Reuniting philosophy and science to advance cancer research

Cancers rely on multiple, heterogeneous processes at different scales, pertaining to many biomedical fields. Therefore, understanding cancer is necessarily an interdisciplinary task that requires placing specialised experimental and clinical research into a broader conceptual, theoretical, and methodological framework. Without such a framework, oncology will collect piecemeal results, with scant dialogue between the different scientific communities studying cancer. We argue that one important way forward in service of a more successful dialogue is through greater integration of applied sciences (experimental and clinical) with conceptual and theoretical approaches, informed by philosophical methods. By way of illustration, we explore six central themes: (i) the role of mutations in cancer; (ii) the clonal evolution of cancer cells; (iii) the relationship between cancer and multicellularity; (iv) the tumour microenvironment; (v) the immune system; and (vi) stem cells. In each case, we examine open questions in the scientific literature through a philosophical methodology and show the benefit of such a synergy for the scientific and medical understanding of cancer.

Ser71 Phosphorylation Inhibits Actin-Binding of Profilin-1 and Its Apoptosis-Sensitizing Activity

The essential actin-binding factor profilin-1 (Pfn1) is a non-classical tumor suppressor with the abilities toboth inhibit cellular proliferation and augment chemotherapy-induced apoptosis. Besides actin, Pfn1 interacts with proteins harboring the poly-L-proline (PLP) motifs. Our recent work demonstrated that both nuclear localization and PLP-binding are required for tumor growth inhibition by Pfn1, and this is at least partially due to Pfn1 association with the PLP-containing ENL protein in the Super Elongation Complex (SEC) and the transcriptional inhibition of pro-cancer genes. In this paper, by identifying a phosphorylation event of Pfn1 at Ser71 capable of inhibiting its actin-binding and nuclear export, we provide in vitro and in vivo evidence that chemotherapy-induced apoptotic sensitization by Pfn1 requires its cytoplasmic localization and actin-binding. With regard to tumor growth inhibition byPfn1, our data indicate a requirement for dynamic actin association and dissociation rendered by reversible Ser71phosphorylation and dephosphorylation. Furthermore, genetic and pharmacological experiments showed that Ser71 of Pfn1 can be phosphorylated by protein kinase A (PKA). Taken together, our data provide novel mechanistic insights into the multifaceted anticancer activities of Pfn1 and how they are spatially-defined in the cell and differentially regulated by ligand-binding.

Longitudinal change in left ventricular 4D flow kinetic energy after myocardial infarction

Funding Acknowledgements

Type of funding sources: Foundation. Main funding source(s): British Heart Foundation HRUK

Background. Four-dimensional flow (4D flow) cardiovascular magnetic resonance (CMR) imaging provides quantification of intra-cavity left ventricular (LV) flow kinetic energy (KE) parameters in three dimensions. Myocardial infarction (MI) is known to cause acute alterations in intra-cardiac blood flow but assessments of longitudinal changes are lacking.

Purpose. Assess longitudinal changes in LV flow post ST-elevation myocardial infarction (STEMI).

Method. Twenty acutely reperfused STEMI patients (13 men, 7 women, mean age 54 ± 9 years) underwent 3T CMR acutely (within 5-7 days) and 3 months post-MI.  CMR protocol included functional imaging, late gadolinium enhancement and 4D flow. Using Q-MASS, LV KE parameters were derived and indexed to LV end-diastolic volume (LVKEiEDV). Based on acute ejection fraction (EF), patients were grouped as follows: preserved (pEF) EF >50%, reduced (rEF) EF <50% including mild (rEF= 40-49%), moderate to severe (EF <40%) impairment. 

Results. Out of 20 patients, 13 had rEF acutely (7 mild rEF, 6 moderate to severe rEF). Acute LVKEiEDV parameters varied significantly between pEF and rEF (Table). At 3 months, pEF and mild rEF patients showed a significant (P < 0.05) reduction in average, systolic and peak-A wave LVKEiEDV. Mild rEF patients also had significant (P < 0.05) reduction in minimal and peak-E wave LVKEiEDV. However in patients with moderate to severe rEF in the acute scan, there were no significant change by 3 months (Figure).

