How can patient preferences be used and communicated in the regulatory evaluation of medicinal products? Findings and recommendations from IMI PREFER and call to action.

Objective: Patients have unique insights and are (in-)directly affected by each decision taken throughout the life cycle of medicinal products. Patient preference studies (PPS) assess what matters most to patients, how much, and what trade-offs patients are willing to make. IMI PREFER was a six-year European public-private partnership under the Innovative Medicines Initiative that developed recommendations on how to assess and use PPS in medical product decision-making, including in the regulatory evaluation of medicinal products. This paper aims to summarize findings and recommendations from IMI PREFER regarding i) PPS applications in regulatory evaluation, ii) when and how to consult with regulators on PPS, iii) how to reflect PPS in regulatory communication and iv) barriers and open questions for PPS in regulatory decision-making. Methods: PREFER performed six literature reviews, 143 interviews and eight focus group discussions with regulators, patient representatives, industry representatives, Health Technology Assessment bodies, payers, academics, and clincians between October 2016 and May 2022. Results: i) With respect to PPS applications, prior to the conduct of clinical trials of medicinal products, PPS could inform regulators' understanding of patients' unmet needs and relevant endpoints during horizon scanning activities and scientific advice. During the evaluation of a marketing authorization application, PPS could inform: a) the assessment of whether a product meets an unmet need, b) whether patient-relevant clinical trial endpoints and outcomes were studied, c) the understanding of patient-relevant effect sizes and acceptable trade-offs, and d) the identification of key (un-)favorable effects and uncertainties. ii) With respect to consulting with regulators on PPS, PPS researchers should ideally have early discussions with regulators (e.g., during scientific advice) on the PPS design and research questions. iii) Regarding external PPS communication, PPS could be reflected in the assessment report and product information (e.g., the European Public Assessment Report and the Summary of Product Characteristics). iv) Barriers relevant to the use of PPS in regulatory evaluation include a lack of PPS use cases and demonstrated impact on regulatory decision-making, and need for (financial) incentives, guidance and quality criteria for implementing PPS results in regulatory decision-making. Open questions concerning regulatory PPS use include: a) should a product independent broad approach to the design of PPS be taken and/or a product-specific one, b) who should optimally be financing, designing, conducting, and coordinating PPS, c) when (within and/or outside clinical trials) to perform PPS, and d) how can PPS use best be operationalized in regulatory decisions. Conclusion: PPS have high potential to inform regulators on key unmet needs, endpoints, benefits, and risks that matter most to patients and their acceptable trade-offs. Regulatory guidelines, templates and checklists, together with incentives are needed to foster structural and transparent PPS submission and evaluation in regulatory decision-making. More PPS case studies should be conducted and submitted for regulatory assessment to enable regulatory discussion and increase regulators' experience with PPS implementation and communication in regulatory evaluations.

Increased LGR6 Expression Sustains Long-Term Wnt Activation and Acquisition of Senescence in Epithelial Progenitors in Chronic Lung Diseases.

Chronic lung diseases (CLDs) represent a set of disorders characterized by the progressive loss of proper lung function. Among severe CLDs, the incidence of chronic obstructive pulmonary disease (COPD) and idiopathic pulmonary fibrosis (IPF) has grown over the last decades, mainly in the elderly population. Several studies have highlighted an increased expression of senescence-related markers in the resident progenitor cells in COPD and IPF, possibly undermining epithelial integrity and contributing to the progression and the aggravation of both diseases. Recently, the chronic activation of the canonical Wnt/ß-catenin pathway was shown to induce cellular senescence. Here, we investigated the localization and the expression of leucin-rich repeat-containing G-protein-coupled receptor 6 (LGR6), a protein that activates and potentiates the canonical Wnt signalling. Through immunohistochemical analyses, we identified a lesion-associated rise in LGR6 levels in abnormal lung epithelial progenitors in COPD and IPF when compared to histologically normal tissues. Moreover, in areas of aberrant regeneration, chronic damage and fibrosis, LGR6-expressing epithelial progenitors displayed a major increase in the expression of senescence-associated markers. Our study suggests the involvement of LGR6 in the chronic activation of the Wnt/ß-catenin pathway, mediating the impairment and exhaustion of epithelial progenitors in COPD and IPF.

