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Activation of Wnt signalling due to inability to degrade β-catenin is found in >85% of colorectal cancers. Approximately half of colon cancers express a constitutively active KRAS protein. A significant fraction of patients show both abnormalities. We previously reported that simultaneous down-regulation of both β-catenin and KRAS was necessary to induce significant cell death and tumor growth inhibition of colorectal cancer cells. Although attractive, an RNAi-based therapeutic approach is still far from being employed in the clinical setting. Therefore, we sought to recapitulate our previous findings by the use of small-molecule inhibitors of β-catenin and KRAS. We show here that the β-catenin inhibitors PKF115-584 and pyrvinium pamoate block β-catenin-dependent transcriptional activity and synergize with the KRAS inhibitor S-trans, trans-farnesylthiosalicylic acid (FTS, salirasib) in colon cancer cells driven by Wnt and KRAS oncogenic signals, but not in cells carrying BRAF mutations. The combined use of these compounds was superior to the use of any drug alone in inducing cell growth arrest, cell death, MYC and survivin down-modulation, and inhibition of anchorage-independent growth. Expression analysis of selected cancer-relevant genes revealed down-regulation of CD44 as a common response to the combined treatments. These data provide a proof of principle for a combination therapeutic strategy in colorectal cancer.

Anaplastic lymphoma kinase (ALK) is a tyrosine kinase receptor involved in both solid and hematological tumors. About 80% of ALK‐positive anaplastic large‐cell lymphoma (ALCL) cases are characterized by the t(2;5)(p23;q35) translocation, encoding for the aberrant fusion protein nucleophosmin (NPM)‐ALK, whereas 5% of non‐small‐cell lung cancer (NSCLC) patients carry the inv(2)(p21;p23) rearrangement, encoding for the echinoderm microtubule‐associated protein‐like 4 (EML4)‐ALK fusion. The ALK/c‐MET/ROS inhibitor crizotinib successfully improved the treatment of ALK‐driven diseases. However, several cases of resistance appeared in NSCLC patients, and ALK amino acid substitutions were identified as a leading cause of resistance to crizotinib. Second‐generation ALK inhibitors have been developed in order to overcome crizotinib resistance. In this work, we profiled in vitro the activity of crizotinib, AP26113, ASP3026, alectinib, and ceritinib against six mutated forms of ALK associated with clinical resistance to crizotinib (C1156Y, L1196M, L1152R, G1202R, G1269A, and S1206Y) and provide a classification of mutants according to their level of sensitivity/resistance to the drugs. Since the biological activity of ALK mutations extends beyond the specific type of fusion, both NPM‐ALK‐ and EML4‐ALK‐positive cellular models were used. Our data revealed that most mutants may be targeted by using different inhibitors. One relevant exception is represented by the G1202R substitution, which was highly resistant to all drugs (>10‐fold increased IC50 compared to wild type) and may represent the most challenging mutation to overcome. These results provide a prediction of cross‐resistance of known crizotinib‐resistant mutations against all second‐generation tyrosine kinase inhibitors (TKIs) clinically available, and therefore could be a useful tool to help clinicians in the management of crizotinib‐resistance cases. ALK is a tyrosine kinase receptor involved both in ALCL and NSCLC. Patients affected by these diseases are treated with the ALK inhibitor crizotinib, but patients relapsed after treatment due to crizotinib conferring resistance point mutations selection. Activities of four second‐generation ALK inhibitors on crizotinib‐resistant mutants are reported.

