Enhanced Tumor Volume Research Articles

METTL5: A Potential Biomarker for Nonsmall Cell Lung Cancer That Promotes Cancer Cell Proliferation by Interacting with IGF2BP3.

Objective: To examine if METTL5 promotes the proliferation of nonsmall cell lung cancer (NSCLC) cells by interacting with IGF2BP3. Methods: The expression patterns of METTL5 and IGF2BP3 in NSCLC tissues, their relationship with survival rate, and their correlation were analyzed using bioinformatics and clinical sample analyses. The effects of METTL5 overexpression and IGF2BP3 knockdown, as well as those of METTL5 knockdown and IGF2BP3 overexpression, on the proliferation of NSCLC cells were analyzed by transfecting appropriate constructs. The interaction between METTL5 and IGF2BP3 was verified using the co-immunoprecipitation (Co-IP) assay. The invivo effects of METTL5 and IGF2BP3 on NSCLC growth were analyzed using the tumor-bearing nude mouse model. Results: METTL5 and IGF2BP3 expression levels were positively correlated and were associated with poor clinical prognosis. The METTL5 and IGF2BP3 expression levels were upregulated in the clinical NSCLC samples. IGF2BP3 expression did not affect METTL5 expression but was regulated by METTL5. IGF2BP3 overexpression mitigated the METTL5 knockdown-induced impaired cell proliferation. Meanwhile, IGF2BP3 knockdown suppressed METTL5-mediated NSCLC cell proliferation. The Co-IP assay results revealed the interaction between METTL5 and IGF2BP3 in NSCLC cells. IGF2BP3 knockdown suppressed tumor growth, whereas IGF2BP3 overexpression enhanced tumor volume and quality. Conclusion: METTL5 induces NSCLC cell proliferation by interacting with IGF2BP3. Thus, METTL5 is a potential biomarker and a therapeutic target for NSCLC.

Blockade of the CD47/SIRPα checkpoint axis potentiates the macrophage-mediated anti-tumor efficacy of tafasitamab.

Macrophages are one of the key mediators of the therapeutic effects exerted by monoclonal antibodies, such as the anti-CD19 antibody tafasitamab, approved in combination with lenalidomide for the treatment of relapsed or refractory (r/r) diffuse large B cell lymphoma (DLBCL). However, antibody-dependent cellular phagocytosis (ADCP) in the tumor microenvironment can be counteracted by increased expression of the inhibitory receptor SIRPα on macrophages and its ligand, the immune checkpoint molecule CD47 on tumor cells. The aim of this study was to investigate the impact of the CD47-SIRPα axis on tafasitamabmediated phagocytosis and explore the potential of anti-CD47 blockade to enhance its antitumor activity. Elevated expression of both SIRPα and CD47 was observed in DLBCL patient-derived lymph node biopsies compared to healthy controls. CRISPR-mediated CD47 overexpression impacted tafasitamab-mediated ADCP in vitro and increased expression of SIRPα on macrophages correlated with decreased ADCP activity of tafasitamab against DLBCL cell lines. Combination of tafasitamab and an anti-CD47 blocking antibody enhanced ADCP activity of in vitro generated macrophages. Importantly, tafasitamab-mediated phagocytosis was elevated in combination with CD47 blockade using primary DLBCL cells and patient-derived lymphoma-associated macrophages (LAMs) in an autologous setting. Furthermore, lymphoma cells with low CD19 expression were efficiently eliminated by the combination treatment. Finally, combined treatment of tafasitamab and an anti-CD47 antibody resulted in enhanced tumor volume reduction and survival benefit in lymphoma xenograft mouse models. These findings provide evidence that CD47 blockade can enhance the phagocytic potential of tumor targeting immunotherapies such as tafasitamab and suggest there is value in exploring the combination in the clinic.

Comparison of quantitative volumetric analysis and linear measurement for predicting the survival of Barcelona Clinic Liver Cancer 0- and A stage hepatocellular carcinoma after radiofrequency ablation.

