Brachytherapy Approach Using 177Lu Conjugated Gold Nanostars and Evaluation of Biodistribution, Tumor Retention, Dosimetry and Therapeutic Efficacy in Head and Neck Tumor Model

Brachytherapy can provide sufficient doses to head and neck squamous cell carcinoma (HNSCC) with minimal damage to nearby normal tissues. In this study, the β−-emitter 177Lu was conjugated to DTPA-polyethylene glycol (PEG) decorated gold nanostars (177Lu-DTPA-pAuNS) used in surface-enhanced Raman scattering and photothermal therapy (PTT). The accumulation and therapeutic efficacy of 177Lu-DTPA-pAuNS were compared with those of 177Lu-DTPA on an orthotopic HNSCC tumor model. The SPECT/CT imaging and biodistribution studies showed that 177Lu-DTPA-pAuNS can be accumulated in the tumor up to 15 days, but 177Lu-DTPA could not be detected at 24 h after injection. The tumor viability and growth were suppressed by injected 177Lu-DTPA-pAuNS but not nonconjugated 177Lu-DTPA, as evaluated by bioluminescent imaging. The radiation-absorbed dose of the normal organ was the highest in the liver (0.33 mSv/MBq) estimated in a 73 kg adult, but that of tumorsphere (0.5 g) was 3.55 mGy/MBq, while intravenous injection of 177Lu-DTPA-pAuNS resulted in 1.97 mSv/MBq and 0.13 mGy/MBq for liver and tumorsphere, respectively. We also observed further enhancement of tumor-suppressive effects by a combination of 177Lu-DTPA-pAuNS and PTT compared to 177Lu-DTPA-pAuNS alone. In conclusion, 177Lu-DTPA-pAuNS may be considered as a potential radiopharmaceutical agent for HNSCC brachytherapy.

DDRE-10. SCREENING OF EPIGENETIC COMPOUNDS IN GLIOMA AND GLIOBLASTOMA IDENTIFIES NOVEL THERAPEUTICS FOR THEIR POTENTIAL TREATMENT

BACKGROUND 28% of primary central nervous system tumors are glioma and glioblastoma. These tumors are responsible for 80% of malignant brain neoplasms and most brain tumor related deaths. Despite modern therapies, patients with grade II gliomas have an average survival of 8-15 years, while patients with grade III tumors have an average survival of 3-5 years, and patients with glioblastoma have an average survival of 12-15 months. The lack of a curative treatment for this group of tumors supports additional research and novel approaches to identify more effective therapies. METHODS In this study, we developed a high-throughput drug screen and culture system to identify epigenetic inhibitor compounds with the potential to reduce glioma and glioblastoma viability. RESULTS We screened 33 tumors: 18 glioblastoma, 8 oligodendroglioma, and 7 astrocytoma. The top three most effective compounds across the full glioma cohort were all HDAC inhibitors; in order from most effective: panobinostat (average tumor viability = 52.5% +/-14.1SD; p=2.16x10-61), LAQ824 (average tumor viability = 58.1% +/-18SD; p=1.48x10-45), and HC Toxin (average tumor viability = 64% +/-21.1SD; p= 1.16x10-33). Additionally, HDAC inhibition was also the most effective across each histopathological glioma type: astrocytoma, oligodendroglioma, and glioblastoma. UNC0631(G9a inhibitor) and JIB-04(KDM inhibitor) were the most effective compounds in the six recurrent tumors, though HDAC inhibition was still significantly effective in this group. We also evaluated drug sensitivity with respect to tumor grade, prior treatment, de novo vs progressive etiology, EGFR amplification, IDH mutation, MGMT methylation, and patient gender. CONCLUSIONS After screening a large glioma cohort against a panel of epigenetic inhibitors, we found HDAC inhibition most effectively reduced tumor viability across all histopathological types and grades. These findings require further in vivo validation.

DDRE-20. HIGH-THROUGHPUT SCREENING OF FDA-APPROVED COMPOUNDS IN GLIOMA AND GLIOBLASTOMA IDENTIFIES NOVEL THERAPEUTICS

BACKGROUND Glioma and glioblastoma comprise 28% of all primary central nervous system tumors and cause the majority of primary brain tumor deaths. Despite substantial research into the molecular pathogenesis and genetic landscape of glioma, no currently approved therapies are curative for any glioma or glioblastoma. Patients with glioblastoma have an average survival time of 12-15 months, while patients with grade III gliomas have an average survival time of 3-5 years, and patients with grade II gliomas have an average survival time of 8-15 years. The lack of a curative treatment for these tumors necessitates additional research into novel therapies. METHODS In this study, we developed a high-throughput drug screen and culture system to identify existing FDA-approved therapies with the potential to inhibit glioma viability. RESULTS In total, we screened 39 tumors: 21 glioblastoma, 10 oligodendroglioma, and 8 astrocytoma. Carfilzomib was the most effective compound across the cohort, decreasing the average tumor viability to 39.0% +/- 16.5%SD. Regardless of tumor grade, MGMT methylation, EGFR amplification, tumor recurrence and etiology, tumor histology, prior treatment, and patient gender, carfilzomib significantly reduced cell viability in every tumor; though was not necessarily the most effective compound in each of these groups. We found HDAC inhibition to be the most effective treatment in grade 1 astrocytomas. However, HDAC inhibition was surpassed by carfilzomib and RNA transcription inhibitors in all higher grades. Interestingly, EGFR inhibition, while significantly effective in 36 tumors, was consistently less effective than carfilzomib across the cohort, though did surpass the effectiveness of HDAC inhibition in grade III gliomas. CONCLUSIONS FDA approved compounds can effectively inhibit glioma tumor viability. Specifically, carfilizomib holds great promise. Further in vivo studies are needed to confirm these findings.

