Targeting HIF2α Translation with Tempol in VHL-Deficient Clear Cell Renal Cell Carcinoma

The tumor suppressor gene, Von Hippel-Lindau (VHL), is frequently mutated in the most common form of kidney cancer, clear cell renal cell carcinoma (CCRCC). In hypoxic conditions, or when there is a VHL mutation, the hypoxia inducible factors, HIF1α and HIF2α, are stabilized and transcribe a panel of genes associated with cancer such as vascular endothelial growth factor receptor (VEGFR), platelet derived growth factor (PDGF), and glucose transporter 1 (GLUT1). Recent studies in clear cell kidney cancer have suggested that HIF2α, but not HIF1α, is the critical oncoprotein in the VHL pathway. Therefore, targeting HIF2α could provide a potential therapeutic approach for patients with advanced CCRCC. Since iron regulatory protein 1 (IRP1) is known to inhibit the translation of HIF2α, we investigated whether Tempol, a stable nitroxide that activates IRP1 towards IRE-binding, might have a therapeutic effect on a panel of human CCRCC cells expressing both HIF1α and HIF2α. We first evaluated the protein expression of HIF1α and HIF2α in 15 different clear cell renal carcinoma cell lines established from patient tumors in our laboratory. Tempol decreased the expression of HIF2α, and its downstream targets in all the cell lines of the panel. This effect was attributed to a dramatic increase of IRE-binding activity of IRP1. Several cell lines were found to have an increased IRP1 basal activity at 20% O₂ compared to 5% O₂, which may lower HIF2α expression in some of the cell lines in a VHL-independent manner. Taken together our data identify Tempol as an agent with potential therapeutic activity targeting expression of HIF2α in VHL-deficient clear cell kidney cancer and illustrate the importance of studying biochemical processes at relevant physiological O2 levels.     

Programmed Cell Death Ligand 1 Expression in Resected Non–Small Cell Lung Cancer

BackgroundRecently, anti–programmed cell death 1 (PD-1) and anti–programmed cell death ligand 1 (PD-L1) immunotherapies have yielded promising outcomes for patients with advanced non–small cell lung cancer (NSCLC) and led to great interest in applying these agents to treat resectable early-stage NSCLC. The objective of our study was to evaluate PD-L1 protein expression in resectable early-stage NSCLC specimens from a large Northern European cohort, examine the relationship to clinical characteristics, and demonstrate the prognostic role in resected NSCLC.Materials and MethodsA large cohort of 875 NSCLC tumors consisted of 337 patients from Sweden and 538 patients from Norway was studied. All the patients had undergone pulmonary resection, and most patients had had early-stage NSCLC. PD-L1 protein expression was assessed by immunohistochemistry using the Dako PD-L1 22C3 pharmDx kit. The tumor proportion score for PD-L1 protein expression was compared with comprehensive demographic and clinicopathologic data.ResultsThe overall prevalence of PD-L1 protein expression in the resectable NSCLC cohort was 9.5% at a tumor proportion score cutoff of ≥ 50%. Stage I NSCLC had lower PD-L1 expression compared with that of the other stages (P = .0012). PD-L1 expression correlated with wild-type EGFR gene expression (P = .0156) and mutated KRAS gene expression (P = .0004). No significant association was found between PD-L1 expression and mortality after multivariable adjustment for clinical characteristics, although the survival curves showed PD-L1 expression significantly correlated with a poor prognosis in the total NSCLC cohort and in the adenocarcinoma subgroup.ConclusionPD-L1 expression in the present large cohort of resectable NSCLC was relatively low compared with data from clinical trials of advanced NSCLC. PD-L1 expression correlated positively with tumor stage, wild-type EGFR, and KRAS mutation. PD-L1 expression was not found as an independent prognostic factor in the present study. These findings could be important in the future when evaluating the role of anti–PD-1/PD-L1 immunotherapy in the setting of neoadjuvant or adjuvant trials for early-stage resectable NSCLC.     

Effect of 5-aza-2’-deoxycytidine on Cell Proliferation of Nonsmall Cell Lung Cancer Cell Line A549 Cells and Expression of the TFPI-2 Gene