The prognostic role of the tumor volume in patients with hepatocellular carcinoma (HCC) at the Barcelona Clinic Liver Cancer (BCLC) 0 and A stages remains unclear. This study aims to compare the volumetric measurement with linear measurement in early HCC burden profile and clarify the optimal cut-off value of the tumor volume. The consecutive patients diagnosed with HCC who underwent initial and curative-intent radiofrequency ablation (RFA) were included retrospectively. The segmentation was performed semi-automatically, and enhanced tumor volume (ETV) as well as total tumor volume (TTV) were obtained. The patients were categorized into high- and low-tumor burden groups according to various cutoff values derived from commonly used diameter values, X-tile software, and decision-tree analysis. The inter- and intra-reviewer agreements were measured using the intra-class correlation coefficient. Univariate and multivariate time-to-event Cox regression analyses were performed to identify the prognostic factors of overall survival. A total of 73 patients with 81 lesions were analyzed in the whole cohort with a median follow-up of 31.0 (interquartile range: 16.0–36.3). In tumor segmentation, excellent consistency was observed in intra- and inter-reviewer assessments. There was a strong correlation between diameter-derived spherical volume and ETV as well as ETV and TTV. As opposed to all linear candidates and 4,188 mm3 (sphere equivalent to 2 cm in diameter), ETV >14,137 mm3 (sphere equivalent to 3 cm in diameter) or 23,000 mm3 (sphere equivalent to 3.5 cm in diameter) was identified as an independent risk factor of survival. Considering the value of hazard ratio and convenience to use, when ETV was at 23,000 mm3, it was regarded as the optimal volumetric cut-off value in differentiating survival risk. The volumetric measurement outperforms linear measurement on tumor burden evaluation for survival stratification in patients at BCLC 0 and A stages HCC after RFA.

Phage‐Derived Oncolytic Viruses with 3C from Seneca Valley Virus for Targeted Therapy of Cervical Cancer

AbstractCancer gene therapy based on various gene delivery vectors has some potential but also has obvious disadvantages. In this study, a new M13 phage‐based oncolytic virus is constructed that carried the RGD peptides to target tumor cells and the 3C gene of Seneca Valley virus (SVV) preceded by a eukaryotic initial transcriptional region (ITR) to transcribe an oncolytic protein to kill tumor cells. Recombinant virus particles of 1200 nm in length are obtained in large quantities by transfecting the recombinant M13 phage plasmid into the host BL2738 and are investigated in vitro in tumor cells and in vivo in tumor‐bearing mice to evaluate their antitumor effect. The experiments using Hela cells confirm that the engineered M13 phage can target and enter Hela cells, and express the SVV 3C protein, resulting in apoptosis of target cells by upregulating the expression of caspase 3. Furthermore, the results of experiments in vivo also show that the recombinant phage significantly inhibits the enhanced tumor volume in nude mice compared to the control groups. The M13 phage may be engineered to fuse with a variety of oncolytic proteins to inhibit the growth of tumor cells in the future, providing a promising phage‐based targeted oncolytic reagent.

Initial Outcomes And Treatment-Associated Toxicities Using Stereotactic MRI-Guided Adaptive Radiation Therapy For Pancreatic Cancer Patients Treated At A Single Institution

High dose stereotactic body radiotherapy (SBRT) may offer improved outcomes for pancreatic cancer patients, but treatment delivery remains a challenge due to tumor proximity to organs-at-risk (OAR) and daily anatomic variability. Stereotactic MRI-guided adaptive radiation therapy (SMART) with real-time tumor tracking allows for improved dose delivery and OAR sparing by accounting for anatomic changes with each treatment. This study reports initial outcomes, treatment-associated toxicities, and dosimetric outcomes in locally advanced, metastatic, and/or recurrent pancreatic cancer patients treated using SMART. We performed a retrospective analysis of locally advanced, metastatic, and/or recurrent pancreatic cancer patients who underwent adaptive planning with MRI-guided radiation treatments. Charts were reviewed for follow-up, imaging, and laboratory values, including CA19-9 and absolute lymphocyte count. A plan was generated for each patient after initial CT and MR-simulation. At each treatment, MR imaging was obtained for the daily anatomy and the initial (unadapted) plan was compared to obtain a predicted dose to target volumes and OARs using a prescribed dose ranging from 30-50 Gy in 3-5 fractions. If constraints were not met or coverage was inadequate, an adaptive plan was generated based on the anatomy imaged on the day of treatment. From June 2018 to February 2020, a total of 23 patients were analyzed. With a median follow up of 5 months, we observed 15/19 (79%) with local control, 12/19 (63%) distal metastatic control, and a median overall survival of 19 months from cancer diagnosis. We observed no grade 3 or higher treatment related toxicities. Two patients were found to have an absolute lymphocyte count less than 0.5 x 103 cells/μl within six months of radiation, and 11/17 (65%) had lower CA19-9 six months after radiation treatment compared to before treatment. Of the 23 patients treated, there were 71 adaptive plans available for analysis. Compared to unadapted plans, adaptive fractions had improved coverage of PTV (84.94% vs. 73.36% at 100% of prescribed dose) and CTV (94.62% vs 88.08% at 95% of prescribed dose). Unadapted plans were more likely to exceed OAR constraints with 63 of 71 (89%) unadapted fractions predicted to violate prescribed duodenal, stomach, or small bowel constraints. Moreover, 34/71 (48%) of unadapted fractions violated constraints for 2 of 3 abdominal OARs and 10/71 (14%) violated constraints for all 3 compared to none for adapted fractions. Stereotactic adaptive MRI-guided radiotherapy demonstrated minimal treatment-related toxicities, enhanced tumor volume coverage, and improved adherence to OAR constraints in pancreatic cancer patients. Additional follow up is needed to further assess outcomes of these patients.

