Hsc70 phosphorylation patterns and calmodulin regulate AP2 Clathrin-Coated-Vesicle life span for cell adhesion protein transport

AP2 forms AP2 CCV with clathrin and over 60 additional coat proteins. Due to this complexity, we have a limited understanding of CCV life cycle regulation. Synapses contain canonical AP2 CCV, canCCV, and more stable, thereby longer lived, AP2 CCV. The more stable AP2 CCV can be distinguished from canCCV due to the stable binding of Hsc70 to clathrin. The AP1/σ1B complex knockout leads to impaired synaptic vesicle recycling and altered endosomal protein sorting. This causes as a secondary phenotype the twofold upregulation of endocytosis by canCCV and by more stable AP2 CCV. These stable CCV are more stabilized than their wt counterpart, hence stCCV. They have less of the uncoating proteins synaptojanin1 and Hsc70, and more of the coat stabilizing AAK1. Hsc70 clathrin dissociation activity is regulated by complex phosphorylation patterns. Two major groups of hyper- and of hypo-phosphorylated Hsc70 proteins are formed. The latter are enriched in wt stable CCV and stabilized stCCV. Hsc70 T265 phosphorylation regulates binding of CaM/Ca2+. CaM/Ca2+ binding to the T265 domain blocks Hsc70 homodimerization and its concentration in stCCV required for clathrin disassembly. Kinases DYRK1A and CaMK-IIδ can phosphorylate T265 preventing CaM/Ca2+ binding. Their and the levels of STK38L and STK39/Cab39, which are able to phosphorylate additional Hsc70 residues are reduced in stCCV. The stCCV pathway sorts specifically the cell adhesion proteins CHL1 and Neurocan, supporting our model of that the stCCV pathway fulfills specific functions in synaptic plasticity.

Development and Evaluation of an Eco-Friendly Hand Sanitizer Formulation Valorized from Fruit Peels

Hand sanitizer usage has proven to be a common and practical method for reducing the spread of infectious diseases which can be caused by many harmful pathogens. There is a need for alcohol-free hand sanitizers because most hand sanitizers on the market are alcohol-based, and regular use of them can damage the skin and can be hazardous. India is the world's largest producer of fruits and one of the major problems after fruit consumption is their peels, causing waste management problems and contributing to the formation of greenhouse gases leading to air pollution and adding to the problem of climate change. Valorization of such wastes into other value-added products and their incorporation into formulations of eco-friendly alcohol-free hand sanitizers would solve these issues, save the environment, benefit the society, and help in achieving the sustainable development goals. Thus, this research focuses on formulating an effective natural alcohol-free hand sanitizer that harnesses the antimicrobial properties of the various types of bioactive components found in fruit peels of pomegranate, sweet lime, and lemon. The peel extracts and the formulated sanitizer proved considerable antimicrobial activity against the pathogenic Escherichia coli and hand microflora. Molecular docking was also applied to examine ligand-protein interaction patterns and predict binding conformers and affinity of the sanitizer phytocompounds towards target proteins in COVID-19, influenza, and pneumonia viruses. The binding affinities and the protein-ligand interactions virtual studies revealed that the sanitizer phytocompounds bind with the amino acids in the target proteins' active sites via hydrogen bonding interactions. As a result, it is possible to formulate a natural, alcohol-free hand sanitizer from fruit peels that is effective against pathogenic germs and viruses using the basic structure of these potential findings.

AN EVALUATION OF ANTIBIOTIC PRESCRIPTION PRACTICES: PERSPECTIVES OF VETERINARY TRAINEES AND PRACTICING VETERINARIANS

Antibiotic resistance is a major worldwide problem that has an impact on the well-being of humans as well as animals. Antibiotic resistance is caused by the misuse and excessive use of antibiotics. The key to reducing this issue lies in educating veterinary medical learners on the proper and accountable utilization of antibiotics for the care of animals. Objective - using awareness-raising and instruction as the foundation, this research of Indian veterinary learners can help resolve the issue of antibiotic resistance throughout the care of animals. The questionnaire survey was taken between June and July 2022 and it was aimed at learners registered in veterinary medical studies at academic and research institutions in India. The study included 500 pupils overall. The purpose of the survey was to gather information about students' knowledge of antibiotics, including antibiotic resistance, as well as their feelings on the consequences of antibiotic resistance on the globe at large and their acquaintance with the one health ideology. According to this study's findings, 83.3 percent of respondents thought antibiotic resistance was a serious problem. 57.92 percent of respondents understood the issue's worldwide consequences and its one health ideology. The study emphasizes the significance of expanding the veterinary educational program to include thorough instruction on prudent antibiotic usage and the concepts of one health.

EXPLORING CLINICAL VARIATIONS AND CO-MORBID TRENDS IN PD-MCI GROUPS

Parkinson's Disease in Mild Cognitive Impairment (PD-MCI) is a complex condition characterized by a variety of cognitive problems that coexist with the physical symptoms of Parkinson's disease (PD). This study aims to examine the different medical indicators and associated tendencies among different PD-MCI groups. We investigated 132 people who had been given PD-MCI diagnoses. Utilizing SPSS, statistical evaluations are carried out. In overall PD-MCI variants, this investigation found that visuospatial ability and attentional/executive performance are the most impaired cognitive areas. It was also noticed that distinct PD-MCI groups had variances in their neurological characteristics, in multi domain amnesia (Non-Memory) PD-MCI patients exhibiting especially severe issues with unstable posture and walking. The intricacy of PD- Mild Cognitive Impairment (MCI) is highlighted by those results, which also imply that the interplay between mental and physical signs may be controlled by a number of interrelated factors, such as particular cognitive areas, brain surfaces, and the general level of cognitive impairment.

Cancer-associated mesothelial cells are regulated by the anti-Müllerian hormone axis

Cancer-associated mesothelial cells (CAMCs) in the tumor microenvironment are thought to promote growth and immune evasion. We find that, in mouse and human ovarian tumors, cancer cells express anti-Müllerian hormone (AMH) while CAMCs express its receptor AMHR2, suggesting a paracrine axis. Factors secreted by cancer cells induce AMHR2 expression during their reprogramming into CAMCs in mouse and human in vitro models. Overexpression of AMHR2 in the Met5a mesothelial cell line is sufficient to induce expression of immunosuppressive cytokines and growth factors that stimulate ovarian cancer cell growth in an AMH-dependent way. Finally, syngeneic cancer cells implanted in transgenic mice with Amhr2-/- CAMCs grow significantly slower than in wild-type hosts. The cytokine profile of Amhr2-/- tumor-bearing mice is altered and their tumors express less immune checkpoint markers programmed-cell-death 1 (PD1) and cytotoxic T lymphocyte-associated protein 4 (CTLA4). Taken together, these data suggest that the AMH/AMHR2 axis plays a critical role in regulating the pro-tumoral function of CAMCs in ovarian cancer.

Abstract 3988: The role of HER3 mutations in the progression of colon cancer and modulation of drug sensitivity and resistance

Colorectal cancer is a disease of the colon and rectum that will claim about 52,580 American lives in2022. The most common treatment of colorectal cancer is surgery plus chemotherapy, although thereare some FDA approved targeted therapies such as regorafenib (targeting VEGF) or cetuximab (targetingEGFR). EGFR, along with HER2, HER3, and HER4 are members of the HER family of receptor tyrosinekinases that upon homo- or heterodimerization activate downstream signaling, growth, and survivalpathways. In recent years, more attention has been paid to HER2 and HER3’s roles in colorectal cancers,as they may cause resistance to targeted therapies. OWe are investigating naturally occurring mutantHER3’s role in colorectal cancer, as about 6% of all colorectal cancers contain a HER3 mutation. We arecurrently investigating how HER3 mutations may affect sensitivity to current therapies through HERfamily receptor dimerization and be involved in tumor metastasis. We are assessing the degree to whichmutant and wild-type HER3 have the ability to dimerize with EGFR, HER2, MET, and IGF1R the resultingeffects in colon cancer, as these receptor tyrosine kinases are HER3 binding partners. As HER3 bindingpartners are diverse, it may be that the pathway HER3 and its binding partner activate may influencetreatment strategy. It has been noted that mutant HER2 and HER3 could confer sensitivity to HER familyinhibitors, i.e. afatinib, in bladder cancer, and we have seen a difference in IC50 values of afatinibbetween cell lines containing wild-type or mutant HER3. If mutant HER3 is involved in therapeuticresistance or sensitivity and tumor progression, our findings may present a new biomarker for targetedtreatments in colorectal cancer with the eventual goal of increased overall patient survival.

Citation Format: Mary K. Kilroy, Rosalin Mishra, Anastasia Stupecki, Wasim Feroz, Samar Alanazi, Joan T. Garrett. The role of HER3 mutations in the progression of colon cancer and modulation of drug sensitivity and resistance. [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2023; Part 1 (Regular and Invited Abstracts); 2023 Apr 14-19; Orlando, FL. Philadelphia (PA): AACR; Cancer Res 2023;83(7_Suppl):Abstract nr 3988.

RIDR-PI-103, ROS-activated prodrug PI3K inhibitor inhibits cell growth and impairs the PI3K/Akt pathway in BRAF and MEK inhibitor-resistant BRAF-mutant melanoma cells

Reactive oxygen species (ROS) levels are elevated after acquisition of resistance to v-raf murine sarcoma viral oncogene homolog B1 (BRAF) inhibitors including dabrafenib and MEK inhibitors such as trametinib in BRAF-mutant melanoma. To circumvent toxicity to PI-103 (a pan PI3K inhibitor), we utilized a novel ROS-induced drug release (RIDR)-PI-103, with a self-cyclizing moiety linked to PI-103. Under high ROS conditions, RIDR-PI-103 releases PI-103, which inhibits conversion of phosphatidylinositol 4,5-bisphosphate (PIP 2 ) to phosphatidylinositol 3,4,5-triphosphate (PIP 3 ). Previous findings demonstrate that trametinib and dabrafenib-resistant (TDR) cells maintain p-Akt levels compared to parental counterparts and have significantly higher ROS. This is a rationale to explore the efficacy RIDR-PI-103 in TDR cells. We tested the effect of RIDR-PI-103 on melanocytes and TDR cells. RIDR-PI-103 exhibited less toxicity compared to PI-103 at 5 µM in melanocytes. RIDR-PI-103 significantly inhibited TDR cell proliferation at 5 and 10 µM. Twenty-four hour treatment with RIDR-PI-103 inhibited p-Akt, p-S6 (Ser240/244) and p-S6 (Ser235/236). We assessed the mechanism of activation of RIDR-PI-103, using glutathione or t-butyl hydrogen peroxide (TBHP) on the TDR cells in the presence or absence of RIDR-PI-103. Addition of the ROS scavenger glutathione to RIDR-PI-103 significantly rescued the cell proliferation in TDR cell lines while addition of the ROS inducer TBHP and RIDR-PI-103 inhibited cell proliferation in WM115 and WM983B TDR cell lines. Examining the efficacy of RIDR-PI-103 on BRAF and MEK inhibitor-resistant cells will expand possible treatment options and open avenues for the development of new ROS-based treatment therapies for BRAF-mutant melanoma patients.