Wnt/ß-Catenin Inhibition Disrupts Carboplatin Resistance in Isogenic Models of Triple-Negative Breast Cancer.

Triple-Negative Breast Cancer (TNBC) is the most aggressive breast cancer subtype, characterized by limited treatment options and higher relapse rates than hormone-receptor-positive breast cancers. Chemotherapy remains the mainstay treatment for TNBC, and platinum salts have been explored as a therapeutic alternative in neo-adjuvant and metastatic settings. However, primary and acquired resistance to chemotherapy in general and platinum-based regimens specifically strongly hampers TNBC management. In this study, we used carboplatin-resistant in vivo patient-derived xenograft and isogenic TNBC cell-line models and detected enhanced Wnt/ß-catenin activity correlating with an induced expression of stem cell markers in both resistant models. In accordance, the activation of canonical Wnt signaling in parental TNBC cell lines increases stem cell markers' expression, formation of tumorspheres and promotes carboplatin resistance. Finally, we prove that Wnt signaling inhibition resensitizes resistant models to carboplatin both in vitro and in vivo, suggesting the synergistic use of Wnt inhibitors and carboplatin as a therapeutic option in TNBC. Here we provide evidence for a prominent role of Wnt signaling in mediating resistance to carboplatin, and we establish that combinatorial targeting of Wnt signaling overcomes carboplatin resistance enhancing chemotherapeutic drug efficacy.

PPP2R4 dysfunction promotes KRAS-mutant lung adenocarcinoma development and mediates opposite responses to MEK and mTOR inhibition.

KRAS-mutant lung adenocarcinomas represent the largest molecular subgroup of non-small cell lung cancers (NSCLC) and are notorious for their dismal survival perspectives. To gain more insights in etiology and therapeutic response, we focused on the tumor suppressor Protein Phosphatase 2A (PP2A) as a player in KRAS oncogenic signaling. We report that the PP2A activator PTPA (encoded by PPP2R4) is commonly affected in NSCLC by heterozygous loss and low-frequent loss-of-function mutation, and this is specifically associated with poorer overall survival of KRAS-mutant lung adenocarcinoma patients. Reduced or mutant PPP2R4 expression in A549 cells increased anchorage-independent growth in vitro and xenograft growth in vivo, correlating with increased Ki67 and c-MYC expression. Moreover, KrasG12D-induced lung tumorigenesis was significantly accelerated in Ppp2r4 gene trapped mice as compared to Ppp2r4 wild-type. A confined kinase inhibitor screen revealed that PPP2R4-depletion induced resistance against selumetinib (MEK inhibitor), but unexpectedly sensitized cells for temsirolimus (mTOR inhibitor), in vitro and in vivo. Our findings underscore a clinically relevant role for PTPA loss-of-function in KRAS-mutant NSCLC etiology and kinase inhibitor response.

Lgr6: From Stemness to Cancer Progression.

Lung cancer is the leading cause of cancer-related deaths worldwide with poor prognosis, mainly due to the delay in the diagnosis. Adenocarcinoma, a subtype of non-small cell lung cancer, has the highest incidence and significant recurrence rates. Experimental and clinical researches suggested that the presence of cancer stem cells could support the development, malignization and resistance of lung cancer. Unfortunately, our knowledge in the field is still limited. Here we report our findings regarding a cell population expressing LGR6, an epithelial stem cell marker. Under the pressure of a fine regulated p38α MAPK/mir-17-92 axis, LGR6+ stem cells produce differentiated bronchioalveolar cells, in the normal lung. LGR6 is enriched in tumour cells during adenocarcinoma progression. Similar to normal stem cells, LGR6+ cancer cells show self-renewal and differentiation capacities, alongside with a higher oncogenic potential. Our studies suggest a disruption in the p38α MAPK/mir-17-92 network, that enhances Wnt pathway activity, could be responsible for the selection of malignant LGR6+ tumour cells. These results support the existence of a cell population with stem-like characteristics and strong oncogenic potential. This population could be useful for predictive diagnosis and a novel target for improved and more effective therapies against metastases and recurrences of lung adenocarcinomas.

