Potential Of Tumor Cells Research Articles

Inhibition of the ATR-DNAPKcs-RB axis drives G1/S-phase transition and sensitizes triple-negative breast cancer (TNBC) to DNA holliday junctions

Targeting the DNA damage response (DDR) is a promising strategy in oncotherapy, as most tumor cells are sensitive to excess damage due to their repair defects. Ataxia telangiectasia mutated and RAD3-related protein (ATR) is a damage response signal transduction sensor, and its therapeutic potential in tumor cells needs to be precisely investigated. Herein, we identified a new axis that could be targeted by ATR inhibitors to decrease the DNA-dependent protein kinase catalytic subunit (DNAPKcs), downregulate the expression of the retinoblastoma (RB), and drive G1/S-phase transition. Four-way DNA Holliday junctions (FJs) assembled in this process could trigger S-phase arrest and induce lethal chromosome damage in RB-positive triple-negative breast cancer (TNBC) cells. Furthermore, these unrepaired junctions also exerted toxic effects to RB-deficient TNBC cells when the homologous recombination repair (HRR) was inhibited. This study proposes a precise strategy for treating TNBC by targeting the DDR and extends our understanding of ATR and HJ in tumor treatment.

Anti-tumor effect of berberine on chronic lymphocytic leukemia cells

Chronic lymphocytic leukemia (CLL) is a blood malignancy that is characterized by remarkable expression of CD69 and Ki67 in CLL cells. Elevated levels of Cleaved-Poly (ADP-ribose) polymerase-1 (PARP1) and microRNA-155 (MiR-155) are related to poor prognosis of disease. Berberine as a natural isoquinoline alkaloid, has shown an anti-tumor potential in tumor cells. The objective of present study was to explore some aspects of molecular mechanisms of berberine effect in CLL cells. To analyze the expression of CD69 and Ki67 using flow cytometry, 16 peripheral blood samples and seven bone marrow aspirates were collected from CLL patients. Isolated peripheral blood mononuclear cells (PBMCs) and bone marrow mononuclear cells (BMMCs) were treated with 25µM of berberine for 24h. The level of miR-155 expression was subsequently evaluated by real-time PCR. Furthermore, western blot was used for assessment of cleaved PARP1. Our results demonstrated a significant reduction in CD69 and Ki67 expression on CD19+ cells when the cells were treated by berberine. Interestingly, the expression level of miR-155 was reduced after berberine treatment in compare to the control group. Furthermore, western blotting revealed an increased level of cleaved PARP1 in dose-dependently manner in CLL cells. The results confirmed the anti-tumor impact of berberine on CLL cells through reducing CD69, Ki67, and miR-155 expression and increasing cleaved PARP1 may be considered as an option for future clinical studies.

A Selective Reduction of Osteosarcoma by Mitochondrial Apoptosis Using Hydroxyapatite Nanoparticles.

BackgroundIn recent years, using hydroxyapatite nanoparticles (HANPs) for tumor therapy attracted increasing attention because HANPs were found to selectively suppress the growth of tumor cells but exhibit ignorable toxicity to normal cells.PurposeThis study aimed to investigate the capacities of HANPs with different morphologies and particle sizes against two kinds of osteosarcoma (OS) cells, human OS 143B cells and rat OS UMR106 cells.MethodsSix kinds of HANPs with different morphologies and particle sizes were prepared by wet chemical method. Then, the antitumor effect of these nanoparticles was characterized by means of in vitro cell experiments and in vivo tumor-bearing mice model. The underlying antitumor mechanism involving mitochondrial apoptosis was also investigated by analysis of intracellular calcium, expression of apoptosis-related genes, reactive oxygen species (ROS), and the endocytosis efficiency of the particles in tumor cells.ResultsBoth in vitro cell experiments and in vivo mice model evaluation revealed the anti-OS performance of HANPs depended on the concentration, morphology, and particle size of the nanoparticles, as well as the OS cell lines. Among the six HANPs, rod-like HANPs (R-HANPs) showed the best inhibitory activity on 143B cells, while needle-like HANPs (N-HANPs) inhibited the growth of UMR106 cells most efficiently. We further demonstrated that HANPs induced mitochondrial apoptosis by selectively raising intracellular Ca2+ and the gene expression levels of mitochondrial apoptosis-related molecules, and depolarizing mitochondrial membrane potential in tumor cells but not in MC3T3-E1, a mouse pre-osteoblast line. Additionally, the anti-OS activity of HANPs also linked with the endocytosis efficiency of the particles in the tumor cells, and their ability to drive oxidative damage and immunogenic cell death (ICD).ConclusionThe current study provides an effective strategy for OS therapy where the effectiveness was associated with the particle morphology and cell line.

