Quantum Dots: Synthesis, Antibody Conjugation, and HER2-Receptor Targeting for Breast Cancer Therapy

Breast cancer is becoming one of the main lethal carcinomas in the recent era, and its occurrence rate is increasing day by day. There are different breast cancer biomarkers, and their overexpression takes place in the metastasis of cancer cells. The most prevalent breast cancer biomarker is the human epidermal growth factor receptor2 (HER2). As this biomarker is overexpressed in malignant breast tissues, it has become the main focus in targeted therapies to fight breast cancer. There is a cascade of mechanisms involved in metastasis and cell proliferation in cancer cells. Nanotechnology has become extremely advanced in targeting and imaging cancerous cells. Quantum dots (QDs) are semiconductor NPs, and they are used for bioimaging, biolabeling, and biosensing. They are synthesized by different approaches such as top-down, bottom-up, and synthetic methods. Fully human monoclonal antibodies synthesized using transgenic mice having human immunoglobulin are used to target malignant cells. For the HER2 receptor, herceptin® (trastuzumab) is the most specific antibody (Ab), and it is conjugated with QDs by using different types of coupling mechanisms. This quantum dot monoclonal antibody (QD-mAb) conjugate is localized by injecting it into the blood vessel. After the injection, it goes through a series of steps to reach the intracellular space, and bioimaging of specifically the HER2 receptor occurs, where apoptosis of the cancer cells takes place either by the liberation of Ab or the free radicals.

Integrative multiomics-histopathology analysis for breast cancer classification

Histopathologic evaluation of biopsy slides is a critical step in diagnosing and subtyping breast cancers. However, the connections between histology and multi-omics status have never been systematically explored or interpreted. We developed weakly supervised deep learning models over hematoxylin-and-eosin-stained slides to examine the relations between visual morphological signal, clinical subtyping, gene expression, and mutation status in breast cancer. We first designed fully automated models for tumor detection and pathology subtype classification, with the results validated in independent cohorts (area under the receiver operating characteristic curve ≥ 0.950). Using only visual information, our models achieved strong predictive performance in estrogen/progesterone/HER2 receptor status, PAM50 status, and TP53 mutation status. We demonstrated that these models learned lymphocyte-specific morphological signals to identify estrogen receptor status. Examination of the PAM50 cohort revealed a subset of PAM50 genes whose expression reflects cancer morphology. This work demonstrates the utility of deep learning-based image models in both clinical and research regimes, through its ability to uncover connections between visual morphology and genetic statuses.

Ferritin Conjugates With Multiple Clickable Amino Acids Encoded by C-Terminal Engineered Pyrrolysyl-tRNA Synthetase

This study reports the application of expanding genetic codes in developing protein cage-based delivery systems. The evolved Methanosarcina mazei pyrrolysyl-tRNA synthetase (PylRS)•tRNAPyl pairs derived from directed evolution are examined to probe their recognition for para-substituted phenylalanine analogs. The evolved MmPylRS, AzFRS, harboring a wide range of substrates, is further engineered at the C-terminal region into another variant, AzFRS-MS. AzFRS-MS shows suppression of the elevated sfGFP protein amount up to 10 TAG stop codons when charging p-azido-l-phenylalanine (AzF, 4), which allows the occurrence of click chemistry. Since protein nanocages used as drug delivery systems that encompass multiple drugs through a site-specific loading approach remain largely unexplored, as a proof of concept, the application of AzFRS-MS for the site-specific incorporation of AzF on human heavy chain ferritin (Ftn) is developed. The Ftn-4 conjugate is shown to be able to load multiple fluorescence dyes or a therapeutic agent, doxorubicin (Dox), through the strain-promoted azide-alkyne cycloaddition (SPAAC) click reaction. Aiming to selectively target Her2+ breast cancer cells, Ftn-4-DOX conjugates fused with a HER2 receptor recognition peptide, anti-Her2/neu peptide (AHNP), is developed and demonstrated to be able to deliver Dox into the cell and to prolong the drug release. This work presents another application of evolved MmPylRS systems, whose potential in developing a variety of protein conjugates is noteworthy.

The EGF Domains of MUC4 Oncomucin Mediate HER2 Binding Affinity and Promote Pancreatic Cancer Cell Tumorigenesis

The HER2 receptor and its MUC4 mucin partner form an oncogenic complex via an extracellular region of MUC4 encompassing three EGF domains that promotes tumor progression of pancreatic cancer (PC) cells. However, the molecular mechanism of interaction remains poorly understood. Herein, we decipher at the molecular level the role and impact of the MUC4EGF domains in the mediation of the binding affinities with HER2 and the PC cell tumorigenicity. We used an integrative approach combining in vitro bioinformatic, biophysical, biochemical, and biological approaches, as well as an in vivo study on a xenograft model of PC. In this study, we specified the binding mode of MUC4EGF domains with HER2 and demonstrate their “growth factor-like” biological activities in PC cells leading to stimulation of several signaling proteins (mTOR pathway, Akt, and β-catenin) contributing to PC progression. Molecular dynamics simulations of the MUC4EGF/HER2 complexes led to 3D homology models and identification of binding hotspots mediating binding affinity with HER2 and PC cell proliferation. These results will pave the way to the design of potential MUC4/HER2 inhibitors targeting the EGF domains of MUC4. This strategy will represent a new efficient alternative to treat cancers associated with MUC4/HER2 overexpression and HER2-targeted therapy failure as a new adapted treatment to patients.