Conclusion. Following MI, 4D flow LVKE derived biomarkers significantly decreased over time in pEF and mild rEF groups but not in moderate to severe rEF group. 4D flow assessment might provide incremental prognostic value beyond EF assessment alone.

Table pEF (n = 7) rEF (n = 13) V1 V2 P-value V1 V2 P-value EF(%) 56 ± 5 55 ± 4 0.40 41 ± 7 47 ± 9 0.01 Infarct Size(%) 31 ± 20 15 ± 9 0.04 18 ± 13† 16 ± 11 0.41 LV KEiEDV parameters Average(µJ/ml) 9 ± 2 7 ± 2 0.02 10 ± 3† 8 ± 3 0.01 Minimal(µJ/ml) 1 ± 0.6 1 ± 0.5 0.46 1.3 ± 0.5 1 ± 0.6 0.03 Systolic(µJ/ml) 10 ± 4 7 ± 2 <0.01 12 ± 4† 7 ± 3 <0.01 Diastolic(µJ/ml) 8 ± 3 7 ± 2 0.13 9 ± 3 8 ± 3 0.09 Peak-E wave(µJ/ml) 22 ± 9 23 ± 8 0.44 20 ± 7 18 ± 10 0.23 Peak-A wave(µJ/ml) 18 ± 10 11 ± 4 0.04 17 ± 9 14 ± 7 0.02 †P < 0.05 V1 comparison between pEF and rEF Abstract Figure

Zena Werb (1945–2020)

Pioneering cancer biologist and beloved mentor

Perturbed myoepithelial cell differentiation in BRCA mutation carriers and in ductal carcinoma in situ

Myoepithelial cells play key roles in normal mammary gland development and in limiting pre-invasive to invasive breast tumor progression, yet their differentiation and perturbation in ductal carcinoma in situ (DCIS) are poorly understood. Here, we investigated myoepithelial cells in normal breast tissues of BRCA1 and BRCA2 germline mutation carriers and in non-carrier controls, and in sporadic DCIS. We found that in the normal breast of non-carriers, myoepithelial cells frequently co-express the p63 and TCF7 transcription factors and that p63 and TCF7 show overlapping chromatin peaks associated with differentiated myoepithelium-specific genes. In contrast, in normal breast tissues of BRCA1 mutation carriers the frequency of p63⁺TCF7⁺ myoepithelial cells is significantly decreased and p63 and TCF7 chromatin peaks do not overlap. These myoepithelial perturbations in normal breast tissues of BRCA1 germline mutation carriers may play a role in their higher risk of breast cancer. The fraction of p63⁺TCF7⁺ myoepithelial cells is also significantly decreased in DCIS, which may be associated with invasive progression.

Abstract B62: Perturbed myoepithelial cell differentiation in BRCA mutation carriers and in DCIS (ductal carcinoma in situ)

The normal mammary gland is composed of multiple cell types, including luminal and myoepithelial cells. Myoepithelial cells have also been referred to as natural tumor suppressors due to their inhibitory effect on various neoplastic phenotypes, including tumor cell growth, invasion, and angiogenesis. We have previously determined that DCIS-associated myoepithelial cells lack clonal genetic aberrations, but their DNA methylation and gene expression patterns are distinct from that of normal myoepithelial cells, implying perturbed differentiation. We also showed that myoepithelial cells play key roles in preventing tumor growth and invasive progression in experimental models of DCIS, and in immune escape in breast cancer. These data support the hypothesis that the progressive loss of normal myoepithelial cell function in DCIS is a key step in the transition to invasive breast carcinomas, and assessing myoepithelial markers may identify patients with high risk of progression. However, the mechanisms underlying myoepithelial cell aberrations and eventual loss in DCIS are not well understood. In the present study, we used a combination of genomic profiling of human tissue samples and functional assays in a DCIS model to investigate regulators of normal myoepithelial cells and perturbations of these in BRCA mutation carriers and in DCIS. We first explored cellular heterogeneity of the CD10+ cell population in normal human breast tissues of nulliparous and parous women, from reduction mammoplasties and BRCA1 and BRCA2 mutation carriers undergoing prophylactic mastectomy. We identified two distinct CD10+ cell populations distinguished by the expression of CD44 and characterized their gene expression profiles. We also profiled CD10+ cells from BRCA1 and BRCA2 mutation carriers compared to normal noncarriers and found a clear separation of three distinct groups reflecting germline mutation status. Next we defined the p63 cistrome and the enhancer landscape of normal myoepithelial cells and identified alterations of these due to germline BRCA mutation status. Based on our initial results, we focused in p63 and TCF7 as these two transcription factors appear to be central for establishing myoepithelial cell fate. To address the functional relevance of p63 and TCF7 in myoepithelial cell differentiation, we used the MCFDCIS xenograft model of DCIS. These results support the hypothesis that myoepithelial cells play key roles in invasive progression and have significant impact on our understanding of DCIS progression and the increased breast cancer risk of BRCA mutation carriers.

