Grb7 knockout mice develop normally but litters born to knockout females fail to thrive.

Background: Growth factor receptor-bound 7 (Grb7) is an adaptor protein involved in signal transduction downstream of multiple receptor tyrosine kinases, including ERBB, FGFR, and PDGFR pathways. Experimental studies have implicated Grb7 in regulating cell proliferation, survival, migration, and invasion through its large repertoire of protein-protein interactions.

Results: Here, we describe the generation and characterization of a Grb7 knockout mouse.

Pan-cancer distribution of cleaved cell-surface amphiregulin, the target of the GMF-1A3 antibody drug conjugate.

Amphiregulin is a transmembrane protein which, when cleaved by the TACE/ADAM17 protease, releases a soluble epidermal growth factor receptor ligand domain that promotes proliferation of normal and malignant cells. We previously described a rabbit monoclonal antibody, GMF-1A3, that selectively recognizes the cell-associated cleaved amphiregulin epitope. Antibody-drug conjugates had anti-tumor activity against human breast cancer xenografts.

Optimized infection control practices augment the robust protective effect of vaccination for ESRD patients during a hemodialysis facility SARS-CoV-2 outbreak.

Background: While dialysis patients are at greater risk of serious SARS-CoV-2 complications, stringent infection prevention measures can help mitigate infection and transmission risks within dialysis facilities. We describe an outbreak of 14 cases diagnosed in a hospital-based outpatient ESRD facility over 13 days in the second quarter of 2021, and our coordinated use of epidemiology, viral genome sequencing, and infection control practices to quickly end the transmission cycle.

Methods: Symptomatic patients and staff members were diagnosed by RT-PCR.

Emergence and onward transmission of a SARS-CoV-2 E484K variant among household contacts of a bamlanivimab-treated patient.

The implementation of monoclonal antibody therapeutics during the COVID-19 pandemic altered the selective pressures encountered by SARS-CoV-2, raising the possibility of selection for resistant variants. Within-host viral evolution was reported in treated immunocompromised individuals but whether this signifies a real risk of onward transmission is unclear. We used a regional SARS-CoV-2 sequencing program to monitor lineages with clinically relevant variants in identified patients, which facilitated analysis of parameters potentially relevant to new variant emergence.

Anti-tumor efficacy of an MMAE-conjugated antibody targeting cell surface TACE/ADAM17-cleaved Amphiregulin in breast cancer.

Background: The Epidermal Growth Factor Receptor (EGFR) ligand, Amphiregulin (AREG), is a key proliferative effector of estrogen receptor signaling in breast cancer and also plays a role in other malignancies. AREG is a single-pass transmembrane protein proteolytically processed by TACE/ADAM17 to release the soluble EGFR ligand, leaving a residual transmembrane stalk that is subsequently internalized.

Methods: Using phage display, we identified antibodies that selectively recognize the residual transmembrane stalk of cleaved AREG.

Outbreak or pseudo-outbreak? Integrating SARS-CoV-2 sequencing to validate infection control practices in a dialysis facility.

Background: The COVID-19 pandemic poses a particularly high risk for End Stage Renal Disease (ESRD) patients so rapid identification of case clusters in ESRD facilities is essential. Nevertheless, with high community prevalence, a series of ESRD patients may test positive contemporaneously for reasons unrelated to their shared ESRD facility. Here we describe a series of 5 cases detected within 11 days in November 2020 in a hospital-based 32-station ESRD facility in Southwest Wisconsin, the subsequent facility-wide testing, and the use of genetic sequence analysis to evaluate links between cases.

Acquisition of Cabozantinib-Sensitive MET D1228N Mutation During Progression on Crizotinib in MET-Amplified Triple-Negative Breast Cancer.

Background: Targeting of somatic MET mutations using crizotinib has led to strong clinical responses, most frequently in patients with lung cancer, raising the possibility of adopting similar treatment strategies in patients with MET alterations in other cancer types.

Patient And Methods: We describe a patient with advanced triple-negative breast cancer with a 30-fold amplification of MET. Next-generation sequencing of pre- and postprogression biopsies was performed to identify the resistance mechanism emerging after an initial exceptional response to crizotinib.

