Marked Reduction In Tumor Size Research Articles

Abstract 14694: An Uncommon Mass, in an Uncommon Location, in a Common Patient?

Background: Myeloid sarcomas (MS) are rare extramedullary tumors composed of mature or immature myeloid cells. The heart is an uncommon site for this neoplasm. Case Presentation: A 68-year-old woman with a remote history of acute myeloid leukemia (AML) and allogeneic stem cell transplant presented with dyspnea. Her oxygen saturation was 70% on room air. Transthoracic echocardiography (TTE) revealed a nonhomogeneous intrapericardial mass measuring 6.3 cm by 10.0 cm, invading the right atrium and compressing the right ventricle (Figure 1). Due to persistent hypoxia, additional investigation with agitated saline contrast revealed a right-to-left intra-cardiac shunt. Cardiac magnetic resonance imaging showed invasion of the right and left ventricles, extension into the superior vena cava, and encasement of the right coronary artery. Due to worsening hypoxemia, vasopressin infusion and inhaled epoprostenol were initiated to reduce intracardiac shunting. Direct cardiac mass biopsy was considered prohibitive risk, however, a pericardiocentesis allowed for cytologic analysis of pericardial fluid which revealed atypical white blood cells, and subsequent flow cytometry indicated an aberrant myeloid population with monocytic features consistent with MS. She initiated chemotherapy with decitabine and low dose cytarabine. On day 6 of chemotherapy, she started external beam radiation therapy. A repeat TTE on day 10 of therapy showed a marked reduction in tumor size and intracardiac shunting. Discussion: MS can manifest before the development of bone marrow disease, following treatment for bone marrow disease, as relapse or progression of previous myelodysplastic or myeloproliferative neoplasms. With approximately fifty cases reported in the literature, most achieved temporary remission. Our approach to management included chemotherapy with decitabine and cytarabine and subsequent external-beam radiotherapy.

Inhibition of Ly-49/LILRB-MHC-I interactions by anti-MHC-I augments innate and adaptive immunity.

Abstract Mouse NK cells recognize MHC-I antigens via stochastically expressed inhibitory Ly49 receptors. The loss of MHC-I expression on tumor cells (“missing self”) abrogates inhibitory signals, resulting in NK activation. We have identified an anti-mouse pan MHC-I mAb (M1/42), which blocks Ly49-MHC-I interactions but not TCR-MHC-I interactions. Administration of M1/42 in vivo markedly activated IFNg-producing NK cells that further drove the proliferation of NK cells and memory phenotype (MP) T cells and profoundly augmented adaptive immunity against viral infection and cancer metastasis. In contrast to mouse Ly-49 antigens, human killer cell inhibitory receptors bind to HLA at a site overlapping the TCR binding site and blocking of KIR binding to MHC-I would inhibit TCR recognition. However, two anti-pan-human MHC-I abs (DX17 and W6/32) markedly induced NK cell proliferation and IFNg production in cultures of human PBMC. DX17 potently blocked the interaction of leukocyte Ig-like inhibitory receptors LILRB1, B2, B3 and B5 with human MHC-I but had no effect on TCR-MHC-I interactions. The crystal structure of a DX17 Fab/MHC-I complex reveals that the footprint of DX17 overlaps the LILRB1 binding site on MHC-I. Administration of W6/32 Fab to humanized mice (PBMC reconstituted NSG or NK cell reconstituted NOG-IL-15) induced human NK and MP T cell proliferation. Marked reduction of tumor size was seen when NOG-hIL-15Tg mice were reconstituted with CD3 −cells and then treated with W6/32 Fab. DX17 Fc silenced mAb (DX17 LALAPG) activated human tumor infiltrating lymphocytes and monocytes. These results strongly suggest that inhibition of LILRB-MHC-I interactions by anti-MHC-I in humans may result in marked augmentation of anti-tumor immunity. This work was supported by the Intramural Research Program of NIAID, NIH.

EXTH-68. ONCOMAGNETIC TREATMENT SELECTIVELY KILLS GLIOMA CANCER CELLS BY INDUCING OXIDATIVE STRESS AND DNA DAMAGE

Abstract A new noninvasive therapeutic device developed in our laboratory called the Oncomagnetic device provides a novel approach to glioblastoma (GBM) treatment. It involves repeated stimulation with oscillating magnetic fields (sOMF) produced by spinning permanent magnets. It is technologically and mechanistically distinct from the Optune® device approved by the FDA for the treatment of newly diagnosed and recurrent GBM. Use of this device in one end-stage GBM patient reversed the progression of his recurrent tumor causing >30% reduction in its contrast-enhanced volume within 4 weeks of treatment. Mice with implanted mouse glioma cells in their brains also showed marked reduction in tumor size, increased survival (p< 0.05, n = 10) and higher DNA damage (g-H2AX foci) after sOMF treatment with a whole-body stimulation method developed by us. Normal mice exposed to sOMF for 4 months had no adverse effects on the brain and other organs. In-vitro, sOMF markedly increased reactive oxygen species (ROS) levels in cancer cells leading to the selective death of these cells, while sparing normal neurons and astrocytes. Detection of g-H2AX and 53BP1 foci showed that sOMF caused significant DNA damage in GBM cells and diffuse intrinsic pontine glioma (DIPG) cells but not in normal astroglial SVGp12 cells. Furthermore, sOMF exposure for just 2 h resulted in >40% loss of surviving GBM and DIPG cell colonies detected by clonogenic cell survival assay, similar to that produced by 2 Gy radiation dose. This loss was rescued by the antioxidant Trolox. These results indicate that sOMF stimulation has high anticancer potency comparable to low dose radiation therapy at the cellular level with an underlying mechanism of action that is substantially different from that proposed for Optune® TTF.