Cryoablation of Extra-Abdominal Desmoid Tumors: A Single-Center Experience with Literature Review.

Cryoablation (CA) has gained popularity in the treatment of benign and malignant musculoskeletal tumors. While extra-abdominal desmoid (EAD) tumors are not malignant, they remain challenging to treat because of their high local recurrence rate. We reviewed all EAD tumors treated with CA at our institution between November 2012 and March 2020. Fourteen procedures were performed on nine females and one male (mean age, 33 ± 18 years) as either first-line (n = 4) or salvage therapy (n = 6) with curative intent (n = 8) or tumor debulking (n = 2). Mean tumor size was 63.6 cm3 (range, 3.4–169 cm3). Contrast-enhanced MRI was performed before treatment and at 3-, 6-, and 12-month follow-up. Treatment outcome was based on the change in enhanced tumor volume (ET-V). For curatively treated patients, the mean ET-V change was −97 ± 7%, −44 ± 143%, and +103 ± 312% at 3, 6, and 12 months, respectively. For debulking patients, the mean ET-V change was −98 ± 4%, +149 ± 364%, and +192 ± 353% at 3, 6, and 12 months, respectively. During a mean follow-up of 53.7 months (range, 12–83 months), one grade III and one grade IV complication were noted. We found CA to be safe and well tolerated in patients with EAD.

Can Breast Magnetic Resonance Imaging Assess Tumor Response to Preoperative Accelerated Partial Breast Irradiation?

While Magnetic Resonance Imaging (MR) is commonly performed after neoadjuvant systemic therapy for breast cancer to assess tumor response to therapy, little is known about the tumor response on MR after preoperative radiation. We sought to evaluate the MR changes in patients with Stage IA luminal breast cancer after preoperative accelerated partial breast irradiation (APBI) treated in the prone position and compare the MR changes with tumor diameter on pathology. We hypothesize that following preoperative ABPI there will be a detectable change on MR in maximum contrast enhancement (MCE), time to contrast enhancement (CE) or CE tumor volume that will correspond to reduction in tumor size. Women ≥50 years of age with Stage IA luminal breast cancer enrolled on an IRB approved trial were studied. Using a Q-fix™ therapy positioning device prototype, a CT Simulation in the prone position and then an MR were acquired and fused to contour GTV. Preoperative APBI was 3850 cGy in 10 fractions BID with a minimum of 6-hours between fractions. Another CE-MR was obtained 4 weeks after APBI prior to breast conserving surgery (BCS) on a 3T MR. Gadolinium MR contrast agent was injected at standard dose and rate after completing the first series; 5 series were acquired at 90 second intervals after contrast injection. A visual and quantitative assessment using region of interest was performed to assess the intensity, kinetics and volume of the lesion CE. We used a slice selective segmentation approach to determine the 3D volume and the longest axis diameter. The MCE compared to baseline and the time to MCE was determined. An experienced reader performed a visual classification to assess the MR volume-based changes and kinetic enhancement changes. To estimate the change in invasive tumor size occurring under APBI, we compared the longest axis size on the baseline CE-MR to longest diameter on pathology. Thirteen patients had both MRs and pathology available. Median age was 66 years old (range 51-78). Median days between pre-therapy MR and ABPI was 13 (range 8-19). Median days from ABPI to second MR and BCS was 33 (range 21-40) and 40 (range 34-52), respectively. Eight (62%) patients had a reduction of MCE after APBI, 7 of which had a decrease in pathological size. Ten (77%) patients had an increase of time to MCE. The average reduction of the contrast enhanced tumor volume was 22%. The tumor diameter shrinkage from pre-treatment CE-MR to histology was on average 49%. In 4 patients we found a longest diameter reduction of less than <25%, while in 3 patients 25-50%, and >50% in 6 patients. The treatment effect of preoperative ABPI can be detected on CE-MR. Most irradiated tumors showed either a reduction in maximum contrast enhancement and/or longer time to maximum contrast enhancement. This study demonstrates that preoperative radiation induces changes on MR reflecting treatment effect on tumor vasculature and/or tumor necrosis. Future analysis will include a detailed pathological review.

