bims-cagime Biomed News
on Cancer, aging and metabolism
Issue of 2021‒10‒17
forty-three papers selected by
Kıvanç Görgülü
Technical University of Munich

  1. EJNMMI Res. 2021 Oct 12. 11(1): 104
      The incidence and lethality of pancreatic ductal adenocarcinoma (PDAC) will continue to increase in the next decade. For most patients, chemotherapeutic combination therapies remain the standard of care. The development and successful implementation of precision oncology in other gastrointestinal tumor entities point to opportunities also for PDAC. Therefore, markers linked to specific therapeutic responses and important subgroups of the disease are needed. The MYC oncogene is a relevant driver in PDAC and is linked to drug resistance and sensitivity. Here, we update recent insights into MYC biology in PDAC, summarize the connections between MYC and drug responses, and point to an opportunity to image MYC non-invasively. In sum, we propose MYC-associated biology as a basis for the development of concepts for precision oncology in PDAC.
    Keywords:  MYC; Pancreatic cancer; Precision oncology; Targeted therapies
  2. Trends Cancer. 2021 Oct 11. pii: S2405-8033(21)00194-1. [Epub ahead of print]
      Macropinocytosis, an evolutionarily conserved endocytic mechanism that mediates non-specific fluid-phase uptake, is potently upregulated by various oncogenic pathways. It is now well appreciated that high macropinocytic activity is a hallmark of many human tumors, which use this adaptation to scavenge extracellular nutrients for fueling cell growth. In the context of the nutrient-scarce tumor microenvironment, this process provides tumor cells with metabolic flexibility. However, dependence on this scavenging mechanism also illuminates a potential metabolic vulnerability. As such, there is a great deal of interest in understanding the molecular underpinnings of macropinocytosis. In this review, we will discuss the most recent advances in characterizing macropinocytosis: the pathways that regulate it, its contribution to the metabolic fitness of cancer cells, and its therapeutic potential.
    Keywords:  RAS; macropinocytosis; membrane ruffling; metabolic fitness; nutrient scavenging
  3. Nat Commun. 2021 Oct 13. 12(1): 5989
      Liquid-liquid phase separation promotes the formation of membraneless condensates that mediate diverse cellular functions, including autophagy of misfolded proteins. However, how phase separation participates in autophagy of dysfunctional mitochondria (mitophagy) remains obscure. We previously discovered that nuclear receptor Nur77 (also called TR3, NGFI-B, or NR4A1) translocates from the nucleus to mitochondria to mediate celastrol-induced mitophagy through interaction with p62/SQSTM1. Here, we show that the ubiquitinated mitochondrial Nur77 forms membraneless condensates capable of sequestrating damaged mitochondria by interacting with the UBA domain of p62/SQSTM1. However, tethering clustered mitochondria to the autophagy machinery requires an additional interaction mediated by the N-terminal intrinsically disordered region (IDR) of Nur77 and the N-terminal PB1 domain of p62/SQSTM1, which confers Nur77-p62/SQSTM1 condensates with the magnitude and liquidity. Our results demonstrate how composite multivalent interaction between Nur77 and p62/SQSTM1 coordinates to sequester damaged mitochondria and to connect targeted cargo mitochondria for autophagy, providing mechanistic insight into mitophagy.
  4. Genome Biol. 2021 Oct 14. 22(1): 289
      BACKGROUND: Pancreatic ductal adenocarcinoma initiation is most frequently caused by Kras mutations.RESULTS: Here, we apply biological, biochemical, and network biology methods to validate GEMM-derived cell models using inducible KrasG12D expression. We describe the time-dependent, chromatin remodeling program that impacts function during early oncogenic signaling. We find that the KrasG12D-induced transcriptional response is dominated by downregulated expression concordant with layers of epigenetic events. More open chromatin characterizes the ATAC-seq profile associated with a smaller group of upregulated genes and epigenetic marks. RRBS demonstrates that promoter hypermethylation does not account for the silencing of the extensive gene promoter network. Moreover, ChIP-Seq reveals that heterochromatin reorganization plays little role in this early transcriptional program. Notably, both gene activation and silencing primarily depend on the marking of genes with a combination of H3K27ac, H3K4me3, and H3K36me3. Indeed, integrated modeling of all these datasets shows that KrasG12D regulates its transcriptional program primarily through unique super-enhancers and enhancers, and marking specific gene promoters and bodies. We also report chromatin remodeling across genomic areas that, although not contributing directly to cis-gene transcription, are likely important for KrasG12D functions.
    CONCLUSIONS: In summary, we report a comprehensive, time-dependent, and coordinated early epigenomic program for KrasG12D in pancreatic cells, which is mechanistically relevant to understanding chromatin remodeling events underlying transcriptional outcomes needed for the function of this oncogene.
    Keywords:  Epigenomics; KRAS; Pancreatic cancer
  5. Nature. 2021 Oct 13.
      Human epithelial tissues accumulate cancer-driver mutations with age1-9, yet tumour formation remains rare. The positive selection of these mutations suggests that they alter the behaviour and fitness of proliferating cells10-12. Thus, normal adult tissues become a patchwork of mutant clones competing for space and survival, with the fittest clones expanding by eliminating their less competitive neighbours11-14. However, little is known about how such dynamic competition in normal epithelia influences early tumorigenesis. Here we show that the majority of newly formed oesophageal tumours are eliminated through competition with mutant clones in the adjacent normal epithelium. We followed the fate of nascent, microscopic, pre-malignant tumours in a mouse model of oesophageal carcinogenesis and found that most were rapidly lost with no indication of tumour cell death, decreased proliferation or an anti-tumour immune response. However, deep sequencing of ten-day-old and one-year-old tumours showed evidence of selection on the surviving neoplasms. Induction of highly competitive clones in transgenic mice increased early tumour removal, whereas pharmacological inhibition of clonal competition reduced tumour loss. These results support a model in which survival of early neoplasms depends on their competitive fitness relative to that of mutant clones in the surrounding normal tissue. Mutant clones in normal epithelium have an unexpected anti-tumorigenic role in purging early tumours through cell competition, thereby preserving tissue integrity.