CAMP Signaling in Cancer: A PKA-CREB and EPAC-Centric Approach.

Cancer is one of the most common causes of death globally. Despite extensive research and considerable advances in cancer therapy, the fundamentals of the disease remain unclear. Understanding the key signaling mechanisms that cause cancer cell malignancy may help to uncover new pharmaco-targets. Cyclic adenosine monophosphate (cAMP) regulates various biological functions, including those in malignant cells. Understanding intracellular second messenger pathways is crucial for identifying downstream proteins involved in cancer growth and development. cAMP regulates cell signaling and a variety of physiological and pathological activities. There may be an impact on gene transcription from protein kinase A (PKA) as well as its downstream effectors, such as cAMP response element-binding protein (CREB). The position of CREB downstream of numerous growth signaling pathways implies its oncogenic potential in tumor cells. Tumor growth is associated with increased CREB expression and activation. PKA can be used as both an onco-drug target and a biomarker to find, identify, and stage tumors. Exploring cAMP effectors and their downstream pathways in cancer has become easier using exchange protein directly activated by cAMP (EPAC) modulators. This signaling system may inhibit or accelerate tumor growth depending on the tumor and its environment. As cAMP and its effectors are critical for cancer development, targeting them may be a useful cancer treatment strategy. Moreover, by reviewing the material from a distinct viewpoint, this review aims to give a knowledge of the impact of the cAMP signaling pathway and the related effectors on cancer incidence and development. These innovative insights seek to encourage the development of novel treatment techniques and new approaches.

Bovine Pancreatic RNase A: An Insight into the Mechanism of Antitumor Activity In Vitro and In Vivo.

In this investigation, we extensively studied the mechanism of antitumor activity of bovine pancreatic RNase A. Using confocal microscopy, we show that after RNase A penetration into HeLa and B16 cells, a part of the enzyme remains unbound with the ribonuclease inhibitor (RI), resulting in the decrease in cytosolic RNAs in both types of cells and rRNAs in the nucleoli of HeLa cells. Molecular docking indicates the ability of RNase A to form a complex with Ku70/Ku80 heterodimer, and microscopy data confirm its localization mostly inside the nucleus, which may underlie the mechanism of RNase A penetration into cells and its intracellular traffic. RNase A reduced migration and invasion of tumor cells in vitro. In vivo, in the metastatic model of melanoma, RNase A suppressed metastases in the lungs and changed the expression of EMT markers in the tissue adjacent to metastatic foci; this increased Cdh1 and decreased Tjp1, Fn and Vim, disrupting the favorable tumor microenvironment. A similar pattern was observed for all genes except for Fn in metastatic foci, indicating a decrease in the invasive potential of tumor cells. Bioinformatic analysis of RNase-A-susceptible miRNAs and their regulatory networks showed that the main processes modulated by RNase A in the tumor microenvironment are the regulation of cell adhesion and junction, cell cycle regulation and pathways associated with EMT and tumor progression.

Periostin in lymph node pre-metastatic niches governs lymphatic endothelial cell functions and metastatic colonization