Determination of Significant Pretreatment Factors that Predict Survival in Indonesian Subjects with Breast Cancer

BACKGROUND: The determination of the pre-treatment’s survival predictive factors is very important as a basis for clinicians to educate and determine appropriate management for patients. AIM: This study aimed to determine the pre-treatment risk factors that predict survival in Indonesian subjects with breast cancer. METHODS: This was a cohort retrospective study conducted on breast cancer subjects visiting Sanglah General Hospital from 2016 to 2020. Data were collected from Indonesian Cancer Registry medical records such as age, tumor size, lymph nodes, metastasis, Karnofsky score, serum CA15-3 level, hormonal receptor status (ER/PR), HER2, Ki-67, LVI, tumor-infiltrating lymphocytes, cell type, histological grade, and survival status until December 2020. Data were tabulated and analyzed statistically using SPSS 25.0. RESULTS: The median survival of breast cancer in this study was 47 months (SD 4.851). Majority of breast cancer subjects with mortality outcome were those who had Karnofsky score less than 70, tumor size ≥5 cm with infiltration, presence of contralateral lymph node, with metastasis, serum CA15-3 level >25 IU/mL, negative hormonal receptor, negative HER2 receptor, Ki67 higher than 14, negative lymphovascular invasion, negative tumor-infiltrating lymphocytes, and histological Grade 3. Age and pathological type were not significantly differed the breast cancer outcome. CONCLUSION: There were significant effects of tumor size, KGB status, metastasis, serum CA15-3 levels, hormone receptor, HER2 receptor, Karnofsky score, lymphovascular invasion, tumor-infiltrating lymphocytes, and histological grade on breast cancer subjects’ survival.

Targeting HER2 Expressing Tumors with a Potent Drug Conjugate Based on an Albumin Binding Domain-Derived Affinity Protein

Albumin binding domain derived affinity proteins (ADAPTs) are a class of small and folded engineered scaffold proteins that holds great promise for targeting cancer tumors. Here, we have extended the in vivo half-life of an ADAPT, targeting the human epidermal growth factor receptor 2 (HER2) by fusion with an albumin binding domain (ABD), and armed it with the highly cytotoxic payload mertansine (DM1) for an investigation of its properties in vitro and in vivo. The resulting drug conjugate, ADAPT6-ABD-mcDM1, retained binding to its intended targets, namely HER2 and serum albumins. Further, it was able to specifically bind to cells with high HER2 expression, get internalized, and showed potent toxicity, with IC50 values ranging from 5 to 80 nM. Conversely, no toxic effect was found for cells with low HER2 expression. In vivo, ADAPT6-ABD-mcDM1, radiolabeled with 99mTc, was characterized by low uptake in most normal organs, and the main excretion route was shown to be through the kidneys. The tumor uptake was 5.5% ID/g after 24 h, which was higher than the uptake in all normal organs at this time point except for the kidneys. The uptake in the tumors was blockable by pre-injection of an excess of the monoclonal antibody trastuzumab (having an overlapping epitope on the HER2 receptor). In conclusion, half-life extended drug conjugates based on the ADAPT platform of affinity proteins holds promise for further development towards targeted cancer therapy.

Pertuzumab and Trastuzumab Combination with Concomitant Locoregional Radiotherapy for the Treatment of Breast Cancers with HER2 Receptor Overexpression

Background: The combination of pertuzumab and trastuzumab dual HER2 blockade with concomitant curative dose locoregional breast radiotherapy in patients with metastatic breast cancer is an important part of treatment strategy. Methods: This was a retrospective study conducted at the Institut Curie on all patients treated concomitantly with pertuzumab/trastuzumab and locoregional breast radiotherapy. Toxicity was evaluated according to the NCICTCAEv4.0. Overall survival, progression-free survival and locoregional recurrence-free survival were evaluated in metastatic patients who were initially well controlled by chemotherapy, for whom local treatment was decided by the multidisciplinary team. Results: Fifty-five patients treated between October 2013 and December 2019 were included, with a median follow-up of 4.1 years. The median age was 53 years (range: 28–81). All patients received curative dose radiotherapy (RT) concomitantly with pertuzumab and trastuzumab (Pertu/Trastu). The median radiation dose was 50 Gy. Safety evaluation did not reveal any significant adverse effects, with 3 cases of grade 3 radiodermatitis (5.4%), but no significant gastrointestinal or cardiac toxicity. The mean difference in LVEF before any chemotherapy and after radiotherapy was −2.43% (p < 0.01). Conclusions: This study demonstrates that the combination of locoregional breast RT with dual HER2 blockade by Pertu/Trastu was very well tolerated, suggesting that RT can be safely administered to patients with HER2-positive breast cancer.