Growth hormone receptor antagonism downregulates ATP-binding cassette transporters contributing to improved drug efficacy against melanoma and hepatocarcinoma in vivo

Knockdown of GH receptor (GHR) in melanoma cells in vitro downregulates ATP-binding cassette-containing (ABC) transporters and sensitizes them to anti-cancer drug treatments. Here we aimed to determine whether a GHR antagonist (GHRA) could control cancer growth by sensitizing tumors to therapy through downregulation of ABC transporters in vivo. We intradermally inoculated Fluc-B16-F10 mouse melanoma cells into GHA mice, transgenic for a GHR antagonist (GHRA), and observed a marked reduction in tumor size, mass and tumoral GH signaling. Moreover, constitutive GHRA production in the transgenic mice significantly improved the response to cisplatin treatment by suppressing expression of multiple ABC transporters and sensitizing the tumors to the drug. We confirmed that presence of a GHRA and not a mere absence of GH is essential for this chemo-sensitizing effect using Fluc-B16-F10 allografts in GH knockout (GHKO) mice, where tumor growth was reduced relative to that in GH-sufficient controls but did not sensitize the tumor to cisplatin. We extended our investigation to hepatocellular carcinoma (HCC) using human HCC cells in vitro and a syngeneic mouse model of HCC with Hepa1-6 allografts in GHA mice. Gene expression analyses and drug-efflux assays confirm that blocking GH significantly suppresses the levels of ABC transporters and improves the efficacy of sorafenib towards almost complete tumor clearance. Human patient data for melanoma and HCC show that GHR RNA levels correlate with ABC transporter expression. Collectively, our results validate in vivo that combination of a GHRA with currently available anti-cancer therapies can be effective in attacking cancer drug resistance.

A Large Parotid Hemangioma Managed Successfully with Propranolol

The treatment of parotid hemangiomas has posed a challenge. A male infant presented with large hemangioma of the right parotid gland diagnosed at the age of 3 months. Starting at the age of 4 months, he was treated with oral propranolol for 10 months, which led to a marked reduction in tumor size and strawberry hemangioma. Our case shows that propranolol is effective and safe in treating large parotid infantile hemangioma.

VMAT Grid Therapy: A Widely Applicable Planning Approach

PurposeTo describe a novel and practical volumetric modulated arc therapy (VMAT) planning approach for grid therapy. Methods and MaterialsDose is prescribed to 1.5-cm diameter spherical contours placed throughout the gross tumor volume (GTV). Placement of spheres is variable, but they must maintain at least a 3-cm (center to center) separation, and the edge of any sphere must be at least 1 cm from any organ at risk (OAR). Three concentric ring structures are used during optimization to confine the highest doses to the center of the spheres and maximize dose sparing between them. The end result is alternating regions of high and low dose throughout the GTV and minimal dose to OARs. High-intensity flattening filter-free (FFF) modes are used to efficiently deliver the plans, and entire treatments typically take only 15 to 20 minutes. ResultsThe approach is illustrated with 2 examples treated at our institution. Patient #1 had a 1703-cm3 mediastinal mass and was prescribed 20 Gray (Gy) to 24 spherical regions within the GTV. Patient #2 had a 3680-cm3 abdominal tumor and was prescribed 18 Gy to 32 spherical regions within the GTV. Both patients received additional consolidative radiation approximately 1 week after the initial VMAT grid treatment. Each patient experienced marked reduction in tumor size and symptomatic relief without treatment-related complications. ConclusionsWe have described in detail a planning approach for VMAT grid therapy treatments that can typically be delivered in a clinically practical time span. The VMAT approach is especially useful for tumors that are surrounded by sensitive critical structures. As many centers offer VMAT treatments, the approach is widely accessible and can be readily implemented once appropriate patient selection and delivery processes are established.