Objective: The present study employed 5-aza-2’-deoxycytidine (5-Aza-CdR) to treat non-small cell lung cancer(NSCLC) cell line A549 to investigate the effects on proliferation and expression of the TFPI-2 gene. Methods:Proliferation was assessed by MTT assay after A549 cells were treated with 0, 1, 5, 10 μmol/L 5-Aza-CdR, a specificdemethylating agent, for 24 ,48 and 72h. At the last time point cells were also analyzed by flow cytometry (FCM)to identify any change in their cell cycle profiles. Methylation-specific polymerase chain reaction (MSPCR), realtime polymerase chain reaction(real-time PCR) and western blotting were carried out to determine TFPI-2 genemethylation status, mRNA expression and protein expression. Results: MTT assay showed that the growth ofA549 cells which were treated with 5-Aza-CdR was significantly suppressed as compared with the control group(0 μmol/L 5-Aza-CdR). After treatment with 0, 1, 5, 10 μmol/L 5-Aza-CdR for 72h, FCM showed their proportionin G0/G1 was 69.7±0.99%, 76.1±0.83%, 83.8±0.35%, 95.5±0.55% respectively (P<0.05), and the proportion in Swas 29.8±0.43%, 23.7±0.96%, 15.7±0.75%, 1.73±0.45%, respectively (P<0.05), suggesting 5-Aza-CdR treatmentinduced G0/G1 phase arrest. MSPCR showed that hypermethylation in the promoter region of TFPI-2 genewas detected in control group (0 μmol/L 5-Aza-CdR), and demethylation appeared after treatment with 1, 5,10 μmol/L 5-Aza-CdR for 72h. Real-time PCR showed that the expression levels of TFPI-2 gene mRNA were1±0, 1.49±0.14, 1.86±0.09 and 5.80±0.15 (P<0.05) respectively. Western blotting analysis showed the relativeexpression levels of TFPI-2 protein were 0.12±0.01, 0.23±0.02, 0.31±0.02, 0.62±0.03 (P<0.05). TFPI-2 proteinexpression in A549 cells was gradually increased significantly with increase in the 5-Aza-CdR concentration.Conclusions: TFPI-2 gene promoter methylation results in the loss of TFPI-2 mRNA and protein expressionin the non-small cell lung cancer cell line A549, and 5-Aza-CdR treatment could induce the demethylation ofTFPI-2 gene promoter and restore TFPI-2 gene expression. These findings provide theoretic evidence for clinicaltreatment of advanced non-small cell lung cancer with the demethylation agent 5-Aza-CdR. TFPI-2 may be onemolecular marker for effective treatment of advanced non-small cell lung cancer with 5-Aza-CdR.     

Hyperthermia Enhances Thermal-Neutron–Induced Cell Death of Human Glioblastoma Cell Lines at Low Concentrations of 10B

Purpose: To examine the ability of pre- vs. post-irradiation hyperthermia to enhance the effectiveness of thermal neutrons to kill human glioblastoma cells.Methods and Materials: Human glioblastoma cell lines, T98G, A7, A172, and U 87MG, were exposed to thermal neutrons from the Kyoto University Research (KUR) reactor or to ⁶⁰Co γ-rays. Hyperthermia was tested before and after irradiation of T98G (44°C, 15 min) and A7 cells (44°C, 40 min), and with different concentrations (0–30 ppm) of ¹⁰B-boric acid. The biological end point of all experiments was cell survival measured by a colony formation assay.Results: The relative biological effectiveness (RBE) values of thermal neutrons for these cell lines compared with ⁶⁰Co γ-rays were 1.8–2.0 at their D₀ values. When T98G and A7 cells were heated after thermal neutron irradiation, there was a synergistic effect at low ¹⁰B concentrations (up to 5 ppm for T98G and up to 10 ppm for A7 cells). With high concentrations of boron (10–30 ppm for T98G and 20–30 ppm for A7 cells), hyperthermia and neutron irradiation interact additively rather than synergistically. There was no enhancement when cells were heated before thermal neutron irradiation. These results suggest that the radiosensitizing effect of hyperthermia may be attributed to partial inhibition of the repair of the potentially lethal damage caused by neutron irradiation.     

Non-Clear Cell Renal Cell Carcinoma: Does the Mammalian Target of Rapamycin Represent a Rational Therapeutic Target?

Non-clear cell renal cell carcinomas (nccRCCs) comprise a heterogenous and poorly characterized group of tumor types for which few treatments have been approved. Although targeted therapies have become the cornerstones of systemic treatment for metastatic renal cell carcinoma, patients with nccRCC have been excluded from many pivotal clinical trials. As such, robust clinical evidence supporting the use of these agents in patients with nccRCC is lacking. Here, we review the disparate nccRCC subtypes, the criteria for diagnosis, and the prognoses associated with each subtype, in addition to evaluating the potential use of mammalian target of rapamycin (mTOR) inhibitors in treating patients with nccRCC. Both genetic analyses and preclinical research indicate a central role for mTOR in nccRCC; a therapy that targets this ubiquitous regulator of cellular signaling could prove efficacious across various tumor subtypes. Results from recent studies exploring targeted therapies as both monotherapy and combination therapy have provided early indications of efficacy in patients with nccRCC. Exploratory analyses support further research with the mTOR inhibitors everolimus and temsirolimus in patients with nccRCC. Current clinical practice guidelines support the use of mTOR inhibitors in patients with nccRCC; however, these recommendations are based on low levels of evidence. Further results from randomized, controlled clinical trials are needed to determine the optimal choice of therapy for patients with nccRCC. Results from ongoing clinical trials of mTOR inhibitors and other agents in nccRCC, as well as their impact on the nccRCC treatment paradigm, are eagerly awaited.     