Maximum diameter versus volumetric assessment for the response evaluation of vestibular schwannomas receiving stereotactic radiotherapy.

PurposeTo explore the feasibility of maximum diameter as a response assessment method for vestibular schwannomas (VS) after stereotactic radiosurgery or fractionated stereotactic radiotherapy (RT), we analyzed the concordance of RT responses between maximum diameters and volumetric measurements.Materials and MethodsForty-two patients receiving curative stereotactic radiosurgery or fractionated stereotactic RT for VS were analyzed retrospectively. Twelve patients were excluded: 4 did not receive follow-up magnetic resonance imaging (MRI) scans and 8 had initial MRI scans with a slice thickness >3 mm. The maximum diameter, tumor volume (TV), and enhanced tumor volume (ETV) were measured in each MRI study. The percent change after RT was evaluated according to the measurement methods and their concordances were calculated with the Pearson correlation. The response classifications were determined by the assessment modalities, and their agreement was analyzed with Cohen kappa statistics.ResultsMedian follow-up was 31.0 months (range, 3.5 to 86.5 months), and 90 follow-up MRI studies were analyzed. The percent change of maximum diameter correlated strongly with TV and ETV (r(p) = 0.85, 0.63, p = 0.000, respectively). Concordance of responses between the Response Evaluation Criteria in Solid Tumors (RECIST) using the maximum diameters and either TV or ETV were moderate (kappa = 0.58; 95% confidence interval, 0.32-0.85) or fair (kappa = 0.32; 95% confidence interval, 0.05-0.59), respectively.ConclusionThe percent changes in maximum diameter and the responses in RECIST were significantly concordant with those in the volumetric measurements. Therefore, the maximum diameters can be used for the response evaluation of VS following stereotactic RT.

Tumor cell culture on collagen–chitosan scaffolds as three-dimensional tumor model: A suitable model for tumor studies

Tumor cells naturally live in three-dimensional (3D) microenvironments, while common laboratory tests and evaluations are done in two-dimensional (2D) plates. This study examined the impact of cultured 4T1 cancer cells in a 3D collagen–chitosan scaffold compared with 2D plate cultures. Collagen–chitosan scaffolds were provided and passed confirmatory tests. 4T1 tumor cells were cultured on scaffolds and then tumor cells growth rate, resistance to X-ray radiation, and cyclophosphamide as a chemotherapy drug were analyzed. Furthermore, 4T1 cells were extracted from the scaffold model and were injected into the mice. Tumor growth rate, survival rate, and systemic immune responses were evaluated. Our results showed that 4T1 cells infiltrated the scaffolds pores and constructed a 3D microenvironment. Furthermore, 3D cultured tumor cells showed a slower proliferation rate, increased levels of survival to the X-ray irradiation, and enhanced resistance to chemotherapy drugs in comparison with 2D plate cultures. Transfer of extracted cells to the mice caused enhanced tumor volume and decreased life span. This study indicated that collagen–chitosan nanoscaffolds provide a suitable model of tumor that would be appropriate for tumor studies.