The regulatory microRNA miR-150 is involved in the development of hemopathies and is downregulated in T-lymphomas, such as anaplastic large-cell lymphoma (ALCL) tumors. ALCL is defined by the presence or absence of translocations that activate the anaplastic lymphoma kinase (ALK), with nucleophosmin-ALK (NPM-ALK) fusions being the most common. Here, we compared samples of primary NPM-ALK(+) and NPM-ALK(-) ALCL to investigate the role of miR-150 downstream of NPM-ALK. Methylation of the MIR150 gene was substantially elevated in NPM-ALK(+) biopsies and correlated with reduced miR-150 expression. In NPM-ALK(+) cell lines, DNA hypermethylation-mediated miR-150 repression required ALK-dependent pathways, as ALK inhibition restored miR-150 expression. Moreover, epigenetic silencing of miR-150 was due to the activation of STAT3, a major downstream substrate of NPM-ALK, in cooperation with DNA methyltransferase 1 (DNMT1). Accordingly, miR-150 repression was turned off following treatment with the DNMT inhibitor, decitabine. In murine NPM-ALK(+) xenograft models, miR-150 upregulation induced antineoplastic activity. Treatment of crizotinib-resistant NPM-ALK(+) KARPAS-299-CR06 cells with decitabine or ectopic miR-150 expression reduced viability and growth. Altogether, our results suggest that hypomethylating drugs, alone or in combination with other agents, may benefit ALK(+) patients harboring tumors resistant to crizotinib and other anti-ALK tyrosine kinase inhibitors (TKIs). Moreover, these results support further work on miR-150 in these and other ALK(+) malignancies.

Anaplastic lymphoma kinase-positive (ALK+) anaplastic large-cell lymphoma (ALCL) is a subtype of non-Hodgkin lymphoma characterized by expression of the oncogenic NPM/ALK fusion protein. When resistant or relapsed to front-line chemotherapy, ALK+ ALCL prognosis is very poor. In these patients, the ALK inhibitor crizotinib achieves high response rates, however 30–40% of them develop further resistance to crizotinib monotherapy, indicating that new therapeutic approaches are needed in this population. We here investigated the efficacy of upfront rational drug combinations to prevent the rise of resistant ALCL, in vitro and in vivo. Different combinations of crizotinib with CHOP chemotherapy, decitabine and trametinib, or with second-generation ALK inhibitors, were investigated. We found that in most cases combined treatments completely suppressed the emergence of resistant cells and were more effective than single drugs in the long-term control of lymphoma cells expansion, by inducing deeper inhibition of oncogenic signaling and higher rates of apoptosis. Combinations showed strong synergism in different ALK-dependent cell lines and better tumor growth inhibition in mice. We propose that drug combinations that include an ALK inhibitor should be considered for first-line treatments in ALK+ ALCL.

CD1d-restricted invariant NKT (iNKT) cells are a subset of T lymphocytes endowed with innate effector functions that aid in the establishment of adaptive T and B cell immune responses. iNKT cells have been shown to play a spontaneous protective role against experimental tumors. Yet, the interplay between iNKT and tumor-specific T cells in cancer immune surveillance/editing has never been addressed. The transgenic adenocarcinoma of the mouse prostate (TRAMP) is a realistic model of spontaneous oncogenesis, in which the tumor-specific cytotoxic T cell (CTL) response undergoes full tolerance upon disease progression. We report here that lack of iNKT cells in TRAMP mice resulted in the appearance of more precocious and aggressive tumors that significantly reduced animal survival. TRAMP mice bearing or lacking iNKT cells responded similarly to a tumor-specific vaccination and developed tolerance to a tumor-associated antigen at comparable rate. Hence, our data argue for a critical role of iNKT cells in the immune surveillance of carcinoma that is independent of tumor-specific CTL.

Most of the anaplastic large-cell lymphoma (ALCL) cases carry the t(2;5; p23;q35) that produces the fusion protein NPM-ALK (nucleophosmin-anaplastic lymphoma kinase). NPM-ALK-deregulated kinase activity drives several pathways that support malignant transformation of lymphoma cells. We found that in ALK-rearranged ALCL cell lines, NPM-ALK was distributed in equal amounts between the cytoplasm and the nucleus. Only the cytoplasmic portion was catalytically active in both cell lines and primary ALCL, whereas the nuclear portion was inactive because of heterodimerization with NPM1. Thus, about 50% of the NPM-ALK is not active and sequestered as NPM-ALK/NPM1 heterodimers in the nucleus. Overexpression or relocalization of NPM-ALK to the cytoplasm by NPM genetic knockout or knockdown caused ERK1/2 (extracellular signal-regulated protein kinases 1 and 2) increased phosphorylation and cell death through the engagement of an ATM/Chk2- and γH2AX (phosphorylated H2A histone family member X)-mediated DNA-damage response. Remarkably, human NPM-ALK-amplified cell lines resistant to ALK tyrosine kinase inhibitors (TKIs) underwent apoptosis upon drug withdrawal as a consequence of ERK1/2 hyperactivation. Altogether, these findings indicate that an excess of NPM-ALK activation and signaling induces apoptosis via oncogenic stress responses. A ‘drug holiday’ where the ALK TKI treatment is suspended could represent a therapeutic option in cells that become resistant by NPM-ALK amplification.