Non–Clear Cell Renal Cell Carcinoma: How New Biological Insight May Lead to New Therapeutic Modalities

Treatment for patients with metastatic non–clear cell renal cancer (RCC), who constitute 25% of all RCC patients, is largely undefined and tested algorithms remain unsatisfactory. Response rates to targeted therapy are not as high as in patients with clear cell subtypes, but novel agents provide a clinically meaningful response in some individuals. The research leading to characterization of the pathways involved in clear cell renal cancer has been recognized as a role model for the development of therapies based on genetic and molecular tumor characteristics. Similar research now provides increasing insight into signal transduction in non–clear cell subtypes. This review will present and discuss the current evidence of pathways involved in the most common non–clear cell subtypes. In addition, we will review how this may lead to the development of new treatment modalities. New targets and clinical trials will be highlighted.     

Will Testicular Germ Cell Tumors Remain Untargetable?

Testicular Germ cell tumors (TGCT) represent the most common solid tumors affecting young men. They constitute a distinct entity because of their embryonic origin and their unique biological behavior. Recently, new preclinical data on genetic and epigenetic susceptibility profiles, biological signaling machinery as well as on molecular patterns of tumors and pathways of pathogenesis helped to elucidate the pathogenesis and the differentiation of TGCTs and to understand the mechanisms behind the development of resistance to treatment. In the present work, we have reviewed new clues to the development, differentiation and progression of TGCTs. We focus on the most important epigenetic and molecular biomarkers, and discussed their diagnostic and prognostic accuracy compared to the currently used biomarkers. The mechanisms underlying the development of resistance to cisplatin and commonly used chemotherapeutic agents are also discussed in detail. Finally, we summarize failed and ongoing clinical trials using targeted therapies in resistant TGCTs, and analyze the potential of new targeted therapies. Open image in new window     

Blastic Plasmacytoid Dendritic Cell Neoplasm–Current Insights

Blastic plasmacytoid dendritic cell neoplasm (BPDCN) is a rare clonal hematologic malignancy of plasmacytoid dendritic cell precursors. The presentation and clinical course of BPDCN is widely heterogeneous and was most recently categorized as a distinct clinical entity by the World Health Organization in 2016. The expanded understanding of the pathobiology of BPDCN has improved diagnostic accuracy and informed novel targeted therapeutic options. The United States Food and Drug Administration-approval of tagraxofusp (SL-401) in December 2018 has focused attention on this leukemia frequently associated with skin involvement. Herein, we aim to: (1) review etiology; (2) summarize diagnostic criteria; and (3) discuss historic treatments and novel therapies for BPDCN.     

Cell death. 1+1≠2

Michael Yaffe and colleagues show that pretreatment with one targeted drug for a specific period of time can increase the sensitivity of triple-negative breast cancer cells to standard chemotherapy.     

Cell signalling: weighing up TGFβ signals

The Hippo pathway couples cell polarity complexes to extrinsic signalling pathways.     

Induction of P3NS1 Myeloma Cell Death and Cell Cycle Arrest by Simvastatin and/or γ-Radiation

The present study was conducted to investigate the effect of γ-radiation alone or combined with a cytotoxicdrug, simvastatin, on viability and cell cycling of a myeloma cell line. P3NS1 myeloma cells were treated withthe selected dose of simvastatin (0.1μM/l) 24 hours prior to γ-irradiation (0.25, 0.5 and 1Gy). The cell viability,induction of apoptosis, cell death, cell cycling, generation of ROS, and expression of P53, Bax, Bcl2, caspase3,PARP1 and Fas genes were estimated. The results indicated that simvastatin (0.1μM/l) treatment for 24 hoursprior to γ- irradiation increased cell death to 37.5% as compared to 4.81% by radiation (0.5Gy) alone. It was foundthat simvastatin treatment before irradiation caused arrest of cells in G0/G1 and G2/M phases as assessed usingflow cytometry. Interestingly, simvastatin treatment of P3NS1 cells increased the intracellular ROS productionand decreased antioxidant enzyme activity with increased P53, Bax and Caspase3 gene expression while thatof Bcl2 was decreased. Consequently, our results indicated that pre-treatment with simvastatin increased radiosensitivity of myeloma tumor cells in addition to apoptotic effects through an intrinsic mitochondrial pathway.     

Cancer Cell揭示肿瘤与免疫细胞的信息交流

<正>路德维希癌症研究中心的科研人员研究了趋化因子在调节实体瘤中T细胞聚集中的作用。结果表明,趋化因子CCL5和CXCL9过表达与实体瘤中的CD8+T细胞浸润有关,这两种分子在肿瘤与免疫细胞间的信息交流起到关键作用。该研究结果发表于近期的《Cancer Cell》杂志。此次研究主要目的是研究在肿瘤微环境中肿瘤细胞与免疫细胞究竟     

Paraneoplastic Guillain-Barré Syndrome in Small Cell Lung Cancer

Guillain-Barré syndrome (GBS) is defined as an acute, autoimmune polyradiculoneuropathy. It is a rare disease that occurs at a rate of 1.11 cases per 100,000 person-years. However, once infected, up to 20%percnt; of patients develop severe disability, and approximately 5%percnt; die. There have been reports of GBS in different cancers. Among them, there are 6 previous reports of GBS in small cell lung cancer. Here, we report a case of a 52-year-old man who was diagnosed with GBS in the setting of small cell lung cancer with chemotherapy.Key Words: Guillain-Barré syndrome, Small cell lung cancer, Paraneoplastic syndrome