Although lymph node (LN) metastasis is an important prognostic parameter in cervical cancer, the tissue remodeling at a pre-metastatic state is poorly documented in LNs. We here identified periostin (POSTN) as a component of non-metastatic LNs by applying proteomic analyses and computerized image quantifications on LNs of patients with cervical cancer. We provide evidence for remarkable modifications of POSTN and lymphatic vessel distributions and densities in non-metastatic sentinel and metastatic human LNs, when compared to distant non-metastatic LNs. POSTN deposition at a pre-metastatic stage was demonstrated in a pre-clinical murine model (the ear sponge assay). Its expression by fibroblastic LN cells was assessed by in situ hybridization and in vitro cultures. In vitro, POSTN promoted lymphatic endothelial cell functions and tumor cell proliferation. Accordingly, the in vivo injection of recombinant POSTN together with VEGF-C boosted the lymphangiogenic response, while the metastatic potential of tumor cells was drastically reduced using a POSTN blocking antibody. This translational study also supports the existence of an unprecedented dialog “in cascade”, between the primary tumor and the first pelvic nodal relay in early cervical cancer, and subsequently from pelvic LN to para-aortic LNs in locally advanced cervical cancers. Collectively, this work highlights the association of POSTN deposition with lymphangiogenesis in LNs, and provides evidence for a key contribution of POSTN in promoting VEGF-C driven lymphangiogenesis and the seeding of metastatic cells.

CD44/Folate Dual Targeting Receptor Reductive Response PLGA-Based Micelles for Cancer Therapy.

In this study, a novel poly (lactic-co-glycolic acid) (PLGA)-based micelle was synthesized, which could improve the therapeutic effect of the antitumor drug doxorubicin hydrochloride (DOX) and reduce its toxic and side effects. The efficient delivery of DOX was achieved by active targeting mediated by double receptors and stimulating the reduction potential in tumor cells. FA-HA-SS-PLGA polymer was synthesized by amidation reaction, and then DOX-loaded micelles were prepared by dialysis method. The corresponding surface method was used to optimize the experimental design. DOX/FA-HA-SS-PLGA micelles with high drug loading rate and encapsulation efficiency were prepared. The results of hydrophilic experiment, critical micelle concentration determination, and hemolysis test all showed that DOX/FA-HA-SS-PLGA micelles had good physicochemical properties and biocompatibility. In addition, both in vitro reduction stimulus response experiment and in vitro release experiment showed that DOX/FA-HA-SS-PLGA micelles had reduction sensitivity. Molecular docking experiments showed that it can bind to the target protein. More importantly, in vitro cytology studies, human breast cancer cells (MCF-7), human non-small cell lung cancer cells (A549), and mouse colon cancer cells (CT26) were used to demonstrate that the dual receptor-mediated endocytosis pathway resulted in stronger cytotoxicity to tumor cells and more significant apoptosis. In and in vivo antitumor experiment, tumor-bearing nude mice were used to further confirm that the micelles with double targeting ligands had better antitumor effect and lower toxicity. These experimental results showed that DOX/FA-HA-SS-PLGA micelles have the potential to be used as chemotherapeutic drugs for precise tumor treatment.

Chamaejasmenin B, an Inhibitor for Metastatic Outgrowth, Reversed M2-Dominant Macrophage Polarization in Breast Tumor Microenvironment.

Metastasis is a multistep process that depends on the interactions between tumor cells and their microenvironment. Macrophages in the tumor microenvironment show high polarization plasticity and have a paradoxical role in cancer progression. Hijacked by tumor-promoting signals, the polarization status of macrophages was pathologically disturbed and believed to be the decisive mechanism forcing the progression of metastasis. In this study, we explored the immunological activity of Chamaejasmin B (ICJ), a previously proved inhibitor for metastasis, in macrophages from metastatic microenvironment. When intravenously injected of 4T1 cells in mice, ICJ significantly inhibited its metastatic outgrowth. Taking tumor cell and macrophage as a functional integrity, an adoptive transfer model was established in vitro to exclude the direct effect of ICJ on tumor. The findings suggest a dual influence of ICJ on both tumors and macrophages, as indicated by the rebalance of macrophage polarization and suppression of clonogenic potential in tumor cells. Mechanistically, ICJ redirected M2-dominant polarization of tumor-associated macrophage in an IL-4-mTOR-dependent manner. Collectively, our study revealed that ICJ rebalanced macrophage polarization in malignant microenvironment and showed promising effect in suppressing metastatic outgrowth in breast cancer model.