Targeted therapy is an effective, rational, and safe approach to solid and hematological tumors treatment. Unfortunately, a significant fraction of patients treated with tyrosine kinase inhibitors (TKI) relapses mainly because of gene amplification, mutations, or other bypass mechanisms. Recently a growing number of papers showed how, in some cases, resistance due to oncogene overexpression may be associated with drug addiction: cells able to proliferate in the presence of high TKI doses become also TKI dependent, undergoing cellular stress, and apoptosis/death upon drug withdrawal. Notably, if a sub-cellular population survives TKI discontinuation it is also partially re-sensitized to the same drug. Thus, it is possible that a subset of patients relapsing upon TKI treatment may benefit from a discontinuous therapeutic schedule. We focused on two different hematologic malignancies, chronic myeloid leukemia (CML) and anaplastic large cell lymphoma (ALCL), both successfully treatable with TKIs. The two models utilized (LAMA and SUP-M2) differed in having oncogene overexpression as the sole cause of drug resistance (CML), or additionally carrying kinase domain mutations (ALCL). In both cases drug withdrawal caused a sudden overload of oncogenic signal, enhanced mitochondria activity, induced the release of a high amount of reactive oxygen species (ROS), and caused genotoxic stress and massive cell death. In LAMA cells (CML) we could rescue the cells from death by partially blocking downstream oncogenic signaling or lowering ROS detrimental effect by adding reduced glutathione.

Background Bosutinib is a recently approved ABL inhibitor. In spite of the well-documented effectiveness of BCR-ABL inhibitors in treating chronic myeloid leukemia, development of resistance is a continuous clinical challenge. Transporters that facilitate drug uptake and efflux have been proposed as one potential source of resistance to tyrosine kinase inhibitor treatment. Our aim was to determine which carriers are responsible for bosutinib transport. Methods K562S cells overexpressing the drug transporters ABCB1, ABCG2, and SLC22A1 were generated, characterized and used in proliferation assay and intracellular uptake and retention assay (IUR). In vivo experiments were performed in nude mice injected with K562S, K562DOX cells (overexpressing ABCB1), and K562DOX silenced for ABCB1 (K562DOX/sh P-GP). Results The IUR assay using C-14 bosutinib showed that only ABCB1 was responsible for active bosutinib transport. K562DOX cells showed the lowest intracellular level of bosutinib, while K562DOX cells treated with the ABCB1 inhibitor verapamil showed intracellular bosutinib levels comparable with parental K562S. Proliferation assays demonstrated that K562DOX are resistant to bosutinib treatment while verapamil is able to restore the sensitivity to the drug. Nude mice injected with K562DOX and treated with bosutinib showed very limited response and quickly relapsed after stopping treatment while K562S as well as K562DOX/sh P-GP remained tumor-free. Conclusions Our data suggest that the analysis of ABCB1 expression levels might help determine treatment options for patients exhibiting resistance to bosutinib.