Abstract 1792: MAPK1 p.D321N mutation confers sensitive to erlotinib in head and neck squamous cell carcinoma (HNSCC)

Abstract The annual incidence of head and neck squamous cell carcinoma (HNSCC) is ~0.88 million worldwide (IARC, WHO 2018). Despite great success of precision medicine in major cancers such as lung cancer and breast cancers, there are limited precision therapies for HNSCC. We previously reported an HNSCC patient whose tumor harbored a somatic MAPK1 p.E322K mutation demonstrating exceptional clinical response to erlotinib, an EGFR inhibitor. Subsequent laboratory investigation confirmed the ability of MAPK1 p.E322K to hyperactivate EGFR, thus causing erlotinib sensitivity in HNSCC models, both in vitro and in vivo. Here, we sequenced 105 tumors from Hong Kong (HK) HNSCC patients by next-generation sequencing (NGS) on MAPK1 gene and we found a 5.71% rate (6/105 tumors) of MAPK1 somatic mutation in HK-HNSCC. This rate appears to be relatively higher than the 1.75% (9/521 tumors) rate in the US-TCGA HNSCC cohort (P=0.0288). Apart from the MAPK1 p.E322K mutation found in the US-TCGA HNSCC cohort, we identified novel MAPK1 p.R135K and p.D321N mutations in our HK cohort which were absent in the US TCGA HNSCC. Pan-cancer mapping of MAPK1 somatic mutations revealed that MAPK1 p.R135K and p.D321N mutations are also recurrent hotspot mutation in TCGA pan-cancers (32 cancer types). Strikingly, based on the X-ray crystallography of the human MAPK1 protein, R135 and D321 amino acid residues both reside on the same kinase interaction motif (KIM) domain as E322 (all are within a 13Å distance in 3D). Thus, we further investigated if MAPK1 p.R135K and p.D321N mutations might function similarly as MAPK1 p.E322K mutant in terms of their abilities to drive HNSCC growth, and erlotinib sensitivity in HNSCC models. We employed the same FaDu retroviral infection method to study these mutations as we did previously, and we found that MAPK1 p.D321N (P<0.0001) was a driver for HNSCC proliferation, while MAPK1 p.R135K was not (all vs. MAPK1-wildtype). Subsequent in vivo erlotinib treatment experiments with xenografts bearing these mutants and MAPK1-wildtype showed that MAPK1 p.D321N tumors demonstrated heightened sensitivity to erlotinib with marked reduction of tumor size, tumor cell positivity, as well as membranous pEGFR expression when compared to vehicle treatment (P=0.0037). Whereas MAPK1 p.R135K tumors only showed a trend for erlotinib sensitivity (P=0.0646), with reduction in membranous p-EGFR expression by erlotinib in the tumors. Thus, MAPK1 p.D321N mutation confers erlotinib-sensitivity in HNSCC system. Further clinical investigation is warranted to further explore the relationship between various MAPK1 mutations and erlotinib sensitivity in HNSCC patients. Citation Format: Hoi Lam Ngan, Peony Hiu Yan Poon, Yu-Xiong Su, Jason Yik Kuen Chan, Kwok-Wai Lo, Chun Kit Yeung, Yuchen Liu, Eileen Wong, Hui Li, Chin Wang Lau, Wenying Piao, Vivian Wai Yan Lui. MAPK1 p.D321N mutation confers sensitive to erlotinib in head and neck squamous cell carcinoma (HNSCC) [abstract]. In: Proceedings of the Annual Meeting of the American Association for Cancer Research 2020; 2020 Apr 27-28 and Jun 22-24. Philadelphia (PA): AACR; Cancer Res 2020;80(16 Suppl):Abstract nr 1792.

Nanovesicle-mediated delivery of anticancer agents effectively induced cell death and regressed intrahepatic tumors in athymic mice

Hepatocellular carcinoma is highly resistant to chemotherapy. Here we evaluated the use and efficacy of milk-derived nanovesicles (MNV) as an approach to improve delivery of anticancer agents into HCC cells and intrahepatic tumors. We developed a protocol for isolation of MNVs from skim milk using ultracentrifugation, and characterized using nanoparticle tracking analysis (NTA) and electron microscopy. MNVs were loaded with doxorubicin (dox-MNV) or miR221 antisense oligonucleotides (anti-miR221-MNV), and further evaluated using spectrophotometry, NTA, and zeta potential measurements. HepG2, Hep3B, and PLC/PRF/5 HCC cells in culture were treated with dox-MNV and anti-miR221-MNV and evaluated with drug delivery and anticancer activity. The efficacy of dox-MNV and anti-miR221-MNV to arrest tumor growth in vivo was assessed on intrahepatic tumors induced in nude mice. Cellular uptake studies showed plain and dox-MNV attained saturation within 4 h of treatment. Cytotoxicity studies on HepG2, Hep3B, and PLC/PRF/5 HCC cells with dox-MNV at 1 µM resulted in 20% cell death at 24 h, 50% at 48 h, and 80% at 72 h. HepG2 cells treated with dox-MNV and anti-miR221-MNV exhibited nuclear disintegration, and apoptosis within 24 h. Combination treatment of intrahepatic tumors with dox-MNV and anti-miR221-MNV resulted in marked reduction of tumor size and increased survival rate in nude mice. Our studies demonstrated that MNVs can be effectively used for successful delivery of anticancer agents into HCC cells and intrahepatic tumors. MNV-mediated targeted delivery of anticancer agents could be an efficient modality for the treatment of malignant HCC and might produce a great impact on anticancer therapy.