  6. Cell. 2021 Oct 07. pii: S0092-8674(21)01105-3. [Epub ahead of print]
      Intratumoral heterogeneity is a critical frontier in understanding how the tumor microenvironment (TME) propels malignant progression. Here, we deconvolute the human pancreatic TME through large-scale integration of histology-guided regional multiOMICs with clinical data and patient-derived preclinical models. We discover "subTMEs," histologically definable tissue states anchored in fibroblast plasticity, with regional relationships to tumor immunity, subtypes, differentiation, and treatment response. "Reactive" subTMEs rich in complex but functionally coordinated fibroblast communities were immune hot and inhabited by aggressive tumor cell phenotypes. The matrix-rich "deserted" subTMEs harbored fewer activated fibroblasts and tumor-suppressive features yet were markedly chemoprotective and enriched upon chemotherapy. SubTMEs originated in fibroblast differentiation trajectories, and transitory states were notable both in single-cell transcriptomics and in situ. The intratumoral co-occurrence of subTMEs produced patient-specific phenotypic and computationally predictable heterogeneity tightly linked to malignant biology. Therefore, heterogeneity within the plentiful, notorious pancreatic TME is not random but marks fundamental tissue organizational units.
    Keywords:  cancer-associated fibroblasts; pancreatic cancer; patient-derived organoids; proteomics; stromal heterogeneity; systems biology; treatment resistance; tumor microenvironment
  7. Gastroenterology. 2021 Oct 07. pii: S0016-5085(21)03618-0. [Epub ahead of print]
      BACKGROUND & AIMS: Pancreatic ductal adenocarcinoma (PDA) patients have not yet benefitted from the revolution in cancer immunotherapy due in large part to a dominantly immunosuppressive tumor microenvironment (TME). MEK inhibition combined with autophagy inhibition leads to transient tumor responses in some PDA patients. We examined the functional effects of combined MEK and autophagy inhibition on the PDA immune microenvironment and the efficacy of synergizing the combined inhibition of MEK and autophagy with CD40 agonism against PDA using immunocompetent model systems.METHODS: We implanted immunologically "cold" murine PDA cells orthotopically in WT C57BL/6J mice. We administered combinations of inhibitors of MEK1/2, inhibitors of autophagy and CD40 agonism and measured anticancer efficacy and immune sequel using mass cytometry (CyTOF) and CODEX multiplexed immunofluorescence imaging analysis to characterize the TME. We also used human and mouse PDA cell lines and human macrophages in vitro, to perform functional assays to elucidate the cellular effects induced by the treatments.
    RESULTS: We find that co-inhibition of MEK (using cobimetinib, COBI) and autophagy (using mefloquine, MFQ), but not either treatment alone, activates the STING/Type I Interferon pathway in tumor cells which in turn activates paracrine tumor associated macrophages (TAMs) toward an immunogenic M1-like phenotype. This switch is further augmented by a CD40 agonism (aCD40). Triple therapy (COBI+MFQ+aCD40) achieved cytotoxic T cell activation in an immunologically "cold" mouse PDA model, leading to enhanced anti-tumor immunity.
    CONCLUSIONS: MEK and autophagy co-inhibition coupled with CD40 agonism invokes immuno-repolarization and is an attractive therapeutic approach for PDA immunotherapy development.
    Keywords:  Autophagy; CD40 agonism; MAPK Pathway; Macrophage polarization; Pancreatic ductal adenocarcinoma
  8. Cancer Discov. 2021 Oct 14.
      Metastasis is an inefficient process in which the vast majority of cancer cells are fated to die, partly because they experience oxidative stress. Metastasizing cancer cells migrate through diverse environments that differ dramatically from their tumor of origin, leading to redox imbalances. The rare metastasizing cells that survive undergo reversible metabolic changes that confer oxidative stress resistance. We review the changes in redox regulation that cancer cells undergo during metastasis. By better understanding these mechanisms, it may be possible to develop pro-oxidant therapies that block disease progression by exacerbating oxidative stress in cancer cells. SIGNIFICANCE: Oxidative stress often limits cancer cell survival during metastasis, raising the possibility of inhibiting cancer progression with pro-oxidant therapies. This is the opposite strategy of treating patients with antioxidants, an approach that worsened outcomes in large clinical trials.
  9. IUBMB Life. 2021 Oct 15.
      Autophagy is an intracellular catabolic process that degrades cytoplasmic components for recycling in response to stressed conditions, such as nutrient deprivation. Dysregulation of autophagy is associated with various diseases, including cancer. Although autophagy plays dichotomous and context-dependent roles in cancer, evidence has emerged that cancer cells exploit autophagy for metabolic adaptation. Autophagy is upregulated in many cancer types through tumor cell-intrinsic proliferation demands and the hypoxic and nutrient-limited tumor microenvironment (TME). Autophagy-induced breakdown products then fuel into various metabolic pathways to supply tumor cells with energy and building blocks for biosynthesis and survival. This bidirectional regulation between autophagy and tumor constitutes a vicious cycle to potentiate tumor growth and therapy resistance. In addition, the pro-tumor functions of autophagy are expanded to host, including cells in TME and distant organs. Thus, inhibition of autophagy or autophagy-mediated metabolic reprogramming may be a promising strategy for anticancer therapy. Better understanding the metabolic rewiring mechanisms of autophagy for its pro-tumor effects will provide insights into patient treatment.
