Favor Tumor Progression Research Articles

Oncogenic Properties of the EBV ZEBRA Protein.

Epstein Barr Virus (EBV) is one of the most common human herpesviruses. After primary infection, it can persist in the host throughout their lifetime in a latent form, from which it can reactivate following specific stimuli. EBV reactivation is triggered by transcriptional transactivator proteins ZEBRA (also known as Z, EB-1, Zta or BZLF1) and RTA (also known as BRLF1). Here we discuss the structural and functional features of ZEBRA, its role in oncogenesis and its possible implication as a prognostic or diagnostic marker. Modulation of host gene expression by ZEBRA can deregulate the immune surveillance, allow the immune escape, and favor tumor progression. It also interacts with host proteins, thereby modifying their functions. ZEBRA is released into the bloodstream by infected cells and can potentially penetrate any cell through its cell-penetrating domain; therefore, it can also change the fate of non-infected cells. The features of ZEBRA described in this review outline its importance in EBV-related malignancies.

Hypoxia-mediated changes in bone marrow microenvironment in breast cancer dormancy.

Breast cancer (BC) remains a clinical challenge despite improved treatments and public awareness to ensure early diagnosis. A major issue is the ability of BC cells (BCCs) to survive as dormant cancer cells in the bone marrow (BM), resulting in the cancer surviving for decades with the potential to resurge as metastatic cancer. The experimental evidence indicates similarity between dormant BCCs and other stem cells, resulting in the preponderance of data to show dormant BCCs being cancer stem cells (CSCs). The BM niche and their secretome support BCC dormancy. Lacking in the literature is a comprehensive research to describe how the hypoxic environment within the BM may influence the behavior of BCCs. This information is relevant to understand the prognosis of BC in young and aged individuals whose oxygen levels differ in BM. This review discusses the changing information on vascularity in different regions of the BM and the impact on endogenous hematopoietic stem cells (HSCs). This review highlights the necessary information to provide insights on vascularity of different BM regions on the behavior of BCCs, in particular a dormant phase. For instance, how the transcription factor HIF1-α (hypoxia-inducible factor 1 alpha), functioning as first responder under hypoxic conditions, affects the expression of specific gene networks involved in energy metabolism, cell survival, tumor invasion and angiogenesis. This enables cell fate transition and facilitates tumor heterogeneity, which in turn favors tumor progression and resistance to anticancer treatments Thus, HIF1-α could be a potential target for cancer treatment. This review describes epigenetic mechanisms involved in hypoxic responses during cancer dormancy in the bone marrow. The varied hypoxic environment in the BM is relevant to understand the complex process of the aging bone marrow for insights on breast cancer outcome between the young and aged.

Long-Term Exposure of Early-Transformed Human Mammary Cells to Low Doses of Benzo[a]pyrene and/or Bisphenol A Enhances Their Cancerous Phenotype via an AhR/GPR30 Interplay.

It is of utmost importance to decipher the role of chronic exposure to low doses of environmental carcinogens on breast cancer progression. The early-transformed triple-negative human mammary MCF10AT1 cells were chronically (60 days) exposed to low doses (10−10 M) of Benzo[a]pyrene (B[a]P), a genotoxic agent, and/or Bisphenol A (BPA), an endocrine disruptor. Our study revealed that exposed MCF10AT1 cells developed, in a time-dependent manner, an acquired phenotype characterized by an increase in cancerous properties (anchorage independent growth and stem-like phenotype). Co-exposure of MCF10AT1 cells to B[a]P and BPA led to a significantly greater aggressive phenotype compared to B[a]P or BPA alone. This study provided new insights into the existence of a functional interplay between the aryl hydrocarbon receptor (AhR) and the G protein-coupled receptor 30 (GPR30) by which chronic and low-dose exposure of B[a]P and/or BPA fosters the progression of MCF10AT1 cells into a more aggressive substage. Experiments using AhR or GPR30 antagonists, siRNA strategies, and RNAseq analysis led us to propose a model in which AhR signaling plays a “driver role” in the AhR/GPR30 cross-talk in mediating long-term and low-dose exposure of B[a]P and/or BPA. Retrospective analysis of two independent breast cancer cohorts revealed that the AhR/GPR30 mRNA expression signature resulted in poor breast cancer prognosis, in particular in the ER-negative and the triple-negative subtypes. Finally, the study identified targeting AhR and/or GPR30 with specific antagonists as a strategy capable of inhibiting carcinogenesis associated with chronic exposure to low doses of B[a]P and BPA in MCF10AT1 cells. Altogether, our results indicate that the engagement of both AhR and GPR30 functions, in particular in an ER-negative/triple-negative context of breast cells, favors tumor progression and leads to poor prognosis.