Skull base plasmacytoma: A unique case of POEMS syndrome with a plasmacytoma causing craniocervical instability

IntroductionPlasmacytomas, considered to be the solitary counterparts of multiple myeloma, are neoplastic monoclonal plasma cell proliferations within soft tissue or bone. Plasmacytomas often present as a collection of findings known as POEMS-syndrome (Polyneuropathy, Organomegaly, Endocrinopathy, M-Protein spike, and Skin changes). Case descriptionWe present a report of a 47 yo male diagnosed with POEMS-syndrome secondary to a skull base plasmacytoma. The mass resulted in marked instability of the cranio-cervical junction due to bony erosion. Following an induction course of chemotherapy, he showed clinical improvement with a marked reduction in tumor size and underwent an autologous peripheral blood stem cell transplant for systemic treatment of his POEMS-syndrome. Following completion of systemic treatment, he then underwent a definitive occipital-cervical fusion without complications. His neurologic exam upon dismissal was stable with subjective improvement in left upper extremity strength. Postoperative radiographs confirmed spinal alignment and pathological examination of a small biopsy from C1 revealed benign fibrous tissue. ConclusionTo the best of our knowledge, this is the first report of a skull-base plasmacytoma associated with POEMS-syndrome, causing cranio-cervical instability. The approach of systemic therapy combined with temporary external fixation, followed by definitive occipital cervical fusion resulted in a good outcome for this patient.

Sclerosing thymoma-like thymic amyloidoma with nephrotic syndrome: a case report

BackgroundPrimary localized amyloidosis presenting as an isolated mediastinal mass is extremely rare, especially in the thymus. Sclerosing thymoma is also an extremely rare anterior mediastinal tumor, pathologically characterized by extensive sclerotic lesions with hyalinization and calcification. Only 14 cases of sclerosing thymoma and five cases of thymic amyloidosis have been reported to date.Case presentationA 78-year-old Japanese woman was diagnosed as having sclerosing thymoma (Masaoka stage IVa pericardial dissemination)-like thymic amyloidoma. She was diagnosed as having either lung cancer or mediastinal tumor with pericardial dissemination, and received palliative treatment. Three years later, she was readmitted with a complaint of general malaise. Since minimal change nephrotic syndrome was suspected based on the disease onset and selectivity index of urinary protein, steroid pulse therapy was started. Subsequently, because a marked reduction in tumor size was observed during maintenance treatment with prednisolone, a thoracoscopic needle biopsy was performed for a definitive diagnosis. According to the pathological findings and clinical investigations, a final diagnosis of sclerosing thymoma (Masaoka stage IVa pericardial dissemination)-like thymic amyloidoma was made.ConclusionsThis is a case report of sclerosing thymoma-like thymic amyloidoma. Both sclerosing thymoma and thymic amyloidoma are extremely rare diseases: only 14 cases of sclerosing thymoma and five cases of thymic amyloidosis have been reported to date. In either diagnosis, our case is the first case in which marked reduction in tumor size was observed with steroid therapy. All reported cases of sclerosing thymomas underwent surgical resection, but steroid therapy to sclerosing thymoma has not been reported. It is still unknown whether steroid therapy is effective or not. The hyalinized components of sclerosing thymoma possibly contain amyloid deposits. The marked reduction in tumor size with steroid therapy may result in amyloid deposits. The association between sclerosing thymoma and thymic amyloidoma remains uncertain. Sclerosing thymoma should be stained with Congo red.

Primary Ewing sarcoma of the kidney: a case report and treatment review

Ewing sarcomas/primitive neuroectodermal tumors (ES/PNET) of the kidney are rarely found high-grade malignant tumors, offering poor prognosis. Although established treatment guidelines for ES of kidney are scarce, a multi-modality treatment approached is typically implemented. Herein, we report a 14-year-old female patient with ES of right kidney. Post-nephrectomy disease recurrence was treated with chemotherapy (i.e., vincristine, doxorubicin and cyclophosphamide); marked reduction in tumor size (i.e., from 18.5×11.3cm2 to 3.7×2.2cm2;~96% reduction in size) as per computed tomography images was observed. We present our treatment experience and review from the available literature.

P53/Rb inhibition induces metastatic adrenocortical carcinomas in a preclinical transgenic model.

Adrenocortical carcinoma (ACC) is a rare cancer with poor prognosis. Pan-genomic analyses identified p53/Rb and WNT/β-catenin signaling pathways as main contributors to the disease. However, isolated β-catenin constitutive activation failed to induce malignant progression in mouse adrenocortical tumors. Therefore, there still was a need for a relevant animal model to study ACC pathogenesis and to test new therapeutic approaches. Here, we have developed a transgenic mice model with adrenocortical specific expression of SV40 large T-antigen (AdTAg mice), to test the oncogenic potential of p53/Rb inhibition in the adrenal gland. All AdTAg mice develop large adrenal carcinomas that eventually metastasize to the liver and lungs, resulting in decreased overall survival. Consistent with ACC in patients, adrenal tumors in AdTAg mice autonomously produce large amounts of glucocorticoids and spontaneously activate WNT/β-catenin signaling pathway during malignant progression. We show that this activation is associated with downregulation of secreted frizzled related proteins (Sfrp) and Znrf3 that act as inhibitors of the WNT signaling. We also show that mTORC1 pathway activation is an early event during neoplasia expansion and further demonstrate that mTORC1 pathway is activated in ACC patients. Preclinical inhibition of mTORC1 activity induces a marked reduction in tumor size, associated with induction of apoptosis and inhibition of proliferation that results in normalization of corticosterone plasma levels in AdTAg mice. Altogether, these data establish AdTAg mice as the first preclinical model for metastatic ACC.