HER2 inhibition increases non-muscle myosin IIA to promote tumorigenesis in HER2+ breast cancers

HER2 is over-expressed in around 15% to 20% of breast cancers. HER3 plays a critical role in HER2 mediated tumorigenesis. Increased HER3 transcription and protein levels occur upon inhibition of HER2. We aimed to identify proteins that bound to HER3 upon inhibition of the HER family with the pan-HER inhibitor neratinib in HER2+ breast cancer cells. Immunoprecipitation of HER3 followed by mass spectrometry experiments found non-muscle myosin IIA (NMIIA) increased upon neratinib treatment relative to vehicle DMSO treatment. MYH9 is the gene that encodes for the heavy chain of NMIIA. Breast cancer patients with high MYH9 were significantly associated with a shorter disease specific survival compared to patients with low MYH9 expression from the METABRIC cohort of patients. In addition, high MYH9 expression was associated with HER2+ tumors from this cohort. Immunoblots of whole cell lysates of BT474 and MDA-MB-453 HER2+ breast cancer cells demonstrated elevated HER3 and NMIIA protein levels upon neratinib treatment for 24 hours. To examine the role of NMIIA in HER2+ breast cancer, we modulated NMIIA levels in BT474 and MDA-MB-453 cells using doxycycline inducible shRNA targeting MYH9. MYH9 knockdown reduces HER3 protein levels and concomitant reduction in downstream P-Akt. In addition, loss of MYH9 suppresses cell growth, proliferation, migration, and invasion. Our data reveals that NMIIA regulates HER3 and loss of NMIIA reduces HER2+ breast cancer growth.

HER3 Alterations in Cancer and Potential Clinical Implications

In recent years, the third member of the HER family, kinase impaired HER3, has become a target of interest in cancer as there is accumulating evidence that HER3 plays a role in tumor growth and progression. This review focuses on HER3 activation in bladder, breast, colorectal, and lung cancer disease progression. HER3 mutations occur at a rate up to ~10% of tumors dependent on the tumor type. With patient tumors routinely sequenced for gene alterations in recent years, we have focused on HER3 mutations in bladder, breast, colon, and lung cancers particularly in response to targeted therapies and the potential to become a resistance mechanism. There are currently several HER3 targeting drugs in the pipeline, possibly improving outcomes for cancer patients with tumors containing HER3 activation and/or alterations.

Abstract 5412: Role of her3 mutations on breast cancer oncogenesis

We sought to determine if naturally occurring mutations in HER3 could drive oncogenic growth of HER3KO HER2+ HCC1569 cells in which endogenous HER3 has been eliminated via CRISPR-Cas9. A series of HER3 mutations identified in breast cancer patients (F94L, V104L, G284R, D297Y, T355I, and E928G) were introduced using lentiviral transduction and stable cell lines were generated in HER3KOHCC1569 cells via puromycin selection. We identified HER3V104L mutation to have higher cell proliferation and higher p-HER3 expression compared to wild-type (wt) and empty-vector (EV) HER3. We observed that HCC1569HER3KO cells stably expressing WT and V104L were sensitive to increasing doses of neratinib (0.1-0.5 µM) concentration. Next we analyzed if this mutation rendered resistance to the recently FDA- approved irreversible HER2 tyrosine kinase inhibitor, tucatinib. Our data indicated that both that V104L cells were sensitive to higher concentration of tucatinib compared to neratinib. In parallel experiments, we utilized COS7 cells to examine the signaling properties of HER3V104L. Our data indicated that transient transfection of COS7 cells with HER3V104L mutant significantly induces p-HER3/p-AKT and p-HER2 expression compared to WT HER3 in a ligand dependent manner. In addition, we observed that the V104L mutation stabilizes HER3 protein expression independent of HER2 and ligand stimulation. Experiments are ongoing to determine whether V104L induced HER3 stabilization and downstream signaling activation is dependent on HER3 binding partners including EGFR, HER2 or HER4. We also aim to understand how the V104L mutation stabilizes HER3 expression. Structural modeling of V104L mutation will provide insight about the mechanism of stabilization of the HER3 protein. We will use MCF10A and HEK293 cells to determine the effect of the V104L mutation on HER3 expression and downstream signaling. We also aim to decipher the signaling mechanism that drives the oncogenic potential of V104L mutation. In addition, we are using various PDXs with different HER3 mutations to determine other driver HER3 mutations in breast cancer and how this can be targeted in the clinic using HER targeted therapy.

Citation Format: Rosalin Mishra, Mary Kate Kilroy, Hima Patel, Samar Alanazi, Joan T. Garrett. Role of her3 mutations on breast cancer oncogenesis [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2022; 2022 Apr 8-13. Philadelphia (PA): AACR; Cancer Res 2022;82(12_Suppl):Abstract nr 5412.

Abstract 5356: RIDR-PI-103, ROS-activated PI3K inhibitor prodrug inhibits cell growth and impairs the PI3K/Akt pathway in BRAF and MEK inhibitor resistant BRAF-mutant melanoma cells

The five-year survival rate for patients diagnosed with metastatic melanoma is only 27%. About half of melanomas have the presence of the BRAFV600E oncoprotein, which leads to hyperactivation of the mitogen activated protein kinase (MAPK) pathway. The MAPK pathway is known to crosstalk with the PI3K/Akt pathway. Treatment with the BRAF inhibitor, Dabrafenib and the MEK inhibitor, Trametinib is limited as patient responses begin to drop due to acquired resistance to these kinase inhibitors. High concentrations of reactive oxygen species (ROS) accompany this resistance. ROS-induced drug release (RIDR)-PI-103 is a novel prodrug with a self-cyclizing moiety linked to PI-103, a PI3K inhibitor. Under high ROS conditions, RIDR-PI-103 releases PI-103, which inhibits conversion of PIP2 to PIP3. We have generated Trametinib and Dabrafenib resistant (TDR) cells for 3 BRAF-mutant cell lines: A375, WM115 and WM983B from parental (drug sensitive) cell lines. Studies in our lab demonstrate that TDR cells maintain p-Akt levels compared to parental counterparts and have significantly higher ROS. This is a rationale to explore the efficacy RIDR-PI-103 in TDR cells. We tested the effect of RIDR-PI-103 on cell viability for 1789C melanocytes, 1788B melanocytes, A375 TDR, WM983B TDR, and WM115 TDR using an MTT proliferation assay. RIDR-PI-103 exhibited less toxicity as compared to PI-103 at 5 µM in normal melanocytes. While RIDR-PI-103 significantly inhibited TDR cell proliferation at 5 and 10 µM compared to cells treated with vehicle DMSO and melanocytes. This effect was consistent when TDR cells were treated with RIDR-PI-103 in long-term crystal violet cell proliferation assays. WM115 TDR and WM983B TDR cells were highly sensitive to RIDR-PI-103 at 5 µM, while A375 TDR cells had only ~50% inhibition at 5 µM in both cell proliferation assays. 24 hour treatment with RIDR-PI-103 inhibited p-Akt (S473) along with downstream p-S6 (S240/244) and p-S6 (235/236). To examine the mechanism of action of RIDR-PI-103 and to test that the drug release is ROS induced, we assessed the effect of glutathione (GSH), an antioxidant on the TDR cells in the presence or absence of RIDR-PI-103. GSH alone did not affect proliferation of TDR cells. Addition of GSH to RIDR-PI-103 significantly rescued the cell proliferation in all three TDR cell lines. We next tested the effect of t-butyl hydrogen peroxide (TBHP), a ROS inducer on TDR cells with lower concentrations of RIDR-PI-103. Addition of TBHP to RIDR-PI-103 significantly induced proliferation in TDR cells. Ongoing experiments are focused on assessing the effect of RIDR-PI-103 on the mTOR pathway. Examining the efficacy of RIDR-PI-103 on BRAF and MEK inhibitor resistant cells will expand possible treatment options and open up avenues for the development of new treatment therapies for BRAF-mutant melanoma patients.

Citation Format: Hima Patel, Rosalin Mishra, Adam Wier, Nazanin Mokhtarpour, Edward J. Merino, Joan T. Garrett. RIDR-PI-103, ROS-activated PI3K inhibitor prodrug inhibits cell growth and impairs the PI3K/Akt pathway in BRAF and MEK inhibitor resistant BRAF-mutant melanoma cells [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2022; 2022 Apr 8-13. Philadelphia (PA): AACR; Cancer Res 2022;82(12_Suppl):Abstract nr 5356.