Per-Feature Accuracy of Liver Imaging Reporting and Data System Locoregional Treatment Response Algorithm: A Systematic Review and Meta-Analysis

We aimed to investigate the accuracy of each imaging feature of LI-RADS treatment response (LR-TR) viable category for diagnosing tumor viability of locoregional therapy (LRT)-treated HCC. Studies evaluating the per feature accuracy of the LR-TR viable category on dynamic contrast-enhanced CT or MRI were identified in databases. A bivariate random-effects model was used to calculate the pooled sensitivity, specificity, and diagnostic odds ratio (DOR) of LR-TR viable features. Ten studies assessing the accuracies of LR-TR viable features (1153 treated observations in 971 patients) were included. The pooled sensitivities and specificities for diagnosing viable HCC were 81% (95% confidence interval [CI], 63–92%) and 95% (95% CI, 88–98%) for nodular, mass-like, or irregular thick tissue (NMLIT) with arterial phase hyperenhancement (APHE), 55% (95% CI, 34–75%) and 96% (95% CI, 94–98%) for NMLIT with washout appearance, and 21% (95% CI, 6–53%) and 98% (95% CI, 92–100%) for NMLIT with enhancement similar to pretreatment, respectively. Of these features, APHE showed the highest pooled DOR (81 [95% CI, 25–261]), followed by washout appearance (32 [95% CI, 13–82]) and enhancement similar to pretreatment (14 [95% CI, 5–39]). In conclusion, APHE provided the highest sensitivity and DOR for diagnosing viable HCC following LRT, while enhancement similar to pretreatment showed suboptimal performance.

Assessment of Tumor Cell Death After Percutaneous Ultrasound– Guided Radiofrequency Ablation of Breast Carcinoma: A Prospective Study

Background: Current trends in breast cancer treatment include the use of less aggressive surgeries to reduce morbidity, shorten hospital stays and improve cosmetic results. The aim of the study is to assess tumor cell viability after percutaneous ultrasound (US)-guided radiofrequency ablation (RFA) for small breast cancer by a combination of staining techniques. Methods: A prospective study was conducted at a single institution from 2013 to 2017. Twenty women with invasive ductal carcinoma of the breast measuring ≤ 20 mm were treated with US-guided RFA followed immediately by surgical resection. Tumor viability pre- and post-RFA was assessed with Hematoxylin and Eosin (H&E), Nicotinamide adenine dinucleotide (NADH), Succinate dehydrogenase (SDH), Cytochrome c oxidase (COX), Terminal deoxynucleotidyl transferase dUTP nick end labeling (TUNEL) and Cytokeratin 18 and 19 (CK18/CK19) staining techniques. Outcomes and correlation with the different techniques were evaluated with principal component analysis Cronbach’s alpha. Results: Oxidative enzymes in frozen sections showed loss of SDH and NADH in 13 of the 16 tumors (81%) and COX in 11 of the 13 tumors (84%). In paraffin-embedded tissues, CK18 was negative or markedly reduced in 98% and CK19 in 100% of the cases. Lack of evidence of cell death was seen in 3 cases where the maximum temperature achieved at the center of the tumor was ≤ 70ºC. The reliability and internal consistency between the different staining techniques was high (Cronbach’s alpha, 0.8), with concordance between the staining results of the oxidative enzymes and of CK18/CK19. Conclusion: Loss of tumor viability in small breast tumors after US-guided percutaneous RFA could be assessed in our series with different staining methods. CK18 and CK19 could be used in paraffin-embedded tissues as surrogate markers of tumor cell viability after immediate RFA.

Calcium carbonate nanoparticles stimulate cancer cell reprogramming to suppress tumor growth and invasion in an organ-on-a-chip system

The acidic microenvironment of solid tumors induces the propagation of highly invasive and metastatic phenotypes. However, simulating these conditions in animal models present challenges that confound the effects of pH modulators on tumor progression. To recapitulate the tumor microenvironment and isolate the effect of pH on tumor viability, we developed a bifurcated microfluidic device that supports two different cell environments for direct comparison. RFP-expressing breast cancer cells (MDA-MB-231) were cultured in treatment and control chambers surrounded by fibrin, which received acid-neutralizing CaCO3 nanoparticles (nanoCaCO3) and cell culture media, respectively. Data analysis revealed that nanoCaCO3 buffered the pH within the normal physiological range and inhibited tumor cell proliferation compared to the untreated control (p < 0.05). Co-incubation of cancer cells and fibroblasts, followed by nanoCaCO3 treatment showed that the nanoparticles selectively inhibited the growth of the MDA-MB-231 cells and reduced cellular migration of these cells with no impact on the fibroblasts. Sustainable decrease in the intracellular pH of cancer cells treated with nanoCaCO3 indicates that the extracellular pH induced cellular metabolic reprogramming. These results suggest that the nanoCaCO3 can restrict the aggressiveness of tumor cells without affecting the growth and behavior of the surrounding stromal cells.