    Keywords:  anticancer therapy; autophagy; cancer; metabolism; tumor microenvironment
  10. Mech Ageing Dev. 2021 Oct 09. pii: S0047-6374(21)00155-X. [Epub ahead of print] 111583
      Despite continued increases in human life expectancy, the factors determining the rate of human biological aging remain unknown. Without understanding the molecular mechanisms underlying aging, efforts to prevent aging are unlikely to succeed. The tumor suppression theory of aging introduced here proposes somatic mutation as the proximal cause of aging, but postulates that oncogenic transformation and clonal expansion, not functional impairment, are the relevant consequences of somatic mutation. Obesity and caloric restriction accelerate and decelerate aging due to their effect on cell proliferation, during which most mutations arise. Most phenotypes of aging are merely tumor-suppressive mechanisms that evolved to limit malignant growth, the dominant age-related cause of death in early and middle life. Cancer limits life span for most long-lived mammals, a phenomenon known as Peto's paradox. Its conservation across species demonstrates that mutation is a fundamental but hard limit on mammalian longevity. Cell senescence and apoptosis and differentiation induced by oncogenes, telomere shortening or DNA damage evolved as a second line of defense to limit the tumorigenic potential of clonally expanding cells, but accumulating senescent cells, senescence-associated secretory phenotypes and stem cell exhaustion eventually cause tissue dysfunction and the majority, if not most, phenotypes of aging.
    Keywords:  aging; cancer; cell senescence; somatic mutation; tumor suppression
  11. Nat Commun. 2021 Oct 13. 12(1): 5977
      Muscle diseases and aging are associated with impaired myogenic stem cell self-renewal and fewer proliferating progenitors (MPs). Importantly, distinct metabolic states induced by glycolysis or oxidative phosphorylation have been connected to MP proliferation and differentiation. However, how these energy-provisioning mechanisms cooperate remain obscure. Herein, we describe a mechanism by which mitochondrial-localized transcriptional co-repressor p107 regulates MP proliferation. We show p107 directly interacts with the mitochondrial DNA, repressing mitochondrial-encoded gene transcription. This reduces ATP production by limiting electron transport chain complex formation. ATP output, controlled by the mitochondrial function of p107, is directly associated with the cell cycle rate. Sirt1 activity, dependent on the cytoplasmic glycolysis product NAD+, directly interacts with p107, impeding its mitochondrial localization. The metabolic control of MP proliferation, driven by p107 mitochondrial function, establishes a cell cycle paradigm that might extend to other dividing cell types.
  12. Sci Rep. 2021 Oct 15. 11(1): 20526
      UNC51-like kinase-1 (ULK1) is the catalytic component of the autophagy pre-initiation complex that stimulates autophagy via phosphorylation of ATG14, BECLN1 and other autophagy proteins. ULK1 has also been shown to specifically promote mitophagy but the mechanistic basis of how has remained unclear. Here we show that ULK1 phosphorylates the BNIP3 mitochondrial cargo receptor on a critical serine residue (S17) adjacent to its amino terminal LIR motif. ULK1 similarly phosphorylates BNIP3L on S35. Phosphorylation of BNIP3 on S17 by ULK1 promotes interaction with LC3 and mitophagy. ULK1 interaction also promotes BNIP3 protein stability by limiting its turnover at the proteasome. The ability of ULK1 to regulate BNIP3 protein stability depends on an intact "BH3" domain and deletion of its "BH3" domain reduces BNIP3 turnover and increases BNIP3 protein levels independent of ULK1. In summary ULK1 promotes mitophagy by both stabilization of BNIP3 protein and via phosphorylation of S17 to stimulate interaction with LC3.
  13. Gastroenterology. 2021 Oct 12. pii: S0016-5085(21)03623-4. [Epub ahead of print]
      BACKGROUND & AIMS: Metabolic syndrome (MetS) is reversible; however, the effect of changes in MetS status on pancreatic cancer risk is unknown. We aimed to investigate the effects of changes and persistence in MetS status on pancreatic cancer risk.METHODS: This nationwide cohort study included 8,203,492 adults without cancer who underwent two consecutive biennial health screenings provided by the Korean National Health Insurance System between 2009 and 2012 and were followed up until 2017. MetS was defined as the presence of three of its five components, which were evaluated at two consecutive biennial health screenings. Participants were categorized into the MetS-free, MetS-recovered, MetS-developed, or MetS-persistent group. Multivariable Cox proportional hazards regression models were used.
    RESULTS: During the 40,464,586 person-years of follow-up (median, 5.1 years), 8,010 individuals developed pancreatic cancer. Compared to the MetS-free group, the MetS-persistent group had the highest risk of pancreatic cancer (hazard ratio [HR] 1.30, 95% CI 1.23-1.37), followed by the MetS-developed group (HR 1.17, 95% CI 1.09-1.25) and the MetS-recovered group (HR 1.12, 95% CI 1.04-1.21) after adjusting for potential confounders (P for trend < 0.001). The MetS-recovered group was associated with a lower risk of pancreatic cancer than that in the MetS-persistent group (P<0.001). The association between changes in MetS status and pancreatic cancer risk did not differ according to sex or obesity (all P for interactions > 0.05).
    CONCLUSIONS: In this study, recovering from MetS was associated with a reduced risk of pancreatic cancer compared to persistent MetS, suggesting that pancreatic cancer risk can be altered by changes in MetS.
    Keywords:  Malignant tumor; Pancreatic neoplasms; Prevention; Risk factors
  14. World J Stem Cells. 2021 Sep 26. 13(9): 1307-1317
      Previously regarded as simple fat storage particles, new evidence suggests that lipid droplets (LDs) are dynamic and functional organelles involved in key cellular processes such as membrane biosynthesis, lipid metabolism, cell signalling and inflammation. Indeed, an increased LD content is one of the most apparent features resulting from lipid metabolism reprogramming necessary to support the basic functions of cancer cells. LDs have been associated to different cellular processes involved in cancer progression and aggressiveness, such as tumorigenicity, invasion and metastasis, as well as chemoresistance. Interestingly, all of these processes are controlled by a subpopulation of highly aggressive tumoral cells named cancer stem cells (CSCs), suggesting that LDs may be fundamental elements for stemness in cancer. Considering the key role of CSCs on chemoresistance and disease relapse, main factors of therapy failure, the design of novel therapeutic approaches targeting these cells may be the only chance for long-term survival in cancer patients. In this sense, their biology and functional properties render LDs excellent candidates for target discovery and design of combined therapeutic strategies. In this review, we summarise the current knowledge identifying LDs and CSCs as main contributors to cancer aggressiveness, metastasis and chemoresistance.