Amphiregulin deletion strongly attenuates the development of estrogen receptor-positive tumors in p53 mutant mice.

Purpose: The epidermal growth factor receptor ligand, Amphiregulin, is a transcriptional target of estrogen receptor alpha and is required for pubertal mammary gland development. Previous studies using immortalized human breast cancer cell line xenografts have suggested that Amphiregulin may be an important effector of estrogen receptor alpha during breast cancer development, at least in immune-compromised animals. Here, we evaluate the requirement for Amphiregulin in an immune-competent mouse model which is prone to developing estrogen receptor-positive tumors.

InferAMP, a python web app for copy number inference from discrete gene-level amplification signals noted in clinical tumor profiling reports.

As somatic next-generation sequencing gene panel analysis in advanced cancer patients is becoming more routine, oncologists are frequently presented with reports containing lists of genes with increased copy number. Distinguishing which of these amplified genes, if any, might be driving tumor growth and might thus be worth considering targeting can be challenging. One particular issue is the frequent absence of genomic contextual information in clinical reports, making it very challenging to determine which reported genes might be co-amplified and how large any such amplicons might be.

Sequential treatment failures in response to BRAF/MEK and immune checkpoint inhibitors mediated by MAP2K2 and B2M mutations in melanoma.

Although the treatment of metastatic melanoma has been significantly improved by both anti-BRAF/MEK and checkpoint immunotherapies, resistance to these treatment modalities remains a substantial clinical problem. Multiple clinical studies are addressing the optimal sequencing of these agents in larger patient cohorts, but successful long-term individualized treatment will likely require the elucidation of resistance mechanisms from post-progression samples. Here, we describe a patient with BRAF-V600E-positive metastatic melanoma who was sequentially treated with BRAF/MEK inhibitors (dabrafenib/trametinib) and checkpoint inhibitor immunotherapy (nivolumab, followed by pembrolizumab).

MTORC1/2 Inhibition as a Therapeutic Strategy for Mutant Cancers.

mutations are common in clinical molecular profiling, yet an effective means to target these cancers has yet to be developed. MTORC1 inhibitors are often used off-label for patients with mutant cancers with only limited data to support this approach. Here we describe a cohort of patients treated with cancers possessing mutations activating the PI3K signaling cascade with minimal benefit to treatment with the MTORC1 inhibitor everolimus.

Loss of amphiregulin reduces myoepithelial cell coverage of mammary ducts and alters breast tumor growth.

Background: Amphiregulin (AREG), a ligand of the epidermal growth factor receptor, is not only essential for proper mammary ductal development, but also associated with breast cancer proliferation and growth. In the absence of AREG, mammary ductal growth is stunted and fails to expand. Furthermore, suppression of AREG expression in estrogen receptor-positive breast tumor cells inhibits in-vitro and in-vivo growth.

Mutant GATA3 Actively Promotes the Growth of Normal and Malignant Mammary Cells.

Background/aim: GATA3, a transcription factor expressed in luminal breast epithelial cells, is required for mammary gland development. Heterozygous GATA3 mutations occur in up to 15% of estrogen receptor (ER)-positive breast tumors and have been proposed to be null alleles resulting in haploinsufficiency; however, the mutation spectrum of GATA3 in breast cancer is in sharp contrast to that found in HDR syndrome, a true GATA3 haploinsufficiency disease.

Materials And Methods: Transgenic mice, 3D cultures and xenografts were used to examine the effect of mutant GATA3 expression on mammary cell proliferation.

The RUNX1/IL-34/CSF-1R axis is an autocrinally regulated modulator of resistance to BRAF-V600E inhibition in melanoma.

Resistance to current therapies still impacts a significant number of melanoma patients and can be regulated by epigenetic alterations. Analysis of global cytosine methylation in a cohort of primary melanomas revealed a pattern of early demethylation associated with overexpression of oncogenic transcripts. Loss of methylation and associated overexpression of the CSF 1 receptor (CSF1R) was seen in a majority of tumors and was driven by an alternative, endogenous viral promoter in a subset of samples.

Adaptation of an amplicon-based human cancer next-generation sequencing panel assay for murine tumors.