Abstract 5661: HER2 inhibition increases non-muscle myosin IIa to promote tumorigenesis in HER2+ breast cancers

HER2 is amplified in about 20% of breast cancers. HER3 is as essential as HER2 for maintaining cell viability in HER2+ breast cancer cells. It is known that inhibition of HER2 tyrosine kinase activity results in upregulation of HER3 transcription and phosphorylation. We sought to identify HER3 binding partners upon pharmacological inhibition of HER2 using neratinib. We immunoprecipitated HER3 using a HER3 antibody from BT474 cells treated ± neratinib. Fmass spectrometry experiments identified non-muscle myosin IIA (NMIIA) increased upon inhibition of HER2 with neratinib and decreased under DMSO control treatment from HER3 immunoprecipitates. To validate the presence of NMIIA, we performed immunoprecipitation experiments in BT474 and MDA-MB-453 cells using a HER3 antibody. Immunoblots showed increased NMIIA levels upon treatment with 200nM neratinib for 24 hours in both cell lines. Myosin heavy chain 9 (MYH9) gene encodes a protein called non-muscle myosin of class II, isoform A (NMIIA). It localizes to actin stress fibers and has been implicated in many cell functions. To confirm the interaction between HER3 and NMIIA we immunoprecipitated NMIIA from BT474 and MDA-MB-453 cells using a NMIIA antibody. Immunoblots indicated that HER3 levels were increased upon inhibition of HER2 with 200 nM neratinib for 24 hours. We next examined overall survival of primary breast cancer patients who have high gene expression for MYH9 from the METABRIC cohort. We observed that patients with high levels of MYH9 have a statistically significant worse overall survival versus patients with low levels of MYH9. Furthermore, we evaluated the overall levels of HER3 and MYH9 mRNA and protein upon treatment with neratinib in BT474 and MDA-MB-453 whole cell lysates. RT-qPCR and immunoblots showed increased HER3 and NM-IIA mRNA and protein levels upon neratinib treatment for 24 hours We examined the affect NMIIA loss has on HER3 signaling. Transduced MDA-MB-453 and BT474 cells with shMYH9 and doxycycline induction demonstrate a reduction in HER3 protein levels compared to cells transduced with a control sequence and doxycycline induction. We observed a concomitant reduction in P-HER3 (Y1289), downstream P-Akt (T308), and P-Erk1/2. In addition, NM-IIA knockdown suppresses cells growth, proliferation, migration, and invasion. In conclusion, there is a bidirectional relationship between NMIIA and HER signaling in HER2+ breast cancer cells. HER2 inhibition increases NMIIA and NMIIA promotes HER3 expression. Loss of NMIIA reduces HER3 protein and concomitant reductions in PI3K/Akt and MAPK signaling. Loss of NMIIA in combination with HER2 inhibition results in reduction in HER2+ breast cancer cell proliferation, growth on matrigel, migration, and invasion. Studies are ongoing to decipher the mechanisms for the bidirectional relationship between NMIIA and HER signaling.

Citation Format: Samar M. Alanazi, Rosalin Mishra, Hima Patel, Mary K. Kilroy, Joan T. Garrett. HER2 inhibition increases non-muscle myosin IIa to promote tumorigenesis in HER2+ breast cancers [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2022; 2022 Apr 8-13. Philadelphia (PA): AACR; Cancer Res 2022;82(12_Suppl):Abstract nr 5661.

Deciphering the link between Diabetes mellitus and SARS-CoV-2 infection through differential targeting of microRNAs in the human pancreas

PURPOSE

Coronavirus Disease 2019 (COVID-19) severity and Diabetes mellitus affect each other bidirectionally. However, the cause of severe acute respiratory syndrome coronavirus 2 (SARS-CoV2) infection on the incidence of diabetes is unclear. In the SARS-CoV-2-infected cells, host microRNAs (miRNAs) may target the native gene transcripts as well as the viral genomic and subgenomic RNAs. Here, we investigated the role of miRNAs in linking Diabetes to SARS-CoV-2 infection in the human pancreas.

METHODS

Differential gene expression and disease enrichment analyses were performed on an RNA-Seq dataset of human embryonic stem cell-derived (hESC) mock-infected and SARS-CoV-2-infected pancreatic organoids to obtain the dysregulated Diabetes-associated genes. The miRNA target prediction for the Diabetes-associated gene transcripts and the SARS-CoV-2 RNAs has been made to determine the common miRNAs targeting them. Minimum Free Energy (MFE) analysis was done to identify the miRNAs, preferably targeting SARS-CoV-2 RNAs over the Diabetes-associated gene transcripts.

RESULTS

The gene expression and disease enrichment analyses of the RNA-Seq data have revealed five biomarker genes, i.e., CP, SOCS3, AGT, PSMB8 and CFB that are associated with Diabetes and get significantly upregulated in the pancreas following SARS-CoV-2-infection. Four miRNAs, i.e., hsa-miR-298, hsa-miR-3925-5p, hsa-miR-4691-3p and hsa-miR-5196-5p, showed preferential targeting of the SARS-CoV-2 genome over the cell's Diabetes-associated messenger RNAs (mRNAs) in the human pancreas.

CONCLUSION

Our study proposes that the differential targeting of the Diabetes-associated host genes by the miRNAs may lead to diabetic complications or new-onset Diabetes that can worsen the condition of COVID-19 patients.

Abstract P5-10-05: HER2 inhibition increases non-muscle myosin IIa to promote tumorigenesis in HER2+ breast cancers

HER2 is amplified in about 20% of breast cancers. HER3 is as essential as HER2 for maintaining cell viability in HER2+ breast cancer cells. Inhibition of HER2 tyrosine kinase activity results in upregulation of HER3 transcription and phosphorylation. We sought to identify HER3 binding partners upon pharmacological inhibition of HER2 using the irreversible pan HER inhibitor neratinib. We immunoaffinity-purified HER3 from HER2+ BT474 cells treated ± neratinib. Following immunoprecipitation using a HER3 antibody, binding partners were released under reducing conditions. Mass spectrometry experiments identified non-muscle myosin IIA (NMIIA) increased upon inhibition of HER2 with neratinib and decreased under DMSO control treatment from HER3 immunoprecipitates. To validate the presence of NMIIA, we performed immunoprecipitation experiments in HER2+ BT474 and MDA-MB-453 cells using a HER3 antibody. Immunoblots showed increased NMIIA levels upon treatment with 200nM neratinib for 24 hours in both cell lines. Myosin heavy chain 9 (MYH9) gene encodes the protein NMIIA. NMIIA localizes to actin stress fibers and has been implicated in regulation of cell contractility and stress fiber organization.To test if there is an interaction between HER3 and NMIIA, we immunoprecipitated NMIIA from BT474 and MDA-MB-453 cells using an NMIIA antibody. The products were analyzed using immunoblots. The results indicated that HER3 levels were increased upon inhibition of HER2 with 200 nM neratinib for 24 hours.We next examined long term overall survival of primary breast cancer patients who have high and low levels of gene expression for MYH9 from the METABRIC cohort. We observed that patients with high levels of MYH9 have a statistically significant worse overall survival versus patients who express low levels of MYH9.We next sought to examine overall levels of HER3 and MYH9 mRNA and protein upon treatment with neratinib in HER2+ breast cancer whole cell lysates. We observed that mRNA and protein levels of both HER3 and MYH9 increased upon HER2 inhibition with 24 hours of neratinib treatment. To further investigate the role of NMIIA, we knocked out NMIIA in BT474 and MDA-MB-453 using inducible lentiviral shRNA targeting MYH9. This system utilizes the Tet-On 3G induction system and is a highly controlled system that consists of an inducible RNA polymerase II promoter. In the presence of doxycycline, the TRE3G promoter is bound and activated by the constitutively expressed Tet-On 3G trans-activator protein. Non-targeting shRNA was used as control and cells were selected in 1-2 ug/ml puromycin. Western blot analysis demonstrated that cells infected with lentiviral shRNA targeting MYH9 treated with doxycycline had reduced protein expression of NMIIA. BT474 and MDA-MB-453 transduced with shMYH9 were used to perform growth, migration, and invasion assays. The results indicated that MYH9 knockdown + neratinib treatment suppresses BT474 and MDA-MB-453 growth, migration, and invasion. Currently, in vivo xenograft experiments examining BT474 and MDA-MB-453 tumor growth ±NMIIA shRNA in the presence or absence of neratinib treatment are underway. In conclusion, we have identified that NMIIA mRNA and protein levels are increased in the presence of neratinib treatment. Our data reveals that HER2 inhibition increases NMIIA to promote HER2+ breast cancer growth.

Citation Format: Samar M Alanazi, Rosalin Mishra, Hima Patel, Long Yuan, Mary Kate Kilroy, Joan T Garrett. HER2 inhibition increases non-muscle myosin IIa to promote tumorigenesis in HER2+ breast cancers [abstract]. In: Proceedings of the 2021 San Antonio Breast Cancer Symposium; 2021 Dec 7-10; San Antonio, TX. Philadelphia (PA): AACR; Cancer Res 2022;82(4 Suppl):Abstract nr P5-10-05.

Salivary parameters and their correlation with neutrophil counts in children with acute lymphoblastic leukemia

BACKGROUND

Chemotherapy for Acute Lymphoblastic Leukemia (ALL) is known to render children immuno-deficient. A concomitant suppression of local defence mechanisms, such as saliva may further aggravate the adverse consequences of chemotherapy. The present study was conducted to evaluate alterations in salivary flow rate, pH and buffering capacity and to correlate these parameters with Absolute Neutrophil Counts (ANC).

METHODS

A cohort of 43 patients, aged 3-12 years were evaluated for the aforementioned parameters at baseline, post-induction and post-consolidation phases. Salivary collection was done and ANC was measured from routine haematological reports.

RESULTS

A decrease in the salivary parameters was observed at the end of Induction phase as compared to baseline, with a statistically significant decrease in unstimulated salivary flow rates (p < 0.01). Statistically significant positive correlations were found between ANC and salivary flow rate (p = 0.005), pH (p < 0.00) and buffering capacity (p < 0.00). On testing the significance of these correlations, all the values for these parameters were found to be statistically significant.

CONCLUSION

Salivary parameters showed derangements over the phases of chemotherapy, with maximum decrease at the end of induction phase. The positive correlations of salivary parameters with ANC of the subjects may be considered indicative of a concomitant immunological compromise in these children.

A mutant wfs1 zebrafish model of Wolfram syndrome manifesting visual dysfunction and developmental delay

Wolfram syndrome (WS) is an ultra-rare progressive neurodegenerative disorder defined by early-onset diabetes mellitus and optic atrophy. The majority of patients harbour recessive mutations in the WFS1 gene, which encodes for Wolframin, a transmembrane endoplasmic reticulum protein. There is limited availability of human ocular and brain tissues, and there are few animal models for WS that replicate the neuropathology and clinical phenotype seen in this disorder. We, therefore, characterised two wfs1 zebrafish knockout models harbouring nonsense wfs1a and wfs1b mutations. Both homozygous mutant wfs1a^-/- and wfs1b^-/- embryos showed significant morphological abnormalities in early development. The wfs1b^-/- zebrafish exhibited a more pronounced neurodegenerative phenotype with delayed neuronal development, progressive loss of retinal ganglion cells and clear evidence of visual dysfunction on functional testing. At 12 months of age, wfs1b^-/- zebrafish had a significantly lower RGC density per 100 μm² (mean ± standard deviation; 19 ± 1.7) compared with wild-type (WT) zebrafish (25 ± 2.3, p < 0.001). The optokinetic response for wfs1b^-/- zebrafish was significantly reduced at 8 and 16 rpm testing speeds at both 4 and 12 months of age compared with WT zebrafish. An upregulation of the unfolded protein response was observed in mutant zebrafish indicative of increased endoplasmic reticulum stress. Mutant wfs1b^-/- zebrafish exhibit some of the key features seen in patients with WS, providing a versatile and cost-effective in vivo model that can be used to further investigate the underlying pathophysiology of WS and potential therapeutic interventions.