Chemotherapy-triggered changes in stromal compartment drive tumor invasiveness and progression of breast cancer

BackgroundChemotherapy remains a standard treatment option for breast cancer despite its toxic effects to normal tissues. However, the long-lasting effects of chemotherapy on non-malignant cells may influence tumor cell behavior and response to treatment. Here, we have analyzed the effects of doxorubicin (DOX) and paclitaxel (PAC), commonly used chemotherapeutic agents, on the survival and cellular functions of mesenchymal stromal cells (MSC), which comprise an important part of breast tumor microenvironment.MethodsChemotherapy-exposed MSC (DOX-MSC, PAC-MSC) were co-cultured with three breast cancer cell (BCC) lines differing in molecular characteristics to study chemotherapy-triggered changes in stromal compartment of the breast tissue and its relevance to tumor progression in vitro and in vivo. Conditioned media from co-cultured cells were used to determine the cytokine content. Mixture of BCC and exposed or unexposed MSC were subcutaneously injected into the immunodeficient SCID/Beige mice to analyze invasion into the surrounding tissue and possible metastases. The same mixtures of cells were applied on the chorioallantoic membrane to study angiogenic potential.ResultsTherapy-educated MSC differed in cytokine production compared to un-exposed MSC and influenced proliferation and secretory phenotype of tumor cells in co-culture. Histochemical tumor xenograft analysis revealed increased invasive potential of tumor cells co-injected with DOX-MSC or PAC-MSC and also the presence of nerve fiber infiltration in tumors. Chemotherapy-exposed MSC have also influenced angiogenic potential in the model of chorioallantoic membrane.ConclusionsData presented in this study suggest that neoadjuvant chemotherapy could possibly alter otherwise healthy stroma in breast tissue into a hostile tumor-promoting and metastasis favoring niche. Understanding of the tumor microenvironment and its complex net of signals brings us closer to the ability to recognize the mechanisms that prevent failure of standard therapy and accomplish the curative purpose.

Abstract 1178: Role of error-prone polymerases on glioma cell resistance to Temozolomide

Abstract Translesion DNA polymerases are capable of replicating damaged DNA without removing lesions, performing translesion synthesis (TLS), a mechanism known by DNA damage tolerance. Tumor cells use this mechanism in order to survive lesions caused by chemotherapy and therefore this may be a strategy that those cells use to resist treatments. Moreover, this process is error-prone and can lead to mutagenesis increasing resistance potential of tumor cells. Little is known about the role of TLS in in tumor therapy with Temozolomide (TMZ). This drug is an alkylating agent that damage DNA. Our aim is to investigate how TMZ affects TLS mutated cells, to understand how these polymerases are related to tumor cells resistance to this chemotherapeutic agent. Hence, we firstly treated POLH mutated cells and analyzed cell proliferation by flow cytometry, cell viability by a colorimetric assay (XTT) and for survival by apoptotic markers (such sub-G1) and clonogenic assays. In fact, POLH mutated cells are more sensitive to TMZ, indicating that TLS mechanisms are important to overcome DNA damage. TCGA data was also used to analyze TLS expression in glioblastoma patients. Curiously, in recurrently patients treated with TMZ, POLK expression was significantly increased. Therefore, we constructed U251-MG CRISPR/CAS9 knockout cells, for POLK and POLI TLS DNA polymerases enzymes genes. Gene KO was validated using Sanger sequencing and mutations resulted in stop codon. These POLI and POLK mutated cells had impaired viability after TMZ treatment. Moreover, genotoxic stress, as indicated by phosphorylated gH2AX, were increased in TMZ-treated cells and was higher in mutated cells compared to Wild-type cells. It is also possible to observe cell cycle arrest, mainly in G2 phase instead of S phase, after 48 h in all three mutated cells, which is not observed in control, wild type, cells. To analyze closer the DNA replication, we also performed fiber assay, surprisingly there was no difference in between KO cells treated with TMZ and WT treated cells! In summary, we can infer that TLS polymerases protect tumor cells from TMZ-induced DNA damage and thus play important roles on overcoming resistance to this drug. As perspectives for this work, we intend to observe further how replication is affected in these mutated cells treated with TMZ, since the lack of difference and the non observation of S phase arrest, may indicate that the role of translesion synthesis may not be the main role in this context. Citation Format: Marcela Teatin Latancia, André Uchimura Bastos, Natália C Moreno, Davi Jardim, Clarissa RR Rocha, Giovana Leandro, Carlos Frederico Martins Menck. Role of error-prone polymerases on glioma cell resistance to Temozolomide [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2021; 2021 Apr 10-15 and May 17-21. Philadelphia (PA): AACR; Cancer Res 2021;81(13_Suppl):Abstract nr 1178.