Citation Format: Lina Ding, Ying Su, Muhammad Ekram, Sung Jin Huh, Noga Bloushtain-Qimron, Sibgat Choudhury, William Hines, Jun Yao, Mina Bissell, Kornelia Polyak. Perturbed myoepithelial cell differentiation in BRCA mutation carriers and in DCIS (ductal carcinoma in situ) [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 B62.

Training the next generation of biomedical investigators in glycosciences

This position statement originated from a working group meeting convened on April 15, 2015, by the NHLBI and incorporates follow-up contributions by the participants as well as other thought leaders subsequently consulted, who together represent research fields relevant to all branches of the NIH. The group was deliberately composed not only of individuals with a current research emphasis in the glycosciences, but also of many experts from other fields, who evinced a strong interest in being involved in the discussions. The original goal was to discuss the value of creating centers of excellence for training the next generation of biomedical investigators in the glycosciences. A broader theme that emerged was the urgent need to bring the glycosciences back into the mainstream of biology by integrating relevant education into the curricula of medical, graduate, and postgraduate training programs, thus generating a critical sustainable workforce that can advance the much-needed translation of glycosciences into a more complete understanding of biology and the enhanced practice of medicine.

Subcellular localization and Ser-137 phosphorylation regulate tumor-suppressive activity of profilin-1

The actin-binding protein profilin-1 (Pfn1) inhibits tumor growth and yet is also required for cell proliferation and survival, an apparent paradox. We previously identified Ser-137 of Pfn1 as a phosphorylation site within the poly-l-proline (PLP) binding pocket. Here we confirm that Ser-137 phosphorylation disrupts Pfn1 binding to its PLP-containing ligands with little effect on actin binding. We find in mouse xenografts of breast cancer cells that mimicking Ser-137 phosphorylation abolishes cell cycle arrest and apoptotic sensitization by Pfn1 and confers a growth advantage to tumors. This indicates a previously unrecognized role of PLP binding in Pfn1 antitumor effects. Spatial restriction of Pfn1 to the nucleus or cytoplasm indicates that inhibition of tumor cell growth by Pfn1 requires its nuclear localization, and this activity is abolished by a phosphomimetic mutation on Ser-137. In contrast, cytoplasmic Pfn1 lacks inhibitory effects on tumor cell growth but rescues morphological and proliferative defects of PFN1 null mouse chondrocytes. These results help reconcile seemingly opposed cellular effects of Pfn1, provide new insights into the antitumor mechanism of Pfn1, and implicate Ser-137 phosphorylation as a potential therapeutic target for breast cancer.

