In this review, we highlight the role of intratumoral heterogeneity, focusing on the clinical and biological ramifications this phenomenon poses. Intratumoral heterogeneity arises through complex ...genetic, epigenetic, and protein modifications that drive phenotypic selection in response to environmental pressures. Functionally, heterogeneity provides tumors with significant adaptability. This ranges from mutual beneficial cooperation between cells, which nurture features such as growth and metastasis, to the narrow escape and survival of clonal cell populations that have adapted to thrive under specific conditions such as hypoxia or chemotherapy. These dynamic intercellular interplays are guided by a Darwinian selection landscape between clonal tumor cell populations and the tumor microenvironment. Understanding the involved drivers and functional consequences of such tumor heterogeneity is challenging but also promises to provide novel insight needed to confront the problem of therapeutic resistance in tumors.
Non-small cell lung cancer (NSCLC) tumors harboring mutations in EGFR ultimately relapse to therapy with EGFR tyrosine kinase inhibitors (EGFR TKIs). Here, we show that resistant cells without the ...p.T790M or other acquired mutations are sensitive to the Aurora B (AURKB) inhibitors barasertib and S49076. Phospho-histone H3 (pH3), a major product of AURKB, is increased in most resistant cells and treatment with AURKB inhibitors reduces the levels of pH3, triggering G1/S arrest and polyploidy. Senescence is subsequently induced in cells with acquired mutations while, in their absence, polyploidy is followed by cell death. Finally, in NSCLC patients, pH3 levels are increased after progression on EGFR TKIs and high pH3 baseline correlates with shorter survival. Our results reveal that AURKB activation is associated with acquired resistance to EGFR TKIs, and that AURKB constitutes a potential target in NSCLC progressing to anti-EGFR therapy and not carrying resistance mutations.
The levels of cell free circulating tumor DNA (ctDNA) in plasma correlated with treatment response and outcome in systemic lymphomas. Notably, in brain tumors, the levels of ctDNA in the ...cerebrospinal fluid (CSF) are higher than in plasma. Nevertheless, their role in central nervous system (CNS) lymphomas remains elusive. We evaluated the CSF and plasma from 19 patients: 6 restricted CNS lymphomas, 1 systemic and CNS lymphoma, and 12 systemic lymphomas. We performed whole exome sequencing or targeted sequencing to identify somatic mutations of the primary tumor, then variant-specific droplet digital PCR was designed for each mutation. At time of enrolment, we found ctDNA in the CSF of all patients with restricted CNS lymphoma but not in patients with systemic lymphoma without CNS involvement. Conversely, plasma ctDNA was detected in only 2/6 patients with restricted CNS lymphoma with lower variant allele frequencies than CSF ctDNA. Moreover, we detected CSF ctDNA in 1 patient with CNS lymphoma in complete remission and in 1 patient with systemic lymphoma, 3 and 8 months before CNS relapse was confirmed; indicating CSF ctDNA might detect CNS relapse earlier than conventional methods. Finally, in 2 cases with CNS lymphoma, CSF ctDNA was still detected after treatment even though a complete decrease in CSF tumor cells was observed by flow cytometry (FC), indicating CSF ctDNA better detected residual disease than FC. In conclusion, CSF ctDNA can better detect CNS lesions than plasma ctDNA and FC. In addition, CSF ctDNA predicted CNS relapse in CNS and systemic lymphomas.
HIV viral reservoirs are established very early during infection. Resident memory T cells (T
) are present in tissues such as the lower female genital tract, but the contribution of this subset of ...cells to the pathogenesis and persistence of HIV remains unclear. Here, we show that cervical CD4
T
display a unique repertoire of clusters of differentiation, with enrichment of several molecules associated with HIV infection susceptibility, longevity and self-renewing capacities. These protein profiles are enriched in a fraction of CD4
T
expressing CD32. Cervical explant models show that CD4
T
preferentially support HIV infection and harbor more viral DNA and protein than non-T
. Importantly, cervical tissue from ART-suppressed HIV
women contain high levels of viral DNA and RNA, being the T
fraction the principal contributor. These results recognize the lower female genital tract as an HIV sanctuary and identify CD4
T
as primary targets of HIV infection and viral persistence. Thus, strategies towards an HIV cure will need to consider T
phenotypes, which are widely distributed in tissues.