Subsequent Ultrasound Vascular Targeting Therapy of Hepatocellular Carcinoma Improves the Treatment Efficacy

The response of hepatocellular carcinoma (HCC) to anti-vascular ultrasound therapy (AVUS) can be affected by the inherent differences in tumor vascular structure, and the functionality of tumor vessels at the time of treatment. In this study, we evaluate the hypothesis that repeated subsequent AVUS therapies are a possible approach to overcome these factors and improve the therapeutic efficacy of AVUS. HCC was induced in 30 Wistar rats by oral ingestion of diethylnitrosamine (DEN) for 12 weeks. A total of 24 rats received treatment with low intensity, 2.8 MHz ultrasound with an intravenous injection of microbubbles. Treated rats were divided into three groups: single therapy group (ST), 2-days subsequent therapy group (2DST), and 7-days subsequent therapy group (7DST). A sham control group did not receive ultrasound therapy. Tumor perfusion was measured by quantitative contrast-enhanced ultrasound (CEUS) nonlinear and power-Doppler imaging. Tumors were harvested for histologic evaluation of ultrasound-induced vascular changes. ANOVA was used to compare the percent change of perfusion parameters between the four treatment arms. HCC tumors treated with 2DST showed the largest reduction in tumor perfusion, with 75.3% reduction on average for all perfusion parameters. The ST group showed an average decrease in perfusion of 54.3%. The difference between the two groups was significant p < 0.001. The 7DST group showed a reduction in tumor perfusion of 45.3%, which was significant compared to the 2DST group (p < 0.001) but not different from the ST group (p = 0.2). The use of subsequent targeted AVUS therapies applied shortly (two days) after the first treatment enhanced the anti-vascular effect of ultrasound. This gain, however, was lost for a longer interval (1 week) between the therapies, possibly due to tumor necrosis and loss of tumor viability. These findings suggest that complex interplay between neovascularization and tumor viability plays a critical role in treatment and, therefore, must be actively monitored following treatment by CEUS for optimizing sequential treatment.

The Key Role of Staging Definitions for Assessment of Downstaging for Hepatocellular Carcinoma

The success of liver transplant (LT) for hepatocellular carcinoma (HCC) is dependent on accurate tumor staging using validated imaging criteria, and adherence to acceptable criteria based on tumor size and number. Other factors including α-fetoprotein (AFP) and response to local regional therapy (LRT) have now played a larger role in candidate selection. Tumor downstaging is defined as reduction in the size of viable tumors using LRT to meet acceptable criteria for LT, and serves as a selection tool for a subgroup of HCC with more favorable biology. The application of tumor downstaging requires a structured approach involving three key components in tumor staging—initial tumor stage and eligibility criteria, tumor viability assessment following LRT, and target tumor stage prior to LT—and incorporation of AFP into staging and treatment response assessments. In this review, we provide in-depth discussions of the key role of these staging definitions in ensuring successful outcome.

Hypoxia-induced PLOD1 overexpression contributes to the malignant phenotype of glioblastoma via NF-κB signaling

Procollagen lysyl hydroxylase 1 (PLOD1) is highly expressed in malignant tumors such as esophageal squamous cell carcinoma, gastric cancer, and colorectal cancer. Bioinformatics analysis revealed that PLOD1 is associated with the progression of GBM, particularly the most malignant mesenchymal subtype (MES). Moreover, in the TCGA and CGGA datasets, the mean survival time of patients with high PLOD1 expression was significantly shorter than that of patients with low expression. The clinical samples confirmed this result. Therefore, we aimed to investigate the effect of PLOD1 on the development of mesenchymal GBM in vitro and in vivo and its possible mechanisms. Molecular experiments were conducted on the patient-derived glioma stem cells and found that PLOD1 expressed higher in tumor tissues and cancer cell lines of patients with GBM, especially in the MES. PLOD1 also enhanced tumor viability, proliferation, migration, and promoted MES transition while inhibited apoptosis. Tumor xenograft results also indicated that PLOD1 overexpression significantly promotes malignant behavior of tumors. Mechanistically, bioinformatics analysis further revealed that PLOD1 expression was closely associated with the NF-κB signaling pathway. Besides, we also found that hypoxic environments also enhanced the tumor-promoting effects of PLOD1. In conclusion, overexpression of PLOD1 may be an important factor in the enhanced invasiveness and MES transition of GBM. Thus, PLOD1 is a potential treatment target for mesenchymal GBM or even all GBM.