Unraveling Adipocytes and Cancer Links: Is There a Role for Senescence?

Senescence is characterized by a permanent cell cycle arrest that is elicited in response to different stresses. In addition, senescent cells undergo multiple other phenotypic alterations, such as autophagy modulation, metabolic reprogramming, and the senescence-associated secretory phenotype (SASP). These senescence-related and inflammatory effects prevail within tumors and are strongly controlled by cancer properties, and inflammatory mediators further maintain and propagate the senescence process to adjacent cells. It is important to consider these detrimental effects that may drive tumorigenesis or cancer relapse. Importantly, cancer-associated adipocytes (CAAs) are one of the primary stromal cells in various tumor microenvironments and favor tumor progression by releasing various factors that can mediate local and systemic effects. However, it remains unclear whether CAAs possess senescent features. In this review, we discuss the complex relationship between senescence and CAAs and highlight important considerations for therapeutics.

Breast Adipocyte Co-culture Increases the Expression of Pro-angiogenic Factors in Macrophages.

Obese individuals with breast cancer have a poorer prognosis and higher risk of metastatic disease vs. non-obese patients. Adipose tissue in obese individuals is characterized by an enhanced macrophage infiltration, creating a microenvironment that favors tumor progression. Here, we demonstrate a role for adipocyte-macrophage interactions in the regulation of angiogenesis. Co-culture of THP-1 macrophages with human breast adipocytes led to increased expression of the pro-angiogenic growth factor, vascular endothelial growth factor A (VEGFA). Several adipocyte-derived proteins including leptin, insulin, IL-6, and TNF-α were each capable of increasing VEGFA expression in THP-1 macrophages, identifying these as possible mediators of the changes that were observed with co-culture. Furthermore, analysis of THP-1 culture media by antibody array revealed that THP-1 secrete several other pro-angiogenic signals in response to adipocyte co-culture, including interleukin 8 (IL-8), matrix metalloproteinase 9 (MMP9), pentraxin 3 (PTX3), and serpin E1 (plasminogen activator inhibitor 1, PAI1) after co-culture with human adipocytes. We used an in vitro endothelial tube formation assay with human vascular endothelial cells to evaluate the effects of THP-1 culture media on angiogenesis. Here, culture media from THP-1 cells previously exposed to human adipocytes stimulated endothelial tube formation more significantly than THP-1 cells cultured alone. In summary, we find that adipocyte co-culture stimulates the expression of pro-angiogenic mediators in macrophages and has pro-angiogenic effects in vitro, thus representing a possible mechanism for the enhanced risk of breast cancer progression in obese individuals.

Chromosomes function as a barrier to mitotic spindle bipolarity in polyploid cells.

Ploidy variations such as genome doubling are frequent in human tumors and have been associated with genetic instability favoring tumor progression. How polyploid cells deal with increased centrosome numbers and DNA content remains unknown. Using Drosophila neuroblasts and human cancer cells to study mitotic spindle assembly in polyploid cells, we found that most polyploid cells divide in a multipolar manner. We show that even if an initial centrosome clustering step can occur at mitotic entry, the establishment of kinetochore-microtubule attachments leads to spatial chromosome configurations, whereby the final coalescence of supernumerary poles into a bipolar array is inhibited. Using in silico approaches and various spindle and DNA perturbations, we show that chromosomes act as a physical barrier blocking spindle pole coalescence and bipolarity. Importantly, microtubule stabilization suppressed multipolarity by improving both centrosome clustering and pole coalescence. This work identifies inhibitors of bipolar division in polyploid cells and provides a rationale to understand chromosome instability typical of polyploid cancer cells.

Overexpression of molecule GRP94 favors tumor progression in lung adenocarcinoma by interaction with regulatory T cells.