Abstract 1163: Histone deacetylase inhibitors as potential differentiation therapy in lung adenocarcinoma

Abstract Impaired differentiation is a common feature of cancer. In contrast to chemotherapy, the goal of differentiation therapy is to exhaust the malignant potential of tumour cells through the reactivation of developmental programs rather than cell death. The Switch/Sucrose Non-Fermentable (SWI/SNF) DNA remodelling complexes play a vital role in regulating cellular differentiation and have been strongly implicated in cancer. SWI/SNF complexes bind to the DNA-histone scaffold and initiate transcription via the recruitment of vital cellular transcriptional machinery including histone acetyltransferases. Next-generation sequencing has identified mutations in at least 10 genes encoding subunits of the SWI/SNF complexes that are recurrently mutated in cancers originating in nearly every body tissue, collectively occurring in >25% of all human malignancies. Lung adenocarcinoma (LAC) accounts for >40% of all lung cancers and has an 18% of overall 5-year survival. Mutations in SMARCA4 are believed to occur in >12% of LAC. Using a panel of characterized human LAC cell lines we show a marked sensitivity of the HDACi, HDACi, exclusively to SMARCA4-null LAC only. This is preceded by increased H3K27ac, decreased H3K27me3 and decreased EZH2 expression. Sustained low-dose panobinostat treatment of SMARCA4-mutant LAC cell lines, results in unique gene expression changes consistent with differentiation, not observed in SMARCA4 wildtype lines. To further demonstrate the specific dependence of loss of SMARCA4 on response to HDACi, we generated three isogenic cell lines using CRISPR KO. H358, H441 and H2009 SMARCA4 KO LAC cell lines were markedly more sensitive to panobinostat than their wildtype parental lines. Lastly, panobinostat treatment results in tumour growth arrest and increased survival in SMARCA4-deficient LAC cell line xenografts and PDX models in vivo but not in SMARCA4-intact LAC models. Together, these data suggest that SMARCA4-deficient LAC are dependent on HDAC activity to maintain an undifferentiated state and are therefore highly susceptible to epigenetic differentiation therapy. Citation Format: Wai Chin Chong, Vijesh Vaghjiani, Jason Edward Cain. Histone deacetylase inhibitors as potential differentiation therapy in lung adenocarcinoma [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2021; 2021 Apr 10-15 and May 17-21. Philadelphia (PA): AACR; Cancer Res 2021;81(13_Suppl):Abstract nr 1163.

Immunotherapy: New insights in breast cancer treatment.

Breast cancer being the most malignant and lethal disease persistent among women globally. Immunotherapy as a new treatment modality has emerged in understanding the loopholes in the treatment of breast cancer which is mainly attributed to the potential of tumor cells to evade and survive the immune response by developing various strategies. Therefore, improved understanding of the immune evasion by cancer cells and the monoclonal antibodies against PD- and PD-L1 can help us in the diagnosis of this malignancy. Here in this article, I have highlighted that in addition to focusing on other strategies for breast cancer treatment, the involvement of immune system in breast cancer is vital for the understanding of this malignancy. Further, the complete involvement of immune system in the relapse or recurrence of the breast tumor and have also highlighted the role of vaccines, PD-1 and CTLA-4 with the recent advances in the field. Moreover, in addition to the application of immunotherapy as a sole therapy, combinations of immunotherapy with various strategies like targeting it with MEK inhibitors, Vaccines, chemotherapy and PARP inhibitor has shown to have significant benefits is also discussed in this article.