EPIG-18PYROSEQUENCING ANALYSIS OF THE MGMT PROMOTER METHYLATION STATUS IN NEWLY DIAGNOSED GLIOBLASTOMA CORRELATES WITH VOLUMETRIC CHANGES OF UNRESECTED ENHANCED LESIONS IN MRI AFTER STANDARD RADIATION AND TEMOZOLOMIDE THERAPY

BACKGROUND: Although it is recognized that methylation status of MGMT promoter is predictive for the response to temozolomide in newly diagnosed glioblastoma (GBM), at least in elderly patients, there is no study examining the ability of quantitative MGMT methylation status to predict volumetric changes of residual tumor in magnetic resonance images (MRIs) after surgery, radiation and temozolomide therapy. In this study, we performed retrospective volumetric analysis of the residual tumor in glioblastoma patients and investigated the relationship of MGMT status assessed by pyrosequencing. METHOD: Among 160 newly diagnosed GBM patients treated in our institute since 2006, volumetric analysis of the residual tumor was performed retrospectively in patients who were with residual unresected tumors after surgery, treated with standard radiation and temozolomide therapy. Patients who were without residual tumors or treated with bevacizumab were excluded. The MGMT methylation status was quantitatively assessed by averaging methylation at the 16 CpG sites measured by pyrosequencing. Enhanced tumor volume in MRI was measured at four time points of pre-operation, beginning of the treatments, three and six months after the initial treatment. RESULT: Forty four patients were enrolled (M:F = 25:19, median age: 61 y.o., median KPS: 70). The quantitative MGMT methylation data and tumor volume ratio, normalized to pre-treatment volume, were significantly correlated at 3 and 6 months after the initial treatment (p = 0.0002 and 0.0004, respectively). For the response rate, patients with lower MGMT methylation than 10% showed more progressive disease (defined as more than 50% gain in tumor volume) compared to patients with higher MGMT methylation than 10% at 3 and 6 months after initial treatment (3 months: 67.9% vs 18.8%, 6 months: 70.8% vs 15.4%, respectively). CONCLUSION: Quantitative MGMT methylation status analyzed by pyrosequencing may be useful to predict disease progression in glioblastomas treated with partial tumor removal followed by radiation and temozolomide therapy.

Abstract 1445: Overexpression of angiotensin II type 1 receptor induces epithelial-mesenchymal transition and promotes tumorigenesis of human breast cancer cells

Abstract Propose: Accumulating evidence suggests that angiotensin II type 1 receptor (AGTR1) is involved in tumorigenesis and metastasis in many types of cancer, however little is known about its role in breast cancer. Our objective of the present study is to investigate the effect of AGTR1 overexpression on cell proliferation, epithelial-mesenchymal transition (EMT), migration, invasion, angiogenesis and tumorigenesis of human breast cancer. Methods: To determine the role of AGTR1, MCF7 cells were stably transfected with an expression construct carrying the GFP cDNA for AGTR1. MTS assay, Matrigel invasion assay, wound healing assay, Western blotting and immunofluorescence were used. For in vivo study, parental MCF7 or AGTR1-MCF7 cells were subcutaneously injected into the left and right flanks of nude mice. Tumor growth and angiogenesis were determined. Results and conclusion: AGTR1-MCF7 cells, expressing high level of AGTR1 exhibited significant increases in cell proliferation, migration and invasion capacities compared with parental MCF7 cells. Furthermore, AGTR1-MCF7 cells displayed the mesenchymal phenotype, as evidenced by elongated spindle morphology, decreased E-cadherin level, increased N-cadherin and snail, and nuclear accumulation of smad3 and smad4. Interestingly, blockade of smad4 using small interfering RNA strongly induced mesenchymal to epithelial transition (MET) and restoration of E-cadherin expression in AGTR1-MCF7 cells, suggesting that AGTR1-induced EMT is ultimately mediated by smad4 activation. Finally, we showed that AGTR1 overexpression enhanced tumor volume (p&amp;lt;0.001, n = 10) and weight (p&amp;lt;0.01) as well as increased angiogenesis in human breast cancer xenograft in vivo. In summary, we demonstrate that AGTR1 overexpression promotes cell proliferation, EMT, angiogenesis and tumorigenic properties of breast cancer cells. Our findings suggest that AGTR1 could be a useful target of therapy in breast cancer. Citation Format: Eunhye Oh, Ji Young Kim, Youngkwan Cho, Nahyun Lee, Hyunsook An, Jun Suk Kim, Jae Hong Seo. Overexpression of angiotensin II type 1 receptor induces epithelial-mesenchymal transition and promotes tumorigenesis of human breast cancer cells. [abstract]. In: Proceedings of the 106th Annual Meeting of the American Association for Cancer Research; 2015 Apr 18-22; Philadelphia, PA. Philadelphia (PA): AACR; Cancer Res 2015;75(15 Suppl):Abstract nr 1445. doi:10.1158/1538-7445.AM2015-1445