BackgroundEndoplasmic reticulum stress exists within a tumor. Glucose‐regulated protein 94 (GRP94) is a stress‐induced chaperone protein involved in tumor development and progression. Its role in myeloma, colon cancer, and other tumors has been confirmed, but its role in lung cancer is unclear. This study aimed to determine the role of GRP94 in lung cancer progression and prognostic prediction.MethodsImmunohistochemical staining of GRP94 in human lung adenocarcinoma (AD) and corresponding normal tissue was performed, and its relationship with FOXP3+ regulatory T‐cell (Treg) infiltration analyzed. We investigated the role of GRP94 in the behavior of lung AD cells by inhibiting GRP94 expression in A549 cells. Western blotting was used to detect the TGF‐β/SMAD2 signaling molecules and explore the possible molecular mechanism of GRP94.ResultsGRP94 mRNA (encoded by HSP90B1) and protein levels were upregulated and elevated, respectively, in lung AD compared to normal lung tissues. High GRP94 expression was associated with an advanced disease stage and poor survival. There was a positive correlation between GRP94 expression and FOXP3+ Treg infiltration into lung AD tissues. Our results confirm that GRP94 knockdown inhibits cell proliferation and promotes cell apoptosis by increasing caspase‐7 and CHOP levels in lung AD cells. TGF‐β and SMAD2 protein levels were decreased after GRP94 depletion.ConclusionsOur study revealed that that GRP94 expression in lung AD favors tumor progression and predicts poor prognosis. The oncogenic role of GRP94 may involve inducing Treg infiltration by promoting the TGF‐β signaling pathway.Key points GRP94 protein levels were elevated in lung AD tissues compared to normal lung tissues. The high expression of GRP94 in lung AD favors tumor progression and predicts poor prognosis.The oncogenic role of the molecule GRP94 may involve the stimulation of Treg infiltration via promotion of the TGF‐β signaling pathway.

Cycling hypoxia promotes a pro-inflammatory phenotype in macrophages via JNK/p65 signaling pathway

Cycling hypoxia (cyH), also called intermittent hypoxia, occurs in solid tumors and affects different cell types in the tumor microenvironment and in particular the tumor-associated macrophages (TAMs). As cyH and TAMs both favor tumor progression, we investigated whether cyH could drive the pro-tumoral phenotype of macrophages. Here, the effects of cyH on human THP-1 macrophages and murine bone marrow-derived macrophages (BMDM), either unpolarized M0, or polarized in M1 or M2 phenotype were studied. In M0 macrophages, cyH induced a pro-inflammatory phenotype characterized by an increase in TNFα and IL-8/MIP-2 secretion. CyH amplified the pro-inflammatory phenotype of M1 macrophages evidenced by an increased pro-inflammatory cytokine secretion and pro-inflammatory gene expression. Furthermore, cyH increased c-jun activation in human M0 macrophages and highly increased c-jun and NF-κB activation in M1 macrophages. C-jun and p65 are implicated in the effects of cyH on M0 and M1 macrophages since inhibition of their activation prevented the cyH pro-inflammatory effects. In conclusion, we demonstrated that cyH induces or amplifies a pro-inflammatory phenotype in M0 and M1 macrophages by activating JNK/p65 signaling pathway. These results highlight a specific role of cyH in the amplification of tumor-related inflammation by modulating the inflammatory phenotype of macrophages.

The biology of Lonp1: More than a mitochondrial protease.

Initially discovered as a protease responsible for degradation of misfolded or damaged proteins, the mitochondrial Lon protease (Lonp1) turned out to be a multifaceted enzyme, that displays at least three different functions (proteolysis, chaperone activity, binding of mtDNA) and that finely regulates several cellular processes, within and without mitochondria. Indeed, LONP1 in humans is ubiquitously expressed, and is involved in regulation of response to oxidative stress and, heat shock, in the maintenance of mtDNA, in the regulation of mitophagy. Furthermore, its proteolytic activity can regulate several biochemical pathways occurring totally or partially within mitochondria, such as TCA cycle, oxidative phosphorylation, steroid and heme biosynthesis and glutamine production. Because of these multiple activities, Lon protease is highly conserved throughout evolution, and mutations occurring in its gene determines severe diseases in humans, including a rare syndrome characterized by Cerebral, Ocular, Dental, Auricular and Skeletal anomalies (CODAS). Finally, alterations of LONP1 regulation in humans can favor tumor progression and aggressiveness, further highlighting the crucial role of this enzyme in mitochondrial and cellular homeostasis.