Improved oral efficacy of epirubicin through polymeric nanoparticles: pharmacodynamic and toxicological investigations

Epirubicin (EPI) elicits poor-oral bioavailability hence commercially available as injection for intravenous administration which follows a rapid increase and fast decay in plasma drug concentration often needs a frequent dosing that may lead to serious side effects. Aim of the present study is to develop a nanoparticulate system which could deliver epirubicin effectively via oral administration and could eventually promote new concept “chemotherapy at home.” In this perspective, epirubicin loaded Poly-lactide-co-glycolic acid nanoparticles (EPI-NPs) were developed by double emulsion evaporation techniques and evaluated for its safety and efficacy against Ehrlich’s Ascites (EAT) induced tumor in balb/c mice. In vivo fate of nanoparticles after oral administration in Albino wistar rats was also studied. EPI-NPs showed marked reduction in tumor size ∼40% while tumor size was increased 3.55 and 3.28 folds in control as well as in group treated orally with free epirubicin solution (EPI-S), respectively. Furthermore, toxicological evaluation demonstrated insignificant difference in levels of biomarkers including MDA, CAT, SOD, LDH, CK-MB, AST and ALT when EPI-NPs-oral treatment was compared with control group while levels of these biomarkers were found extremely significant in group treated with EPI-S (i.v). and demonstrated increment in LDH (p < 0.001), CK-MB (p < 0.001), AST (p < 0.001), ALT (p < 0.001) and MDA levels (p < 0.001) and reduction in SOD (p < 0.001) and CAT levels (p < 0.001) thus confirmed better safety profile of EPI-NPs oral than EPI-S i.v. Biodistribution study demonstrated the presence of NPs in different body organs and blood which suggests probability of NPs translocation across intestine thus at the tumor site.

A case of giant prolactinoma, initially misdiagnosed as sinonasal neuroendocrine carcinoma

Abstract Giant prolactinomas are defined as pituitary tumors greater than 4 cm, often associated with very high prolactin level (> 1000 ng/mL). They are relatively rare tumors and can present differently from typical prolactinomas. They can be highly invasive, resulting in acute neurological complication at the time of presentation. We present a case of a young woman with giant prolactinoma initially misdiagnosed as sinonasal neuroendocrine carcinoma. The acute presentation of headache, ptosis and impending brain herniation, requiring emergent ventriculostomy and intubation, led to the clinical suspicion of a more sinister diagnosis. Transnasal biopsy of the mass was consistent with sinonasal neuroendocrine carcinoma, and chemotherapy was planned. Laboratory testing, however, revealed an elevated prolactin (27,400 ng/mL, after 1:100 dilution). Re-review of pathology with additional immunohistochemical staining was requested and confirmed the diagnosis of prolactinoma. After 5 months of cabergoline treatment, prolactin level has decreased to 118 ng/mL. There has been a marked reduction in tumor size and an almost complete resolution of neurological symptoms. Given their atypical presentation and potential for sharing common immunohistochemical stains with other neuroendocrine neoplasms, giant prolactinomas extending into the nasal cavity can be misdiagnosed as other neuroendocrine neoplasms which may develop at this site. Accurate diagnosis is imperative to prevent unnecessary surgery and/or radiation and to ensure implementation of dopamine agonist therapy.

Anti-Myeloma Activity by the Combination of the JAK2 Inhibitor Ruxolitinib with Lenalidomide and Corticosteroids