A randomized controlled trial of restricted versus standard fluid management in late preterm and term infants with transient tachypnea of the newborn

BACKGROUND

Transient tachypnea of the newborn(TTNB) is the most common respiratory morbidity in late preterm and term babies and is pathophysiologically related to delayed lung fluid clearance after birth. Mimicking low physiological fluid intake in the initial period of life may accelerate the recovery from TTNB. In a randomized controlled trial, we compared the roles of restricted versus standard fluid management in babies with TTNB requiring respiratory support.

METHODS

This parallel group,non-blinded, stratified randomized controlled trial was conducted in a level III neonatal unit of eastern India. Late preterm and term babies with TTNB requiring continuous positive airway pressure (CPAP) were randomly allocated to standard and restricted fluid arms for the first 72 hours (hrs). Primary outcome was CPAP duration.

RESULTS

In total, 100 babies were enrolled in this study with 50 babies in each arm. CPAP duration was significantly less in the restricted arm (48[42, 54] hrs vs 54[48,72] hrs, p = 0.002). However, no difference was observed in the incidence of CPAP failure between the two arms. In the subgroup analysis, the benefit of reduced CPAP duration persisted in late preterm but not in term infants. However, the effect was not significant in the late preterm babies exposed to antenatal steroid.

CONCLUSION

This trial demonstrated the safety and effectiveness of restrictive fluid strategy in reducing CPAP duration in late preterm and term babies with TTNB. Late preterm babies, especially those not exposed to antenatal steroid were the most benefitted by this strategy.

Wire mesh capped DRPS based bronchial dosimeter for personal inhalation dosimetry due to radon progeny

A study has been carried out to experimentally determine the calibration factor (CF) of the passive bronchial dosimeter, which consists of a direct radon progeny sensor capped with a 100-wire mesh. First, the CF was determined in controlled environmental conditions simulated in a calibration chamber. With aerosol concentrations varying from 10⁴p cm^-3to 10⁵p cm^-3and relative humidity varying from 60% to 80% in the chamber, CF was observed to be nearly constant with an average value of (3.8 ± 0.5) × 10^-3mSv tracks^-1cm². Then, the CF was determined in real indoor environments in which it was again observed to be almost constant and the mean value was found to be (5.6 ± 0.1) × 10^-3mSv tracks^-1cm². Pooling all the data on CFs obtained under controlled conditions and in real indoor environments, a lognormal distribution of the CF was observed with a geometric mean and geometric standard deviation of 0.0052 mSv tracks^-1cm²and 1.28 respectively. The experimentally determined value of CF was found to be in close agreement with the theoretically estimated value, taking into consideration the unattached fraction of radon progeny. This dosimeter is passive, cheap, lightweight and, moreover, the CF being stable against environmental variations, will be useful in monitoring inhalation doses due to radon progeny for occupational workers.

PI3K Inhibitors in Cancer: Clinical Implications and Adverse Effects

The phospatidylinositol-3 kinase (PI3K) pathway is a crucial intracellular signaling pathway which is mutated or amplified in a wide variety of cancers including breast, gastric, ovarian, colorectal, prostate, glioblastoma and endometrial cancers. PI3K signaling plays an important role in cancer cell survival, angiogenesis and metastasis, making it a promising therapeutic target. There are several ongoing and completed clinical trials involving PI3K inhibitors (pan, isoform-specific and dual PI3K/mTOR) with the goal to find efficient PI3K inhibitors that could overcome resistance to current therapies. This review focuses on the current landscape of various PI3K inhibitors either as monotherapy or in combination therapies and the treatment outcomes involved in various phases of clinical trials in different cancer types. There is a discussion of the drug-related toxicities, challenges associated with these PI3K inhibitors and the adverse events leading to treatment failure. In addition, novel PI3K drugs that have potential to be translated in the clinic are highlighted.

Phosphoinositide 3-Kinase (PI3K) Reactive Oxygen Species (ROS)-Activated Prodrug in Combination with Anthracycline Impairs PI3K Signaling, Increases DNA Damage Response and Reduces Breast Cancer Cell Growth

RIDR-PI-103 is a novel reactive oxygen species (ROS)-induced drug release prodrug with a self-cyclizing moiety linked to a pan-PI3K inhibitor (PI-103). Under high ROS, PI-103 is released in a controlled manner to inhibit PI3K. The efficacy and bioavailability of RIDR-PI-103 in breast cancer remains unexplored. Cell viability of RIDR-PI-103 was assessed on breast cancer cells (MDA-MB-231, MDA-MB-361 and MDA-MB-453), non-tumorigenic MCF10A and fibroblasts. Matrigel colony formation, cell proliferation and migration assays examined the migratory properties of breast cancers upon treatment with RIDR-PI-103 and doxorubicin. Western blots determined the effect of doxorubicin ± RIDR-PI-103 on AKT activation and DNA damage response. Pharmacokinetic (PK) studies using C57BL/6J mice determined systemic exposure (plasma concentrations and overall area under the curve) and T1/2 of RIDR-PI-103. MDA-MB-453, MDA-MB-231 and MDA-MB-361 cells were sensitive to RIDR-PI-103 vs. MCF10A and normal fibroblast. Combination of doxorubicin and RIDR-PI-103 suppressed cancer cell growth and proliferation. Doxorubicin with RIDR-PI-103 inhibited p-AktS473, upregulated p-CHK1/2 and p-P53. PK studies showed that ~200 ng/mL (0.43 µM) RIDR-PI-103 is achievable in mice plasma with an initial dose of 20 mg/kg and a 10 h T1/2. (4) The prodrug RIDR-PI-103 could be a potential therapeutic for treatment of breast cancer patients.

Myths, facts and scope of spinal cord tolerance dose revision in Intensity modulated SIB treatment of locally advanced head and neck cancer: A dosimetrical and radiobiological demonstration

PURPOSE

To explore the possibility of revising the spinal cord tolerance dose in Simultaneously Integrated Boost (SIB) intensity modulated treatment plan of locally advanced head and neck (H&N) cancer and assessment of achieved planning gain due to the revision. In SIB regimen, the Organ at Risk (OARs) tolerance dose is equally distributed throughout the treatment. Clinicians have usually considered the spinal cord tolerance to be the same as in conventional technique. However, in SIB fractionation regimen with intensity modulation treatment, the spinal cord may receive a physical dose of 45Gy, with much lesser dose per fraction than 2Gy per fraction. So when the dose of spinal cord is distributed throughout the treatment, the tolerance dose limit of physical dose can be considered higher than the usual conventional dose limits. In this study, an attempt has been made to explore the possibilities of dose escalation and treatment planning benefits while exploiting this "Window of Opportunity (WoO)" of increase in spinal cord and Planning Risk Volume (PRV) spinal cord tolerance dose.

MATERIAL AND METHODS

A total of 12 patients CT data set along with approved structure set of H&N cancer used for treatment planning in. Three independent SIB VMAT plans named as SPC, SPR and SPDE were generated for the 12 patients. First plan (SPC) was generated by considering standard spinal cord tissue constraint of maximum dose of 45Gy and PRV spinal cord maximum dose 50Gy as per QUANTEC summary and second plan (SPR) was generated considering spinal cord tissue constraint of maximum dose 52.50Gy and PRV spinal cord maximum dose 56.35Gy while optimization and dose calculation. The objectives for rest of the Organ at Risk (OAR) were kept same in both the plans during optimization and dose calculation. The SPC plan was copied for creation of third plan (SPDE) in which dose was escalated by increasing dose per fraction for target volumes such that dose to spinal cord reached a maximum dose of 52.50Gy and PRV spinal cord maximum dose of 56.35Gy. In this plan there have been changes to only dose per fraction, however dose optimization and dose calculation have not been performed. Radiobiological parameters TCP and NTCP were also calculated by using indigenously developed software.

RESULTS

Considering the increase of spinal cord tolerance dose as "window of opportunity", a sufficient escalation in physical dose, Biological Effective Dose (BED) and Tumor Control Probability (TCP) was observed for all target volumes with acceptable level of NTCP values.

CONCLUSION

Sufficient dose escalation and increased in TCP for target volumes or effective planning benefits can be achieved by revising the spinal cord tolerance dose in intensity modulated SIB treatment of locally advanced H&N cancers.

Abstract 1894: Role of IGF1R in mediating resistance to MAPK pathway inhibitors in BRAF-mutant melanoma

Melanoma is the most aggressive form of skin cancer originating in the pigment producing melanocytes of the skin. The five year survival rate for patients diagnosed with metastatic melanoma is only 23%. Around 60% of the melanomas encompass the active BRAFV600E oncoprotein, which is critical for survival and proliferation of the melanoma cells as a consequence of hyperactivation of theMAPK pathway. This opened up avenues for development of BRAF inhibitors and subsequently the development of MEK inhibitors. Co-targeting of BRAF and MEK with Dabrafenib and Trametinib respectively, results in a response rate of about 70% in patients harboring the BRAF mutation. The use of these inhibitors is limited as patients relapse on treatment typically within 6 months due to the development of acquired resistance. Recent studies have identified various resistance mechanisms including involvement of various receptor tyrosine kinases. In order to decipher novel mechanisms of resistance, we generated double resistant cell lines to BRAF and MEK inhibitor in WM115, WM983 and A375 human melanoma cell lines harboring BRAFV600 mutations using Dabrafenib and Trametinib over a course of 9-11 months. The drug resistant cell lines exhibited increased viability and maintenance of downstream p-ERK protein as compared to their drug sensitive counterparts. Receptor tyrosine kinase array revealed an increase in phosphorylated HER3, AXL, EGFR and IGF1R in the drug resistant cells versus drug sensitive cells. Quantitative PCR data revealed an upregulation of these molecules along with an increase in the expression of some of their ligands at the mRNA level. RNA-seq analysis identified IGF1R and IGF2BP2 to be upregulatedin the resistant cell lines compared to parental cell lines.IGF2BP2 is a tumor promoter and drives cancer proliferation in a variety of malignancies and is correlated with poor survival.Our next experiments are focused on testing the efficacy of IGF1R inhibitors in the drug resistant cell lines and their downstream effector signaling molecules in vitro and in vivo. Further, we aim to decipher the mechanism by which IGF2BP2 regulates the IGF1R signaling pathway in MAPK inhibitors resistant melanoma setting. Delineating the role of IGF1R in mediating resistance to BRAF and MEK inhibitors will help expand possible treatment options to aid in long-term success for BRAF-mutant melanoma patients.