    Keywords:  Cancer stem cells; Chemoresistance; Lipid droplets; Lipid metabolism; Lipids; Stemness
  15. STAR Protoc. 2021 Dec 17. 2(4): 100850
      This protocol describes the assembly and use of MitoPunch to deliver mitochondria containing mitochondrial DNA (mtDNA) into cells lacking mtDNA (ρ0 cells). MitoPunch generates stable isolated mitochondrial recipient clones with restored mtDNA and recovered respiration, enabling investigation of mtDNA mutations and mtDNA-nuclear DNA interactions in a range of cell types. For complete details on the use and execution of this protocol, please refer to Sercel et al. (2021) and Patananan et al. (2020).
    Keywords:  Biotechnology and bioengineering; Cell Biology; Cell culture; Cell-based Assays; Metabolism
  16. Autophagy. 2021 Oct 13. 1-6
      Nucleophagy, the selective subtype of autophagy that predominantly targets only a selected and (nonessential) portion of the nucleus, and rarely the nucleus in its entirety, for degradation, reinforces the paradigm that nucleophagy recycling is a meticulous and highly delicate process guarded by fail-safe mechanisms. Our goal in this commentary is to encourage autophagy researchers and other scientists to explore nucleophagy blind spots and gain advanced insights into the diverse roles of this process and its selective modality as they pertain to intranuclear quality control and cellular homeostasis. Identifying and deciphering nucleophagic signaling, regulation, molecular mechanism(s) and its mediators, cargo composition and nuclear membrane dynamics under numerous physiological and/or pathological settings will provide important advances in our understanding of this critical type of organelle-selective autophagy.Abbreviations: INM, inner nuclear membrane; LN, late nucleophagy; mRNA, messenger RNA; NE, nuclear envelope; NL, nuclear lamina; NPC(s), nuclear pore complex(es); NVJ(s), nucleus-vacuole junction(s); ONM, outer nuclear membrane; PMN, piecemeal microautophagy of the nucleus; PND, programmed nuclear death; PNuD, programmed nuclear destruction; rDNA/rRNA, ribosomal DNA/RNA.
    Keywords:  Cargo; degradation; homeostasis; macronucleophagy; membrane; micronucleophagy; mode; nucleophagy; nucleus; vacuole
  17. Mol Cell. 2021 Oct 04. pii: S1097-2765(21)00749-8. [Epub ahead of print]
      Rapid protein degradation enables cells to quickly modulate protein abundance. Dysregulation of short-lived proteins plays essential roles in disease pathogenesis. A focused map of short-lived proteins remains understudied. Cycloheximide, a translational inhibitor, is widely used in targeted studies to measure degradation kinetics for short-lived proteins. Here, we combined cycloheximide chase assays with advanced quantitative proteomics to map short-lived proteins under translational inhibition in four human cell lines. Among 11,747 quantified proteins, we identified 1,017 short-lived proteins (half-lives ≤ 8 h). These short-lived proteins are less abundant, evolutionarily younger, and less thermally stable than other proteins. We quantified 103 proteins with different stabilities among cell lines. We showed that U2OS and HCT116 cells express truncated forms of ATRX and GMDS, respectively, which have lower stability than their full-length counterparts. This study provides a large-scale resource of human short-lived proteins under translational arrest, leading to untapped avenues of protein regulation for therapeutic interventions.
    Keywords:  TMTpro tags; multiplexed quantitative proteomics; protein degradation; protein half-lives; short-lived proteins
  18. Autophagy. 2021 Oct 13. 1-3
      Formation of the double-membrane autophagosome requires membrane reorganization of the endomembrane system to generate membrane precursors. The ER-Golgi trafficking system has been shown to provide membranes for phagophore growth. Nonetheless, how the components of the ER-Golgi system are redirected toward autophagosome biogenesis remains unclear. Here, we identify a new type of membrane contact formed between the ER-Golgi intermediate compartment (ERGIC) and the ER-exit sites (ERES) under macroautophagy/autophagy-induction conditions. The ERGIC-ERES contact is established by the TMED9-PREB/SEC12 interaction and regulates the biogenesis of the ERGIC-COPII vesicles, which we found previously act as a membrane template for LC3 lipidation and autophagosome formation.
    Keywords:  Autophagosome; COPII; ERES; ERGIC; SEC12; TMED9; autophagy
  19. Nat Commun. 2021 Oct 15. 12(1): 6035
      Between 6-20% of the cellular proteome is under circadian control and tunes mammalian cell function with daily environmental cycles. For cell viability, and to maintain volume within narrow limits, the daily variation in osmotic potential exerted by changes in the soluble proteome must be counterbalanced. The mechanisms and consequences of this osmotic compensation have not been investigated before. In cultured cells and in tissue we find that compensation involves electroneutral active transport of Na+, K+, and Cl- through differential activity of SLC12A family cotransporters. In cardiomyocytes ex vivo and in vivo, compensatory ion fluxes confer daily variation in electrical activity. Perturbation of soluble protein abundance has commensurate effects on ion composition and cellular function across the circadian cycle. Thus, circadian regulation of the proteome impacts ion homeostasis with substantial consequences for the physiology of electrically active cells such as cardiomyocytes.
  20. Mol Omics. 2021 Oct 11. 17(5): 725-739
      Paradoxically, oncogenes that drive cell cycle progression may also trigger pathways leading to senescence, thereby inhibiting the growth of tumorigenic cells. Knowledge of how these pathways operate, and how tumor cells may evade these pathways, is important for understanding tumorigenesis. The Y1 cell line, which harbors an amplification of the proto-oncogene Ras, rapidly senesces in response to the mitogen fibroblast growth factor-2 (FGF-2). To gain a more complete picture of how FGF-2 promotes senescence, we employed a multi-omics approach to analyze histone modifications, mRNA and protein expression, and protein phosphorylation in Y1 cells treated with FGF-2. Compared to control cells treated with serum alone, FGF-2 caused a delayed accumulation of acetylation on histone H4 and higher levels of H3K27me3. Sequencing analysis revealed decreased expression of cell cycle-related genes with concomitant loss of H3K27ac. At the same time, FGF-2 promoted the expression of p21, various cytokines, and MAPK-related genes. Nuclear envelope proteins, particularly lamin B1, displayed increased phosphorylation in response to FGF-2. Proteome analysis suggested alterations in cellular metabolism, as evident by modulated expression of enzymes involved in purine biosynthesis, tRNA aminoacylation, and the TCA cycle. We propose that Y1 cells senesce due to an inability to progress through the cell cycle, which may stem from DNA damage or TGFb signaling. Altogether, the phenotype of Y1 cells is consistent with rapidly established oncogene-induced senescence, demonstrating the synergy between growth factors and oncogenes in driving senescence and bringing additional insight into this tumor suppressor mechanism.