Spotlight on ROS andβ3-Adrenoreceptors Fighting in Cancer Cells

The role of ROS and RNS is a long-standing debate in cancer. Increasing the concentration of ROS reaching the toxic threshold can be an effective strategy for the reduction of tumor cell viability. On the other hand, cancer cells, by maintaining intracellular ROS concentration at an intermediate level called “mild oxidative stress,” promote the activation of signaling that favors tumor progression by increasing cell viability and dangerous tumor phenotype. Many chemotherapeutic treatments induce cell death by rising intracellular ROS concentration. The persistent drug stimulation leads tumor cells to simulate a process called hormesis by which cancer cells exhibit a biphasic response to exposure to drugs used. After a first strong response to a low dose of chemotherapeutic agent, cancer cells start to decrease the response even if high doses of drugs were used. In this framework, β3-adrenoreceptors (β3-ARs) fit with an emerging antioxidant role in cancer. β3-ARs are involved in tumor proliferation, angiogenesis, metastasis, and immune tolerance. Its inhibition, by the selective β3-ARs antagonist (SR59230A), leads cancer cells to increase ROS concentration thus inducing cell death and to decrease NO levels thus inhibiting angiogenesis. In this review, we report an overview on reactive oxygen biology in cancer cells focusing on β3-ARs as new players in the antioxidant pathway.

The immune landscape of chondrosarcoma - potential for therapeutic targeting of CSFR1+ macrophages

Survival rate for Chondrosarcoma (CHS) is at a standstill, more effective treatments are urgently needed. Consequently, a better understanding of CHS biology and its immune environment is crucial to identify new prognostic factors and therapeutic targets.Here, we exhaustively describe the immune landscape of conventional and dedifferentiated CHS. Using IHC and molecular analyses (RT-qPCR), we mapped the expression of immune cell markers (CD3, CD8, CD68, CD163) and immune checkpoints (ICPs) from a cohort of 27 conventional and 49 dedifferentiated CHS. The impact of the density of tumor-infiltrating lymphocytes (TILs), tumor-associated macrophages (TAMs) and immune checkpoints (ICPs) on clinical outcome were analyzed.We reveal that TAMs are the main immune population in CHS. Focusing on dedifferentiated CHS, we found that immune infiltrate composition is correlated with patient outcome, a high CD68+/CD8+ ratio being an independent poor prognostic factor (p < 0.01), and high CD68+ levels being associated with the presence of metastases at diagnosis (p < 0.05). Among the ICPs evaluated, CSF1R, B7H3, SIRPA, TIM3 and LAG3 were expressed at the mRNA level in both CHS subtypes. Furthermore, PDL1 expression was confirmed by IHC exclusively in dedifferentiated CHS (42.6% of the patients) and CSF1R was expressed by TAMs in 89.7% of dedifferentiated CHS (vs 62.9% in conventional).Our results show that the immune infiltrate of CHS is mainly composed of immunosuppressive actors favoring tumor progression. Our results indicate that dedifferentiated CHS could be eligible for anti-PDL1 therapy and more importantly immunomodulation through CSF1R + macrophages could be a promising therapeutic approach for both CHS subtypes.

Presence of Chip-Mutated Autologous Hematopoietic Cells in Mobilized Peripheral Blood Products Is Associated with Shorter Progression-Free Survival after Autologous Transplants for Multiple Myeloma