Citation Format: Hima Patel, Rosalin Mishra, Natasa Broit, Nour Yacoub, Long Yuan, Samar Alanazi, Nicholas Hayward, Peter Johansson, Joan T. Garrett. Role of IGF1R in mediating resistance to MAPK pathway inhibitors in BRAF-mutant melanoma [abstract]. In: Proceedings of the Annual Meeting of the American Association for Cancer Research 2020; 2020 Apr 27-28 and Jun 22-24. Philadelphia (PA): AACR; Cancer Res 2020;80(16 Suppl):Abstract nr 1894.

Abstract 4205: The role of non-muscle myosin IIA in HER2+ breast cancers

HER2 is amplified in about 20% of breast cancers. HER3 plays a critical role in HER2 mediated tumorigenesis. It is now clear that inhibition of HER2 tyrosine kinase activity results in upregulation of HER3 transcription and phosphorylation. We sought to identify HER3 binding partners upon pharmacological inhibition of HER2 using the irreversible pan HER inhibitor neratinib.

We immunoaffinity-purified HER3 from HER2+ BT474 cells treated ± neratinib. Following immunoprecipitation using a HER3 antibody, binding partners were released under reducing conditions. Mass spectrometry experiments identified non-muscle myosin IIA (NMMIIA) increased upon inhibition of HER2 with neratinib and decreased under DMSO control treatment from HER3 immunoprecipitates.

To confirm the presence of NMMIIA, we performed immunoprecipitation experiments in BT474 and MDA-MB-453 cells using a HER3 antibody. Immunoblots showed increased NMMIIA levels upon treatment with 200nM neratinib for 24 hours in both cell lines. Myosin heavy chain 9 (MYH9) gene encodes the protein nonmuscle myosin of class II, isoform A (NMMIIA). NMMIIA localizes to actin stress fibers and has been implicated in regulation of cell contractility and stress fiber organization

To further investigate the role of NMMIIA, we used blebbistatin, a myosin IIa inhibitor, in growth assays using BT474 and MDA-MB-453 breast cancer cells in vitro. The combination of blebbistatin and neratinib significantly decreased the proliferation in both cell lines compared to neratinib or blebbistatin treatment alone.

Additionally, we knocked out myosin IIa in BT474 cells using myosin IIa specific siRNA to examine the effect of myosin IIa silencing on HER3 and Myosin IIa protein levels in the presence or absence of neratinib treatment. Results indicated that in BT474 cells knockdown of NMMIIA resulted in both decreased HER3 and Myosin IIa protein expression and that neratinib treatment rescued this effect.

We next examined long term overall survival of primary breast cancer patients who have high and low levels of MYH9 gene expression from the METABRIC cohort. We observed that patients with high levels of MYH9 have a statistically significant worse overall survival versus patients who express low levels of MYH9.

Currently, further experiments are ongoing to determine the mechanism of action of the Myosin IIA/HER3 complex, which could be an adaptive response to HER2 inhibitors in HER2+ breast cancers and to evaluate the role of myosin IIa on proliferation, migration, and invasion of HER2+ breast cancer cells.

In conclusion, we have identified that neratinib treatment results in increased NMMIIA bound to HER3. Further studies to determine if NMMIIA could play a role in invasion of HER2+ breast cancer cells and/or resistance to HER2 inhibitors are ongoing.

Citation Format: Samar M. Alanazi, Rosalin Mishra, Long Yuan, Hima Patel, Joan Garrett. The role of non-muscle myosin IIA in HER2+ breast cancers [abstract]. In: Proceedings of the Annual Meeting of the American Association for Cancer Research 2020; 2020 Apr 27-28 and Jun 22-24. Philadelphia (PA): AACR; Cancer Res 2020;80(16 Suppl):Abstract nr 4205.

Case Report of an 18 Year Old Girl with Solid Pseudo-papillary Tumor of Pancreas

Solid Pseudo-papillary Tumor (SPT) of the pancreas is a rare tumor which typically affects young women without any significant clinical symptoms. Solid Pseudopapillary Tumor usually shows an indolent behavior and only rare cases recur and/or metastasize after complete resection. Here is a case report of 18 years old girl who presented to our centre with complaints of severe epigastric pain and underwent pancreatic parenchyma saving surgery for a large pancreatic head mass. In conclusion, Solid Pseudo-papillary Tumor being a large tumor possess a low malignant potential in which R0 resection has excellent prognosis.

BRAF Mutant Melanoma Adjusts to BRAF/MEK Inhibitors via Dependence on Increased Antioxidant SOD2 and Increased Reactive Oxygen Species Levels

B-Rapidly Accelerated Fibrosarcoma (BRAF) mutations are found in about 50% of melanoma patients. Treatment with Food and Drug Administration (FDA)-approved BRAF and MAP/ERK kinase (MEK) inhibitors has improved progression free and overall survival of patients with BRAF mutant melanoma. However, all responders develop resistance typically within 1 year of treatment with these inhibitors. Evidence indicates that reactive oxygen species (ROS) levels are elevated after BRAF pathway inhibition treatment. We aim to decipher the role of mitochondrial antioxidant proteins relative to ROS levels and BRAF pathway inhibitor resistance. We observed BRAF mutant melanoma cells treated with the combination of a MEK inhibitor (trametinib) and a BRAF inhibitor (dabrafenib), exhibited elevated ROS levels, both in in vitro and in vivo melanoma models. We next generated trametinib- and dabrafenib-resistant (TDR) cells and found increased ROS levels after acquisition of resistance. An immunofluorescence experiment showed an increase of DNA damage in TDR cell lines. Furthermore, we observed that TDR cells increased superoxide dismutase 2 (SOD2), an antioxidant, at both mRNA and protein levels, with the upregulation of the transcription factor Nuclear Factor (NF)-κB. Knockdown of SOD2 significantly reduced the growth of BRAF pathway inhibitor-resistant cells. In addition, the results indicate that TDR cells can be re-sensitized to BRAF pathway inhibitors by the ROS scavenger, N-Acetyl Cysteine (NAC). Overall, these data indicate that BRAF pathway inhibitor-resistant cells can compensate for elevated ROS via increased expression of the antioxidant SOD2.

ASSESSMENT OF DOSE DUE TO AMBIENT Rn222/Rn220 PROGENY IN DIFFERENT DWELLINGS OF JAMMU AND KASHMIR STATE, INDIA

The un-attached part of radon (222Rn) progeny is one of the imperative variables for the definitive evaluation of the effective dose from the radon exposure perspective, and it might fluctuate enormously in various ecological conditions. Therefore, estimate dispersion of 222Rn/220Rn progeny, un-attached part and aerosol concentration was estimated in an indoor domain of Jammu and Kashmir State, India utilizing progeny deposition based sensors. Distinctive sorts of residence were picked up for this exploratory examination and maximum 222Rn and thoron (220Rn) descendants concentration was found in working environments or workplaces when contrasted from other abodes because of low ventilation rate. The average evaluated portions of an unattached for 222Rn and 220Rn are 0.29 and 0.26 and in addition, observed to be most extreme in work environments. The age-dependent dose has furthermore been determined utilizing attached and un-attached 222Rn/220Rn progeny concentrations. The dose to trachea-bronchial region and aerosol concentrations has additionally been estimated.

T11TS immunotherapy potentiates the repressed calcineurin-NFAT signalling pathway of T cells in Cryptococcus neoformans infected rats: a cue towards T-cell activation for antifungal immunity

AIMS

To examine the modulation of the interacting partners of the calcineurin (CaN)-NFAT pathway in T cells during Cryptococcus neoformans fungal infection and post-T11TS immunotherapy.

METHODS AND RESULTS

Wistar rats were infected with C. neoformans and followed by immunotherapy with immune-potentiator T11TS. T cells were analysed by flow cytometry, immunoblotting and nuclear translocation study. The signalling proteins LCK, FYN, LAT, PLCγ1 and CaN in T cells were regulated by C. neoformans infection resulting in reduced nuclear translocation of NFAT and IL-2 expression. Following T11TS immunotherapy, the expressions of the above-mentioned proteins were boosted and thus resulting in the clearance of C. neoformans from lung and spleen.

CONCLUSIONS

The precise mechanism of suppression of the T-cell function by C. neoformans is still unknown. Previously, we have shown that T11TS positively regulates the function of T cells to abrogate glioma and other immunosuppressive conditions. T11TS immunotherapy increased the expression of the above signalling partners of the CaN-NFAT pathway in T cells and improved nuclear retention of NFAT. As a result, an increased IL-2 expression leads to activation and proliferation of T cells.

SIGNIFICANCE AND IMPACT OF THE STUDY

Our results demonstrate the role of T11TS in restoring the CaN-NFAT signalling pathway in T cells. It identifies T11TS as an immunotherapeutic agent with potential clinical outcomes to counteract C. neoformans infection.

Abstract P3-10-04: Efficacy of RIDRPI103, a reactive oxygen species (ROS) activated prodrug in treatment of breast cancer

The Phosphatidylinositol-3 kinases (PI3Ks) is a family of lipid kinases encoded by PIK3C isoform genes. PI3K phosphorylates phosphatidylinositol 4,5-bisphosphate (PIP2) to phosphatidylinositol 3,4,5-triphosphate (PIP3), leading to AKT phosphorylation along with other proteins containing a PH domain. Phosphorylation of AKT stimulates protein synthesis and cancer cell growth. PI3K pathway is hyper-activated in &gt;60% of clinical breast cancer patients due to aberrations in the genes encoding HER2, PTEN, PIK3CA, or AKT1-3 leading to de novo and acquired treatment resistance. There has been intense interest in developing drugs that target PI3K. However, drugs targeting PI3K activity are toxic, due to the physiological roles of PI3Ks in basic cellular processes.