  21. Cancers (Basel). 2021 Sep 23. pii: 4754. [Epub ahead of print]13(19):
      In cancer, two unique and seemingly contradictory behaviors are evident: on the one hand, tumors are typically stiffer than the tissues in which they grow, and this high stiffness promotes their malignant progression; on the other hand, cancer cells are anchorage-independent-namely, they can survive and grow in soft environments that do not support cell attachment. How can these two features be consolidated? Recent findings on the mechanisms by which cells test the mechanical properties of their environment provide insight into the role of aberrant mechanosensing in cancer progression. In this review article, we focus on the role of high stiffness on cancer progression, with particular emphasis on tumor growth; we discuss the mechanisms of mechanosensing and mechanotransduction, and their dysregulation in cancerous cells; and we propose that a 'yin and yang' type phenomenon exists in the mechanobiology of cancer, whereby a switch in the type of interaction with the extracellular matrix dictates the outcome of the cancer cells.
    Keywords:  ECM; anchorage-independence; mechanosensing; rigidity sensing; tumor stiffness
  22. Cancers (Basel). 2021 Sep 28. pii: 4842. [Epub ahead of print]13(19):
      We aimed to evaluate the association of circulating growth differentiation factor 15 (GDF-15) with cachexia symptoms and the biological activity of advanced pancreatic cancer (APC). Treatment-naïve patients with liver metastasis of APC or with benign pancreatic disease were retrospectively analyzed. Clinical data, blood samples, and biopsy specimens of liver metastasis were collected prior to anti-cancer treatment. Serum GDF-15 levels and multiple protein expressions in lysates extracted from liver metastasis were measured by enzyme-linked immuno-sorbent assay and reverse-phase protein array, respectively. The cut-off for serum GDF-15 was determined as 3356.6 pg/mL, the mean plus two standard deviations for benign pancreatic disease. The high-GDF-15 group was characterized as showing low Karnofsky performance status (KPS) (p = 0.037), poor Eastern Cooperative Oncology Group performance status (ECOG-PS) (p = 0.049), severe appetite loss (p = 0.011), and high serum levels of carbohydrate antigen 19-9 (p = 0.019) and C-reactive protein (p = 0.009). Tumors of the high-GDF-15 group expressed high levels of phosphorylated (p)JNK (p = 0.007) and pAkt (p = 0.040). APC patients with high serum GDF-15 showed signatures of cachexia and activation of the signaling pathways involving Akt and JNK in the tumor. This study indicated circulating GDF-15 could be associated with cachectic symptoms in APC.
    Keywords:  anorexia; cancer cachexia; growth differentiation factor 15; pancreatic cancer
  23. Am J Surg. 2021 Oct 08. pii: S0002-9610(21)00564-X. [Epub ahead of print]
      BACKGROUND: Weight changes during neoadjuvant chemotherapy (NAC) for pancreatic cancer (PDAC) are not well studied. We hypothesized that weight loss may predict poor outcomes.METHODS: Weight change from NAC initiation to pancreatectomy was grouped: gain (≥5%), stable, and loss (≥5%). Pathologic, postoperative, and survival outcomes were compared.
    RESULTS: 95 patients were included: 31.6% lost weight, 58.9% maintained weight, and 9.5% gained weight. There were no differences in chemotherapeutic regimens. Median recurrence-free survival (RFS) and overall survival (OS) were similar between patients with stable weight and those who lost weight (RFS: 9.6vs14.0months; OS: 25.8vs26.7months). Among those who gained weight, RFS (29.5months) and OS (38.4months) were greater relative to the other weight categories. On multivariable regression, weight gain was associated with improved RFS compared to loss (HR = 0.16).
    CONCLUSION: Most patients maintain or lose weight during NAC, and weight loss does not predict poor outcomes. Weight gain may predict improved RFS.
    Keywords:  Body weight; Neoadjuvant therapy; Pancreas neoplasm; Survival analysis; Weight loss
  24. J Cachexia Sarcopenia Muscle. 2021 Oct 11.
      BACKGROUND: Cachexia is characterized by a negative protein and energy balance leading to loss of adipose tissue and muscle mass. Cancer cachexia negatively impacts treatment tolerability and prognosis. Supportive interventions should be initiated as early as possible. Biomarkers for early prediction of continuing weight loss during the course of disease are currently lacking.METHODS: In this pilot, observational, cross-sectional, case-control study, cachectic cancer patients undergoing systemic first-line cancer treatment were matched 2:1 with healthy controls according to age, gender and body mass index. Alterations in amino acid and energy metabolism, as indicated by acylcarnitine levels, were analysed using mass spectrometry in plasma samples (PS) and dried blood specimen (DBS). Welch's two-sample t-test was used for comparative analysis of metabolites between cancer patients and healthy matched controls and to identify the metabolomic profiles related to weight loss across different time points. A linear regression model was applied to correlate weight loss and single metabolites as predictor variables. Finally, metabolite pathway enrichment analyses were performed.