Ovarian cancer cells direct monocyte differentiation through a non-canonical pathway

BackgroundAlternatively-activated macrophages (AAMs), an anti-inflammatory macrophage subpopulation, have been implicated in the progression of high grade serous ovarian carcinoma (HGSOC). Increased levels of AAMs are correlated with poor HGSOC survival rates, and AAMs increase the attachment and spread of HGSOC cells in vitro. However, the mechanism by which monocytes in the HGSOC tumor microenvironment are differentiated and polarized to AAMs remains unknown.MethodsUsing an in vitro co-culture device, we cultured naïve, primary human monocytes with a panel of five HGSOC cell lines over the course of 7 days. An empirical Bayesian statistical method, EBSeq, was used to couple RNA-seq with observed monocyte-derived cell phenotype to explore which HGSOC-derived soluble factors supported differentiation to CD68+ macrophages and subsequent polarization towards CD163+ AAMs. Pathways of interest were interrogated using small molecule inhibitors, neutralizing antibodies, and CRISPR knockout cell lines.ResultsHGSOC cell lines displayed a wide range of abilities to generate AAMs from naïve monocytes. Much of this variation appeared to result from differential ability to generate CD68+ macrophages, as most CD68+ cells were also CD163+. Differences in tumor cell potential to generate macrophages was not due to a MCSF-dependent mechanism, nor variance in established pro-AAM factors. TGFα was implicated as a potential signaling molecule produced by tumor cells that could induce macrophage differentiation, which was validated using a CRISPR knockout of TGFA in the OVCAR5 cell line.ConclusionsHGSOC production of TGFα drives monocytes to differentiate into macrophages, representing a central arm of the mechanism by which AAMs are generated in the tumor microenvironment.

Influence of fluid mechanics on metastasis formation

Metastases are the main cause of cancer-related deaths. The chain of events leading to their development is called "the metastatic cascade". The biological and biochemical aspects of this process have been well studied but the importance of biomechanical parameters only recently became a focus in the field. Studies have shown the biological fluids (blood, lymph and interstitial fluid) to play a key role in the metastatic cascade. These fluids participate in the transport of circulating tumor cells (CTCs) as well as the factors that they secrete, while at the same time influencing the events of the metastatic cascade through the forces that they generate. The hemodynamic properties and topological constraints of the vascular architecture control the formation of metastatic niches and the metastatic potential of tumor cells. In this review, we discuss the importance of these mechanical forces and highlight the novel questions and research avenues that they open.

A Potential Invasion-Promoting Role for Ezrin in Endometrial Carcinoma

Background:Ezrin is a cell membrane-cytoskeleton linker that is essential to maintain the normal cell shape and the integrity of cell-cell adhesion. Overexpression of ezrin is correlated with poor prognosis in several malignancies. Aim: To evaluate the expression of ezrin in hyperplastic and neoplastic endometrial tissues and to correlate its expression with the clinical and pathological parameters of endometrial carcinoma. Methods: Tissue sections of 66 specimens including 37 endometrial carcinoma, 16 atypical endometrial hyperplasia and 13 benign endometrial hyperplasia were evaluated for ezrin expression by immunohistochemistry. Results: Ezrin expression was detected in all endometrial carcinoma specimens and in 90% of hyperplasia. There was redistribution of ezrin from membranous expression in endometrial hyperplasia to diffuse cytoplasmic expression in endometrial carcinoma (p < 0.0001). Expression of ezrin was significantly higher in atypical compared to benign hyperplasia (p < 0.001) and it was relatively higher in endometrial carcinoma compared to atypical endometrial hyperplasia (p=0.086). Among the carcinoma specimens, expression of ezrin was significantly associated with invasion of myometrium (p=0.001), higher FIGO stage (p=0.008) and the presence of vascular tumor emboli (p=0.001). Muscle-invasive tumor cells expressed significantly higher levels of ezrin compared to non-invasive cells of the same tumor tissue (p < 0.0001). Tumor size, tumor grade and villoglandular morphology did not correlate significantly with ezrin expression. Conclusion: Ezrin was overexpressed in endometrial carcinoma and its expression was associated with the invasive potential of tumor cells.

