Verification of optimal conditions for the scattering correction of 123I-FP-CIT SPECT on a single-photon emission tomography system with a two-detector whole-body cadmium-zinc-telluride semiconductor detector.

To identify the optimal scattering correction for 123I-FP-CIT SPECT (DAT-SPECT) using a two-detector whole-body cadmium-zinc-telluride semiconductor detector (C-SPECT) system with a medium-energy high-resolution sensitivity (MEHRS) collimator. The C-SPECT system with the MEHRS collimator assessed image quality and quantification using a striated phantom. Different reconstruction methods and scattering correction settings were compared, including filtered back projection (FBP) and ordered subset expectation maximization (OSEM). Higher %contrast and %CV values were observed > 10% subwindow (SW) for all conditions, with no significant differences between images without scattering correction and those < 7% SW. The FBP images show a greater increase in %CV > 10% SW than the OSEM images. The specific binding ratio in the radioactivity ratio of 8:1 was higher than the true value under all conditions. The C-SPECT system with an MEHRS collimator provided accurate scattering suppression and enabled high-quality imaging for DAT-SPECT. Careful setting of the scattering correction is essential for total count accuracy.

Evaluation of Collimators in a High-Resolution, Whole-Body SPECT/CT Device with a Dual-Head Cadmium-Zinc-Telluride Detector for 123I-FP-CIT SPECT.

The study aim was to evaluate the adaptation of collimators to 123I-N-fluoropropyl-2b-carbomethoxy-3b-(4-iodophenyl)nortropane (123I-FP-CIT) dopamine transporter SPECT (DAT-SPECT) by a high-resolution whole-body SPECT/CT system with a cadmium-zinc-telluride detector (C-SPECT) in terms of image quality, quantitation, diagnostic performance, and acquisition time. Methods: Using a C-SPECT device equipped with a wide-energy, high-resolution collimator and a medium-energy, high-resolution sensitivity (MEHRS) collimator, we evaluated the image quality and quantification of DAT-SPECT for an anthropomorphic striatal phantom. Ordered-subset expectation maximization iterative reconstruction with resolution recovery, scatter, and attenuation correction was used, and the optimal collimator was determined on the basis of the contrast-to-noise ratio (CNR), percentage contrast, and specific binding ratio. The acquisition time that could be reduced using the optimal collimator was determined. The optimal collimator was used to retrospectively evaluate diagnostic accuracy via receiver-operating-characteristic analysis and specific binding ratios for 41 consecutive patients who underwent DAT-SPECT. Results: When the collimators were compared in the phantom verification, the CNR and percentage contrast were significantly higher for the MEHRS collimator than for the wide-energy high-resolution collimator (P < 0.05). There was no significant difference in the CNR between 30 and 15 min of imaging time using the MEHRS collimator. In the clinical study, the areas under the curve for acquisition times of 30 and 15 min were 0.927 and 0.906, respectively, and the diagnostic accuracies of the DAT-SPECT images did not significantly differ between the 2 times. Conclusion: The MEHRS collimator provided the best results for DAT-SPECT with C-SPECT; shorter acquisition times (<15 min) may be possible with injected activity of 167-186 MBq.

Regulation of Oncogenic Targets by Tumor-Suppressive miR-150-3p in Lung Squamous Cell Carcinoma.

Several recent studies have shown that both strands of certain miRNAs derived from miRNA duplexes are involved in cancer pathogenesis. Our own recent studies revealed that both strands of the miR-150 duplex act as tumor-suppressive miRNAs in lung adenocarcinoma (LUAD) through the targeting of several oncogenes. The aim of the study here was to further investigate the tumor-suppressive roles of miR-150-3p (the passenger strand) in lung squamous cell carcinoma (LUSQ) and its control of cancer-promoting genes in LUSQ cells. The downregulation of miR-150-3p in LUSQ tissues was confirmed by data in The Cancer Genome Atlas (TCGA). The ectopic expression of miR-150-3p attenuated cancer cell aggressive features, e.g., cell cycle arrest, migration and invasive abilities. Our target search strategy successfully identified a total of 49 putative targets that were listed as subjects of miR-150-3p regulation in LUSQ cells. Interestingly, among these targets, 17 genes were categorized as related to the "cell cycle" based on Gene Ontology (GO) classification, namely CENPA, CIT, CCNE1, CCNE2, TIMELESS, BUB1, MCM4, HELLS, SKA3, CDCA2, FANCD2, NUF2, E2F2, SUV39H2, CASC5, ZWILCH and CKAP2). Moreover, we show that the expression of HELLS (helicase, lymphoid specific) is directly controlled by miR-150-3p, and its expression promotes the malignant phenotype of LUSQ cells.