Non-small-cell lung cancer patients with activating epidermal growth factor receptor (EGFR) mutations typically benefit from EGFR tyrosine kinase inhibitor treatment. However, virtually all patients ...succumb to acquired EGFR tyrosine kinase inhibitor resistance that occurs via diverse mechanisms. The diversity and unpredictability of EGFR tyrosine kinase inhibitor resistance mechanisms presents a challenge for developing new treatments to overcome EGFR tyrosine kinase inhibitor resistance. Here, we show that Akt activation is a convergent feature of acquired EGFR tyrosine kinase inhibitor resistance, across a spectrum of diverse, established upstream resistance mechanisms. Combined treatment with an EGFR tyrosine kinase inhibitor and Akt inhibitor causes apoptosis and synergistic growth inhibition in multiple EGFR tyrosine kinase inhibitor-resistant non-small-cell lung cancer models. Moreover, phospho-Akt levels are increased in most clinical specimens obtained from EGFR-mutant non-small-cell lung cancer patients with acquired EGFR tyrosine kinase inhibitor resistance. Our findings provide a rationale for clinical trials testing Akt and EGFR inhibitor co-treatment in patients with elevated phospho-Akt levels to therapeutically combat the heterogeneity of EGFR tyrosine kinase inhibitor resistance mechanisms.EGFR-mutant non-small cell lung cancer are often resistant to EGFR tyrosine kinase inhibitor treatment. In this study, the authors show that resistant tumors display high Akt activation and that a combined treatment with AKT inhibitors causes synergistic tumour growth inhibition in vitro and in vivo.
The presence of cirrhosis increases the mortality of patients with peptic ulcer bleeding (PUB). Both acute variceal bleeding (AVB) and PUB are associated with substantial mortality in cirrhosis. This ...multicenter cohort study was performed to assess whether the mortality of patients with cirrhosis with PUB is different from that of those with AVB. Patients with cirrhosis and acute gastrointestinal bleeding were consecutively included and treated with somatostatin and proton pump inhibitor infusion from admission and with antibiotic prophylaxis. Emergency endoscopy with endoscopic therapy was performed within the first 6 hours. 646 patients with AVB and 144 with PUB were included. There were baseline differences between groups, such as use of gastroerosive drugs or β‐blockers. Child‐Pugh and Model for End‐Stage Liver Disease MELD scores were similar. Further bleeding was more frequent in the AVB group than those in the PUB group (18% vs. 10%; odds ratio OR = 0.50; 95% confidence interval CI = 0.29‐0.88). However, mortality risk at 45 days was similar in both groups (19% in the AVB group vs. 17% in the PUB group; OR = 0.85; 95% CI = 0.55‐1.33; P = 0.48). Different parameters, such as Child‐Pugh score, acute kidney injury, acute on chronic liver failure, or presence of shock or bacterial infection, but not the cause of bleeding, were related to the risk of death. Only 2% of the PUB group versus 3% of the AVB group died with uncontrolled bleeding (P = 0.39), whereas the majority of patients in either group died from liver failure or attributed to other comorbidities. Conclusion: Using current first‐line therapy, patients with cirrhosis and acute peptic ulcer bleeding have a similar survival than those with variceal bleeding. The risk of further bleeding is higher in patients with variceal hemorrhage. However, few patients in both groups died from uncontrolled bleeding, rather the cause of death was usually related to liver failure or comorbidities. (Hepatology 2018;67:1458‐1471).
Despite recent advances in the management of BRCA1 mutated high-grade serous ovarian cancer (HGSC), the physiology of these tumors remains poorly understood. Here we provide a comprehensive molecular ...understanding of the signaling processes that drive HGSC pathogenesis with the addition of valuable ubiquitination profiling, and their dependency on BRCA1 mutation-state directly in patient-derived tissues. Using a multilayered proteomic approach, we show the tight coordination between the ubiquitination and phosphorylation regulatory layers and their role in key cellular processes related to BRCA1-dependent HGSC pathogenesis. In addition, we identify key bridging proteins, kinase activity, and post-translational modifications responsible for molding distinct cancer phenotypes, thus providing new opportunities for therapeutic intervention, and ultimately advance towards a more personalized patient care.
