PTBP3 regulates proliferation of lung squamous cell carcinoma cells via CDC25A‐mediated cell cycle progression

Background The roles of Polypyrimidine tract-binding protein 3 (PTBP3) in regulating lung squamous cell carcinoma (LUSC) cells progression is unclear. The aim of this study was to investigate the role of PTBP3 in LUSC. Methods Expression and survival analysis of PTBP3 was firstly investigated using TCGA datasets. Quantitative reverse transcription PCR and Western blot were performed to detect PTBP3 expression in clinical samples. Moreover, cell counting kit 8 (CCK-8) assays, colony formation assays and in vivo tumor formation assays were used to examine the effects of PTBP3 on LUSC cell proliferation. RNA-sequence and analysis explores pathways regulated by PTBP3.Flow cytology was used analyzed cell cycle. Cell cycle-related markers were analyzed by Western blot. Results PTBP3 was found to be overexpressed in LUSC tissues compared with normal tissues. High PTBP3 expression was significantly correlated with poor prognosis. In vitro and vivo experiments demonstrated that PTBP3 knockdown caused a significant decrease in the proliferation rate of cells. Bioinformatics analysis showed that PTBP3 involved in cell cycle pathway regulation in LUSC. Furthermore, PTBP3 knockdown arrested cell cycle progression at S phase via decreasing CDK2/Cyclin A2 complex. In addition, downregulation of PTBP3 significantly decreased the expression of CDC25A. Conclusions Our results suggest that PTBP3 regulated LUSC cell proliferation via cell cycle and might be a potential target for molecular therapy of LUSC.

Integrated Analysis to Obtain Potential Prognostic Signature in Glioblastoma

Glioblastoma multiforme (GBM) is the most malignant and multiple tumors of the central nervous system. The survival rate for GBM patients is less than 15 months. We aimed to uncover the potential mechanism of GBM in tumor microenvironment and provide several candidate biomarkers for GBM prognosis. In this study, ESTIMATE analysis was used to divide the GBM patients into high and low immune or stromal score groups. Microenvironment associated genes were filtered through differential analysis. Weighted gene co-expression network analysis (WGCNA) was performed to correlate the genes and clinical traits. The candidate genes’ functions were annotated by enrichment analyses. The potential prognostic biomarkers were assessed by survival analysis. We obtained 81 immune associated differentially expressed genes (DEGs) for subsequent WGCNA analysis. Ten out of these DEGs were significantly associated with targeted molecular therapy of GBM patients. Three genes (S100A4, FCGR2B, and BIRC3) out of these genes were associated with overall survival and the independent test set testified the result. Here, we obtained three crucial genes that had good prognostic efficacy of GBM and may help to improve the prognostic prediction of GBM.

Peptide Receptor Radionuclide Therapy Targeting the Somatostatin Receptor: Basic Principles, Clinical Applications and Optimization Strategies

Peptide receptor radionuclide therapy (PRRT) consists of the administration of a tumor-targeting radiopharmaceutical into the circulation of a patient. The radiopharmaceutical will bind to a specific peptide receptor leading to tumor-specific binding and retention. The only target that is currently used in clinical practice is the somatostatin receptor (SSTR), which is overexpressed on a range of tumor cells, including neuroendocrine tumors and neural-crest derived tumors. Academia played an important role in the development of PRRT, which has led to heterogeneous literature over the last two decades, as no standard radiopharmaceutical or regimen has been available for a long time. This review provides a summary of the treatment efficacy (e.g., response rates and symptom-relief), impact on patient outcome and toxicity profile of PRRT performed with different generations of SSTR-targeting radiopharmaceuticals, including the landmark randomized-controlled trial NETTER-1. In addition, multiple optimization strategies for PRRT are discussed, i.e., the dose–effect concept, dosimetry, combination therapies (i.e., tandem/duo PRRT, chemoPRRT, targeted molecular therapy, somatostatin analogues and radiosensitizers), new radiopharmaceuticals (i.e., SSTR-antagonists, Evans-blue containing vector molecules and alpha-emitters), administration route (intra-arterial versus intravenous) and response prediction via molecular testing or imaging. The evolution and continuous refinement of PRRT resulted in many lessons for the future development of radionuclide therapy aimed at other targets and tumor types.

High Grade Meningiomas: Current Therapy Based on Tumor Biology

Atypical (WHO grade II) and malignant meningiomas (WHO Grade III) are a rare subset of primary intracranial tumors. Due to the high recurrence rate after surgical resection and radiotherapy, there has been a recent interest in exploring other systemic treatment options for these refractory tumors. Recent advances in molecular sequencing of tumors have elucidated new pathways and drug targets currently being studied. This article provides a thorough overview of novel investigational therapeutics, including targeted therapy, immunotherapy, and new technological modalities for atypical and malignant meningiomas. There is encouraging preclinical evidence regarding the efficacy of the emerging treatments discussed in this chapter. Several clinical trials are currently recruiting patients to translate targeted molecular therapy for recurrent and high-grade meningiomas.