Molecular Signature of Small Cell Lung Cancer after Treatment Failure: The MCM Complex as Therapeutic Target.

Small cell lung cancer (SCLC) is a highly aggressive cancer, and patients who become refractory to first-line treatment have a poor prognosis. The development of effective treatment regimens is urgently needed. In this study, we identified a gene expression signature of SCLC after treatment failure using SCLC clinical specimens (GEO accession number: GSE162102). A total of 1,136 genes were significantly upregulated in SCLC tissues. These upregulated genes were subjected to KEGG pathway analysis, and "cell cycle", "Fanconi anemia", "alcoholism", "systemic lupus erythematosus", "oocyte meiosis", "homologous recombination", "DNA replication", and "p53 signaling" were identified as the enriched pathways among the genes. We focused on the cell cycle pathway and investigated the clinical significance of four genes associated with this pathway: minichromosome maintenance (MCM) 2, MCM4, MCM6, and MCM7. The overexpression of these MCM genes was confirmed in SCLC clinical specimens. Knockdown assays using siRNAs targeting each of these four MCM genes showed significant attenuation of cancer cell proliferation. Moreover, siRNA-mediated knockdown of each MCM gene enhanced the cisplatin sensitivity of SCLC cells. Our SCLC molecular signature based on SCLC clinical specimens after treatment failure will provide useful information to identify novel molecular targets for this disease.

Involvement of Dual Strands of miR-143 (miR-143-5p and miR-143-3p) and Their Target Oncogenes in the Molecular Pathogenesis of Lung Adenocarcinoma.

Our analyses of tumor-suppressive microRNAs (miRNAs) and their target oncogenes have identified novel molecular networks in lung adenocarcinoma (LUAD). Moreover, our recent studies revealed that some passenger strands of miRNAs contribute to cancer cell malignant transformation. Downregulation of both strands of the miR-143 duplex was observed in LUAD clinical specimens. Ectopic expression of these miRNAs suppressed malignant phenotypes in cancer cells, suggesting that these miRNAs have tumor-suppressive activities in LUAD cells. Here, we evaluated miR-143-5p molecular networks in LUAD using genome-wide gene expression and miRNA database analyses. Twenty-two genes were identified as potential miR-143-5p-controlled genes in LUAD cells. Interestingly, the expression of 11 genes (MCM4, RAD51, FAM111B, CLGN, KRT80, GPC1, MTL5, NETO2, FANCA, MTFR1, and TTLL12) was a prognostic factor for the patients with LUAD. Furthermore, knockdown assays using siRNAs showed that downregulation of MCM4 suppressed cell growth, migration, and invasion in LUAD cells. Aberrant expression of MCM4 was confirmed in the clinical specimens of LUAD. Thus, we showed that miR-143-5p and its target genes were involved in the molecular pathogenesis of LUAD. Identification of tumor-suppressive miRNAs and their target oncogenes may be an effective strategy for elucidation of the molecular oncogenic networks of this disease.

Aberrantly expressed PLOD1 promotes cancer aggressiveness in bladder cancer: a potential prognostic marker and therapeutic target.

Bladder cancer (BC) is the ninth most malignant tumor worldwide. Some BC patients will develop muscle-invasive BC (MIBC), which has a 5-year survival rate of approximately 60% due to metastasis. As such, there is an urgent need for novel therapeutic and diagnostic targets for MIBC. Analysis of novel antitumor microRNA (miRNA)-mediated cancer networks is an effective strategy for exploring therapeutic targets and prognostic markers in cancers. Our previous miRNA analysis revealed that miR-140-5p acts as an antitumor miRNA in BC cells. Here, we investigated miR-140-5p regulation of BC molecular pathogenesis. Procollagen-lysine, 2-oxoglutarate 5-dioxygenase 1 (PLOD1) was found to be directly regulated by miR-140-5p, and aberrant expression of PLOD1 was observed in BC clinical specimens. High PLOD1 expression was significantly associated with a poor prognosis (disease-free survival: P = 0.0204; overall survival: P = 0.000174). Multivariate analysis showed PLOD1 expression to be an independent prognostic factor in BC patients (hazard ratio = 1.51, P = 0.0099). Furthermore, downregulation of PLOD1 by siRNAs and a specific inhibitor significantly decreased BC cell aggressiveness. Aberrant expression of PLOD1 was closely associated with BC pathogenesis. In summary, the present study showed that PLOD1 may be a potential prognostic marker and therapeutic target for BC.

