Lessons for the Next Generation of Scientists from the Second Annual Arthur and Sandra Irving Cancer Immunology Symposium.

The Arthur and Sandra Irving Cancer Immunology Symposium has been created as a platform for established cancer immunologists to mentor trainees and young investigators as they launch their research career in the field. By sharing their different paths to success, the senior faculty mentors provide an invaluable resource to support the development of the next generation of leaders in the cancer immunology community. This Commentary describes some of the key topics that were discussed during the 2022 symposium: scientific and career trajectory, leadership, mentoring, collaborations, and publishing. For each of these topics, established investigators discussed the elements that facilitate success in these areas as well as mistakes that can hinder progress. Herein, we outline the critical points raised in these discussions for establishing a successful independent research career. These points are highly relevant for the broader scientific community.

N-acetylcysteine overcomes NF1 loss-driven resistance to PI3Kα inhibition in breast cancer.

A genome-wide PiggyBac transposon-mediated screen and a resistance screen in a PIK3CAH1047R-mutated murine tumor model reveal NF1 loss in mammary tumors resistant to the phosphatidylinositol 3-kinase α (PI3Kα)-selective inhibitor alpelisib. Depletion of NF1 in PIK3CAH1047R breast cancer cell lines and a patient-derived organoid model shows that NF1 loss reduces sensitivity to PI3Kα inhibition and correlates with enhanced glycolysis and lower levels of reactive oxygen species (ROS). Unexpectedly, the antioxidant N-acetylcysteine (NAC) sensitizes NF1 knockout cells to PI3Kα inhibition and reverts their glycolytic phenotype. Global phospho-proteomics indicates that combination with NAC enhances the inhibitory effect of alpelisib on mTOR signaling. In public datasets of human breast cancer, we find that NF1 is frequently mutated and that such mutations are enriched in metastases, an indication for which use of PI3Kα inhibitors has been approved. Our results raise the attractive possibility of combining PI3Kα inhibition with NAC supplementation, especially in patients with drug-resistant metastases associated with NF1 loss.

Hypothalamic hamartoma: a cause of precocious puberty.

Hypothalamic hamartomas are uncommon congenital malformations that present as precocious puberty, gelastic seizures and/or psychiatric disorders. Characteristic changes in MRI scans lead to a diagnosis. Treatment may include surgery or gonadotropin-releasing hormone agonists (GnRHa) depending on clinical manifestations.Here, we describe a case of hypothalamic hamartoma diagnosed in a girl in middle childhood, who presented with early development of secondary sexual characteristics. Physical examination, hormonal study, bone age and pelvic ultrasound findings were consistent with those of precocious puberty. The investigation also included a brain MRI scan, which revealed a small nodule with regular limits in the left hypothalamic region/tuber cinereum. GnRHa treatment and neurosurgical follow-ups were initiated promptly. The patient showed a reversal of secondary sexual characteristics and stable hamartoma size. This case illustrates the importance of brain MRI scans as part of the assessment of suspected precocious puberty because clinical features do not identify patients with an underlying pathology.

Locally sourced: site-specific immune barriers to metastasis.

Tumour cells migrate very early from primary sites to distant sites, and yet metastases often take years to manifest themselves clinically or never even surface within a patient's lifetime. This pause in cancer progression emphasizes the existence of barriers that constrain the growth of disseminated tumour cells (DTCs) at distant sites. Although the nature of these barriers to metastasis might include DTC-intrinsic traits, recent studies have established that the local microenvironment also controls the formation of metastases. In this Perspective, I discuss how site-specific differences of the immune system might be a major selective growth restraint on DTCs, and argue that harnessing tissue immunity will be essential for the next stage in immunotherapy development that reliably prevents the establishment of metastases.

A high-throughput drug screen reveals means to differentiate triple-negative breast cancer.