RNA-sequencing-based comparative analysis of human hepatic progenitor cells and their niche from alcoholic steatohepatitis livers.

Hepatic progenitor cells (HPCs) are small cells with a relative large oval nucleus and a scanty cytoplasm situated in the canals of Hering that express markers of (immature) hepatocytes and cholangiocytes. HPCs are present in large numbers in alcoholic steatohepatitis (ASH), one of the leading causes of chronic liver disease. To date, the mechanisms responsible for proliferation and differentiation of human HPCs are still poorly understood and the role of HPCs in ASH development is unknown. In this study, we aimed to characterise human HPCs and their interactions with other cells through comparison, on both protein and RNA level, of HPC-enriched cell populations from adult human liver tissue using different isolation methods. Fresh human liver tissue was collected from ASH explant livers and HPC-enriched cell populations were obtained via four different isolation methods: side population (SP), epithelial cell adhesion molecule (EpCAM) and trophoblast antigen 2 (TROP-2) membrane marker isolation and laser capture microdissection. Gene expression profiles of fluorescent-activated cell-sorted HPCs, whole liver extracts and laser microdissected HPC niches were determined by RNA-sequencing. Immunohistochemical evaluation of the isolated populations indicated the enrichment of HPCs in the SP, EpCAM+ and TROP-2+ cell populations. Pathway analysis of the transcription profiles of human HPCs showed an enrichment and activation of known HPC pathways like Wnt/ß-catenin, TWEAK and HGF. Integration of the HPC niche profile suggests autocrine signalling by HPCs (TNFα, PDGFB and VEGFA) as well as paracrine signalling from the surrounding niche cells including MIF and IGF-1. In addition, we identified IL-17 A signalling as a potentially novel pathway in HPC biology. In conclusion, we provide the first RNA-seq-based, comparative transcriptome analysis of isolated human HPCs from ASH patients and revealed active signalling between HPCs and their surrounding niche cells in ASH livers and suggest that HPCs can actively contribute to liver inflammation.

C3G knock-down enhances migration and invasion by increasing Rap1-mediated p38α activation, while it impairs tumor growth through p38α-independent mechanisms.

C3G, a Guanine nucleotide Exchange Factor (GEF) for Rap1 and R-Ras, has been shown to play important roles in development and cancer. Previous studies determined that C3G regulates cell death through down-regulation of p38α MAPK activity. Here, we found that C3G knock-down in MEFs and HCT116 cells promotes migration and invasion through Rap1-mediated p38α hyper-activation. These effects of C3G were inhibited by Rap1 knock-down or inactivation. The enhanced migration observed in C3G depleted HCT116 cells was associated with reduction in E-cadherin expression, internalization of ZO-1, actin cytoskeleton reorganization and decreased adhesion. We also found that matrix metalloproteases MMP2 and MMP9 are involved in the pro-invasive effect of C3G down-regulation. Additionally, our studies revealed that both C3G and p38α collaborate to promote growth of HCT116 cells in vitro and in vivo, possibly by enhancing cell survival. In fact, knocking-down C3G or p38α individually or together promoted cell death in vitro, although only the double C3G-p38α silencing was able to increase cell death within tumors. Notably, we found that the pro-tumorigenic function of C3G does not depend on p38α or Rap1 activation. Altogether, our studies uncover novel mechanisms by which C3G controls key aspects of tumorigenesis.

miR-17-92/p38α Dysregulation Enhances Wnt Signaling and Selects Lgr6+ Cancer Stem-like Cells during Lung Adenocarcinoma Progression.