Cellular uptake, cytotoxicity and in-vivo evaluation of Tamoxifen citrate loaded niosomes

One of the main challenges in Tamoxifen cancer therapy is achieving localized, efficient and sustained delivery without harming normal healthy organs. This study focused on evaluating Tamoxifen Citrate (TMC) niosomes for localized cancer therapy through in-vitro breast cancer cytotoxicity as well as in-vivo solid anti-tumor efficacy. Different niosomal formulae were prepared by film hydration technique and characterized for entrapment efficiency% (E. E), vesicle size, morphology, and in-vitro release. The cellular uptake and anti-cancer activity were also tested in-vitro using MCF-7 breast cancer cell line. Moreover, in-vivo anti-tumor efficacy was examined in Ehrlich carcinoma mice model through reporting solid tumor volume regression and tissue TMC distribution. The obtained niosomes prepared with Span 60: cholesterol (1: 1 molar ratio) showed a distinct nano-spherical shape with EE up to 92.3%±2.3. Remarkably prolonged release of TMC following diffusion release behavior was detected. The optimized formula showed significantly enhanced cellular uptake (2.8 fold) and exhibited significantly greater cytotoxic activity with MCF-7 breast cancer cell line. In-vivo experiment showed enhanced tumor volume reduction of niosomal TMC when compared to free TMC. Based on these results, the prepared niosomes demonstrated to be promising as a nano-size delivery vehicle for localized and sustained TMC cancer therapy.

Abstract 2935: Cyclin-dependent kinase 1 regualtes HIF-1α expression to promote tumorigenesis.

Abstract Hypoxia-inducible factor 1 (HIF-1) is a major mediator of tumor physiology, and its activation is correlated with tumor progression, metastasis, and therapeutic resistance. HIF-1 is activated in a broad range of solid tumors due to intra-tumoral hypoxia or genetic alterations that enhance its expression or inhibit its degradation. As a result, decreasing HIF-1α expression represents an attractive strategy to sensitize hypoxic tumors to standard or targeted therapies. Here, we show that cyclin dependent kinase 1 (CDK1) regulates the expression of HIF-1α, independent of its known regulators, such as VHL, p53, and prolyl hydroxolases. Inhibition of CDK1 enhances the proteasomal degradation of HIF-1α, reducing its half-life and steady state levels. In vitro kinase assays reveal that CDK1 directly phosphorylates HIF-1α at a previously unidentified regulatory site, Ser668, to regulate its basal levels and rate of turnover. Mutation of HIF-1α Ser668 to an alanine (S668A) significantly decreased the half-life and steady state levels of HIF-1α, where as mutation to a glutamic acid (S668E) enhanced HIF-1α expression and stability. Importantly, constitutive phosphorylation of HIF-1α at Ser668 was sufficient to stabilize HIF-1α under normoxic conditions, resulting in the transcription of HIF-1 target genes and increased tumor cell invasion in vitro. Furthermore, in vivo xenograft tumor models of HCT116 and RKO colorectal cancer cell lines revealed that stable expression of a phospho-mimetic of HIF-1α this site (S668E) significantly increased tumor proliferation and angiogenesis, resulting in dramatically enhanced tumor volume compared to cells expressing wild-type HIF-1α. Taken together, these findings provide new insights into the regulation of HIF-1α expression and suggest a novel mechanism that may promote HIF-1 deregulation in tumorigenesis. Our results demonstrating CDK-dependent HIF-1α stabilization raise the question of whether the expression of HIF-1α is controlled in a cell cycle-dependent manner during tumorigenesis, even prior to the evolution of significant hypoxia associated with bulky tumor growth in vivo. This finding has previously unrecognized implications for a critical connection between CDK activity and tumor growth, beyond the cell cycle engine. HIF-1α is frequently highly expressed in tumors, independent of hypoxia or its known regulators. The identification of Ser668 phosphorylation as an important regulator of HIF-1α provides a novel mechanism to explain the constitutive expression of HIF-1α in some tumors, most of which also have increased CDK1 and CDK4 activity. It has been well established that HIF-1 inhibition sensitizes solid tumors to radiation, standard chemotherapies and targeted agents. Therefore, inhibition CDK1/4 represents a novel strategy for the treatment of cancer cells with constitutively active HIF-1. Citation Format: Noel A. Warfel, Nathan G. Dolloff, Wafik S. El-Deiry. Cyclin-dependent kinase 1 regualtes HIF-1α expression to promote tumorigenesis. [abstract]. In: Proceedings of the 104th Annual Meeting of the American Association for Cancer Research; 2013 Apr 6-10; Washington, DC. Philadelphia (PA): AACR; Cancer Res 2013;73(8 Suppl):Abstract nr 2935. doi:10.1158/1538-7445.AM2013-2935