Plasticity delineates cancer subtypes with more or less favourable outcomes. In breast cancer, the subtype triple-negative lacks expression of major differentiation markers, e.g., estrogen receptor α (ERα), and its high cellular plasticity results in greater aggressiveness and poorer prognosis than other subtypes. Whether plasticity itself represents a potential vulnerability of cancer cells is not clear. However, we show here that cancer cell plasticity can be exploited to differentiate triple-negative breast cancer (TNBC). Using a high-throughput imaging-based reporter drug screen with 9 501 compounds, we have identified three polo-like kinase 1 (PLK1) inhibitors as major inducers of ERα protein expression and downstream activity in TNBC cells. PLK1 inhibition upregulates a cell differentiation program characterized by increased DNA damage, mitotic arrest, and ultimately cell death. Furthermore, cells surviving PLK1 inhibition have decreased tumorigenic potential, and targeting PLK1 in already established tumours reduces tumour growth both in cell line- and patient-derived xenograft models. In addition, the upregulation of genes upon PLK1 inhibition correlates with their expression in normal breast tissue and with better overall survival in breast cancer patients. Our results indicate that differentiation therapy based on PLK1 inhibition is a potential alternative strategy to treat TNBC.

Metastasis.

Metastasis, the major cause of cancer death, represents one of the major challenges in oncology. Scientists are still trying to understand the biological basis underlying the dissemination and outgrowth of tumor cells, why these cells can remain dormant for years, how they become resistant to the immune system or cytotoxic effects of systemic therapy, and how they interact with their new microenvironment. We asked experts to discuss some of the unknowns, advances, and areas of opportunity related to cancer metastasis.

The type of SARS-CoV-2 vaccine influences serological response in kidney transplant recipients.

Vaccination is a promising strategy to control the ongoing pandemic; however, solid organ recipients tend to develop a weaker immune response to vaccination. Anti-spike SARS-CoV-2 antibodies titers were measured 2-4 weeks post-vaccination completion in 131 KT patients without previous infection. Demographic, clinical, and laboratorial parameters were analyzed to identify which factors contributed to seroconversion. Factors that influenced seroconversion, that occurred in 76 patients (58%), were longer time post-transplant, immunosuppression without an antiproliferative drug and vaccination with mRNA vaccines. Patients who received mRNA vaccines had significantly higher rates of seroconversion compared with adenovirus vector vaccines (67% vs 33%, P < .001) and higher anti-spike IgG titers. These findings reinforce the need to discuss the vaccination strategy in this population, including a third dose with a mRNA vaccine.

Hepatic stellate cells suppress NK cell-sustained breast cancer dormancy.

The persistence of undetectable disseminated tumour cells (DTCs) after primary tumour resection poses a major challenge to effective cancer treatment1-3. These enduring dormant DTCs are seeds of future metastases, and the mechanisms that switch them from dormancy to outgrowth require definition. Because cancer dormancy provides a unique therapeutic window for preventing metastatic disease, a comprehensive understanding of the distribution, composition and dynamics of reservoirs of dormant DTCs is imperative. Here we show that different tissue-specific microenvironments restrain or allow the progression of breast cancer in the liver-a frequent site of metastasis4 that is often associated with a poor prognosis5. Using mouse models, we show that there is a selective increase in natural killer (NK) cells in the dormant milieu. Adjuvant interleukin-15-based immunotherapy ensures an abundant pool of NK cells that sustains dormancy through interferon-γ signalling, thereby preventing hepatic metastases and prolonging survival. Exit from dormancy follows a marked contraction of the NK cell compartment and the concurrent accumulation of activated hepatic stellate cells (aHSCs). Our proteomics studies on liver co-cultures implicate the aHSC-secreted chemokine CXCL12 in the induction of NK cell quiescence through its cognate receptor CXCR4. CXCL12 expression and aHSC abundance are closely correlated in patients with liver metastases. Our data identify the interplay between NK cells and aHSCs as a master switch of cancer dormancy, and suggest that therapies aimed at normalizing the NK cell pool might succeed in preventing metastatic outgrowth.

Prevention of dsRNA-induced interferon signaling by AGO1x is linked to breast cancer cell proliferation.

Translational readthrough, i.e., elongation of polypeptide chains beyond the stop codon, was initially reported for viral RNA, but later found also on eukaryotic transcripts, resulting in proteome diversification and protein-level modulation. Here, we report that AGO1x, an evolutionarily conserved translational readthrough isoform of Argonaute 1, is generated in highly proliferative breast cancer cells, where it curbs accumulation of double-stranded RNAs (dsRNAs) and consequent induction of interferon responses and apoptosis. In contrast to other mammalian Argonaute protein family members with primarily cytoplasmic functions, AGO1x exhibits nuclear localization in the vicinity of nucleoli. We identify AGO1x interaction with the polyribonucleotide nucleotidyltransferase 1 (PNPT1) and show that the depletion of this protein further augments dsRNA accumulation. Our study thus uncovers a novel function of an Argonaute protein in buffering the endogenous dsRNA-induced interferon responses, different than the canonical function of AGO proteins in the miRNA effector pathway. As AGO1x expression is tightly linked to breast cancer cell proliferation, our study thus suggests a new direction for limiting tumor growth.