Network analysis of breast cancer progression and reversal using a tree-evolving network algorithm

The HMT3522 progression series of human breast cells have been used to discover how tissue architecture, microenvironment and signaling molecules affect breast cell growth and behaviors. However, much remains to be elucidated about malignant and phenotypic reversion behaviors of the HMT3522-T4-2 cells of this series. We employed a "pan-cell-state" strategy, and analyzed jointly microarray profiles obtained from different state-specific cell populations from this progression and reversion model of the breast cells using a tree-lineage multi-network inference algorithm, Treegl. We found that different breast cell states contain distinct gene networks. The network specific to non-malignant HMT3522-S1 cells is dominated by genes involved in normal processes, whereas the T4-2-specific network is enriched with cancer-related genes. The networks specific to various conditions of the reverted T4-2 cells are enriched with pathways suggestive of compensatory effects, consistent with clinical data showing patient resistance to anticancer drugs. We validated the findings using an external dataset, and showed that aberrant expression values of certain hubs in the identified networks are associated with poor clinical outcomes. Thus, analysis of various reversion conditions (including non-reverted) of HMT3522 cells using Treegl can be a good model system to study drug effects on breast cancer.

Addressing overdiagnosis and overtreatment in cancer: a prescription for change

A vast range of disorders--from indolent to fast-growing lesions--are labelled as cancer. Therefore, we believe that several changes should be made to the approach to cancer screening and care, such as use of new terminology for indolent and precancerous disorders. We propose the term indolent lesion of epithelial origin, or IDLE, for those lesions (currently labelled as cancers) and their precursors that are unlikely to cause harm if they are left untreated. Furthermore, precursors of cancer or high-risk disorders should not have the term cancer in them. The rationale for this change in approach is that indolent lesions with low malignant potential are common, and screening brings indolent lesions and their precursors to clinical attention, which leads to overdiagnosis and, if unrecognised, possible overtreatment. To minimise that potential, new strategies should be adopted to better define and manage IDLEs. Screening guidelines should be revised to lower the chance of detection of minimal-risk IDLEs and inconsequential cancers with the same energy traditionally used to increase the sensitivity of screening tests. Changing the terminology for some of the lesions currently referred to as cancer will allow physicians to shift medicolegal notions and perceived risk to reflect the evolving understanding of biology, be more judicious about when a biopsy should be done, and organise studies and registries that offer observation or less invasive approaches for indolent disease. Emphasis on avoidance of harm while assuring benefit will improve screening and treatment of patients and will be equally effective in the prevention of death from cancer.

Endothelial cell migration and vascular endothelial growth factor expression are the result of loss of breast tissue polarity

Recruiting a new blood supply is a rate-limiting step in tumor progression. In a three-dimensional model of breast carcinogenesis, disorganized, proliferative transformed breast epithelial cells express significantly higher expression of angiogenic genes compared with their polarized, growth-arrested nonmalignant counterparts. Elevated vascular endothelial growth factor (VEGF) secretion by malignant cells enhanced recruitment of endothelial cells (EC) in heterotypic cocultures. Significantly, phenotypic reversion of malignant cells via reexpression of HoxD10, which is lost in malignant progression, significantly attenuated VEGF expression in a hypoxia-inducible factor 1alpha-independent fashion and reduced EC migration. This was due primarily to restoring polarity: forced proliferation of polarized, nonmalignant cells did not induce VEGF expression and EC recruitment, whereas disrupting the architecture of growth-arrested, reverted cells did. These data show that disrupting cytostructure activates the angiogenic switch even in the absence of proliferation and/or hypoxia and restoring organization of malignant clusters reduces VEGF expression and EC activation to levels found in quiescent nonmalignant epithelium. These data confirm the importance of tissue architecture and polarity in malignant progression.

Spot urine protein/creatinine ratios are unreliable estimates of 24 h proteinuria in most systemic lupus erythematosus nephritis flares

The diagnosis of glomerulonephritis flares in systemic lupus erythematosus (SLE) is usually based on whether the magnitude of proteinuria has changed. Our study tests two methods to assess proteinuric change: protein/creatinine (P/C) ratios of intended 24-h urine collections or that of spot urine samples. Sixty-four patients with glomerulonephritis due to SLE followed in the Ohio SLE Study provided bimonthly paired spot and intended 24-h urine collections. Completeness of each collection was estimated as the ratio of the measured creatinine to the expected creatinine based upon Cockroft-Gault. Intended 24-h urine collections with measured/expected creatinine ratios between 0.5 and 0.9 (237 samples overall) showed ratios that were not significantly different from ratios of complete 24-h urine collections with ratios of 0.9-1.1 (159 samples). To compare spot and 24 h P/C ratios, we randomly selected pairs of samples with measured/expected ratios above 0.75. Consistent with previous studies, spot and 24-h urine P/C ratios showed good correlation over the range of values as well as reasonably strong concordance. Over the range of most SLE glomerulonephritis flares, however, correlation was present but concordance was poor. Our work suggests that the use of spot urine P/C ratios will yield more false-positive and -negative diagnoses of glomerulonephritis flares in patients with SLE than the ratio in 24-h urines.