Multiple Myeloma (MM) remains a cancer of terminally-differentiated plasma cells that reside predominantly within the bone marrow. Malignant plasma cells are nurtured by a permissive microenvironment that favors tumor progression, drug resistance and disease relapse. Recurrent somatic mutations in hematopoietic stem cells, the source of major components in bone marrow niche, lead to age-associated clonal hematopoiesis of indetermined potential (CHIP) and has been associated with inferior survivals among individuals without malignant hematologic disorders. It is possible that these mutations in non-MM cells would affect remission time after transplant. We performed whole exome sequencing to identify CHIP-associated mutations within the autograft utilized to rescue hematopoiesis after high dose melphalan and autologous hematopoietic cell transplant (HCT). We then correlated the presence of CHIP with the outcome of MM patients (pts) following autologous HCT. Methods. MM pts (N=101) that underwent HCT between 2006 and 2017 were studied. DNA was extracted from 1 ml of cryopreserved mobilized hematopoietic cell product. Targeted sequencing was then performed using Tempus xE whole exome platform (Tempus, Chicago, IL) with variable allele frequency (VAF) ≥0.1. Progression-free survival (PFS) and overall survival (OS) were defined as the time from transplantation until event of interest, with censoring at time of last follow up. Cox regression was used for time-to-event outcomes; hazard ratios (HR) and 95% confidence intervals (CI) were reported. P-values were two-sided and those &amp;lt;0.05 were considered statistically significant. Results. The median age was 60.1 years at the time of HCT. 58 pts were male and 43 female; 29 pts were African-American, 1 Asian/Indian and 71 were Caucasian. Seventy five (75%) and 42 (43%) pts had prior exposure to lenalidomide or cyclophosphamide, respectively. Thirty two pts (32%) underwent hematopoietic cell mobilization with GCS-F and plerixafor, 38 pts (38%) with cyclophosphamide and 31 pts (31%) with GCS-F alone. Forty seven pts (47%) had at least one CHIP-associated mutation. The median number of CD34+ yield in the first day was 6.7 x 10e6/kg for pts with CHIP mutations and 5.64 x 10e6/kg for pts without any CHIP mutation (p = 0.4). The presence or absence of CHIP mutations did not impact the yield of CD34+ stem cells collected (Fig. 1). The majority of mutations were either missense variants or mRNA splicing variations (Fig. 2), most commonly SF3B1, ASXL1, TET2 and ASXL2. CHIP mutations were associated with increased age (p= 0.021), but there was no association with prior history of previous cancer, smoking, cytogenetically-defined high risk disease, pre-HCT hemoglobin level or red blood cell mean corpuscular volume. There was also no significant difference between the transplant course between the two groups in terms of neutrophil and platelet engraftment or length of hospital stay. Median follow up was 32 months. During follow up 3 pts develop MDS/AML (2 pts in the CHIP group and one in no CHIP group). Coronary artery disease was the cause of death in one patient in CHIP cohort versus none in the CHIP negative cohort. Myeloma progression was the major cause of death in CHIP and No CHIP cohorts (66% vs. 60%, p=0.48). Median PFS was 19 months in CHIP cohort vs. 39 months in No CHIP group (HR: 0.62, 95% CI: 0.51-0.92, p= 0.001). Median OS has not been reached in the No CHIP group while it was 56 months in CHIP group (HR: 0.78, 95% CI: 0.62-1.04, P=0.09). In multivariate analysis, presence of CHIP remained a significant predictor of worse PFS after adjusting for age, maintenance therapy, high risk disease, performance status, triplet vs. doublet pre-SCT therapy, melphalan dose and MM genetic risk. (Table 2). Conclusion: Here we showed high frequency of large clonal hematopoiesis clones (i.e., VAF ≥0.1) in autograft of MM pts. The presence of this mutations does not impact stem cell yield or transplant course, however it impacts PFS independent of age and other unfavorable factors. Our data highlights high frequency of SF3B1; the role of this mutant in modulating apoptotic factors in myeloma microenvironment should be investigated. Disclosures Malek: Celgene: Consultancy; Amgen: Speakers Bureau; Adaptive: Consultancy; Janssen: Speakers Bureau; Medpacto: Research Funding; Sanofi: Consultancy; Takeda: Consultancy. Caimi:ADC Therapeutics: Research Funding; Celgene: Speakers Bureau; Fate Therapeutics: Membership on an entity's Board of Directors or advisory committees, Speakers Bureau; Kite Pharmaceuticals: Consultancy, Membership on an entity's Board of Directors or advisory committees, Speakers Bureau; Genentech: Consultancy, Membership on an entity's Board of Directors or advisory committees, Research Funding, Speakers Bureau. Caldwell:Tempus Inc.: Employment.

TMIC-05. GLIOBLASTOMA CONTAINS TOPOLOGICALLY DISTINCT PROLIFERATIVE AND METABOLICALLY DEFINED SUBPOPULATIONS OF NESTIN AND GLUT1-POSITIVE CELLS