    RESULTS: Eighteen cases (14 male and 4 female) and 36 paired controls were enrolled. There was a good correlation between baseline PS and DBS of healthy controls for the levels of most amino acids but not for acylcarnitine. Amino acid levels related to cancer metabolism were significantly altered in cancer patients compared with controls in both DBS and PS for arginine, citrulline, histidine and ornithine and in DBS only for asparagine, glutamine, methylhistidine, methionine, ornithine, serine, threonine and leucine/isoleucine. Metabolite enrichment analysis in PS of cancer patients revealed histidine metabolism activation (P = 0.0025). Baseline acylcarnitine analysis in DBS was indicative for alterations of the mitochondrial carnitine shuttle, related to β-oxidation: The ratio palmitoylcarnitine/acylcarnitine (Q2) and the ratio palmitoylcarnitine + octadecenoylcarnitine/acylcarnitine (Q3) were predictive for early weight loss (P < 0.0001) and weight loss during follow-up. Activation of tryptophan metabolism (P = 0.035) in DBS and PS and activation of serine/glycine metabolism (P = 0.017) in PS were also related to early weight loss and across successive time points.
    CONCLUSIONS: We found alterations in amino acid levels most likely attributable to cancer metabolism itself in cancer patients compared with controls. Baseline DBS represent a valuable analyte to study energy metabolism related to cancer cachexia. Acylcarnitine patterns (Q2, Q3) predicted further weight loss in cachectic cancer patients undergoing systemic therapy, and pathway analyses indicated involvement of the serine/glycine and the tryptophan pathway in this condition. Validation in larger cohorts is warranted.
    Keywords:  Biomarkers; Cachexia; Cancer; Mass spectrometry; Metabolomics; Weight loss
  25. Trends Mol Med. 2021 Oct 07. pii: S1471-4914(21)00251-3. [Epub ahead of print]
      Preclinical research shows that autophagy is a modifiable process that holds promise for preventing human age-related disease. However, this knowledge has not been clinically translated. Here, we discuss recent developments in the ability to measure human autophagy, and why it is a critical step for translation.
    Keywords:  ageing; autophagic flux; autophagy; blood; human; translation
  26. Cancer Biol Ther. 2021 Oct 10. 1-7
      BACKGROUND: The technique to analyze circulating tumor DNA (ctDNA) in body fluid (so-called "liquid biopsy") is recently developed.AIMS: Our aim was to assess the utility of liquid biopsy for predicting progression of pancreatic ductal adenocarcinoma (PDAC) after surgical resection or chemotherapy.
    METHODS: A total of 72 patients with PDAC were retrospectively enrolled for this study, 33 treated surgically and 39 given chemotherapy, either FOLFIRINOX (oxaliplatin/irinotecan/fluorouracil/leucovorin) or gemcitabine plus nab-paclitaxel. Prior to treatment, patients were screened for the presence of KRAS mutations (G12D and G12V) in plasma using droplet digital polymerase chain reaction, and outcomes were compared.
    RESULTS: KRAS mutations were identified in plasma samples of 12 patients (36%) underwent surgical resection. Patients with plasma KRAS mutations had significantly shorter disease-free survival (DFS) and overall survival (p < .01 and p = .01, respectively). Of 10 clinical variables analyzed, plasma KRAS mutation was the factor predictive of DFS in multivariate analysis (RR = 3.58, 95% CI: 1.36-9.60; p = .01). Although 12 patients (31%) given chemotherapy tested positive for plasma KRAS mutations, there was no demonstrable relation between plasma KRAS mutations and progression-free survival (PFS) or overall survival (OS) (p = .35 and p = .68, respectively).
    CONCLUSIONS: In patients with PDAC, detection of KRAS mutations in plasma proved independently predictive of early recurrence after surgical resection but did not correlate with PFS following chemotherapy.
    Keywords:  Chemotherapy; disease-free survival; droplet digital polymerase chain reaction; progression-fee survival; surgical resection
  27. Elife. 2021 Oct 15. pii: e69056. [Epub ahead of print]10
      Peripheral nerve injury-induced neuropathic pain is a chronic and debilitating condition characterized by mechanical hypersensitivity. We previously identified microglial activation via release of colony stimulating factor 1 (CSF1) from injured sensory neurons as a mechanism contributing to nerve injury-induced pain. Here we show that intrathecal administration of CSF1, even in the absence of injury, is sufficient to induce pain behavior, but only in male mice. Transcriptional profiling and morphologic analyses after intrathecal CSF1 showed robust immune activation in male but not female microglia. CSF1 also induced marked expansion of lymphocytes within the spinal cord meninges, with preferential expansion of regulatory T-cells (Tregs) in female mice. Consistent with the hypothesis that Tregs actively suppress microglial activation in females, Treg deficient (Foxp3DTR) female mice showed increased CSF1-induced microglial activation and pain hypersensitivity equivalent to males. We conclude that sexual dimorphism in the contribution of microglia to pain results from Treg-mediated suppression of microglial activation and pain hypersensitivity in female mice.
    Keywords:  mouse; neuroscience
  28. Cancers (Basel). 2021 Sep 28. pii: 4869. [Epub ahead of print]13(19):
      BACKGROUND: Desmoplasia is a central feature of the tumor microenvironment in pancreatic ductal adenocarcinoma (PDAC). LDE225 is a pharmacological Hedgehog signaling pathway inhibitor and is thought to specifically target tumor stroma. We investigated the combined use of LDE225 and chemotherapy to treat PDAC patients.METHODS: This was a multi-center, phase I/II study for patients with metastatic PDAC establishing the maximum tolerated dose of LDE225 co-administered with gemcitabine and nab-paclitaxel (phase I) and evaluating the efficacy and safety of the treatment combination after prior FOLFIRINOX treatment (phase II). Tumor microenvironment assessment was performed with quantitative MRI using intra-voxel incoherent motion diffusion weighted MRI (IVIM-DWI) and dynamic contrast-enhanced (DCE) MRI.
    RESULTS: The MTD of LDE225 was 200 mg once daily co-administered with gemcitabine 1000 mg/m2 and nab-paclitaxel 125 mg/m2. In phase II, six therapy-related grade 4 adverse events (AE) and three grade 5 were observed. In 24 patients, the target lesion response was evaluable. Three patients had partial response (13%), 14 patients showed stable disease (58%), and 7 patients had progressive disease (29%). Median overall survival (OS) was 6 months (IQR 3.9-8.1). Blood plasma fraction (DCE) and diffusion coefficient (IVIM-DWI) significantly increased during treatment. Baseline perfusion fraction could predict OS (>222 days) with 80% sensitivity and 85% specificity.