A rapid test for the diagnosis of thrombotic thrombocytopenic purpura using surface enhanced laser desorption/ionization time-of-flight (SELDI-TOF)-mass spectrometry

BACKGROUND

Thrombotic thrombocytopenic purpura (TTP), a life-threatening thrombotic microangiopathy, requires immediate diagnosis and plasma exchange therapy. Development of TTP is related to functional deficiency of ADAMTS-13 protease that leads to the accumulation of ultra large von Willebrand factor (VWF) and subsequent platelet thrombosis. Currently no clinical test is available for the rapid detection of ADAMTS-13 activity.

OBJECTIVES

The goal is to devise a novel method to rapidly detect functional activity of ADAMTS-13 and improve clinical outcome.

METHODS AND RESULTS

A recombinant VWF substrate containing the ADAMTS-13 cleavage site and a 6X Histidine tag was cleaved by ADAMTS-13 in a dose-dependent manner, generating approximately 7739 Da peptide containing a 6X Histidine tag. This cleaved peptide, bound to an IMAC/Nickel ProteinChip, was quantified using Surface Enhanced Laser Desorption/Ionization Time-of-flight Mass Spectrometry (SELDI-TOF-MS). The assay is capable of quantifying ADAMTS-13 activity as low as 2.5% in plasma within 4 h. When the cleaved peptide was quantified as a ratio of an internal control peptide, the test displayed good reproducibility, with an average inter-assay coefficient of variation (CV) of < 33%. Further validation revealed a mean ADAMTS-13 activity of 92.5% +/- 16.6% in 39 healthy donors. Sixteen patients with idiopathic TTP displayed mean ADAMTS-13 activity of 1.73% +/- 3.62%. Further utility of this novel method includes determining the inhibitory titer of ADAMTS-13 antibody in cases of acquired TTP.

CONCLUSIONS

We have devised a novel SELDI-TOF-MS assay that offers a rapid, cost-effective, and functionally relevant test for timely diagnosis and management of TTP.

Point-of-care testing at the millennium

Point-of-care testing (POCT) is a major force in the future evolution of hospital care, with prospects for even greater expansion of accessibility, speed, and also, hopefully, accuracy of results. New developments in POCT technology will predictably occur in three areas: connectivity, test menu expansion, and noninvasiveness. Connectivity for POCT devices has evolved from point-of-service workstations to standardized POCT data transmission protocols to remote roaming wireless connectivity with automatic data capture. POCT test menus will continue to expand, with more coagulation testing, chemistries, and infectious screening, but also on-site drug screening, intraoperative hormone levels, and microchip DNA diagnostics. Noninvasive POCT will expand beyond the GlucoWatch glucose monitor and the Bilichek noninvasive bilirubin monitor to noninvasive CBCs and Pap smears.

The challenges and opportunities of laboratory regionalization

These are some of the major historical trends and rationale for the sea change in laboratory medicine today. The creation of cooperative regional networks and consolidated regional laboratories potentially can: 1) Pool the technologic strengths of individual laboratories across a region; 2) Create economies of scale by combining capacities for certain procedures; 3) Lower unit costs by increasing volumes of business from nonpatients; 4) Span all of the traditional testing venues along the new expanding continuum of care. The authors in this monograph will take the saga forward in time, outlining critical organizational, technologic, and strategic aspects of the newly evolving laboratory of the 21st century.