Defining the molecular and cellular roots of lung cancer relapse after initial treatment remains an imperative to improve survival. Here we report that the lung stem cell marker Lgr6 becomes enriched in non-small cell lung cancer (NSCLC) cells during malignant progression. Lgr6(+) NSCLC cells displayed self-renewal and differentiation properties along with a higher tumorigenic potential. Mechanistic investigations suggested that a defective repression of the miR-17-92 gene cluster was responsible for evolution of a selection for outgrowth of Lgr6(+) NSCLC cells. High levels of expression of miR-19 family members were found to target and downregulate levels of p38α kinase, providing a specific survival signal for Lgr6(+) cells as mediated by increased Wnt/ß-catenin activity. Our results identify a specific stem-like cell population in NSCLC with increased malignant potential, the elucidation of which may enable earlier prognosis and possibly the development of more effective targeted treatments. Cancer Res; 76(13); 4012-22. ©2016 AACR.

A paracrine network regulates the cross-talk between human lung stem cells and the stroma.

The signals that regulate stem cell self-renewal and differentiation in the lung remain elusive. Lung stem cells undergo self-renewal or lineage commitment to replenish tissue, depending on cross-talk with their environment. This environment, also known as the niche, includes mesenchymal and endothelial tissues. Here we define molecular mechanisms involved in the interaction between human lung Lgr6+ stem cells (LSCs) and fibroblasts in a functional microenvironment. We reveal a central role for p38α MAPK in establishing and maintaining such cross-talk, acting in both cell types. In LSCs, p38α induces the expression of SDF-1, which activates the stroma. p38α is essential for fibroblast activation and induction of cytokine expression, in particular TNFα. This paracrine network induces a hierarchical activation leading to the recruitment of endothelium, establishing a functional microenvironment. Disruption of this cross-talk abrogates proper LSC differentiation in vivo and may lead to lung dysfunction and disease.

p38α negatively regulates survival and malignant selection of transformed bronchioalveolar stem cells.

Lung cancer is the cause of most cancer-related deaths in the Western world. Non-small cell lung cancer accounts for almost 80% of all lung cancers, and 50% of this type are adenocarcinomas. The cellular and molecular origin of this type of lung cancer remains elusive and the mechanisms are poorly known. It is known that K-Ras mutations appear in 25-30% of lung adenocarcinomas and it is the best known single mutation that can be related to lung cancers. Recently, it has been suggested that a putative population of mouse bronchioalveolar stem cells could be considered as the cell of origin of adenocarcinomas. These cells are expanded in the early stages of lung tumorigenesis. We have isolated a population of mouse bronchioalveolar stem cells and induced their transformation by oncogenic K-RasG12. Different approaches have shown that an intracellular network linking the p38α MAPK and the PI3K-Pdk1 pathways is involved in regulating the survival and malignant progression of the transformed cells. Absence of p38α catalytic activity leads to further Pdk1 activation (independent of Akt and Erk activity), enhancing the survival and proliferation of the more malignant lung cancer cells. This specifically selects high Sca-1/Sox9 cells that harbour a stronger colonizing potential, as they maintain their capacity to produce secondary tumors after serial transplantations.

Isolation, culture, and potentiality assessment of lung alveolar stem cells.

The cellular and molecular elements involved in the turnover and regeneration of the lung alveolar epithelium remain largely unknown (Kim, Am J Physiol Lung Cell Mol Physiol 293:L1092-1098, 2007). Isolation and characterization of putative stem cells with limited and nonspecific markers have made necessary the use, in parallel, of culture restrictive conditions and optimized reagents to allow selection and long-term expansion of this population.

Regulation of human lung alveolar multipotent cells by a novel p38α MAPK/miR-17-92 axis.