Face-to-face Assessment of COGTEL in Adolescents: Test-Retest Reliability and Association with School Grades / Aplicação Presencial do COGTEL em Adolescentes: a Fiabilidade Teste-Reteste e a Associação com as Notas Escolares

Abstract The Cognitive Telephone Screening Instrument (COGTEL) has shown to be a brief, reliable, and valid instrument to assess cognitive functioning in adults in face-to-face procedures as well as over the phone. So far, no psychometric evaluation exists on its use in adolescents. The present study set out to evaluate the psychometric properties of the face-to-face application of the COGTEL in adolescents in the school context and to analyse the association with school grades. We assessed cognitive performance using COGTEL in face-to-face assessments of 170 adolescents, with retests after 6 months for test-retest reliability. Predictive validity was assessed using school grades. Test-retest reliability for the COGTEL was good (ICC = .77; p < .001). The partial correlation controlling for age between COGTEL and school grades was medium and positive (r = .40; p < .001). School grades alone explained 42% and 36% of the variance in the COGTEL total score in elementary and secondary students, respectively. The present study suggests that COGTEL is a reliable and valid instrument to assess cognitive functioning in adolescents, with the advantage of feasibility in multiple contexts.

Resumo O Instrumento de Rastreio Cognitivo por Telefone (COGTEL) tem demostrado ser um instrumento fiável, válido e breve para avaliar o funcionamento cognitivo em adultos, quer por telefone, quer de forma presencial. Até à data, não foram estudadas as suas características psicométricas para uso em adolescentes. O presente estudo teve por objetivo avaliar as propriedades psicométricas do COGTEL em adolescentes no contexto escolar, através da aplicação presencial, e analisar a associação dos scores com as notas escolares. O desempenho cognitivo foi avaliado em 170 adolescentes, usando o COGTEL em entrevistas presenciais, com um reteste após 6 meses para avaliar a fiabilidade teste-reteste. A validade preditiva foi avaliada com base nas notas escolares. A fiabilidade teste-reteste para o COGTEL foi boa (ICC = 0.77; p < .001). As correlações parciais, controlando pelo efeito da idade, entre o score total do COGTEL e as notas escolares foram moderadas e positivas (r = .40; p < .001). As notas escolares, individualmente, explicaram 42% e 36% da variância total no score total do COGTEL, em alunos do ensino básico e secundário, respetivamente. O presente estudo sugere que o COGTEL é um instrumento fiável e válido para avaliar o funcionamento cognitivo em adolescentes, com a vantagem de ser aplicável em múltiplos contextos.

Reversible Aptamer-Au Plasmon Rulers for Secreted Single Molecules.

Plasmon rulers, consisting of pairs of gold nanoparticles, allow single-molecule analysis without photobleaching or blinking; however, current plasmon rulers are irreversible, restricting detection to only single events. Here, we present a reversible plasmon ruler, comprised of coupled gold nanoparticles linked by a single aptamer, capable of binding individual secreted molecules with high specificity. We show that the binding of target secreted molecules to the reversible plasmon ruler is characterized by single-molecule sensitivity, high specificity, and reversibility. Such reversible plasmon rulers should enable dynamic and adaptive live-cell measurement of secreted single molecules in their local microenvironment.

Mammary Branching Morphogenesis Requires Reciprocal Signaling by Heparanase and MMP-14.

The development of the mammary gland involves formation of a branched arboreal structure resulting from the penetration and proliferation of epithelial cells into the fat pad. The mammary cells invade by remodeling their surrounding extracellular matrix (ECM), which are rich in proteins, and glycans such as heparan sulfate proteoglycans (HSPGs). There is increasing literature on how the interaction between signaling by ECM and matrix metalloproteinases (MMPs) is relevant to morphogenetic and physiological contexts. Here we sought to understand how heparanase, the sole mammalian heparan sulfate-degrading endoglycosidase may regulate mammary gland development. We found a robust localization of heparanase within growing end buds during branching in vivo. Using three-dimensional (3D) organotypic cultures, we showed that heparanase expression and activity are required for mammary epithelial invasion/branching within dense collagen I gels. Morphometric analysis of glands from both heparanase-overexpressing and knockout mice showed a direct correlation between degree of branching and the heparanase levels, confirming our 3D organotypic culture observations. Finally, we uncovered a reciprocal association between levels of heparanase and MMP14, a membrane-bound MMP, shedding further light on how branching occurs within developing mammary glands.