We have developed a novel technology, called RIDR (ROS-Induced Drug Release) which is a self-cyclizing reagent linked to a PI3K inhibitor (PI-103) to eject PI-103 in a controlled manner under oxidative stress in highly aggressive breast cancers including triple negative breast cancer cell lines (TNBCs) and other ER+, HER2+ breast cancer cell lines with activating PIK3CA mutations. We evaluated the efficacy of RIDR-PI-103 (5-100 µM) or PI-103 (0-5 µM) in normal fibroblasts, T47D, MCF-7, MDA-MB-361, BT474, MDA-MB-453 and MDA-MB-231 breast cancer cell lines. We noted that IC50 of PI-103 is 3.34 µM whereas IC50 of RIDR-PI-103 is &gt;100 µM in normal fibroblasts, indicating the toxicity of the PI-103 alone but not the RIDR-PI-103 in normal fibroblasts. Our data indicated that ~30-40 µM RIDR-PI-103 significantly inhibited T47D, MDA-MB-231, MDA-MB-361 and MDA-MB-453 cell proliferation whereas higher concentrations of the drug were effective in BT474 and MCF-7 breast cancer cell lines. Our quantitative PCR data showed that the antioxidant catalase mRNA levels are statistically lower compared to normal fibroblasts in these cancer cell lines indicating that the efficacy of RIDR-PI-103 could be correlated to catalase expression. Doxorubicin is a clinically relevant chemotherapy known to induce reactive oxygen species (ROS) in breast cancer cell lines. We are currently assessing the levels of biomarkers for ROS in formalin-fixed paraffin embedded breast tumors treated without or with chemotherapy including 8-hydroxy-2'-deoxyguanosine (8-oxo-dG) and 4-hydroxy-2-noneal (4HNE). Our data indicated that doxorubicin significantly sensitized MDA-MB-453, MDA-MB-361 and MDA-MB-231 cells to RIDR-PI-103 indicated by significant lower IC50 values of the combined drug treatment versus the single agent. Doxorubicin and RIDR-PI-103 showed a synergistic effect in MDA-MB-361 and MDA-MB-231 cells to inhibit cancer cell proliferation. Doxorubicin was more effective than docetaxel, another chemotherapeutic drug, in sensitizing these cells to growth inhibition. Thus, this novel combination of the ROS-activatable PI3K inhibitor prodrug and chemotherapy provides strong justification for its continued development and future clinical trials for patients stricken with PI3K driven tumors.

In other experiments, we show that a recent FDA-approved CDK4/6 inhibitor, palbociclib, sensitized ER+ breast cancer cell lines (T47D and MDA-MB-361) to RIDR-PI103 using cell viability assays. Experiments are ongoing to determine the mechanism of action of these novel drug combinations that could be potentially translated to clinic for treatment of breast cancer patients.

Citation Format: Rosalin Mishra, Hima Patel, Haizhou Zhu, Aaron White, Long Yuan, Samar Alanazi, Kurt Hodges, Edward J Merino, Joan T Garrett. Efficacy of RIDRPI103, a reactive oxygen species (ROS) activated prodrug in treatment of breast cancer [abstract]. In: Proceedings of the 2019 San Antonio Breast Cancer Symposium; 2019 Dec 10-14; San Antonio, TX. Philadelphia (PA): AACR; Cancer Res 2020;80(4 Suppl):Abstract nr P3-10-04.

ASSESSMENT OF ANNUAL EFFECTIVE DOSE FROM EXPOSURE TO NATURAL RADIOACTIVITY SOURCES IN A CASE-CONTROL STUDY IN BIHOR COUNTY, ROMANIA

The purpose of the article is to evaluate the annual effective dose for 80 women divided into two samples; one sample located in the former uranium Băiţa-Ştei area, hereinafter referred to as case sample, respectively for a control sample, located in the same county, but exposed in most cases to indoor radon activity concentrations <300 Bq m-3. In this regard, the homemade 'RaThoGamma' kit was used, which contained two thermoluminescent dosimeters, a CR-39 track detector (RSKS) for indoor radon activity concentration, two CR-39 track detectors (Radtrak2®/ Radtrak2T®) for radon and thoron activity concentrations as well as Direct Radon Progeny Sensors/Direct Thoron Progeny Sensors for measuring time-averaged radon and thoron progenies concentrations. In addition, a total of 80 water samples were collected in order to evaluate the ingestion dose due to radon and radium activity concentrations in drinking water. The maximum total annual effective dose in the control sample was 14.1 mSv, while in the case sample the maximum annual effective dose was 60.5 mSv. This difference is mainly due to radon progenies inhalation. Other pathways did not show a statistically significant difference between the two samples, showing a minor contribution to the annual effective dose.

Oxidative Cyclization-Induced Activation of a Phosphoinositide 3-Kinase Inhibitor for Enhanced Selectivity of Cancer Chemotherapeutics

In this work, we designed a prodrug that reacts with cellular oxidative equivalents leading to ether cleavage and cyclization to release an active phosphatidylinositol 3-kinase (PI3K) inhibitor. We show that the compound reduces affinity for PI3KA relative to the PI3K inhibitor, is slow to intercellularly oxidize, and is resistant to liver microsomes. We observed modest activity in untreated acute myeloid leukemia cells and 14-fold selectivity relative to non-cancerous cells. The cellular activity of the compound can be modulated by the addition of antioxidants or oxidants, indicating the compound activity is sensitive to cellular reactive oxygen species (ROS) state. Co-treatment with cytosine arabinoside or doxorubicin was used to activate the compound inside cells. We observed strong synergistic activity specifically in acute myeloid leukemia (AML) cancer cells with an increase in selective anticancer activity of up to 90-fold. Thus, these new self-cyclizing compounds can be used to increase the selectivity of anticancer agents.

Abstract 1284: Resistance to BRAF and MEK inhibitors in BRAFV600E mutant melanoma

Melanoma five year survival rates are only 15% for patients with advanced disease. About 50% of melanomas contain the BRAFT1799A transversion which encodes for the constitutively active BRAFV600E oncoprotein. This opened up avenues for development of BRAF inhibitors which resulted in a response rate of about 50% and median progression-free survival of about 5 months. Co-targeting the downstream MEK protein with a MEK inhibitor along with BRAF inhibitor resulted in response rates of about 70% and are now approved as standard of care for patients harboring the BRAF-mutant melanoma. In spite of these successes, their long-term efficacy has been limited due to acquired resistance to these inhibitors. In order to study mechanisms underlying resistance, we generated dabrafenib (BRAF inhibitor) and trametinib (MEK inhibitor) resistant WM115 (WM115 TDR) and WM983 (WM983 TDR) cell lines by adding increasing concentration of the drugs to WM115 and WM983 cells with BRAFV600E mutation (parental cells). We observed that the resistant cells undergo a change in their morphology and continue to remain viable over increasing doses of dabrafenib and trametinib as compared to parental cells demonstrated by MTT cell proliferation assay and Matrigel 3D assay. TDR cells demonstrated maintenance of p-ERK levels at 4 and 24 hours which under the same conditions p-ERK was inhibited in the parental cells. Current studies underway include RNA sequencing in order to decipher differentially expressed genes in the parental and TDR which could mediate resistance to BRAF and MEK inhibitors. Additionally we will examine phosphorylated receptor tyorsine kinases (RTKs) using an array to identify divergences among activation of RTKs in parental versus TDR cells. Deciphering causes of resistance to BRAF and MEK inhibitors will help in the development of novel mechanism-based interventions aiding long-term patient prospects in BRAF-mutant melanoma.

Citation Format: Hima Patel, Rosalin Mishra, Garrett Joan. Resistance to BRAF and MEK inhibitors in BRAFV600E mutant melanoma [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2019; 2019 Mar 29-Apr 3; Atlanta, GA. Philadelphia (PA): AACR; Cancer Res 2019;79(13 Suppl):Abstract nr 1284.

Abstract 389: Role of her3 signaling pathways in er+ and her2+ breast cancers

HER3 is an important molecule that may regulate oncogenic activity in estrogen receptor (ER)+ breast cancers, which accounts for about 70-80% of all breast cancers. HER3 gene expression is highest in ER+ or luminal tumors. Treatment with the ER degrader fulvestrant induces protein expression of HER3 in ER+ clinical breast tumors, suggesting that HER3 may have therapeutic value in luminal breast cancers. About 20% of all breast cancers diagnosed are HER2 positive (+). HER3 is as essential as HER2 for maintaining cell viability in HER2-overexpressing breast cancer cells. We aim to identify proteins that bind to HER3 upon therapeutic inhibition of HER2 or anti-endocrine therapy.

We have found that ERα is upregulated in ER+ T47D and MCF-7 breast cancer cell lines expressing the activating hotspot T355I HER3 mutation compared to HER3 wild-type (WT) cells. We noted that ERα co-immunoprecipitated to HER3-T355I but not to HER3-WT T47D cells. Knocking down HER3 resulted in decreased ERα expression in both HER3-WT and HER3-T355I expressing T47D cells. We are currently analyzing the nuclear expression of endogenous HER3 in MCF-7, T47D, BT474, MDA-MB-361, MDA-MB-453 and SK-BR3 breast cancer cells. We are determining if stimulation with the HER3 ligand heregulin alters the subcellular location of HER3 or the ability to co-immunoprecipitate with ERα in cells expressing exogenous HER3-WT, exogenous HER3-T355I or endogenous HER3.

We are using a proteomics approach to identify HER3-interacting proteins to determine how HER2 inhibition affects the repertoire of HER3 binding partners in HER2+ breast cancer cells. We immunopurified HER3 from BT474 cells treated with DMSO or with neratinib (24 hour treatment). We then identified enrichment of specific proteins by mass spectrometry. MALDI tandem mass spectrometry experiments identified non-muscle myosin-II heavy chain from HER3 immunoprecipitates treated 24 hours with neratinib treatment but not 24 hours of DMSO treatment in BT474 cells. Furthermore, our immunoprecipitation data indicated that there is more myosin-IIa bound to HER3 in response to neratinib treatment. Myosin-IIa has a key role in cytokinesis, cell migration, polarization, adhesion and metastasis. Thus, we aim to decipher the mechanism of action by which myosin-IIa interacts with HER3 and determining if downstream myosin/actin signaling could be a possible target in HER2 over-expressing breast cancer patients who show resistance to HER2 targeted therapy.