Abstract 4089: Investigating translesion synthesis DNA polymerases roles on tumor protection after temozolomide induced DNA damage

Abstract Translesion DNA polymerases are capable of replicating damaged DNA, without removing the lesions, performing translesion synthesis (TLS), a mechanism of DNA damage tolerance. Tumor cells use this mechanism in order to survive lesions caused by chemotherapy and, therefore, this may be a strategy that tumor cells use to resist treatments. Moreover, it is an error-prone process and can lead to mutagenesis increasing resistance potential of tumor cells. Little is known about the role of TLS in Temozolomide (TMZ) tumor treatment. Our aim is to investigate how TMZ affects TLS mutated cells. Hence, we firstly treated primary fibroblasts cells lacking TLS mechanisms (XP-V) and analyzed cell proliferation by flow cytometry, cell viability by a colorimetric assay (XTT), for survival by apoptotic markers (such sub-G1) and clonogenic assays. In fact, XP-V cells are more sensitive to TMZ, indicating that TLS mechanisms are important to overcome DNA damage. TCGA data was also used to analyze TLS expression in glioblastoma patients. Curiously, in recurrently patients treated with TMZ, POLK expression was significantly increased. CRISPR/CAS9 knockout (KO) cells of glioblastoma cell lines, such as U251, were constructed for other TLS DNA polymerases enzymes genes, such as Pol Iota and Pol kappa. Gene KO was validated using Sanger sequencing and mutations resulted in stop codon. These pol iota and pol kappa KO cells had impaired viability after TMZ treatment. Moreover, genotoxic stress, as indicated by phosphorylated gH2AX, were increased in TMZ-treated cells. In summary, we can infer that TLS polymerases protect tumor cells from TMZ-induced DNA damage and thus, play important roles on overcoming resistance to this drug. As perspectives for this work, we intend to observe how replication is affected in these KO cells treated with TMZ by DNA Fiber Assays and measure DNA strand breaks in those cells by comet assay. Financial support: FAPESP, CNPq and CAPES. Citation Format: Marcela Teatin Latancia, André Uchimura Bastos, Natália Cestari Moreno, Davi Jardim, Clarissa RR Rocha, Carlos FM Menck. Investigating translesion synthesis DNA polymerases roles on tumor protection after temozolomide induced DNA damage [abstract]. In: Proceedings of the Annual Meeting of the American Association for Cancer Research 2020; 2020 Apr 27-28 and Jun 22-24. Philadelphia (PA): AACR; Cancer Res 2020;80(16 Suppl):Abstract nr 4089.

Subpopulations of Organoid-Forming Cells Have Different Motility

Cancer stem cells from oropharyngeal squamous cell carcinoma (OPSCC) have the ability to self-renew and differentiate into heterogeneous three-dimensional structures carrying features of tumor cells. Here, we describe a simple and label-free method for generating tumor organoids, and imaging them using live digital holographic microscopy (DHM) on the basis of the phase shift caused by light passing through the cells. We show early events of cell aggregation during tumor-organoid formation, and display their heterogeneity in terms of optical parameters up to an optical volume of 105 µm3. Lastly, by sorting OPSCC epithelial cells, we demonstrate that CD44+ cells displayed greater motility and tumor-forming capacity than those of CD44− cells. These results were in line with previous reports highlighting increased invasive and tumorigenic potential in tumor cells expressing high levels of CD44. Our method provides insight into the formation of tumor organoids, and could be used to assess stemness-associated biomarkers and drug screenings on the basis of tumor organoids.

Comparison of oncologic outcomes for robotic-assisted radical cystectomy (RARC) versus open radical cystectomy (ORC) among locally advanced and node-positive patients: An analysis of the National Cancer Database (NCDB).

e17002 Background: Despite recent concerns of atypical recurrence following RARC, utilization of the modality is increasing. The presumed mechanisms are especially relevant in more aggressive disease, where the metastatic potential of tumor cells may be greater. This study aims to compare the oncologic efficacy of RARC to ORC among patients with stage pT3-4 or node-positive bladder cancer. Methods: A retrospective cohort analysis of pT3-4N0-3 and pT(any)-4N1-3 patients who underwent RARC or ORC from 2010-2016 was performed using the NCDB. Appropriate univariate and multivariable analysis were performed between treatment cohorts. Results: RARC was significantly associated with superior unadjusted survival compared to ORC (median survival relative to ORC; 23.6 mo. vs. 21.6 mo.; P= 0.001). Additionally, RARC was associated with lower proportions of unadjusted 30- and 90-day mortality, positive margin status, and shorter surgical inpatient stay (all respective P&lt; 0.05). However, after adjusting for confounding covariates, multivariable analysis revealed no difference in mortality hazard or odds of secondary outcomes with the exception of inpatient stay (Table). RARC was also significantly associated with higher lymph node yield (increased incidence of &gt; 14 lymph nodes examined relative to ORC; 55% vs. 40%; P&lt; 0.01). Conclusions: RARC is no less safe than ORC for patients with locally advanced or node-positive bladder cancer on the basis of overall, 30- and 90-day survival outcomes. Unadjusted mortality and surgical outcomes in this population demonstrate advantages to the robotic modality. Perioperative benefits may favor RARC, but further randomized control studies are necessary to better elucidate differences between surgical approaches. [Table: see text]

