Concomitant downregulation of proliferation/survival pathways dependent on FGF-R3, JAK2 and BCMA in human multiple myeloma cells by multi-kinase targeting

The identification of proliferation/survival pathways constitutively activated by genetic alterations in multiple myeloma (MM), or sustained by the bone marrow (BM) microenvironment, provides novel opportunities for the development of targeted therapies. The deregulated function of protein tyrosine kinases plays a critical role in driving MM malignant phenotype. We investigated the effects of the multi-target tyrosine kinase inhibitor RPI-1 in a panel of human MM cell lines, including t(4;14) positive cell lines expressing the TK receptor FGF-R3. Cells harboring FGF-R3 activating mutations (KMS11 and OPM2) displayed the highest sensitivity to RPI-1 antiproliferative effect. The stimulating effect of the aFGF ligand was abrogated in cells harboring a non-constitutively active receptor. Drug treatment inhibited activation and expression of the FGF-R3^Y373C mutant as well as aFGF-dependent signaling involving AKT and ERKs. Inhibition of JAK2, an additional RPI-1 target, resulted in STAT3 inactivation. Blockade of these proliferation/survival pathways was associated with caspase-dependent apoptosis. Moreover, drug treatment abrogated proliferative and pro-invasive stimuli provided by conditioned medium from mesenchymal stromal cells. Gene expression profile of KMS11 cells showed 22 upregulated and 52 downregulated genes upon RPI-1 treatment, with an early modulation of genes implicated in MM pathobiology such as SAT-1, MYC, MIP-1α/β, FGF-R3, and the growth factor receptor B-cell maturation antigen (BCMA). Thus, concomitant blockade of FGF-R3 and JAK2 results in inhibition of several MM-promoting pathways, including BCMA-regulated signaling, and downregulation of disease-associated proteins. These data may have therapeutic implications in the design of treatment strategies resulting in the concomitant inhibition of FGF-R3 and JAK2 signaling pathways in t(4;14) MM.     

Intensity-modulated and hypofractionated simultaneous integrated boost adjuvant breast radiation employing statics ports of tomotherapy (TomoDirect): a prospective phase II trial

Purpose

To report the 1-year outcomes of a prospective phase II study on hypofractionated whole-breast intensity-modulated radiotherapy (IM-WBRT) with a simultaneous integrated boost (SIB) to the tumor bed delivered with static ports of tomotherapy (TomoDirect) (TD).

Methods

A prospective cohort of 82 patients was enrolled between 2011 and 2012. Treatment schedule consisted of 45 Gy/20 fractions to the whole breast and 50 Gy/20 fractions to the surgical bed delivered concomitantly with TD over 4 weeks. A one-armed optimal two-stage Simon’s design was selected to test the hypothesis that treatment modality under investigation would decrease acute skin toxicity over historical data using conventional fractionation and sequential boost. Primary endpoint was acute skin toxicity. Secondary endpoints included late toxicity, cosmesis, quality of life and local control.

Results

Median follow-up was 12 months (range 6–18). Maximum detected acute skin toxicity was G0 41 %; G1 53 %; G2 6 %; G3 <1 %. With two G2–G3 acute skin toxicity events in the first stage and four in the second, the study fulfilled the requirements for the definition of the treatment approach under investigation as promising. Late skin toxicity was mild with no >G2 events. Cosmesis was good/excellent in 91 % of patients and fair/poor in 9 %. Quality of life was preserved over time, with the exception of fatigue, which was transiently increased.

Conclusions

Hypofractionated IM-WBRT with a SIB to the tumor bed delivered with TD provides consistent clinical results and it is able to reduce acute skin toxicity rate over conventionally fractionated and sequential boost tomotherapy-based IM-WBRT.     

RET/PTC oncoproteins: molecular targets of new drugs

Ret oncoproteins expressed in thyroid carcinomas represent possible targets for therapeutic intervention. Oncogenic activation of the receptor tyrosine kinase encoding RET gene occurs typically by gene rearrangement in papillary thyroid carcinomas (PTC) and by missense mutation in medullary thyroid carcinomas (MTC). These genetic alterations lead to the expression of deregulated products characterized by ligand-independent activation of the intrinsic tyrosine kinase of Ret. Such features suggest the possibility of using specific tyrosine kinase inhibitors to block the Ret oncoproteins signaling. The present report summarizes the cellular effects of the arylidene 2-indolinone Ret inhibitor RPI-1 (formerly Cpd1) on the human PTC cell line TPC-1 which spontaneously harbors the RET/PTC1 oncogene. The results provide evidence that RPI-1 is able to inhibit cell growth and to interfere with Ret/ptc1-driven signaling. These findings support a role for Ret oncoproteins as therapeutic targets and the pharmacological interest of RPI-1 as a candidate drug for preclinical evaluation on thyroid tumors expressing RET oncogenes.     