    CONCLUSION: LDE225 in combination with gemcitabine and nab-paclitaxel was well-tolerated in patients with metastatic PDAC and has promising efficacy after prior treatment with FOLFIRINOX. Quantitative MRI suggested that LDE225 causes increased tumor diffusion and works particularly well in patients with poor baseline tumor perfusion.
    Keywords:  Hedgehog signaling pathway inhibitor; LDE225; metastatic pancreatic ductal adenocarcinoma; pancreatic neoplasms; quantitative MRI
  29. Semin Cancer Biol. 2021 Oct 07. pii: S1044-579X(21)00252-2. [Epub ahead of print]
      Hypoxia is arguably the first recognized cancer microenvironment hallmark and affects virtually all cellular populations present in tumors. During the past decades the complex adaptive cellular responses to oxygen deprivation have been largely elucidated, raising hope for new anti cancer agents. Despite undeniable preclinical progress, therapeutic targeting of tumor hypoxia is yet to transition from bench to bedside. This review focuses on new pharmacological agents that exploit tumor hypoxia or interfere with hypoxia signaling and discusses strategies to maximize their therapeutic impact.
    Keywords:  HIF inhibitors; HIF1; HIF2; Hypoxia; Hypoxia-activated prodrug
  30. Ann Immunol Immunother. 2021 ;pii: 134. [Epub ahead of print]3(1):
  31. Elife. 2021 Oct 12. pii: e69324. [Epub ahead of print]10
      Single-cell expression profiling opens up new vistas on cellular processes. Extensive cell-to-cell variability at the transcriptomic and proteomic level has been one of the stand-out observations. Because most experimental analyses are destructive we only have access to snapshot data of cellular states. This loss of temporal information presents significant challenges for inferring dynamics, as well as causes of cell-to-cell variability. In particular, we typically cannot separate dynamic variability from within cells ('intrinsic noise') from variability across the population ('extrinsic noise'). Here we make this non-identifiability mathematically precise, allowing us to identify new experimental set-ups that can assist in resolving this non-identifiability. We show that multiple generic reporters from the same biochemical pathways (e.g. mRNA and protein) can infer magnitudes of intrinsic and extrinsic transcriptional noise, identifying sources of heterogeneity. Stochastic simulations support our theory, and demonstrate that 'pathway-reporters' compare favourably to the well-known, but often difficult to implement, dual-reporter method.
    Keywords:  chromosomes; computational biology; gene expression; none; systems biology
  32. Ann Surg Oncol. 2021 Oct 16.
      BACKGROUND: The influence of social determinants of health (SDH) on participation in clinical trials for pancreatic cancer is not well understood. In this study, we describe trends and identify disparities in pancreatic cancer clinical trial enrollment.PATIENTS AND METHODS: This is a retrospective study of stage I-IV pancreatic cancer patients in the 2004-2016 National Cancer Database. Cohort was stratified into those enrolled in clinical trials during first course of treatment versus not enrolled. Bivariate analysis and logistic regression were used to understand the relationship between SDH and clinical trial participation.
    RESULTS: A total of 1127 patients (0.4%) enrolled in clinical trials versus 301,340 (99.6%) did not enroll. Enrollment increased over the study period (p < 0.001), but not for Black patients or patients on Medicaid. The majority enrolled had metastatic disease (65.8%). On multivariate analysis, in addition to year of diagnosis (p < 0.001), stage (p < 0.001), and Charlson score (p < 0.001), increasing age [odds ratio (OR) 0.96, 95% confidence interval (CI) 0.96-0.97], non-white race (OR 0.54, CI 0.44-0.66), living in the South (OR 0.42, CI 0.35-0.51), and Medicaid, lack of insurance, or unknown insurance (0.41, CI 0.31-0.53) were predictors of lack of participation. Conversely, treatment at an academic center (OR 6.36, CI 5.4-7.4) and higher neighborhood education predicted enrollment (OR 2.0, CI 1.55-2.67 for < 7% with no high school degree versus > 21%).
    DISCUSSION: Age, race, insurance, and geography are barriers to clinical trial enrollment for pancreatic cancer patients. While overall enrollment increased, Black patients and patients on Medicaid remain underrepresented. After adjusting for cancer-specific factors, SDH are still associated with clinical trial enrollment, suggesting need for targeted interventions.
    Keywords:  Clinical trials; Health disparities; Pancreatic cancer; Social determinants of health
  33. Nucleic Acids Res. 2021 Oct 13. pii: gkab905. [Epub ahead of print]
      With the proliferating studies of human cancers by single-cell RNA sequencing technique (scRNA-seq), cellular heterogeneity, immune landscape and pathogenesis within diverse cancers have been uncovered successively. The exponential explosion of massive cancer scRNA-seq datasets in the past decade are calling for a burning demand to be integrated and processed for essential investigations in tumor microenvironment of various cancer types. To fill this gap, we developed a database of Cancer Single-cell Expression Map (CancerSCEM,, particularly focusing on a variety of human cancers. To date, CancerSCE version 1.0 consists of 208 cancer samples across 28 studies and 20 human cancer types. A series of uniformly and multiscale analyses for each sample were performed, including accurate cell type annotation, functional gene expressions, cell interaction network, survival analysis and etc. Plus, we visualized CancerSCEM as a user-friendly web interface for users to browse, search, online analyze and download all the metadata as well as analytical results. More importantly and unprecedentedly, the newly-constructed comprehensive online analyzing platform in CancerSCEM integrates seven analyze functions, where investigators can interactively perform cancer scRNA-seq analyses. In all, CancerSCEM paves an informative and practical way to facilitate human cancer studies, and also provides insights into clinical therapy assessments.
  34. PLoS Med. 2021 Oct;18(10): e1003771
      Christopher Abbosh and Charles Swanton discuss circulating tumor DNA as a potential biomarker for neoadjuvant treatment response in solid tumors.