Abstract Glioblastoma (GBM), the most aggressive primary brain malignancy, consists of diverse cell subpopulations expressing a variety of cell lineage markers. Improvements in GBM therapy and survival require a deeper knowledge of the shifting subpopulations of tumorigenic cells within typical GBMs and their relative vulnerabilities. GBM development is associated with the appearance of highly proliferative tumor cells that lead to a hypoxic, metabolically reprogrammed, immunosuppressive microenvironment that favors tumor progression. In addition, GBM contains self-renewing, tumorigenic cancer stem cells (CSC) that contribute to tumor initiation and therapeutic resistance. Using a combined multicolor immunofluorescent and Hematoxylin and Eosin (H&amp;E) staining approach with archival formalin-fixed, paraffin embedded tissue from primary, recurrent, and autopsy glioblastoma specimens, we have investigated the complex topology of the GBM microenvironment with particular focus on the association and distribution of several important functional and metabolic markers. High-resolution tissue image analysis permitted precise colocalization and quantification of four biomarkers (Ki-67, GLUT1, Nestin, Hif-1a) of the entire specimen image and at the single cell level. Our results demonstrate discrete subpopulations with specific regional localization with respect to blood vessels and to each other. In particular, highly proliferative Nestin-positive cells are preferentially located near blood vessels. These cells do not express GLUT1 and are Hif-1a positive. In contrast, GLUT1-positive cells are negative for Nestin, demonstrate low proliferation, and are preferentially located at the zones of pseudopalisading necrosis, furthest from blood vessels. In addition, GLUT1-positive cells show reduced Hif-1a expression compared to Nestin-positive cells. Our novel approach provides a means to identify, characterize, and monitor the changing nature of GBM before and after various treatment modalities with the ultimate aim of revealing selective vulnerabilities in order to retard or cure this neoplasm.

Clinical significance of the immune cell landscape in hepatocellular carcinoma patients with different degrees of fibrosis.

The major causes of morbidity and mortality of patients with chronic liver disease are liver fibrosis and cirrhosis. Previous studies have been concerned with immune dysfunction in the pathogenesis of cirrhosis progress. However, the potential molecular mechanism of how the liver's fibrotic state favors tumor progression is still unclear. We attempted to reveal deviations of the immune cell landscape between various liver tissues and identify key biomarkers associated with patients' outcomes. CIBERSORT was used for estimating the proportions of immune cells in various liver tissues. Comparative studies were carried out by Kruskal-Wallis test and Wilcoxon test. For survival analyses, the Cox proportional hazard regression model, Kaplan-Meier estimates, and log-rank test were used. Significantly different adaptive and innate immune cell types were selected, including T cells, plasma cells, and resting mast cells. Meanwhile, the immune cell landscapes in The Cancer Genome Atlas' (TCGA) hepatocellular carcinoma (HCC) patients with different degrees of fibrosis were also calculated. Comparative studies and survival analysis were carried out. Resting mast cell and activated NK cells in HCC patients with fibrosis was significantly lower than that in other HCC patients without fibrosis. Then, the potential genes involved in immune cells and significantly associated with patients' outcome were identified. These genes may be potential novel checkpoints for immunotherapy, including PVRIG related to NK resting/activated cells and T cell CD8+ infiltration which was recently targeted in breast cancer. Furthermore, Pearson correlation coefficient analysis suggested that PVRIG is significantly positively related to other checkpoint molecules and Teff gene signatures. Alternative treatments, including immunotherapies, are necessary and urgent for HCC. Although checkpoint inhibitors that block CTLA-4 and PD-1 have improved cancer immunotherapies, targeting additional checkpoint receptors may be required to broaden patient response to immunotherapy. Our studies may find possible ways to select novel targets and improve immunotherapy efficacy by disrupting their function and promoting immune infiltration in advanced HCC patients with higher fibrosis and even cirrhosis.

Tumor cells educate mesenchymal stromal cells to release chemoprotective and immunomodulatory factors

Factors released by surrounding cells such as cancer-associated mesenchymal stromal cells (CA-MSCs) are involved in tumor progression and chemoresistance. In this study, we characterize the mechanisms by which naïve mesenchymal stromal cells (MSCs) can acquire a CA-MSCs phenotype. Ovarian tumor cells trigger the transformation of MSCs to CA-MSCs by expressing pro-tumoral genes implicated in the chemoresistance of cancer cells, resulting in the secretion of high levels of CXC chemokine receptors 1 and 2 (CXCR1/2) ligands such as chemokine (C-X-C motif) ligand 1 (CXCL1), CXCL2, and interleukin 8 (IL-8). CXCR1/2 ligands can also inhibit the immune response against ovarian tumor cells. Indeed, through their released factors, CA-MSCs promote the differentiation of monocytes towards M2 macrophages, which favors tumor progression. When CXCR1/2 receptors are inhibited, these CA-MSC-activated macrophages lose their M2 properties and acquire an anti-tumoral phenotype. Both ex vivo and in vivo, we used a CXCR1/2 inhibitor to sensitize ovarian tumor cells to carboplatin and circumvent the pro-tumoral effects of CA-MSCs. Since high concentrations of CXCR1/2 ligands in patients’ blood are associated with chemoresistance, CXCR1/2 inhibition could be a potential therapeutic strategy to revert carboplatin resistance.