Prospective multicenter study of combined treatment with chemotherapy and radiotherapy in breast cancer women with the rare clinical scenario of ipsilateral supraclavicular node recurrence without distant metastases

PURPOSE: To evaluate the role of chemotherapy combined with curative radiotherapy in breast cancer patients who presented with recurrent ipsilateral supraclavicular lymph node metastases (ISLM) without "nonregional disease," we designed an observational study performed prospectively. PATIENTS AND METHODS: Forty-four consecutive patients with ISLM from breast cancer as part of recurrent regional disease without distant metastases were included in this study. All patients received chemotherapy with doxorubicin-based schema or paclitaxel for six courses and curative radiotherapy (60 Gy/30 fractions of 2 Gy/5 days a week). An "involved field" radiation was delivered during the interval between the third and fourth chemotherapy course; hormonal therapy was given based on receptor status. RESULTS: The rate of overall clinical response after chemotherapy and radiotherapy was 94.9%. Median time to progression and overall survival were 28 and 40 months, respectively; the 5-year actuarial overall survival and disease-free survival rates were 35% (95% confidence interval, 19-51) and 20% (95% confidence interval, 6-34), respectively. CONCLUSION: A curative course of intravenous chemotherapy and radical irradiation is feasible in patients with ISLM. All patients presenting recurrence in supraclavicular nodes should be treated with definitive locoregional treatments and systemic therapy because the outcomes are better than might be historically assumed.     

Apoptotic cell death induction and angiogenesis inhibition in large established medullary thyroid carcinoma xenografts by Ret inhibitor RPI-1

Recent evidence indicates that the success of molecular targeted therapies may depend on the identification of drug targets which are essential for the survival of subsets of tumors. RET oncogenes that have been implicated in the development of thyroid carcinomas are emerging as potential therapeutic targets. In the present study, we investigated the efficacy and the cellular bases of antitumor activity of the indolinone Ret tyrosine kinase inhibitor RPI-1 against large established s.c. TT tumor xenograft, a human medullary thyroid carcinoma (MTC) harboring oncogenic MEN-2A-type RET mutation. Oral treatment with RPI-1 caused growth arrest or regression in 81% treated tumors. Following treatment suspension, tumor inhibition was maintained (51%, P < 0.05, 100 days) and cures were achieved in 2/11 mice. In treated tumors, Ret was tyrosine dephosphorylated. Moreover, compared to control tumors, a significant increase in apoptotic cells (210%, P < 0.0001), loss of cellularity (47%, P < 0.0001) and reduction of microvessel density (36%, P < 0.0005) were detected. In vivo effects of RPI-1 were reflected in activation of BAD, cleavage of caspases, apoptotic DNA fragmentation and inhibition of VEGF production observed in in vitro RPI-1-treated TT cells. These findings thus indicate that RPI-1 antitumor effect on the MTC was characterized by apoptosis induction and angiogenesis inhibition. The results, consistent with a dependence on RET oncogene activation for maintenance and survival of MEN2A-type MTC, provide further preclinical rationale for a pharmacological RET-targeted intervention in thyroid cancer.     

Small lesions detectability with the Biograph 16 Hi-Rez PET/CT scanner and fast imaging protocols: performance evaluation using an anthropomorphic thoracic phantom and ROC analyses

Objectives

The purpose of this study was to evaluate the impact on lesion detectability of fast imaging protocols using ¹⁸F-FDG and a 3-dimensional LSO-based PET/CT scanner.

Methods

An anthropomorphic thoracic phantom was used simulating the anatomical structures of radioactivity distribution for the upper torso of an underweight patient. Irregularly shaped targets of small dimensions, the zeolites, were located inside the phantom in an unpredictable position for the observers. Target-to background ratios and target dimensions were selected in order to sample the range of detectability. Repeated imaging was performed to acquire PET images with varying emission scan duration (ESD) of 1, 2, 3 and 4 min/bed and background activity concentrations of 10, 5 and 3 kBq/mL in the torso cavity. Three observers ranked the targets and a receiver operating characteristic analysis was performed for each acquisition protocol.

Results

Detection performances improved when passing from a short (ESD = 1 min) protocol to longer (ESD ≥ 2 min) protocols. This improvement was established with adequate statistical significance.

Conclusions

Short image acquisition times of 1 min/bed using ¹⁸F-FDG and the specific scanner model considered in the study lead to reduced lesion detectability and should be avoided also in underweight patients.