Cells that actively transcribe HIV-1 have been defined as the "active viral reservoir" in HIV-infected individuals. However, important technical limitations have precluded the characterization of ...this specific viral reservoir during both treated and untreated HIV-1 infections. Here, we used a novel single-cell RNA fluorescence
hybridization-flow cytometry (FISH-flow) assay that requires only 15 million unfractionated peripheral blood mononuclear cells (PBMCs) to characterize the specific cell subpopulations that transcribe HIV RNA in different subsets of CD4
T cells. In samples from treated and untreated HIV-infected patients, effector memory CD4
T cells were the main cell population supporting HIV RNA transcription. The number of cells expressing HIV correlated with the plasma viral load, intracellular HIV RNA, and proviral DNA quantified by conventional methods and inversely correlated with the CD4
T cell count and the CD4/CD8 ratio. We also found that after
infection of unstimulated PBMCs, HIV-infected T cells upregulated the expression of CD32. In addition, this new methodology detected increased numbers of primary cells expressing viral transcripts and proteins after
viral reactivation with latency reversal agents. This RNA FISH-flow technique allows the identification of the specific cell subpopulations that support viral transcription in HIV-1-infected individuals and has the potential to provide important information on the mechanisms of viral pathogenesis, HIV persistence, and viral reactivation.
Persons infected with HIV-1 contain several cellular viral reservoirs that preclude the complete eradication of the viral infection. Using a novel methodology, we identified effector memory CD4
T cells, immune cells preferentially located in inflamed tissues with potent activity against pathogens, as the main cells encompassing the transcriptionally active HIV-1 reservoir in patients on antiretroviral therapy. Importantly, the identification of such cells provides us with an important target for new therapies designed to target the hidden virus and thus to eliminate the virus from the human body. In addition, because of its ability to identify cells forming part of the viral reservoir, the assay used in this study represents an important new tool in the field of HIV pathogenesis and viral persistence.
The identification of exclusive markers to target HIV-reservoir cells will represent a significant advance in the search for therapies to cure HIV. Here, we identify the B lymphocyte antigen CD20 as ...a marker for HIV-infected cells in vitro and in vivo. The CD20 molecule is dimly expressed in a subpopulation of CD4-positive (CD4
) T lymphocytes from blood, with high levels of cell activation and heterogeneous memory phenotypes. In lymph node samples from infected patients, CD20 is present in productively HIV-infected cells, and ex vivo viral infection selectively upregulates the expression of CD20 during early infection. In samples from patients on antiretroviral therapy (ART) this subpopulation is significantly enriched in HIV transcripts, and the anti-CD20 monoclonal antibody Rituximab induces cell killing, which reduces the pool of HIV-expressing cells when combined with latency reversal agents. We provide a tool for targeting this active HIV-reservoir after viral reactivation in patients while on ART.
Ovarian cancer (OC) is the fifth cancer death cause in women worldwide. The malignant nature of this disease stems from its unique dissemination pattern. Epithelial-to-mesenchymal transition (EMT) ...has been reported in OC and downregulation of Epithelial cadherin (E-cadherin) is a hallmark of this process. However, findings on the relationship between E-cadherin levels and OC progression, dissemination and aggressiveness are controversial. In this study, the evaluation of E-cadherin expression in an OC tissue microarray revealed its prognostic value to discriminate between advanced- and early-stage tumors, as well as serous tumors from other histologies. Moreover, E-cadherin, Neural cadherin (N-cadherin), cytokeratins and vimentin expression was assessed in TOV-112, SKOV-3, OAW-42 and OV-90 OC cell lines grown in monolayers and under anchorage-independent conditions to mimic ovarian tumor cell dissemination, and results were associated with cell aggressiveness. According to these EMT-related markers, cell lines were classified as mesenchymal (M; TOV-112), intermediate mesenchymal (IM; SKOV-3), intermediate epithelial (IE; OAW-42) and epithelial (E; OV-90). M- and IM-cells depicted the highest migration capacity when grown in monolayers, and aggregates derived from M- and IM-cell lines showed lower cell death, higher adhesion to extracellular matrices and higher invasion capacity than E- and IE-aggregates. The analysis of E-cadherin, N-cadherin, cytokeratin 19 and vimentin mRNA levels in 20 advanced-stage high-grade serous human OC ascites showed an IM phenotype in all cases, characterized by higher proportions of N- to E-cadherin and vimentin to cytokeratin 19. In particular, higher E-cadherin mRNA levels were associated with cancer antigen 125 levels more than 500 U/mL and platinum-free intervals less than 6 months. Altogether, E-cadherin expression levels were found relevant for the assessment of OC progression and aggressiveness.
Celotno besedilo
Dostopno za:
DOBA, IZUM, KILJ, NUK, PILJ, PNG, SAZU, SIK, UILJ, UKNU, UL, UM, UPUK
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