  35. Nat Metab. 2021 Oct 14.
      Tumour necrosis factor (TNF) is a classical, pleiotropic pro-inflammatory cytokine. It is also the first 'adipokine' described to be produced from adipose tissue, regulated in obesity and proposed to contribute to obesity-associated metabolic disease. In this review, we provide an overview of TNF in the context of metabolic inflammation or metaflammation, its discovery as a metabolic messenger, its sites and mechanisms of action and some critical considerations for future research. Although we focus on TNF and the studies that elucidated its immunometabolic actions, we highlight a conceptual framework, generated by these studies, that is equally applicable to the complex network of pro-inflammatory signals, their biological activity and their integration with metabolic regulation, and to the field of immunometabolism more broadly.
  36. Clin Sci (Lond). 2021 Oct 15. 135(19): 2265-2283
      Heart failure with preserved ejection fraction (HFpEF) is a growing public health concern, with rising incidence alongside high morbidity and mortality. However, the pathophysiology of HFpEF is not yet fully understood. The association between HFpEF and the metabolic syndrome (MetS) suggests that dysregulated lipid metabolism could drive diastolic dysfunction and subsequent HFpEF. Herein we summarise recent advances regarding the pathogenesis of HFpEF in the context of MetS, with a focus on impaired lipid handling, myocardial lipid accumulation and subsequent lipotoxicity.
    Keywords:  diastolic dysfunction; heart failure with preserved ejection fraction; lipid metabolism; lipotoxicity; metabolic syndrome
  37. Cell Rep. 2021 Oct 12. pii: S2211-1247(21)01297-3. [Epub ahead of print]37(2): 109833
      Glucose tolerance represents a complex phenotype in which many tissues play important roles and interact to regulate metabolic homeostasis. Here, we perform an analysis of 13C6-glucose tissue distribution, which maps the metabolome and lipidome across 12 metabolically relevant mouse organs and plasma, with integrated 13C6-glucose-derived carbon tracing during oral glucose tolerance test (OGTT). We measure time profiles of water-soluble metabolites and lipids and integrate the global metabolite response into metabolic pathways. During the OGTT, glucose use is turned on with specific kinetics at the organ level, but fasting substrates like β-hydroxybutyrate are switched off in all organs simultaneously. Timeline profiling of 13C-labeled fatty acids and triacylglycerols across tissues suggests that brown adipose tissue may contribute to the circulating fatty acid pool at maximal plasma glucose levels. The GTTAtlas interactive web application serves as a unique resource for the exploration of whole-body glucose metabolism and time profiles of tissue and plasma metabolites during the OGTT.
    Keywords:  13C; brown adipose tissue; de novo lipogenesis; glucose tolerance; lipidomics; metabolite cycling; metabolomics; metabolomics atlas; pathway analysis; tracer analysis
  38. Elife. 2021 Oct 11. pii: e70471. [Epub ahead of print]10
      To assure complete tumor removal, frozen section analysis is the most common procedure for intraoperative pathological assessment of resected tumor margins. However, during one operation, multiple biopsies may be sent for examination, but only few of them are made into cryosections because of the complex preparation protocols and time-consuming pathological analysis, which potentially increases the risk of overlooking tumor involvement. Here, we propose a fluorescence-based pre-screening strategy that allows high-throughput, convenient, and fast gross assessment of resected tumor margins. A dual-activatable cationic fluorescent molecular rotor was developed to specifically illuminate live tumor cells' cytoplasm by emitting two different fluorescence signals in response to elevations in hypoxia-induced nitroreductase (a biochemical marker) and cytoplasmic viscosity (a biophysical marker), two characteristics of cancer cells. The ability of the fluorescent molecular rotor in detecting tumor cells was evaluated in mouse and human specimens of multiple tissues by comparing with hematoxylin and eosin staining. Importantly, the fluorescent molecular rotor achieved 100% specificity in discriminating lung and liver cancers from normal tissue, allowing pre-screening of the tumor-free surgical margins and promoting clinical decision. Altogether, this type of fluorescent molecular rotor and the proposed strategy may serve as a new option to facilitate intraoperative assessment of resected tumor margins.
    Keywords:  biochemistry; chemical biology; human
  39. Nat Commun. 2021 Oct 11. 12(1): 5930
      Malignancy is associated with changes in cell mechanics that contribute to extensive cell deformation required for metastatic dissemination. We hypothesized that the cell-intrinsic physical factors that maintain epithelial cell mechanics could function as tumor suppressors. Here we show, using optical tweezers, genetic interference, mechanical perturbations, and in vivo studies, that epithelial cells maintain higher plasma membrane (PM) tension than their metastatic counterparts and that high PM tension potently inhibits cancer cell migration and invasion by counteracting membrane curvature sensing/generating BAR family proteins. This tensional homeostasis is achieved by membrane-to-cortex attachment (MCA) regulated by ERM proteins, whose disruption spontaneously transforms epithelial cells into a mesenchymal migratory phenotype powered by BAR proteins. Consistently, the forced expression of epithelial-mesenchymal transition (EMT)-inducing transcription factors results in decreased PM tension. In metastatic cells, increasing PM tension by manipulating MCA is sufficient to suppress both mesenchymal and amoeboid 3D migration, tumor invasion, and metastasis by compromising membrane-mediated mechanosignaling by BAR proteins, thereby uncovering a previously undescribed mechanical tumor suppressor mechanism.
  40. Pancreas. 2021 Aug 01. 50(7): 923-932
      ABSTRACT: Pancreatic cancer, especially pancreatic ductal adenocarcinoma (PDAC), has for long remained a deadly form of cancer characterized by high mortality rates resulting from metastasis to multiple organs. Several factors, including the late manifestation of the disease, partly amplified by lack of efficient screening methods, have hampered the drive to design an effective therapeutic strategy to treat this deadly cancer. Understanding the biology of PDAC progression and identifying critical genes regulating these processes are essential to overcome the barriers toward effective treatment. Metastasis suppressor genes have been shown to inhibit multiple steps in the metastatic cascade without affecting primary tumor formation and are considered to hold promise for treating metastatic cancers. In this review, we catalog the bona fide metastasis suppressor genes reported in PDAC and discuss their known mechanism of action.