In conclusion, we have identified two potential novel HER3 binding partners in breast cancer: ERα and myosin-IIa. Deciphering the function of HER3 binding partners has potential implication for understanding the invasive properties of ER+ and HER2+ breast cancers.

Citation Format: Rosalin Mishra, Samar Alanazi, Hima Patel, Long Yuan, Joan T. Garrett. Role of her3 signaling pathways in er+ and her2+ breast cancers [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2019; 2019 Mar 29-Apr 3; Atlanta, GA. Philadelphia (PA): AACR; Cancer Res 2019;79(13 Suppl):Abstract nr 389.

Utilization of Reactive Oxygen Species Targeted Therapy to Prolong the Efficacy of BRAF Inhibitors in Melanoma

BRAF mutations occur in about 50% of melanoma patients. FDA approved BRAF and MEK inhibitors have improved the prognosis of patients with BRAF mutations. However, all responders develop resistance typically within one year of treatment. Recent observations demonstrate that BRAF inhibitors induce reactive oxygen species (ROS) in melanoma cells. A100, identified from a library screen, is a ROS-activated prodrug that self-cyclizes into a stable bicyclic ring and causes DNA double strand breaks. We proposed to examine if ROS activated therapy will inhibit tumor growth and evade resistance to BRAF inhibitors. In this study, the BRAF inhibitor dabrafenib was used to generate resistant cell lines (A375DR, SK-MEL-24DR and WM-115DR). Flow cytometry experiments showed that ROS levels are increased in these dabrafenib-resistant cells as compared to parental cells, assessed by both the H2DCFDA and MitoSOX assays. Furthermore, we observed that resistant cells had increased levels of the mitochondrial enzymes SOD2 and PRDX1, which function to reduce ROS levels in the mitochondria. We found that A100 sensitized the resistant melanoma cells to dabrafenib and induced DNA damage. Co-treatment of both A100 and dabrafenib significantly suppressed in vitro cell proliferation and three- dimensional (3D) matrigel growth. This study suggests that the combination of A100 with a BRAF inhibitor could be a potential strategy to treat melanoma patients with BRAF mutations.

Abstract B44: Role of EGFR/ERBB4 and MAPK signaling in modulating oncogenic potential of ER+ breast cancer cells overexpressing HER3 mutant

We sought to determine if patient-identified mutations in HER3 enhance ER-mediated transformation in human mammary epithelial cells (MCF-7 and T47D). Furthermore, we examined if HER3 mutations confer resistance to ER-specific inhibitors (fulvestrant and 4-hydroxytamoxifen) in ER+ breast cancer cells. A series of HER3 mutations identified in patient breast tumors (F94L, G284R, D297Y, D313H, K329T, T355I, L792V, and E1261A) were introduced and stable cell lines were generated in ER+ T47D and MCF-7 cells using lentiviral transduction. We identified the HER3 T355I mutant that had significantly higher cell proliferation than wild-type (wt) HER3 in ER+ MCF-7 and T47-D cells using several cell-based assays. We sought to determine whether this oncogenic T355I mutant renders resistance to antiestrogen therapy. These mutations counteracted the effect of the ER inhibitor 4-hydroxytamoxifen but not fulvestrant, indicating a possible role in antiestrogen therapy. ER+ cells overexpressing T355I have increased p-HER3 and p-ERK1/2 expression compared to wt or empty vector (ev) control. However, there was no major change in Akt signaling in HER3 T355I mutant as compared to control. Phospho-RTK array results indicate that ER+ T47D T355I whole-cell lysate had increased p-ERBB4 and ER+ MCF-7 T355I cells had enhanced p-EGFR expression, suggesting possible downstream activation of MAPK signaling via two distinct activation routes in ER+ T47D and MCF-7 cells. ER+ MCF-7 and T47D cells overexpressing T355I HER3 mutant were subjected to the ERBB family inhibitor lapatinib in presence or absence of ER inhibitor fulvestrant and specific ERK1/2 inhibitor, SCH772984. The data indicated that combined treatment of lapatinib and fulvestrant had reduced cell proliferation as compared to individual treatment groups both in ER+ cells overexpressing wt and HER3 T355I mutant. We also observed a significant reduction in cell proliferation when these cells were subjected to co-treatment of lapatinib and SCH772984 as compared to individual treatments. These data indicate that induced transforming activity observed in HER3 T355I mutant is via ERBB4/MAPK pathway in T47D cells and EGFR/MAPK in MCF-7 cells. Similar results were obtained in 3D-Matrigel assay under above treatment conditions. The Western blot data indicated that Cyclin D1 and p-ERK1/2 expression is altered in response to combined treatment of lapatinib with or without fulvestrant and SCH772984 in ER+ T47D and MCF-7 cells, indicating that Cyclin D1 mediates signaling downstream of the MAPK pathway. However, Akt signaling is not affected when cells were treated with EGFR family and ERK1/2 inhibitors or combination of both. We also observed ERα expression is upregulated in ER+ T47D and MCF-7 cells overexpressing HER3 mutant. Experiments are ongoing to determine possible crosstalk between HER3 and ER signaling in ER+ cells overexpressing HER3 mutant. Additionally, we tested the effect of knocking down HER3 in cell lines harboring endogenous HER3 mutations. Overall, this study provides the first systematic assessment of how mutations in HER3 affect response of ER+ breast cancers to clinically relevant inhibitors.

Citation Format: Rosalin Mishra, Long Yuan, Thomas Solomon, Samar Alanazi, Joan T. Garrett. Role of EGFR/ERBB4 and MAPK signaling in modulating oncogenic potential of ER+ breast cancer cells overexpressing HER3 mutant [abstract]. In: Proceedings of the AACR Special Conference: Advances in Breast Cancer Research; 2017 Oct 7-10; Hollywood, CA. Philadelphia (PA): AACR; Mol Cancer Res 2018;16(8_Suppl):Abstract nr B44.

Abstract 1896: Patient-derived HER3 mutations transform ER+ and HER2+ breast cancer cells via MAPK pathway activation

We sought to investigate the role of patient-derived HER3 mutations in HER2+ and ER+ breast cancer cells using ectopic expression of HER3 mutants. We aim to identify mechanism(s) by which HER3 mutants enhanced HER2-mediated or hormone-driven transformation and if HER3 mutations confer resistance to HER2 or ER+ inhibitors.

A series of HER3 mutations (F94L, G284R, D297Y, D313H, K329T, T355I, L792V and E1261A) were introduced and stable cell lines were generated in MCF10AHER2 and ER+ MCF-7 and T47D cells using lentiviral transduction. HER3T355I mutant was transforming in ER+ cells. HER3T355I mutant had increased p-HER3 and p-ERK1/2 expression compared to controls expressing wild-type HER3. Receptor tyrosine kinase array results indicated that T47D and MCF-7 overexpressing HER3T355I had increased p-HER4 and p-HER1 expression, respectively. HER3T355I counteracted the effect of the ER inhibitor, 4-hydroxytamoxifen but not fulvestrant. Cells expressing HER3T355I were subjected to lapatinib in presence or absence of ER inhibitor fulvestrant and specific ERK1/2 inhibitor, SCH772984. The data indicated that induced transforming activity observed in HER3T355I is via HER4/MAPK pathway in T47D and HER1/MAPK signaling in MCF-7 cells. Immunoblotting data indicated that cyclin D1 and p-ERK1/2 expressions were altered in response to combined treatment of lapatinib with or without fulvestrant and SCH772984 indicating that cyclinD1 mediated signaling downstream of the MAPK pathway. HER3T355I and HER3WT demonstrated reduced cell proliferation and matrigel colony formation in presence of lapatinib and fulvestrant/SCH772984. We noted crosstalk between ERα and HER3 in T47D cells. Based on structural modelling, T355I likely disrupted the interactions between domain III and the hinge region pocket that stabilized the tethered conformation of HER3T355I, potentially making the hinge more flexible, shifting the equilibrium from the tethered to the untethered state.

Laboratory studies indicated that several HER3 mutants acquired gain-of-function phenotype and were resistant to lapatinib and partially resistant to neratinib in MCF10AHER2 cells. These mutants increased HER2-HER3 hetero-dimerization. However, there was no significant alteration in AKT signalling in HER3 mutants.

We are currently using a proteomics approach to identify HER3-interacting proteins, and determine how HER2 inhibition affects the repertoire of HER3 binding partners in HER2+ breast cancers. We will also mine for HER3 binding partners in ER+ breast cancers by using ReCLIP, a

methodology in which reversible cross-linking precedes HER3 immunoprecipitation and mass spectrometry-based identification of HER3-interacting proteins.

We aim to identify kinases (other than HER2) that phosphorylate HER3 upon therapeutic inhibition of HER2 and PI3K or anti-endocrine therapy.

Citation Format: Rosalin Mishra, Samar Alanazi, Long Yuan, Thomas Solomon, Tarjani M. Thaker, Natalia Jura, Joan T. Garrett. Patient-derived HER3 mutations transform ER+ and HER2+ breast cancer cells via MAPK pathway activation [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2018; 2018 Apr 14-18; Chicago, IL. Philadelphia (PA): AACR; Cancer Res 2018;78(13 Suppl):Abstract nr 1896.