Molecular Pathogenesis of Gene Regulation by the miR-150 Duplex: miR-150-3p Regulates TNS4 in Lung Adenocarcinoma.

Based on our miRNA expression signatures, we focused on miR-150-5p (the guide strand) and miR-150-3p (the passenger strand) to investigate their functional significance in lung adenocarcinoma (LUAD). Downregulation of miR-150 duplex was confirmed in LUAD clinical specimens. In vitro assays revealed that ectopic expression of miR-150-5p and miR-150-3p inhibited cancer cell malignancy. We performed genome-wide gene expression analyses and in silico database searches to identify their oncogenic targets in LUAD cells. A total of 41 and 26 genes were identified as miR-150-5p and miR-150-3p targets, respectively, and they were closely involved in LUAD pathogenesis. Among the targets, we investigated the oncogenic roles of tensin 4 (TNS4) because high expression of TNS4 was strongly related to poorer prognosis of LUAD patients (disease-free survival: p = 0.0213 and overall survival: p = 0.0003). Expression of TNS4 was directly regulated by miR-150-3p in LUAD cells. Aberrant expression of TNS4 was detected in LUAD clinical specimens and its aberrant expression increased the aggressiveness of LUAD cells. Furthermore, we identified genes downstream from TNS4 that were associated with critical regulators of genomic stability. Our approach (discovery of anti-tumor miRNAs and their target RNAs for LUAD) will contribute to the elucidation of molecular networks involved in the malignant transformation of LUAD.

Regulation of KIF2A by Antitumor miR-451a Inhibits Cancer Cell Aggressiveness Features in Lung Squamous Cell Carcinoma.

In the human genome, miR-451a is encoded close to the miR-144 on chromosome region 17q11.2. Our previous study showed that both strands of pre-miR-144 acted as antitumor miRNAs and were involved in lung squamous cell carcinoma (LUSQ) pathogenesis. Here, we aimed to investigate the functional significance of miR-451a and to identify its targeting of oncogenic genes in LUSQ cells. Downregulation of miR-451a was confirmed in LUSQ clinical specimens, and low expression of miR-451a was significantly associated with poor prognosis of LUSQ patients (overall survival: p = 0.035, disease-free survival: p = 0.029). Additionally, we showed that ectopic expression of miR-451a significantly blocked cancer cell aggressiveness. In total, 15 putative oncogenic genes were shown to be regulated by miR-451a in LUSQ cells. Among these targets, high kinesin family member 2A (KIF2A) expression was significantly associated with poor prognosis (overall survival: p = 0.043, disease-free survival: p = 0.028). Multivariate analysis showed that KIF2A expression was an independent prognostic factor in patients with LUSQ (hazard ratio = 1.493, p = 0.034). Aberrant KIF2A expression promoted the malignant transformation of this disease. Analytic strategies based on antitumor miRNAs and their target oncogenes are effective tools for identification of novel molecular pathogenesis of LUSQ.

Involvement of dual-strand of the miR-144 duplex and their targets in the pathogenesis of lung squamous cell carcinoma.