Combination Immunotherapy for Tumors via Sequential Intratumoral Injections of Oncolytic Herpes Simplex Virus 1 and Immature Dendritic Cells

Oncolytic herpes simplex virus 1 (oHSV) vectors treat tumors in preclinical models and have been used safely in phase I clinical trials for patients with cancer. Infection of tumors with oHSV also induces specific antitumor immunity. We investigated whether this immunotherapeutic effect is enhanced by combining oHSV infection with intratumoral administration of immature myeloid dendritic cells (iDC). Subcutaneous neuroblastoma tumors were established in syngeneic immunocompetent mice and sequentially treated with oHSV(G47Delta) and intratumoral iDCs. Tumor volumes and survival were monitored. Antitumor immune responses were evaluated by immunohistochemistry, IFN-gamma ELISPOT, and CTL assay. Treatment was also evaluated in immunodeficient NOD-SCID mice. We observed significant reductions in tumor volumes in mice receiving G47Delta + iDCs compared with those treated with G47Delta or iDC monotherapy. Survival was prolonged, with approximately 90% of tumors eradicated in the combination group. Combination therapy led to enhancement of antitumor immune responses, confirmed by increases in IFN-gamma expression by splenocytes harvested from G47Delta + iDC-treated mice. Splenocytes harvested from G47Delta + iDC-treated mice were effective against neuroblastoma tumor cells in a CTL assay. Immunohistochemistry of combination-treated tumors revealed robust lymphocytic infiltrates. Adding iDCs to G47Delta infection in tumors in NOD-SCID mice did not reduce the rate of growth. Substitution of lipopolysaccharide-matured dendritic cells abrogated the enhanced tumor volume reduction seen with combination therapy with iDCs. Combination treatment of murine tumors with oHSV and iDCs reduces the volume of established tumors and prolongs survival via enhancement of antitumor immunity.

Glutamine Enhances Selectivity of Chemotherapy Through Changes in Glutathione Metabolism

Chemotherapy doses are limited by toxicity to normal tissues. Intravenous glutamine protects liver cells from oxidant injury by increasing intracellular glutathione (GSH) content. The authors hypothesized that supplemental oral glutamine (GLN) would increase the therapeutic index of methotrexate (MTX) by improving host tolerance through changes in glutathione metabolism. The authors examined the effects of oral glutamine on tumor and host glutathione metabolism and response to methotrexate. Thirty-six 300-g Fischer 344 rats were implanted with fibrosarcomas. On day 21 after implantation, rats were randomized to receive isonitrogenous isocaloric diets containing 1 g/kg/day glutamine or glycine (GLY) by gavage. On day 23 after 2 days of prefeeding, rats were randomized to one of the following four groups receiving an intraperitoneal injection of methotrexate (20 mg/kg) or saline (CON): GLN+MTX, GLY+MTX, GLN-CON, or GLY-CON. On day 24, rats were killed and studied for arterial glutamine concentration, tumor volume, kidney and gut glutaminase activity, and glutathione content (tumor, gut, heart, liver, muscle, kidney, and lung). Provision of the glutamine-enriched diets to rats receiving MTX decreased tumor glutathione (2.38 +/- 0.17 in GLN+MTX vs. 2.92 +/- 0.20 in GLY+MTX, p < 0.05), whereas increasing or maintaining host glutathione stores (in gut, 2.60 +/- 0.28 in GLN+MTX vs. 1.93 +/- 0.18; in GLY+MTX, p < 0.05). Depressed glutathione levels in tumor cells increases susceptibility to chemotherapy. Significantly decreased glutathione content in tumor cells in the GLN+MTX group correlated with enhanced tumor volume loss (-0.8 +/- 1.0 mL in GLN+MTX vs. +9.5 +/- 2.0 mL in GLY+MTX, p < 0.05). These data suggest that oral glutamine supplementation will enhance the selectivity of antitumor drugs by protecting normal tissues from and possibly sensitizing tumor cells to chemotherapy treatment-related injury.