The expression and prognostic role of EBP1 and relationship with AR in HER2+ breast cancer.

Human epidermal growth factor receptor (HER)-2 positive (HER2+) breast cancer (BC) has a poor survival rate and is more aggressive in nature. HER2-targeting agents could be beneficial for patients with HER2+ BC. In addition, targeted therapy and chemotherapy have been successfully used. However, a few patients are resistant to treatment. ErbB3 binding protein 1 (EBP1) binds to HER3 and inhibits the proliferation and invasive potential of tumor cells. However, its role in HER2+ BC has not been demonstrated. In this study, we aimed to analyze the relationship between androgen receptor (AR) and EBP1 expression in HER2+ BC. A total of 282 cases (140 cases of HER2+ invasive BC and 142 HER2-negative invasive BC) were included in this study. We performed immunohistochemistry (IHC) to analyze the expression of AR and EBP1; thereafter, we evaluated the relationship between these two biomarkers and estrogen receptor (ER), progesterone receptor (PR), HER2, p53, Ki67 expression, and other clinicopathological parameters. Of the HER2+ cases, 67 (47.9%) showed high expression of EBP1 (EBP1high) and 73 (52.1%) showed low/no expression of EBP1 (EBP1low/no). EBP1 expression was correlated with AR expression, histological grade, and lymphatic metastasis (p < 0.001, < 0.001, and 0.013, respectively). Kaplan-Meier analysis revealed that AR+ and EBP1low/no group had poorer overall survival (OS) and disease-free survival (DFS) compared with other groups (AR- and EBP1low/no, AR+ and EBP1high, and AR- and EBP1high). AR+ and EBP1low/no expression were independent prognostic factors for OS and DFS in HER2+ BC. This study showed the clinicopathological role of EBP1 and AR in HER2+ BC. Targeting EBP1 may be an effective treatment strategy for patients with AR+ HER2+ BC.

2'OMe Modification of Anti-miRNA-21 Oligonucleotide–Peptide Conjugate Improves Its Hybridization Properties and Catalytic Activity

Nowadays, application of miRNases—artificial ribonucleases aimed at degradation of noncoding RNAs, in particular, miRNAs—represents one of the novel experimental approaches to inhibit tumorigenesis. miRNases integrate in their structure an addressing oligonucleotide, which provides specific binding with miRNA target, and a catalytic group, which promotes cleavage of the RNA substrate. Introduction of chemical modifications to the oligonucleotide domain of miRNases in the region that is complementary to miRNA may significantly increase the hybridization properties and nuclease resistance of this type of compound. However, the influence of such structural changes to the ribonuclease activity of miRNases remains unclear. In this work, to investigate the effect of 2'OMe modifications on the activity of miRNases, we synthesized two types of anti-miRNA-21 conjugates of the peptide [(ArgLeu)2Gly]2 and hairpin oligonucleotides in which 14-mer binding region to the miRNA target was fully or partially modified. It is shown that the introduction of 2'OMe modifications promotes a considerable increase in the affinity of miRNases to miRNA-21 but does not change significantly their nuclease resistance. Full modification of conjugates in the region that is complementary to miRNA negatively affects their ribonuclease activity, whereas partial introduction of 2'OMe nucleotides considerably enhances the cleavage activity of miRNases, which leads to a substantial decrease in the proliferation rate and migration potential of tumor cells, which are determined by the miRNA-21 expression. Keywords: oligonucleotide–peptide conjugates, oncogenic miRNA, miRNA-21, 2'OMe modification, human epidermoid carcinoma KB-8-5.