destruct (undergo apoptosis).

14. FIGURE 4: structure of p53
•many p53 mutants are temperature sensitive and restore the p53
activity at the permissive temperature.

15. •synthetic peptides, CDB3 and Peptide 46 which are derived from
53BP2 and C-terminal domain of p53, respectively, restore the
sequence-specific DNA binding and transcriptional activity of p53.
1. STIMA-1 (SH Group-Targeting Compound That Induces
Massive Apoptosis)
 STIMA-1 [2-vinylquinazolin-4-(3H)-one] was identified as one of
the CP-31398 derivatives, which induced mutant p53 (p53R175H
and p53R273H)-dependent growth suppression.
 It works by the mechanism of reactivation of mutant p53.
 Both CP-31398 and STIMA-1 bind to the cysteine residues in the
core domain of mutant p53, leading to stabilization of wild-type
p53 conformation and subsequent restoration of transcriptional
activity

16. STIMA-1 increases the DNA-binding ability of mutant p53, resulting
in up regulation mRNA expression of p21, PUMA, and BAX, and
leading to mutant p53-dependent apoptosis
2. Hsp90 Inhibitors: Geldanamycin, 17-AAG, Ganetespib
These are Compounds that deplete mutant p53.
Blocking the function of heat shock protein 90 (Hsp90) leads to
depletion of several oncogenic proteins, such as Raf-1, ErbB2, and
mutant p53, because Hsp90 contributes to accumulation of mutant
p53 by inactivating p53 ubiquitin ligases
Treatment of cancer cells with 17-AAG, a Hsp90 inhibitor and an
analog of geldanamycin, promotes degradation of varieties of p53
mutants (p53R175H, p53L194F, p53R273H, and p53R280K) and decreases
viability of cells carrying mutant p53.

17. Importantly, another Hsp90 inhibitor, ganestespib, which is 50-
fold more potent than 17-AAG in destabilizing mutant p53 with
little effect on wild-type p53 levels, induces mutant p53 depletion
with increased apoptosis in tumors in vivo.
•Within p53 reactivators, PRIMA-1MET (also known as APR-246) is
the only drug under clinical trials. On the other hand, amongst the
compounds that deplete mutant p53, Hsp90 inhibitors , HDAC
inhibitors , ATO and DSF are under clinical trials for cancer therapy.

18. REFERENCES:
•TITLE SLIDE IMAGE: https://hipwallpaper.com/cancer-cell-wallpapers/
• CANINE BREAST CANCER:
1.Comparative Oncology by Alecsandru Ioan Baba and Cornel Câtoi.
2. Stromelysin-3 Protein Expression in Invasive Breast Cancer: Relation to
Proliferation, Cell Survival and Patients’ Outcome
Lydia Nakopoulou M.D., Effie G Panayotopoulou B.Sc., Ioanna Giannopoulou
B.Sc., Paraskevi Alexandrou, Sophia Katsarou, Pauline Athanassiadou M.D. &
Antonios Keramopoulos M.D.
3. Proteases and Their Inhibitors in Cancer Metastasis edited by J-M. Foidart,
R.J. Muschel
4. https://www.ncbi.nlm.nih.gov/pmc/articles/PMC4516284/
• CANINE OSTEOSARCOMA:
https://www.ncbi.nlm.nih.gov/books/NBK22268/
https://www.researchgate.net/publication/23453542_TP53_Gene_Mutations
_in_Canine_Osteosarcoma
https://www.ncbi.nlm.nih.gov/pmc/articles/PMC4685147/

19. •CANINE MELANOMA
https://www.ncbi.nlm.nih.gov/pmc/articles/PMC5644618/
https://www.ncbi.nlm.nih.gov/pmc/articles/PMC5995433/

20. THANK YOU