Helminth-derived molecules inhibit colitis-associated colon cancer development through NF-κB and STAT3 regulation.

Inflammation is currently considered a hallmark of cancer and plays a decisive role in different stages of tumorigenesis, including initiation, promotion, progression, metastasis and resistance to antitumor therapies. Colorectal cancer is a disease widely associated with local chronic inflammation. Additionally, extrinsic factors such as infection may beneficially or detrimentally alter cancer progression. Several reports have noted the ability of various parasitic infections to modulate cancer development, favoring tumor progression in many cases and inhibiting tumorigenesis in others. The aim of our study was to determine the effects of excreted/secreted products of the helminth Taenia crassiceps (TcES) as a treatment in a murine model of colitis-associated colon cancer (CAC). Here, we found that after inducing CAC, treatment with TcES was able to reduce inflammatory cytokines such as IL-1β, TNF-α, IL-33 and IL-17 and significantly attenuate colon tumorigenesis. This effect was associated with the inhibition of signal transducer and activator of transcription 3 and nuclear factor kappa-light-chain-enhancer of activated B cells (NF-κB) phosphorylation. Furthermore, we determined that TcES interfered with LPS-induced NF-κB p65 activation in human colonic epithelial cell lines in a Raf-1 proto-oncogene-dependent manner. Moreover, in three-dimensional cultures, TcES promoted reorganization of the actin cytoskeleton, altering cell morphology and forming colonospheres, features associated with a low grade of aggressiveness. Our study demonstrates a remarkable effect of helminth-derived molecules on suppressing ongoing colorectal cancer by downregulating proinflammatory and protumorigenic signaling pathways.

HIPK2 role in the tumor-host interaction: Impact on fibroblasts transdifferentiation CAF-like.

The dialogue between cancer cells and the surrounding fibroblasts, tumor‐associated macrophages (TAM), and immune cells can create a tumor microenvironment (TME) able to promote tumor progression and metastasis and induce resistance to anticancer therapies. Cancer cells, by producing growth factors and cytokines, can recruit and activate fibroblasts in the TME inducing their transdifferention in cancer‐associated fibroblasts (CAFs). Then, CAFs, in a reciprocal cross‐talk with cancer cells, sustain cancer growth and survival and support malignancy and tumor resistance to therapies. Therefore, the identification of the molecular mechanisms regulating the interplay between cancer cells and fibroblasts can offer an intriguing opportunity for novel diagnostic and therapeutic anticancer purpose. HIPK2 is a multifunctional tumor suppressor protein that modulates cancer cell growth and apoptosis in response to anticancer drugs and negatively regulates pathways involved in tumor progression and chemoresistance. HIPK2 protein downregulation is induced by hypoxia and hyperglycemia and HIPK2 knockdown favors tumor progression and resistance to therapy other than a pseudohypoxic, inflammatory, and angiogenic cancer phenotype. Therefore, we hypothesized that HIPK2 modulation in cancer cells could contribute to modify the tumor–host interaction. In support of our hypothesis, here we provide evidence that culturing human fibroblasts (hFB) with conditioned media derived from cancer cells undergoing HIPK2 knockdown (CMsiHIPK2) triggered their transdifferentiation CAF‐like, compared to hFB cultured with CM‐derived from HIPK2‐carrying control cancer cells. CAF transdifferentiation was identified by expression of several markers including α‐smooth muscle actin (α‐SMA) and collagen I and correlated with autophagy–mediated caveolin‐1 degradation. Although the molecular mechanisms dictating CAF‐transdifferentiation need to be elucidated, these results open the way to further study the role of HIPK2 in TME remodeling for prognostic and therapeutic purpose.

ADA activity is decreased in lymphocytes from patients with advanced stage of lung cancer.

Cigarette smoking is directly associated with lung cancer. Non-small cell lung carcinoma (NSCLC) represents approximately 80% from all types of lung cancer. This latter is hard to diagnose and to treat due to the lack of symptoms in early stages of the disease. The aim of this study was toevaluate ADA activity and the expression of P2X7, A1, and A2A receptors and in lymphocytes. In addition, the profile of pro-inflammatory and anti-inflammatory cytokines serum levels of patients with lung cancer in advanced stage was evaluated. Patients (n = 13) previously treated for lung cancer at stage IV (UICC) with chemotherapy had their blood collected. Cancer patients showed a decrease in ADA activity and an increase in A1 receptor expression in lymphocytes when compared to the control group. Moreover, patients exhibited an increase in IL-6 and TNF-α, while IL-17 and INF-ϒ serum levels were lower in patients with lung cancer. The decreased ADA activity and the increase in A1 receptor expression may contribute to adenosine pro-tumor effects by increasing IL-6 and TNF-α and decreasing IL-17 and INF-γ serum levels. Our data show an indirect evidence that purinergic signaling may have a role in promoting a profile of cytokines levels that favors tumor progression.