Therapeutic Targets In Breast Cancer Signaling: A Review

For women, the most dominant type of cancer is breast cancer and perhaps one of the most recognizedreasons of death. This is a disorder of many distinct traits, many of which are known as positive hormone receptor, human epidermal receptor-2 (HER2+), and three negative breast cancers (TNBC). Drugs that directly target and kill tumors constitute a rapidly-growing form of molecular therapy for cancer patients. Analysis reveals that stable breast tissue cells exhibit receptors which aren't usually present. As a result, it is imperative to cognize the molecular roots of breast cancer and the myriad compromised pathology-related processes and pathways to ensure progresses in early diagnosis and prevention. This study demonstrates essential cellular pathways relevant for breast cancer including improvements in cell proliferation, apoptosis, and hormone balances in breast tissues. On the basis of these notions, we consider how breast cancer is associated to the creation of potentially therapeutic interventions and predictive biomarkers.

A Novel Circular RNA CircRFX3 Serves as a Sponge for MicroRNA-587 in Promoting Glioblastoma Progression via Regulating PDIA3

An increasing number of studies have indicated that circular RNAs (circRNAs) participate in the progression of numerous tumors. However, the functions of circRNAs in glioblastoma (GBM) remain largely unknown. In this study, we focused on a novel circRNA (hsa_circRFX3_003) that was spliced from RFX3, which we named circRFX3. We confirmed that the expression of circRFX3 was substantially increased in GBM cell lines and clinical GBM tissues. The results of a series of overexpression and knockdown assays indicated that circRFX3 could boost the proliferation, invasion, and migration of GBM cells. By performing dual-luciferase reporter gene and RNA pull-down assays, we verified that circRFX3 could sponge microRNA-587 (miR-587) to exercise its function as a competing endogenous RNA (ceRNA) in the development of GBM. In addition, PDIA3 was proven to be a downstream target of miR-587 and to regulate the Wnt/β-catenin pathway. In conclusion, circRFX3 could act as a cancer-promoting circRNA to boost the development of GBM and regulate the miR-587/PDIA3/β-catenin axis. This study might provide a novel target for the treatment of GBM with molecular therapy.

TMED3/RPS15A Axis promotes the development and progression of osteosarcoma

Background Osteosarcoma is a primary malignant tumor that mainly affects children and young adults. Transmembrane emp24 trafficking protein 3 (TMED3) may be involved in the regulation of malignant cancer behaviors. However, the role of TMED3 in osteosarcoma remains mysterious. In this study, the potential biological function and underlying mechanism of TMED3 in progression of osteosarcoma was elaborated. Methods The expression of TMED3 in osteosarcoma was analyzed by immunohistochemical staining. The biological function of TMED3 in osteosarcoma was determined through loss-of-function assays in vitro. The effect of TMED3 downregulation on osteosarcoma was further explored by xenograft tumor model. The molecular mechanism of the regulation of TMED3 on osteosarcoma was determined by gene expression profile analysis. Results The expression of TMED3 in osteosarcoma tissues was significantly greater than that in matched adjacent normal tissues. Knockdown of TMED3 inhibited the progression of osteosarcoma by suppressing proliferation, impeding migration and enhancing apoptosis in vitro. We further validated that knockdown of TMED3 inhibited osteosarcoma generation in vivo. Additionally, ribosomal protein S15A (RPS15A) was determined as a potential downstream target for TMED3 involved in the progression of osteosarcoma. Further investigations elucidated that the simultaneous knockdown of RPS15A and TMED3 intensified the inhibitory effects on osteosarcoma cells. Importantly, knockdown of RPS15A alleviated the promotion effects of TMED3 overexpression in osteosarcoma cells. Conclusions In summary, these findings emphasized the importance of TMED3/RPS15A axis in promoting tumor progression, which may be a promising candidate for molecular therapy of osteosarcoma.

Acute Lymphoblastic Leukaemia in Johannesburg, South Africa: The State-Sector Experience