Introduction: The JAK2 inhibitor ruxolitinib (RUX) is an inhibitor of the Janus kinase family of protein tyrosine kinases (JAKs) that is effective for the treatment of myeloproliferative diseases. Immunomodulatory drugs (IMiDs) including lenalidomide (LEN) and corticosteroids have shown efficacy for the treatment of multiple myeloma (MM). The JAK-STAT signaling pathway plays key roles in the growth and survival of malignant plasma cells in MM. In this study, we evaluated the preclinical anti-MM effects of RUX in combination with LEN and corticosteroids, both in vitro and in vivo, and in a patient with MM and polycythemia rubra vera (PRV).Methods: The human MM cell lines U266, RPMI8226 and MM1S cells were derived from ATCC. Primary MM tumor cells were isolated from MM patients’ bone marrow aspirates. The cells were seeded at105 cells/100ul/well in 96-well plates and incubated for 24 h in the presence of vehicle, RUX, LEN or dexamethasone (DEX) alone, RUX + LEN, RUX + DEX, or all three drugs together for 48 h. Cell viability was quantified using the MTS cell proliferation assay. In vitro, synergy between ruxolitinib and lenalidomide or dexamethasone was assessed using the median effect method of Chou and Talalay. For the in vivo studies, the human myeloma tumors (LAGκ-1A or LAGκ-2) were surgically implanted into the left superficial gluteal muscle of anaesthetized naive SCID mice. Mice were blindly assigned to one of the experimental groups, and treatment was initiated 7–21 d after tumor implantation. LEN was administered via oral gavage daily (30 mg/kg). RUX (3 mg/kg) was given via intraperitoneal (IP) injection twice daily. Dexamethasone was administered daily (1.5mg/kg) via IP injection. An 88 year old MM patient with PRV who developed MM on RUX alone and then progressed on LEN+DEX was treated with the combination of all three drugs.Results:In vitro, RUX induced concentration-dependent inhibition of viability in all three MM cell lines (U266, RPMI8226 and MM1S) at RUX 50 mM and inhibition of primary MM tumor cells at a higher concentration (100 mM). In contrast, RUX had negligible cytotoxic effects on normal peripheral blood mononuclear cells (PBMCs). We next examined cell viability in the presence of RUX plus LEN or DEX. First, U266 cells were incubated with a fixed concentration of LEN (30 mM) or DEX (40 mM) with increasing concentrations of RUX (0.1–100 mM) for 48 h. At RUX 50 mM, the cytotoxic effects of LEN were enhanced and at RUX 1 mM, the anti-myeloma effect of DEX was increased. Moreover, the cytotoxic effects of RUX, LEN and DEX were greater than RUX in combination with either LEN or DEX in U266 cells. Similar results were obtained using the RPMI8226 and MM1S cell lines as well as primary MM tumor cells. Next, we evaluated RUX in combination with lenalidomide and dexamethasone in vivo using SCID mice bearing either the human LAGκ-1A or LAGκ-2 MM xenografts. RUX (3mg/kg), LEN (15mg/kg) or DEX (1mg/kg) alone did not inhibit tumor growth in either mice bearing LAGκ-1A or LAGκ-2. In contrast, the combination of RUX with DEX but not LEN slightly decreased tumor volume. However, the combination of all three drugs at the same doses showed a marked reduction of tumor size and delay of tumor growth in both human MM xenograft models. In addition, a patient with MM and PRV experienced sustained and ongoing reductions in his serum M-protein, IgG, and 24-urine M-protein with achievement of a partial response on low doses of RUX (2.5 mg twice daily), LEN (2.5 mg daily), and methylprednisolone (20 mg daily) that has been ongoing for more than 12 months after developing MM on RUX alone and then progressing on the combination of LEN and methylprednisolone.Conclusion: This study illustrates that the combination of the JAK2 inhibitor RUX, LEN and corticosteroids shows both preclinical and promising clinical results for the treatment of MM. DisclosuresNo relevant conflicts of interest to declare.

Endoscopic Liquid Nitrogen Spray Cryotherapy in Patients with Post-Surgical Gastric Anatomy: A Multicenter Cryotherapy Users Group Report

Purpose: Endoscopic liquid nitrogen spray cryotherapy has been used for management of dysplastic Barrett's esophagus and also early esophageal cancer. Use of cryotherapy in patients with surgically altered gastric anatomy is a relative contra-indication due to the potential risk of gastrointestinal perforation from expansion of liquid nitrogen and has not been previously reported. Aim: To assess the feasibility and complications of endoscopic spray cryotherapy in patients with post-surgical gastric anatomy. Methods: Our electronic endoscopy databases were used to identify patients with surgically altered gastric anatomy who underwent liquid nitrogen endoscopic spray cryotherapy (CryoSpray Ablation System, CSA Medical, Baltimore, MD). Medical records were reviewed to collect data including procedure indication, post-operative anatomy, therapy time/number of freeze-thaw cycles, number of sessions, follow up period, outcomes and complications. Results: 41 endoscopic cryotherapy procedures were performed in 8 patients with altered foregut anatomy (mean age 69 years, range 44-82; 63% male). 4 patients (50%) had Barrett's esophagus with high grade dysplasia, 1 had esophageal adenocarcinoma, 1 had gastric adenocarcinoma at the gastrojejunal anastomosis, 1 had gastric high grade dysplasia, and 1 had non-dysplastic Barrett's. Post-surgical anatomy included 3 patients with Whipple anatomy, and 1 each with RY gastric bypass, sleeve gastrectomy, fundoplication, Billroth II anatomy, and partial esophagectomy/gastrectomy. The decompression tube was placed in the stomach in 6/8 (75%) patients and in the jejunum in 2/8 patients (25%). 10-20 second freeze-thaw cycles (mean 16.6 seconds/cycle; 3.3 cycles/session, range 2-6) were performed. An average of 5.1 sessions were performed per patient (range 2-14). Mean follow-up time was 16.4 months (range 2-60). Outcomes included complete Barrett's ablation (normal squamous epithelium) in 1, downgrading of gastric high grade to low grade dysplasia in 1, downgrading of high grade dysplasia to non-dysplastic Barrett's in 2, marked reduction in tumor size in 1 (palliative therapy only), reduction in visible Barrett's segment in 2, and no endoscopic change in 1 patient (no prior visible lesion in this patient but pathology had been positive for cancer; therapy ongoing). There were no perforations noted. 2/8 patients (25%) had mild non-cardiac chest pain after cryotherapy. Conclusion: Endoscopic liquid nitrogen spray cryotherapy may be safely used in patients with post-surgical gastric anatomy. Careful placement of the decompression tube remains important.