Abstract 4900: Reactive oxygen species scavenger extends the efficacy of BRAF inhibitors in BRAF-mutant melanoma

We aim to identify whether reactive oxygen species (ROS) targeted therapy using a ROS scavenger, A100, will inhibit tumor growth and evade BRAF inhibitor induced resistance in melanoma cells harboring the endogenous BRAFV600E mutation. We also propose to investigate the mechanism by which A100 sensitizes the dabrafenib-mediated resistance. Dabrafenib-resistant (DR) melanoma cells (WM-115DR, SK-MEL-24DR and A375DR) were generated using increasing doses of dabrafenib. We conducted flow cytometry experiments to measure ROS levels before and after acquisition of resistance. DCF-DA assay indicated upregulation of hydrogen peroxide levels in dabrafenib resistant cell lines versus parental cell lines. Furthermore, dabrafenib resistant cell lines demonstrated elevated superoxide levels as analyzed by MitoSOX. Crystal violet and three-dimensional matrigel assays were performed to analyze the effect of A100 and dabrafenib on cell growth of dabrafenib resistant and parental melanoma cell lines. We observed a statistically significant decrease in cell proliferation and colony formation of dabrafenib resistant cells when subjected to the combination of A100 and dabrafenib compared to single agent dabrafenib or A100. We also noted a trend of inhibition of cell proliferation in response to combined treatment of A100 and dabrafenib in parental cell lines versus the single agent. There was significant reduction in colony formation under similar condition in parental cells. Dabrafenib as a single agent had similar effect in reducing phosphorylated ERK1/2 as compared to co-treatment with A100 in A375, SK-MEL-24 and WM-115 parental cells. As expected, there was no alteration of MAPK signaling in resistant WM-115DR, SK-MEL-24DR and A375DR cells upon treatment with dabrafenib. A100 has been reported to cause DNA damage in leukemia cells. We analyzed the effect of A100 in the presence or absence of dabrafenib on markers of DNA damage. The data suggested that DNA damage is induced by A100 as assessed by increased levels of p-ATM, p-ATR and γ-H2AX. Further, A100 in combination with dabrafenib increased levels of p-ATM, p-ATR and γ-H2AX in parental and dabrafenib resistant cell lines. Proteomics analysis on WM-115 versus WM-115DR cell line was performed to determine alterations in mitochondrial protein expression upon resistance to BRAF inhibitors. The data indicated upregulation of proteins with antioxidant functions including SOD2 (superoxide dismutase [Mn]) and Peroxiredoxin-1 (PRDX1) in WM-115DR cells compared to WM-115 parental which was confirmed by immunoblotting analysis. Overall, this study suggested that the combination of ROS quenching agent (A100) with BRAF inhibitor (dabrafenib) could be a potential strategy to treat BRAF-mutant melanoma patients.

Citation Format: Long Yuan, Rosalin Mishra, Hima Patel, Samar Alanazi, Joan Garrett. Reactive oxygen species scavenger extends the efficacy of BRAF inhibitors in BRAF-mutant melanoma [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2018; 2018 Apr 14-18; Chicago, IL. Philadelphia (PA): AACR; Cancer Res 2018;78(13 Suppl):Abstract nr 4900.

Activating HER3 mutations in breast cancer

Recent studies have highlighted a role of HER3 in ER and HER2-driven breast cancers. We sought to investigate the role of patient-derived HER3 mutations in ER+ and HER2+ breast cancer cells using ectopic expression of HER3 mutants. We found that HER3T355I mutant is activating with increased cell proliferation in ER+ T47D and MCF-7 breast cancer cells lacking HER2 over-expression. Immunoblotting and receptor tyrosine kinase array results indicated that T47D and MCF-7 cells expressing HER3T355I had increased p-HER4 and p-HER1 expression. Our data showed that HER3T355I induced cell proliferation is via HER4/HER1-dependent ERK1/2 and cyclinD1 mediated pathways in ER+ cells. ERα expression is upregulated in ER+ cells expressing HER3T355I mutant. We noted crosstalk between ERα and HER3 in T47D cells. Several HER3 mutants (F94L, G284R, D297Y, T355I, and E1261A) acquired a gain-of-function phenotype in MCF10AHER2 cells and were resistant to lapatinib. These mutants increased HER2-HER3 heterodimerization. Knocking down HER3 from ovarian and colorectal cancers with endogenous HER3 mutations abrogated cancer cell proliferation. Overall, this study provides the first systematic assessment of how mutations in HER3 affect response of ER+ and HER2+ breast cancers to clinically relevant inhibitors and finds that HER3 mutations can be activating independent of HER2 over-expression.

HER3 signaling and targeted therapy in cancer

ERBB family members including epidermal growth factor receptor (EGFR) also known as HER1, ERBB2/HER2/Neu, ERBB3/HER3 and ERBB4/HER4 are aberrantly activated in multiple cancers and hence serve as drug targets and biomarkers in modern precision therapy. The therapeutic potential of HER3 has long been underappreciated, due to impaired kinase activity and relatively low expression in tumors. However, HER3 has received attention in recent years as it is a crucial heterodimeric partner for other EGFR family members and has the potential to regulate EGFR/HER2-mediated resistance. Upregulation of HER3 is associated with several malignancies where it fosters tumor progression via interaction with different receptor tyrosine kinases (RTKs). Studies also implicate HER3 contributing significantly to treatment failure, mostly through the activation of PI3K/AKT, MAPK/ERK and JAK/STAT pathways. Moreover, activating mutations in HER3 have highlighted the role of HER3 as a direct therapeutic target. Therapeutic targeting of HER3 includes abrogating its dimerization partners’ kinase activity using small molecule inhibitors (lapatinib, erlotinib, gefitinib, afatinib, neratinib) or direct targeting of its extracellular domain. In this review, we focus on HER3-mediated signaling, its role in drug resistance and discuss the latest advances to overcome resistance by targeting HER3 using mono- and bispecific antibodies and small molecule inhibitors.

Partial trisomy 16q21➔qter due to an unbalanced segregation of a maternally inherited balanced translocation 46,XX,t(15;16)(p13;q21): a case report and review of literature

Background

Partial trisomy is often the result of an unbalanced segregation of a parental balanced translocation. Partial trisomy16q is characterized by a common, yet non-specific group of craniofacial dysmorphic features, and systemic malformations with limited post-natal survival. Most of the cases of partial trisomy 16q described in the scientific literature have reported only one, or less frequently two cardiac defects in the affected babies. Herein, we report a case of partial trisomy 16q21➔qter with multiple and complex cardiac defects that have not previously been reported in association with this condition.

Case presentation

We report the phenotypic and cytogenetic features of a Sri Lankan female infant with partial trisomy 16q21➔qter. The baby had a triangular face with downslanting eyes, low set ears and a cleft palate. Systemic abnormalities included multiple cardiac defects, namely double outlet right ventricle, ostium secundum atrial septal defect, mild pulmonary stenosis, small patent ductus arteriosus, and bilateral superior vena cavae. An anteriorly placed anus was also observed. The proband was trisomic for 16q21➔qter chromosomal region with a karyotype, 46,XX,der(15)t(15;16)(p13;q21)mat. The chromosomal anomaly was the result of an unbalanced segregation of a maternal balanced translocation; 46,XX,t(15;16)(p13;q21). Partial trisomy 16q was established by fluorescence in-situ hybridization analysis.

Conclusions

The craniofacial dysmorphic features and the presence of cardiac and anorectal malformation in the proband are consistent with the phenotypic spectrum of partial trisomy 16q reported in the scientific literature. More proximal breakpoints in chromosome 16q are known to be associated with multiple cardiac abnormalities and poor long-term survival of affected cases. This report presents a unique case with multiple, complex cardiac defects that have not previously been described in association with a distal breakpoint in 16q. These findings have important diagnostic and prognostic implications.

Effect of chitosan and acetic acid on the shelf life of sea bass fillets stored at refrigerated temperature

Considering the necessity on the use of chitosan and acetic acid as an antimicrobial and antioxidant agents, an attempt was made to study their effect on Asian sea bass fillets stored at refrigerated temperature of 4±1°C. The effectiveness of different antimicrobials (Chitosan and Acetic acid) were measured by disk diffusion method against five bacterial strains (E. coli, Vibrio parahaemolyticus, Staphylococcus aureus, Proteus mirabilis and Pseudomonas fragi) with 1% Acetic acid as (T1), 1% Acetic acid + 1% Chitosan as (T2), 1% Acetic acid + 2% Chi-tosan as (T3) and distilled water as control (C).T2 was more effective in inhibiting all the bacteria except Pseudomo-nas fragi. Treatment T1 was found to be more effective against it whereas the action of T3 on the bacterial strains was also effective but less than the other two treatments. Further, antioxidant property of the treatments were measured by DPPH method which indicated that T3 showed highest % of antioxidative activity (3.94%) followed by T1 (3.85%), T2 (2.62%), and C (1.788%).Thus, it is observed that the antioxidant activity was found to be increased with the increasing concentration of chitosan. Application of chitosan and acetic acid coatings on Asian sea bass ( Lates calcarifer) fillets successfully controlled the TVB-N values, PV and TBA values (p<0.05) when compared to control sample and among all the treatments T2 was found to be the best. Coating of chitosan and acetic acid on the fillets also resulted in improvement of sensory scores as well as acceptability under refrigerated condition.

Genomic alterations of ERBB receptors in cancer: clinical implications

The ERBB family of receptor tyrosine kinases has been implicated in carcinogenesis for over three decades with rigorous attention to EGFR and HER2. ERBB receptors, consisting of EGFR, HER2, HER3, and HER4 are part of a complicated signaling network that activates downstream signaling pathways including PI3K/AKT, Ras/Raf/MAPK, JAK/STAT and PKC. It is well established that EGFR is amplified and/or mutated in gliomas and non-small-cell lung carcinoma while HER2 is amplified and/or over-expressed in breast, gastric, ovarian, non-small cell lung carcinoma, and several other tumor types. With the advent of next generation sequencing and large scale efforts to explore the entire spectrum of genomic alterations involved in human cancer progression, it is now appreciated that somatic ERBB receptor mutations occur at relatively low frequencies across multiple tumor types. Some of these mutations may represent oncogenic driver events; clinical studies are underway to determine whether tumors harboring these alterations respond to small molecule EGFR/HER2 inhibitors. Recent evidence suggests that some somatic ERBB receptor mutations render resistance to FDA-approved EGFR and HER2 inhibitors. In this review, we focus on the landscape of genomic alterations of EGFR, HER2, HER3 and HER4 in cancer and the clinical implications for patients harboring these alterations.

INDOOR RADON, THORON AND THEIR PROGENY CONCENTRATIONS IN HIGH THORON RURAL SERBIA ENVIRONMENTS

This article deals with the variation of radon (Rn), thoron (Tn) and their progeny concentrations expressed in terms of equilibrium equivalent concentrations (EERC and EETC), in 40 houses, in four villages of Sokobanja municipality, Southern Serbia. Two types of passive detectors were used: (1) discriminative radon-thoron detector for simultaneous Rn and Tn gases measurements and (2) direct Tn and Rn progeny sensors (DRPS/DTPS) for measuring Rn and Tn progeny concentrations. Detectors were exposed simultaneously for a single period of 12 months. Variations of Tn and EETC appear higher than those of Rn and EERC. Analysis of the spatial variation of the measured concentrations is also reported. This work is part of a wider survey of Rn, Tn and their progeny concentrations in indoor environments throughout the Balkan region started in 2011 year.