ESR1 mutations in breast cancer.

The acquisition of ligand-independent ESR1 mutations during aromatase inhibitor therapy in metastatic estrogen receptor (ER)-positive breast cancer is a common mechanism of hormonal therapy resistance. Preclinical and clinical studies have demonstrated that ESR1 mutations can preexist in primary tumors and can be enriched during metastasis. Furthermore, ESR1 mutations express a unique transcriptional profile that favors tumor progression, suggesting that selected ESR1 mutations may influence metastasis. Several groups have used sensitive detection methods using patient liquid biopsies to track ESR1 or truncal somatic mutations to predict treatment outcome and tumor progression, and some of these techniques may eventually be used to guide sequential treatment options in patients. Further development and standardization of mutation tracking in circulating tumor DNA is ongoing. Clinically, patients with ESR1 mutations derive clinical benefit when treated with fulvestrant and CDK4/6-targeted therapies, but the development of more potent selective ER degraders and/or new targeted biotherapies are needed to overcome the endocrine-resistant phenotype of ESR1 mutant-bearing tumors. In this review, we discuss the mechanisms of resistance and dissemination of ESR1 mutations as well as the detection methods for ESR1 mutation tracking, newly discovered potential therapeutic targets, and the clinical implications and treatment options for treating patients with ESR1 mutant-bearing tumors.

Abstract 1521: Tumor-produced hyaluronan contributes to the formation tolerogenic immunosuppressive microenvironment

Abstract Immunosuppressive ligand PD-L1 considered as a major player in mechanism of negative regulation of anti-tumor immune response and its expression is highly up-regulated in human and experimental tumors, including bladder cancer. Bladder cancer is characterized by aberrant hyaluronan metabolism resulting in increased HA production in tumor tissue. Hyaluronan or hyaluronic acid (HA) is a prominent component of tumor stroma/microenvironment. Membrane-bound or free extracellular HA favors tumor progression by inducing tumor cell motility, invasive properties, proliferation, production of growth factors and epithelial-mesenchymal transition. Here, we provide evidence that tumor-produced hyaluronan, one of the key tumor stroma components, contributes to the formation of tolerogenic/immunosuppressive tumor microenvironment and stimulated PD-L1 expression. We found that tumor-derived HA specifically binds to CD44 receptor expressed by myeloid precursors, such as myeloid-derived suppressor cells (MDSCs) and promotes its expansion with differentiation toward PD-L1-expressing F4/80+ macrophages. Inhibition of HA synthesis in tumor cells with pharmacologic inhibitor 4-MU, or blockade of CD44 signaling in myeloid cells with antagonistic anti-CD44 antibody, prevented the macrophage differentiation and tumor-induced up-regulation of PD-L1 expression. We also found that tumor-derived HA stimulated production of immunosuppressive and inflammatory factors IL-6, IL-10, TNF-alpha, IL-1beta and PGE2 by myeloid cells in CD44-dependent manner. Moreover, tumor-produced HA stimulated development of PD-L1-expressing macrophages in both murine and human myeloid cells. Our study reveals that tumors may evade the immune system by creating a protective tolerogenic “shield” in the form of tumor-produced HA, which binds to the CD44-expressing tumor-recruited MDSCs, stimulating production of immunosuppressive factors and promoting development of the PD-L1+ macrophages. Inhibiting of hyaluronan synthesis by tumors or targeting HA-CD44 signaling could provide an attractive approach to break tumor-induced immune tolerance and unleash the anti-tumor immune response. Citation Format: Paul R. Dominguez-Gutierrez, Paul Crispen, Sergei A. Kusmartsev. Tumor-produced hyaluronan contributes to the formation tolerogenic immunosuppressive microenvironment [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2019; 2019 Mar 29-Apr 3; Atlanta, GA. Philadelphia (PA): AACR; Cancer Res 2019;79(13 Suppl):Abstract nr 1521.