The hemopexin domain of MMP3 is responsible for mammary epithelial invasion and morphogenesis through extracellular interaction with HSP90ß.

Matrix metalloproteinases (MMPs) are crucial mediators in sculpting tissue architecture and are required for many physiological and pathological processes. MMP3 has been shown to regulate branching morphogenesis in the mammary gland. Ectopic expression of proteolytically active MMP3 in mouse mammary epithelia triggers supernumerary lateral branching and, eventually, tumors. Using a three-dimensional collagen-I (Col-1) gel assay that simulates epithelial invasion and branching, we show that it is the hemopexin domain that directs these processes. Using three different engineered constructs containing a variation on MMP3 structural domains, we confirmed the importance of the hemopexin domain also in primary organoids of the mammary gland. A proteomic screen of MMP3-binding partners surprisingly revealed that the intracellular chaperone heat-shock protein 90 ß (HSP90ß) is present extracellularly, and its interaction with the hemopexin domain of MMP3 is critical for invasion. Blocking of HSP90ß with inhibitory antibodies added to the medium abolished invasion and branching. These findings shift the focus from the proteolytic activity of MMP3 as the central player to its hemopexin domain and add a new dimension to HSP90ß's functions by revealing a hitherto undescribed mechanism of MMP3 regulation. Our data also may shed light on the failure of strategies to use MMP inhibitors in cancer treatment and other related disorders.

The tumor microenvironment is a dominant force in multidrug resistance.

The emergence of clinical drug resistance is still one of the most challenging factors in cancer treatment effectiveness. Until more recently, the assumption has been that random genetic lesions are sufficient to explain the progression of malignancy and escape from chemotherapy. Here we propose an additional perspective, one in which the tumor cells despite the malignant genome could find a microenvironment either within the tumor or as a dormant cell to remain polar and blend into an organized context. Targeting this dynamic interplay could be considered a new avenue to prevent therapeutic resistance, and may even provide a promising effective cancer treatment.

Expression of p120-catenin isoforms correlates with genomic and transcriptional phenotype of breast cancer cell lines.

BACKGROUND: P120-catenin is a member of the Armadillo protein family, which is involved in intercellular adhesion and cell signalling. It directly interacts with the classical cadherins juxtamembrane domain and contributes for both junction formation and its disassembly. Accumulating evidences indicate that p120-catenin is important in tumour formation and progression, although the role of their multiple spliced isoforms in the regulation of cadherin-mediated adhesion of malignant cells is still not well understood. We investigated the expression of p120-catenin isoforms in a collection of breast cancer cell lines with distinct molecular profiles and expressing different cadherins. METHODS: We assessed the expression by RT-PCR and Western-blotting analysis. RESULTS: We observed that the expression of p120-catenin isoforms was associated with the genomic and transcriptional phenotype of breast cancer cells. Besides, the recruitment of p120-catenin isoforms was not apparently related with the particular expression of E-, P- or N-cadherin. CONCLUSION: We demonstrate that mammary tumour cells exhibit a characteristic p120-catenin isoform expression profile, depending from their specific genomic and transcriptional properties. These particular expression patterns, combined with other regulatory proteins and in a specific cellular context, may explain how p120-catenin can either contribute to strength intercellular adhesions or instead to promote cell motility.

P-cadherin expression in breast cancer: a review.

P-cadherin is frequently over-expressed in high-grade invasive breast carcinomas and has been reported to be an enhancer of migration and invasion of breast cancer cells, being correlated with tumour aggressiveness. In addition, expression of P-cadherin is well established as an indicator of poor prognosis in human breast cancer, which has stimulated our interest in studying its role in this setting. This review describes the most important findings on P-cadherin expression and function in normal mammary tissue and breast cancer cells, emphasizing that further research is required to elucidate the role played by this protein in human mammary tumours.