Unlike humans, inbred genetically engineered mice have minimal inter-individual variation and, consequently, offer substantially increased statistical power for robust definition of recurrent cooperating cancer mutations. While technically feasible, whole exome sequencing is expensive and extremely data-intensive. Somatic mutation analysis using panels of 25-75 genes now provides detailed insight into the biology of human tumors.

Assessment of the TRPM8 inhibitor AMTB in breast cancer cells and its identification as an inhibitor of voltage gated sodium channels.

Aims: To assess levels of the calcium permeable transient receptor potential cation channel, subfamily melastatin, member 8 (TRPM8) in breast cancer molecular subtypes and to assess the consequences of TRPM8 pharmacological inhibition with AMTB (an inhibitor of TRPM8) on breast cancer cell lines.

Materials And Methods: Cell viability and migration of breast cancer cells was determined using MTS assays and wound healing assays, respectively. RNA-Seq analysis of breast tumours and qPCR in breast cancer cell lines were used to assess mRNA levels of ion channels.

Implementation and Clinical Utility of an Integrated Academic-Community Regional Molecular Tumor Board.

Purpose: Precision oncology develops and implements evidence-based personalized therapies that are based on specific genetic targets within each tumor. However, a major challenge that remains is the provision of a standardized, up-to-date, and evidenced-based precision medicine initiative across a geographic region.

Materials And Methods: We developed a statewide molecular tumor board that integrates academic and community oncology practices.

Genomic analysis of melanoma evolution following a 30-year disease-free interval.

Ultra-late melanoma recurrence is infrequent, poorly understood and, in most cases, difficult to unambiguously distinguish from a new primary melanoma. We identified a patient with a second melanoma diagnosed after a 30-year disease-free interval, and sought to determine if this new lesion was a recurrence of the original melanoma. Here we report the genomic sequence analysis of the exomes of 2 melanoma lesions isolated from the same individual in 1985 and 2015, and their comparison to each other and to the germline DNA of the patient.

Amphiregulin Is a Critical Downstream Effector of Estrogen Signaling in ERα-Positive Breast Cancer.

Estrogen stimulation promotes epithelial cell proliferation in estrogen receptor (ERα)-positive breast cancer. Many ERα target genes have been enumerated, but the identities of the key effectors mediating the estrogen signal remain obscure. During mouse mammary gland development, the estrogen growth factor receptor (EGFR) ligand amphiregulin acts as an important stage-specific effector of estrogen signaling.

Altered purinergic receptor-Ca²⁺ signaling associated with hypoxia-induced epithelial-mesenchymal transition in breast cancer cells.

Hypoxia is a feature of the microenvironment of many cancers and can trigger epithelial-mesenchymal transition (EMT), a process by which cells acquire a more invasive phenotype with enriched survival. A remodeling of adenosine 5'-triphosphate (ATP)-induced Ca(2+) signaling via purinergic receptors is associated with epidermal growth factor (EGF)-induced EMT in MDA-MB-468 breast cancer cells. Here, we assessed ATP-mediated Ca(2+) signaling in a model of hypoxia-induced EMT in MDA-MB-468 cells.

PI3K-AKT signaling is a downstream effector of retinoid prevention of murine basal cell carcinogenesis.

Basal cell carcinoma (BCC) is the most common human cancer. We have demonstrated previously that topical application of the retinoid prodrug tazarotene profoundly inhibits murine BCC carcinogenesis via retinoic acid receptor γ-mediated regulation of tumor cell transcription. Because topical retinoids can cause adverse cutaneous effects and because tumors can develop resistance to retinoids, we have investigated mechanisms downstream of tazarotene's antitumor effect in this model.

Bisected, complex N-glycans and galectins in mouse mammary tumor progression and human breast cancer.

Bisected, complex N-glycans on glycoproteins are generated by the glycosyltransferase MGAT3 and cause reduced cell surface binding of galectins. Previously, we showed that MGAT3 reduces growth factor signaling and retards mammary tumor progression driven by the Polyoma middle T antigen (PyMT) expressed in mammary epithelium under the mouse mammary tumor virus (MMTV) promoter. However, the penetrance of the tumor phenotype became variable in mixed FVB/N and C57BL/6 female mice and we therefore investigated a congenic C57BL/6 Mgat3(-/-)/MMTV-PyMT model.