The cellular and molecular mechanisms that control lung homeostasis and regeneration are still poorly understood. It has been proposed that a population of cells exists in the mouse lung with the potential to differentiate into all major lung bronchioalveolar epithelium cell types in homeostasis or in response to virus infection. A new population of E-Cad/Lgr6(+) putative stem cells has been isolated, and indefinitely expanded from human lungs, harbouring both, self-renewal capacity and the potency to differentiate in vitro and in vivo. Recently, a putative population of human lung stem cells has been proposed as being c-Kit(+). Unlike Integrin-α6(+) or c-Kit(+) cells, E-Cad/Lgr6(+) single-cell injections in the kidney capsule produce differentiated bronchioalveolar tissue, while retaining self-renewal, as they can undergo serial transplantations under the kidney capsule or in the lung. In addition, a signalling network involving the p38α pathway, the activation of p53 and the regulation of the miR-17-92 cluster has been identified. Disruption of the proper cross-regulation of this signalling axis might be involved in the promotion of human lung diseases.

The many faces of p38 mitogen-activated protein kinase in progenitor/stem cell differentiation.

Regulation of stem cells is essential for development and adult tissue homoeostasis. The proper control of stem cell self-renewal and differentiation maintains organ physiology, and disruption of such a balance results in disease. There are many mechanisms that have been established as stem cell regulators, such as Wnt or Notch signals. However, the intracellular mechanisms that mediate and integrate these signals are not well understood. A new intracellular pathway that has been reported to be involved in the regulation of many stem cell types is that of p38 MAPK (mitogen-activated protein kinase). In particular, p38α is essential for the proper differentiation of many haematopoietic, mesenchymal and epithelial stem/progenitor cells. Many reports have shown that disruption of this kinase pathway has pathological consequences in many organs. Understanding the extracellular cues and downstream targets of p38α in stem cell regulation may help to tackle some of the pathologies associated with improper differentiation and regulation of stem cell function. In the present review we present a vision of the current knowledge on the roles of the p38α signal as a regulator of stem/progenitor cells in different tissues in physiology and disease.

p38alpha MAP kinase is essential in lung stem and progenitor cell proliferation and differentiation.

Stem cell function is central for the maintenance of normal tissue homeostasis. Here we show that deletion of p38alpha mitogen-activated protein (MAP) kinase in adult mice results in increased proliferation and defective differentiation of lung stem and progenitor cells both in vivo and in vitro. We found that p38alpha positively regulates factors such as CCAAT/enhancer-binding protein that are required for lung cell differentiation. In addition, p38alpha controls self-renewal of the lung stem and progenitor cell population by inhibiting proliferation-inducing signals, most notably epidermal growth factor receptor. As a consequence, the inactivation of p38alpha leads to an immature and hyperproliferative lung epithelium that is highly sensitized to K-Ras(G12V)-induced tumorigenesis. Our results indicate that by coordinating proliferation and differentiation signals in lung stem and progenitor cells, p38alpha has a key role in the regulation of lung cell renewal and tumorigenesis.

JNK2 is a positive regulator of the cJun transcription factor.

The cJun NH(2)-terminal kinase (JNK) signal transduction pathway is established to be an important mechanism of regulation of the cJun transcription factor. Studies of Jnk1(-/-) and Jnk2(-/-) mice suggest that the JNK1 and JNK2 isoforms have opposite effects on cJun expression and proliferation. Here, we demonstrate, using a chemical genetic approach, that both JNK1 and JNK2 are positive regulators of these processes. We show that competition between JNK1 and JNK2 contributes to the opposite phenotypes caused by JNK1 and JNK2 deficiency. Our analysis illustrates the power of a chemical genetics approach for the analysis of signal transduction pathways and also highlights the limitations of single gene knockout strategies for the analysis of signaling pathways that are formed by a network of interacting proteins.

Protein kinases and phosphatases as therapeutic targets in cancer.

Protein phosphorylation plays key roles in many physiological processes and is often deregulated in pathological conditions. Our current understanding of how protein kinases and phosphatases orchestrate the phosphorylation changes that control cellular functions has made these enzymes potential drug targets for the treatment of many diseases. The success of the tyrosine kinase inhibitor Gleevec in the treatment of some cancers has further invigorated the development of kinase inhibitors as anti-cancer drugs. A large number of these compounds are currently undergoing clinical trials and there is much expectation on the therapeutic potential of these molecules, as more specific and less toxic drugs than currently used generic chemotherapeutic agents. In this manuscript, we review the current status of more than 30 protein kinase inhibitors with proven or potential therapeutic value for cancer treatment. These include inhibitors of receptor and cytosolic tyrosine kinases as well as compounds that target different families of serine/threonine kinases involved in signalling and cell cycle regulation. We also briefly touch on the prospects of phosphatase inhibitors. The combination of kinase inhibitors to target different components of signalling pathways that are found deregulated in tumours is also emerging as an interesting approach for cancer therapy.