Genetic diversity from a limited repertoire of mutations on different common allelic backgrounds: alpha 1-antitrypsin deficiency variant Pduarte

alpha 1-Antitrypsin (alpha 1AT) is one of the most polymorphic gene loci in the human genome. alpha 1AT variants are typically identified by their migration position in an isoelectric focusing gel at pH 4-5. Heterogeneity of the isoelectric point of alpha 1AT variants, hence variant migration, most often results from amino acid substitutions which alter the net charge of the molecule. We identified an individual heterozygous for an alpha 1AT variant migrating in the "P" variant region which differs from other known "P" variants. Using isoelectric focusing on an immobilized pH gradient at pH 4.50-4.85 the novel P allele, Pduarte, migrates between Pst. albans and Plowell. Densitometric analysis of normal "M" type alpha 1AT and the deficiency variant Plowell major bands separated by isoelectric focusing demonstrates that Pduarte contributes approximately 41% as much alpha 1AT to the total serum alpha 1AT concentration as the normal "M" alpha 1AT, similar to Plowell. Direct DNA sequencing of the proband's genomic DNA demonstrates that the Pduarte allele differs from the normal M1 (V213) allele by two amino acid substitutions, R101 (CGT)-->H(CAT) and D256 (GAT)-->V(GTT). Individually, these amino acid substitutions characterize the normal M4 allele (R101-->H) and the deficient Plowell allele (D256-->V). Thus the Pduarte allele differs from the Plowell allele only by the normal allelic background in which the V256 mutation occurs. Comparison of amino acid sequences among several alpha 1AT variants demonstrates that Pduarte is an example of a more general observation regarding diversity within the PI (protease inhibitor) system.(ABSTRACT TRUNCATED AT 250 WORDS)

Solubility in binary solvent systems: 8. Estimation of binary alkane plus p-dioxane solvent nonideality from measured anthracene solubilities

Experimental solubilities are reported for anthracene in binary solvent mixtures containing p-dioxane with n-hexane, cyclohexane, n-heptane, methylcyclohexane, n-octane, cyclooctane, and isooctane at 25 degrees C. Results of these measurements, used in conjunction with the nearly ideal binary solvent (NIBS) model, enabled excess Gibbs free energies, delta GBCfh, of the seven binary solvent mixtures to be estimated. Estimated values for p-dioxane plus cyclohexane, p-dioxane plus n-heptane, and p-dioxane plus methylcyclohexane mixtures are in reasonable agreement with published values based on vapor pressure measurements.

Expression of integrated Rous sarcoma viruses: DNA rearrangements 5′ to the provirus are common in transformed rat cells but not seen in infected but untransformed cells

The study of Rous sarcoma virus (RSV)-infected rat cell clones offers a novel approach to unravelling the mechanisms controlling eukaryotic gene expression. RSV-transformed rat cell clones frequently contain duplicated proviral sequences immediately upstream of an intact provirus. This category of proviral rearrangement is not seen in cells that remain untransformed after RSV infection nor in subsequently segregating transformants. These results suggest that such rearrangements occur during or soon after proviral integration, and that they may favour early proviral expression.

Environmental influences on serotonin and cyclic nucleotides in rat cerebral cortex

The response to different environmental conditions and negative air ions was investigated on cerebral cortical serotonin and cyclic nucleotides. The results indicated that negative air ions alter the weight of the cerebral cortex and that concentrations of serotonin and cyclic nucleotides can be altered both by different environments and by negative air ions. The data stress the importance of the role of the environment when studying the structure and chemistry of the cerebral cortex.

Pulmonary alveolar proteinosis and cytomegalovirus infection

We report a case of pulmonary alveolar proteinosis (PAP) and cytomegalovirus (CMV) infection occurring in a 5-year-old boy with acute lymphoblastic leukemia. The association of PAP and CMV infection is rare, but the possible etiologic role of CMV in the production of PAP is raised. Pulmonary alveolar proteinosis is being reported with increasing frequency in immunocompromised patients, and this disease may be difficult to distinguish from other causes of diffuse lung disease both clinically and radiologically. Pulmonary alveolar proteinosis, either alone or in combination with CMV infection, should therefore be considered in the differential diagnosis of diffuse lung disease in these cases.