The prognosis of patients with advanced-stage lung squamous cell carcinoma (LUSQ) is poor, and effective treatment protocols are limited. Our continuous analyses of antitumor microRNAs (miRNAs) and their oncogenic targets have revealed novel oncogenic pathways in LUSQ. Analyses of our original miRNA expression signatures indicated that both strands of miR-144 (miR-144-5p, the passenger strand; miR-144-3p, the guide strand) showed decreased expression in cancer tissues. Additionally, low expression of miR-144-5p significantly predicted a poor prognosis in patients with LUSQ by The Cancer Genome Atlas database analyses (overall survival, P = 0.026; disease-free survival, P = 0.023). Functional assays revealed that ectopic expression of miR-144-5p and miR-144-3p significantly blocked the malignant abilities of LUSQ cells, eg, cancer cell proliferation, migration, and invasion. In LUSQ cells, 13 and 15 genes were identified as possible oncogenic targets that might be regulated by miR-144-5p and miR-144-3p, respectively. Among these targets, we identified 3 genes (SLC44A5, MARCKS, and NCS1) that might be regulated by both strands of miR-144. Interestingly, high expression of NCS1 predicted a significantly poorer prognosis in patients with LUSQ (overall survival, P = 0.013; disease-free survival, P = 0.048). By multivariate analysis, NCS1 expression was found to be an independent prognostic factor for patients with LUSQ patients. Overexpression of NCS1 was detected in LUSQ clinical specimens, and its aberrant expression enhanced malignant transformation of LUSQ cells. Our approach, involving identification of antitumor miRNAs and their targets, will contribute to improving our understanding of the molecular pathogenesis of LUSQ.

Dual strands of the miR-145 duplex (miR-145-5p and miR-145-3p) regulate oncogenes in lung adenocarcinoma pathogenesis.

Our original microRNA (miRNA) expression signatures (based on RNA sequencing) revealed that both strands of the miR-145 duplex (miR-145-5p, the guide strand, and miR-145-3p, the passenger strand) were downregulated in several types of cancer tissues. Involvement of passenger strands of miRNAs in cancer pathogenesis is a new concept in miRNA biogenesis. In our continuing analysis of lung adenocarcinoma (LUAD) pathogenesis, we aimed here to identify important oncogenes that were controlled by miR-145-5p and miR-145-3p. Downregulation of miR-145-5p and miR-145-3p was confirmed in LUAD clinical specimens. Functional assays showed that miR-145-3p significantly blocked the malignant abilities in LUAD cells, e.g., cancer cell proliferation, migration and invasion. Thus, the data showed that expression of the passenger strand of the miR-145-duplex acted as an anti-tumor miRNA. In LUAD cells, we identified four possible target genes (LMNB2, NLN, SIX4, and DDC) that might be regulated by both strands of miR-145. Among the possible targets, high expression of LMNB2 predicted a significantly poorer prognosis of LUAD patients (disease-free survival, p = 0.0353 and overall survival, p = 0.0017). Overexpression of LMNB2 was detected in LUAD clinical specimens and its aberrant expression promoted malignant transformation of LUAD cells. Genes regulated by anti-tumor miR-145-5p and miR-145-3p are closely involved in the molecular pathogenesis of LUAD. We suggest that they are promising prognostic markers for this disease. Our approach, based on the roles of anti-tumor miRNAs, will contribute to improved understanding of the molecular pathogenesis of LUAD.

[Estimation of preoperative induction chemoradiotherapy effectiveness for non small-cell lung cancer].

We have performed the clinical evaluations of preoperative induction chemoradiotherapy (CRTx) for 25 patients with non small-cell lung cancer (male: 19, female: 6, mean age: 66.4-year-old). The clinical stages of these patients were IIA: 1, IIB: 7, IIIA: 14, and IIIB: 3, respectively. In the histological type of lung cancer, there were 12 patients of adenocarcinoma, 7 of squamous cell carcinoma, 1 of adenosquamous carcinoma, 1 of anaplastic carcinoma, and 4 of large cell carcinoma. We applied two courses of regimen as the pre-operative chemotherapy (CDDP+DOC or CBDCA+PTX). Twenty-four patients received radiotherapy as the concurrent radiotherapy (44 Gy: 22 patients, 60 Gy: 2 patients). Among the 25 patients, 16 patients accomplished both chemotherapies, and the effects of the treatment were as follows: CR; none, PR; 15, SD; 9, respectively. And the other patient was not an evaluable case due to atelectasis. Histopathological effects (Ef) were Ef-3: 3, Ef-2: 11, Ef-1: 7, Ef-0: 1 and Ef was not evaluable in 3 cases. Post operative pathological findings showed that 14 patients were down staged. There were no operative mortality associated with the operation, and no serious morbidity case was observed. Eighteen patients were survived and 1 patient was survived with tumor metastases. Only one patient died of recurrence in the upper mediastinal lymph nodes, 3 patients died of the brain metastases, one died of hepatic metastasis, and one died of cryptogenic sudden death. As a result, there was no serious operative morbidity observed in the course of this CRTx. We therefore recommend that induction chemoradiotherapy as a beneficial pre-operative treatment.