Introduction Lymphoblastic leukemia (ALL) is a neoplasm of immature lymphoid cells of either B- or T-cell lineage. B-ALL is the more common (particularly in childhood), and has a number of described recurrent genetic abnormalities with distinct clinic-pathological associations. T-ALL comprises a larger proportion of adult ALL (18-23%) than childhood cases (7-15%) in high income countries, and is genetically heterogeneous without clear prognostic associations with genetic subtypes. The frequency of T-ALL and the genetic landscape of B-ALL show regional variation. T-ALL is common among African American children (~25%), but seen infrequently in Asia (~7% of childhood cases). In B-ALL, the translocation t(12;21) and hyperdiploidy predominate among children in Europe and the USA, while KMT2A rearrangement and the translocation t(9;22) are relatively more common in Asia. There is a paucity of literature regarding ALL in Africa; the distribution of its subtypes (B vs T), its genetic composition and outcomes are not known. This study aimed to characterize ALL diagnosed in the state-sector hospitals of Johannesburg, South Africa (SA). Methods Cases diagnosed with ALL in the flow cytometry laboratory at Charlotte Maxeke Johannesburg Academic Hospital (which provides diagnostic immunophenotyping services to all state-sector hospitals of the southern Gauteng region of SA) between 2016-2019 (42 months) were identified and recorded in a database. Pertinent information was documented from the laboratory information system. Results ALL was diagnosed in 181 patients over the time period; pertinent clinical information is reported in Table 1. T-ALL was substantially more common than reported elsewhere, comprising 31.5% and 35.2% of childhood and adult ALL, respectively. Differences were evident in the cytogenetic patterns seen in both B- and T-ALL as compared to other parts of the world. In B-ALL the translocation t(1;19) (which occurs in <10% of cases elsewhere) was the most common recurrent genetic abnormality (23.7%), and the t(9;22) had a relatively high frequency in children <13 years (8.8%) (Figure 1). In T-ALL, karyotypic abnormalities were more common than typical (seen in 80.0% of cases vs 50-70% elsewhere), with derangements of chromosome 6q being the most frequent (19%). The translocation t(10;11) (PICALM-MLLT10) and abnormalities involving the TLX1 (HOX11) and TLX3 (HOX 11L2) genes (which are among the more frequent genetic abnormalities reported internationally) were all uncommon, each occurring in only 2.4% of the cases. Disease outcomes were substantially poorer compared to those reported in high income countries, where survival rates in childhood T-ALL range from 60-80% and exceed 90% in B-ALL. At a median follow-up time of 36 months, only 68.2% (B-ALL) and 27.8% (T-ALL) of children <10 years were alive, while mortality rates among adults exceeded 80% in both T- (86.7%) and B-ALL (83.3%). Survival in patients with T-ALL did not differ between those with high vs low risk clinical features (age >10 years, white cell count >100 x10 9/L), and was significantly worse as compared to those with B-ALL (p = 0.01). Relapse was the dominant cause of death in children <10 years (more so in those with T-ALL), while death due to chemotherapy-related neutropenic sepsis was more common in older patients (particularly those with B-ALL) (Figure 2). Factors associated with disease relapse in B-ALL included KMT2A rearrangement and measurable residual disease (MRD) after induction chemotherapy (as defined by non-quantitative, non-allele specific PCR of IgH/T-cell receptor gene rearrangement status and 4 color flow cytometry (both with sensitivities >0.1%)). Notably, the high risk of relapse associated with MRD was not seen in patients with t(9;22), likely due to the use of targeted molecular therapy in these cases. No significant predictors of survival were identified in T-ALL, but the presence of MRD post-induction was associated with early death due to relapse (<12 months). Conclusion ALL in SA shows distinct differences in the cytogenetic landscape, disease patterns and outcomes. The cause of the poor survival rates likely includes differences in tumour/host biology, late presentation, restricted access to haemopoietic stem cell transplantation in the SA state-sector, and suboptimal neutropenic support. Although rudimentary, available MRD testing is a valuable risk predictor in both B- and T-ALL. Figure 1 Figure 1. Disclosures No relevant conflicts of interest to declare.

CSIG-06. ELUCIDATING THE ROLE OF CO-OCCURRING MUTATIONS IN FGFR1-DRIVEN PEDIATRIC LOW-GRADE GLIOMA

Pediatric low-grade gliomas (pLGGs) have excellent survival, however, with current standard of care, most patients suffer lifelong severe sequalae. pLGGs are almost exclusively driven by single activating mutations in the mitogen-activated protein kinase (MAPK) pathway. As targeted molecular therapy clinical trials focusing on BRAF-altered pLGGs are showing promising results in early clinical trials, similar efforts are underway for FGFR1-altered tumors. In our cohort of FGFR1-4 altered gliomas, we observe frequent occurrence of a second alteration associated with activation of the MAPK or mammalian target of rapamycin (mTOR) pathways in pLGGs. Most commonly in the phosphatase NF1, PIK3CA, PIK3R1 PTPN11 or within the FGFR1 gene itself. However, the impact of second co-occurring mutations on therapeutic response and resistance has not been explored. To address this, we established mouse neural stem cell models over-expressing hot-spot mutated FGFR1 alone or in combination with a second alteration. Immunoblotting revealed that the addition of a second alteration attenuated phosphorylation of ERK, AKT and S6 and influenced cell proliferation both in normal growth conditions and in absence of growth factor. Treatment with an FGFR inhibitor (Infigratinib) showed reduced drug response in double mutant cells compared to hot-spot mutated FGFR1 alone. This was associated with less reduction of phosphorylation of ERK and S6 in the double mutant cells upon treatment. In conclusion, the presence of a second alteration influences proliferation and drug response in models of FGFR1-mutated pLGG, potentially by modulating MAPK and mTOR signaling.