Abstract 4771: Improved antitumor efficacy of an acid-sensitive doxorubicin derivative delivered by thermally responsive elastin-like polypeptides

Abstract Doxorubicin is a widely used anticancer drug used in the treatment of various cancers. It acts as an intercalator of DNA and inhibits topoisomerase II thus preventing cell replication. Its side effects include nausea, myelosuppression, alopecia, and dose-limiting cardiotoxicity. Dox is nonspecific, and high doses are needed to treat cancer cells. These high doses, however, are also harmful to normal cells. Because of this toxicity to normal cells, there is a great need for a delivery system that will target dox to the tumor site. In our research, we have developed a tumor targeted drug delivery system comprising the elastin-like polypeptide (ELP) which is a thermally responsive macromolecule that remains soluble in physiologic temperature but aggregates upon heating at 42 °C in the tumor. The N-terminus of ELP was modified with the cell-penetrating peptide SynB1. The SynB1-ELP construct was further modified by the addition of an acid-sensitive hydrazone derivative of doxorubicin (DOXO), by conjugation with a 6-maleimidocaproyl moiety on the drug to a terminal cysteine residue on ELP. SynB1-ELP-DOXO was found to have a thermal transition temperature of 41 °C. This construct was 2-fold more effective in inhibiting MCF-7 breast cancer cell proliferation at 42 °C than at 37 °C, indicating that the hyperthermia-induced phase transition of ELP increases the local concentration of the drug. This inhibition may be due to apoptosis since apoptosis was enhanced 2.3-fold in MCF-7 cells when SynB1-ELP-DOXO aggregation was induced by hyperthermia. SynB1-ELP-DOXO had a similar accumulation inside the cell as free Dox as shown by confocal fluorescence imaging, and the uptake into the cell was increased by hyperthermia. In the in vivo studies, a marked reduction in tumor size was seen with SynB1-ELP-DOXO exposed to hyperthermia in the E0771 syngeneic breast cancer model in C57BL/6 mice. The efficacy of the construct was further proved by the animal's body weight increasing over time as compared to treatment with free Dox and a decreasing body weight. An ongoing study uses the combination of free Dox and SynB1-ELP-DOXO at lower doses to reduce tumor size. The ELP macromolecule can also be applied to other small molecule therapeutics opening a potential platform technology for this thermally responsive biopolymer. Citation Format: {Authors}. {Abstract title} [abstract]. In: Proceedings of the 103rd Annual Meeting of the American Association for Cancer Research; 2012 Mar 31-Apr 4; Chicago, IL. Philadelphia (PA): AACR; Cancer Res 2012;72(8 Suppl):Abstract nr 4771. doi:1538-7445.AM2012-4771

A TCRMimic Monoclonal Antibody Generated from a Directly Discovered Epitope of p68 RNA Helicase Dramatically Debulks Large Established Tumors through Recognition of a Specific MHC/Peptide Complex.

Abstract Debulking large tumors using monoclonal antibodies (mAb) that specifically recognize unique T cell epitopes represents a novel approach to cancer therapy.Using a mAb designated as a TCRm we recently demonstrated the in vivo suppression of tumor growth. The TCRm had specificity for a peptide/MHC class I molecule expressed on the surface of the tumor cells. In this study we use an innovative direct epitope discovery strategy that led to the identification of peptide YLLPAIVHI in the context of HLA-A*0201 (YLL/A2) in human breast carcinoma cell lines. The peptide is derived from the DEAD Box RNA helicase protein p68, a protein overexpressed and highly phosphorylated in malignant cells. A TCRm antibody (RL6A) was generated and characterized for binding specificity, sensitivity and affinity for the YLL/A2 target. The TCRm specifically stained cells that co-expressed HLA-A2 and p68 but not cells lacking expression of p68 protein or HLA-A2 alone. It binds to cognate peptide/HLA-A2 with an affinity constant (KD) of 5.69 x 10-10 M and recognized specifically the YLL/A2 epitope in human breast cancer tissue but not in normal control breast tissue.Mice implanted in the mammary fat pad with human breast tumor cells grew tumors of considerable size, yet when treated with RL6A TCRm there was a marked reduction in tumor size. Examination of frozen tumor tissue sections revealed significantly greater numbers of apoptotic cells in mice treated with RL6A TCRm than with control antibody. Investigation in vitro showed that TCRm engagement of specific YLL/A2 epitope led to the induction of apoptosis providing the first experimental evidence that MHC signaling could directly mediate tumor cell death. Together, these data indicate that TCRm targeting of specific peptide/MHC complexes unique to tumor cells is effective not only in slowing the growth of tumors but also in dramatically reducing the size of established tumors and suggests a possible novel approach to the treatment of cancer. Citation Information: Cancer Res 2009;69(24 Suppl):Abstract nr 5072.