Chemical genetic analysis of the time course of signal transduction by JNK.

Exposure of primary murine embryonic fibroblasts to tumor necrosis factor (TNF) causes biphasic activation of the c-Jun NH(2)-terminal kinase (JNK) signaling pathway. The early phase (30 min) of the response to TNF is a large and transient increase in JNK activity. This response is followed by a second and more sustained phase of JNK activation that lasts many hours. We employed a chemical genetic strategy to dissect the functional consequences of these two phases of JNK activation. We report that both the early and late phases of JNK activation contribute to TNF-induced gene expression. In contrast, the early transient phase of JNK activation (<1 hr) can signal cell survival, while the later and more sustained phase of JNK activation (1-6 hr) can mediate proapoptotic signaling. These data indicate that the time course of JNK signaling can influence the biological response to JNK activation.

Protein kinases and phosphatases as therapeutic targets in cancer

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Protein phosphorylation plays key roles in many physiologicalprocesses and is often deregulated in pathologicalconditions. Our current understanding of howprotein kinases and phosphatases orchestrate thephosphorylation changes that control cellular functionshas made these enzymes potential drug targetsfor the treatment of many diseases. The success of thetyrosine kinase inhibitor Gleevec in the treatment ofsome cancers has further invigorated the developmentof kinase inhibitors as anti-cancer drugs. Alarge number of these compounds are currently undergoingclinical trials and there is much expectationon the therapeutic potential of these molecules, asmore specific and less toxic drugs than currentlyused generic chemotherapeutic agents. In this manuscript,we review the current status of more than 30protein kinase inhibitors with proven or potentialtherapeutic value for cancer treatment. These includeinhibitors of receptor and cytosolic tyrosine kinasesas well as compounds that target different families ofserine/threonine kinases involved in signalling andcell cycle regulation. We also briefly touch on theprospects of phosphatase inhibitors. The combinationof kinase inhibitors to target different components ofsignalling pathways that are found deregulated in tumoursis also emerging as an interesting approach forcancer therapy

EGF blocks NADPH oxidase activation by TGF-beta in fetal rat hepatocytes, impairing oxidative stress, and cell death.

Epidermal growth factor (EGF) is a survival signal for transforming growth factor-beta (TGF-beta)-induced apoptosis in hepatocytes, phosphatidylinositol 3-kinase (PI 3-K) being involved in this effect. Here, we analyze the possible cross talks between EGF and TGF-beta signals to understand how EGF impairs the early pro-apoptotic events induced by TGF-beta. Data have indicated that neither SMAD nor c-Jun NH2 Terminal Kinase (JNK) activations are altered by EGF, which clearly interferes with events directly related to the radical oxygen species (ROS) production, impairing oxidative stress, p38 MAP kinase activation, and cell death. Activation of a NADPH-oxidase-like system, which is responsible for the early ROS production by TGF-beta, is completely inhibited by EGF, through a PI 3-K-dependent mechanism. Activity of RAC1 increases by TGF-beta, but also by EGF, and both act synergistically to get maximum effects. Fetal rat hepatocytes express nox4, in addition to nox1 and nox2, and TGF-beta clearly upregulates nox4. EGF blocks up-regulation of nox4 by TGF-beta. Interestingly, in the presence of PI 3-K inhibitors, EGF is not able to counteract the nox4 upregulation by TGF-beta. Taking together these results indicate that impairment of TGF-beta-induced NADPH oxidase activation by EGF is a RAC1-independent process and correlates with an inhibition of the mechanisms that address the increase of nox4 mRNA levels by TGF-beta.