Integrating Immunotherapy with Chemotherapy: A New Approach to Drug Repurposing

Triple negative breast cancer (TNBC) is an aggressive breast cancer subtype lacking the three hormonal receptors namely estrogen receptor, progesterone receptor and HER2 receptor, and the only treatment option available for TNBC is chemotherapy. Chemotherapy lacks specificity since it acts on normal healthy cells as well resulting into secondary diseases in TNBC patients. In addition chemotherapy poses recurrence and relapse issues due to the development of chemoresistance among TNBC patients. Immunotherapy remarkably immune checkpoint inhibitors show a great therapeutic potential in TNBC. As TNBC contain an increased TILs (tumor infiltrating lymphocytes) infiltration making it more suitable as a therapeutic target anti-tumor immune strategy. Moreover, evidences have indicated that chemotherapy upregulates the anti-tumor immune response in TNBC. As a result, a combination of immunotherapy with chemotherapy may increase the overall relapse and recurrence free survival of TNBC patients. Therefore, in this chapter we will focus on how the immunotherapy works in TNBC, their effects and consequences. We will further be discussing the clinical studies and the importance of immune checkpoint inhibitors (ICIs) in combination with various therapeutic agents and target. Further, we will explore the processes involved.

Targeting ErbB3 Receptor in Cancer with Inhibitory Antibodies from Llama

The human ErbB3 receptor confers resistance to the pharmacological inhibition of EGFR and HER2 receptor tyrosine kinases in cancer, which makes it an important therapeutic target. Several anti-ErbB3 monoclonal antibodies that are currently being developed are all classical immunoglobulins. We took a different approach and discovered a group of novel heavy-chain antibodies targeting the extracellular domain of ErbB3 via a phage display of an antibody library from immunized llamas. We first produced three selected single-domain antibodies, named BCD090-P1, BCD090-M2, and BCD090-M456, in E. coli, as SUMO fusions that yielded up to 180 mg of recombinant protein per liter of culture. Then, we studied folding, aggregation, and disulfide bond formation, and showed their ultimate stability with half-denaturation of the strongest candidate, BCD090-P1, occurring in 8 M of urea. In surface plasmon resonance experiments, two most potent antibodies, BCD090-P1 and BCD090-M2, bound the extracellular domain of ErbB3 with 1.6 nM and 15 nM affinities for the monovalent interaction, respectively. The receptor binding was demonstrated by immunofluorescent confocal microscopy on four different ErbB3+ cancer cell lines. We observed that BCD090-P1 and BCD090-M2 bind noncompetitively to two distinct epitopes on the receptor. Both antibodies inhibited the ErbB3-driven proliferation of MCF-7 breast adenocarcinoma cells and HER2-overexpressing SK-BR-3 cells, with the EC50 in the range of 0.1–25 μg/mL. BCD090-M2 directly blocks ligand binding, whereas BCD090-P1 does not compete with the ligand and presumably acts through a distinct allosteric mechanism. We anticipate that these llama antibodies can be used to engineer new biparatopic anti-ErbB3 or bispecific anti-ErbB2/3 antibodies.

Differences in Breast Cancer Subtypes Among Racial/Ethnic Groups

PurposeDifferences in incidence of breast cancer subtypes among racial/ethnic groups have been evaluated as a contributing factor in the disparities seen in breast cancer prognosis. We evaluated new breast cancer cases in Hawaii to determine if there were subtype differences according to race/ethnicity that may contribute to known disparities.MethodsWe reviewed 4,318 cases of women diagnosed with breast cancer from two large tumor registries between 2013-2020. We evaluated the new breast cancer cases according to age at diagnosis, self-reported race, and breast cancer subtype (ER, PR, and HER2 receptor status).ResultsWe found both premenopausal and postmenopausal Native Hawaiian women were less likely to be diagnosed with triple negative breast cancer (OR=0.33, P=0.009; OR=0.62, P=0.03 respectively). Premenopausal Japanese women were 71% less likely to be diagnosed with triple positive (ER+/PR+/HER2+) breast cancer (OR=0.29, P=0.0003). Postmenopausal Filipino women were 89% more likely to be diagnosed with ER-/PR-/HER2+ breast cancer (OR=1.89, P=0.02). ConclusionsResults of our study support that there are racial/ethnic differences in breast cancer subtypes among our population which may contribute to the differences in outcome seen. Further evaluation of other clinical and pathological features in each breast cancer subtype may inform potential mechanisms for outcome disparities seen among different racial/ethnic groups.