Thymic squamous cell carcinoma producing granulocyte colony-stimulating factor associated with a high serum level of interleukin 6

Granulocyte colony-stimulating factor (G-CSF)-producing thymic carcinoma is extremely rare. A-66-year-old man presented with an anterior mediastinal mass, and underwent surgical biopsy. He had marked leukocytosis, and his serum levels of G-CSF and interleukin-6 were elevated. Histologically, the tumor consisted of squamous cell carcinoma, which showed positive immunoreactivity for G-CSF. He was treated with thoracic radiotherapy, and chest imaging revealed a marked reduction of tumor size. He was doing well at 8 months after tumor diagnosis.

Oral Dosing of the Novel Proteasome Inhibitor CEP-18770 Shows Marked Anti-Myeloma Effects in SCID-Hu Models of Multiple Myeloma.

Abstract 1840Poster Board I-866Introduction: Currently, there is no orally administered proteasome inhibitor (PI) which has been FDA approved for the treatment of any cancer. The first PI in clinical development, bortezomib, was approved in 2003 following two successful single-agent phase II trials in relapsed multiple myeloma (MM). In contrast to bortezomib which is administered by intravenous bolus, CEP-18770 is a PI that is active as an oral formulation. Furthermore, the efficacy of orally administered CEP-18770 in multiple MM models has not been reported. In this study, we determined the effects of orally administered CEP-18770 therapy at escalating doses either daily or twice weekly in severe combined immunodeficient (SCID) mice bearing human MM that has been serially passaged in SCID mice from bone marrow derived from a MM patient before (LAGκ-1A) and after resistance (LAGκ-1B) to bortezomib developed. Materials and Methods: Each naïve SCID mouse received a 20 — 40 mm3 MM tumor piece which was surgically implanted into the left hind limb superficial gluteal muscle. Seven days post-implantation mice were bled, human IgG levels were measured by ELISA and animals were randomized into treatment groups. CEP-18770 was administered via oral gavage either daily at 5 mg/kg or twice weekly at 10 mg/kg (M, W) throughout the study. Each week, mice were bled for hIgG levels (where applicable) and tumors were measured using standard calipers. Data graphed is the mean ± SEM with n = 15 mice/group. Results: Single-agent CEP-18770 administered orally significantly inhibited tumor growth in bortezomib-sensitive LAGκ-1A-bearing mice. A significant inhibition of both human paraprotein secretion and reduction of tumor volume was observed as soon as three weeks following initiation of treatment with CEP-18770 at 10 mg/kg twice weekly (hIgG: P = 0.0011 and tumor volume: P = 0.001). Furthermore, tumor volume growth to 700 mm3 was delayed by 94% (day 32.5 for control compared to day 63) among animals receiving this treatment regimen when compared to animals receiving no treatment. At day 35, daily administration of the PI at 5 mg/kg also resulted in significant tumor inhibition (hIgG: P < 0.0001 and tumor volume: P < 0.0001). Reductions of tumor growth by 75%, 95%, 97% and 98% on days 28, 35, 42 and 49 respectively, were observed when compared to the control group. The effect of single-agent CEP-18770 dosed orally in SCID mice bearing nonsecretory bortezomib-resistant LAGκ-1B tumors was also evaluated. Four weeks following initiation of treatment, 5 mg/kg administered daily or 10 mg/kg twice weekly, resulted in a significant reduction in tumor volume (P = 0.0327 and P = 0.0018 respectively). Tumor volume growth to 300 mm3 was delayed by 36% (day 31 for control compared to day 42 for CEP-18770-treated group) in animals receiving 5 mg/kg daily compared to animals receiving no treatment. Tumor volume at 220 mm3 was delayed by 50% (day 28 for control compared to day 42 for CEP-18770-treated mice) among animals receiving 10 mg/kg twice weekly when compared to the untreated control group. Reductions of tumor growth by 78%, 73%, 74% and 70% on days 35, 42, 49 and 56 respectively, were observed when compared to the control group. Moreover, body weights measured at treatment cessation were not significantly different between pre- and post-treatment levels for both treatment groups and MM tumor types. Conclusions: The results of these studies show a marked reduction of tumor size and delay of tumor growth, when compared to the control group, following oral administration of CEP-18770 in LAGκ-1A and LAGκ-1B-bearing mice. The potential availability of an oral PI will greatly enhance the convenience of administration of drugs in this class as bortezomib has only shown efficacy when given intravenously. Other PIs that are bioavailable and active orally in preclinical studies in the treatment of MM are now in early clinical development. The data presented in our study provide further support for clinical development of CEP-18770 as an oral formulation for the treatment of MM. Disclosures:Berenson:Cephalon, Inc.: Consultancy, Honoraria, Research Funding, Speakers Bureau.