Although mood-congruent memory (MCM), or the tendency to recall information consistent with one’s mood, is a robust phenomenon in human depression, to our knowledge, it has never been demonstrated in animals. Mice were subjected to social isolation (SI) or crowding for 12 hours and had their depressive-like behaviour (evaluated by the forced swim, tail suspension, sucrose preference and splash tests) or their serum corticosterone concentrations evaluated. In addition, we determined the temporal forgetting curve of the plus-maze discriminative avoidance task (PM-DAT) and examined the effects of SI or crowding on memory retrieval in the PM-DAT. Finally, we verified the effects of metyrapone pretreatment on reinstatement of memory retrieval or on the increase of corticosterone levels induced by SI. Twelve hours of SI produced depressive-like behaviour, enhanced corticosterone concentration and reinstated retrieval of a forgotten discriminative aversive (i.e., negatively valenced) task. Depressive-like behaviour was critical for this facilitative effect of SI because 12 hours of crowding neither induced depressive-like behaviour nor enhanced retrieval, although it increased corticosterone levels at the same magnitude as SI. However, corticosterone increase was a necessary condition for MCM in mice, in that the corticosterone synthesis inhibitor metyrapone abolished SI-induced retrieval reinstatement. Our study did not investigate the effects of the social manipulations proposed here in a positively valenced task. To our knowledge, the present paper provides the first evidence of MCM in animal models.

Paclitaxel plus ramucirumab is recommended as a second-line treatment regimen in patients with advanced HER2-negative gastric or gastro-oesophageal junction cancer. We aimed to assess whether switch maintenance or early second-line therapy with paclitaxel plus ramucirumab improved outcomes compared with continuation of oxaliplatin and fluoropyrimidine doublet chemotherapy as a first-line strategy. ARMANI was a multicentre, open-label, randomised, phase 3 trial done in 31 hospitals in Italy. We enrolled patients aged 18 years or older with an Eastern Cooperative Oncology Group performance status of 0 or 1 and locally advanced unresectable or metastatic HER2-negative gastric or gastro-oesophageal junction cancer, who had disease control after 3 months of FOLFOX (leucovorin, fluorouracil, and oxaliplatin) or CAPOX (capecitabine and oxaliplatin). Patients were randomly assigned (1:1) to either paclitaxel 80 mg/m2 on days 1, 8, and 15 plus ramucirumab at 8 mg/kg on days 1 and 15 every 28 days intravenously (switch maintenance group) or continuation of oxaliplatin-based doublet chemotherapy (FOLFOX or CAPOX) for an additional 12 weeks, followed by fluoropyrimidine monotherapy maintenance (control group). Randomisation was stratified by previous gastrectomy (no vs yes), peritoneal carcinomatosis (yes vs no), and primary tumour location (gastro-oesophageal junction vs gastric). Treatment group allocation was done using a web-based system with a minimisation algorithm implementing a random component. The primary endpoint was progression-free survival, analysed on an intention-to-treat basis. The safety population included patients who received at least one dose of the study treatment. This study is registered with ClinicalTrials.gov, NCT02934464, and is complete. Between Jan 1, 2017, and Oct 2, 2023, 280 patients were randomly assigned to receive paclitaxel plus ramucirumab (switch maintenance group; n=144) or to continue FOLFOX or CAPOX (control group; n=136). All patients were White. 180 (64%) of 280 patients were male and 100 (36%) were female. At a median follow-up of 43·7 months (IQR 24·0–57·9), 253 (90%) of 280 patients had a progression-free survival event: 131 (91%) of 144 patients in the switch maintenance group and 122 (90%) of 136 patients in the control group. Median progression-free survival was 6·6 months (95% CI 5·9–7·8) in the switch maintenance group and 3·5 months (2·8–4·2) in the control group (HR 0·61, 95% CI 0·48–0·79; p=0·0002). The assumption of proportional hazards was violated; in an analysis of 24-month restricted mean survival time, restricted mean progression-free survival was 8·8 months (95% CI 7·7–9·9) in the switch maintenance group and 6·1 months (5·0–7·2) in the control group (p=0·0010). The most frequent grade 3–4 treatment-related adverse events were neutropenia (37 [26%] patients in the switch maintenance group vs 13 [10%] patients in the control group), peripheral neuropathy (eight [6%] vs nine [7%]) and arterial hypertension (nine [6%] vs none). Serious adverse events occurred in 28 (20%) of 141 patients in the experimental group and 15 (11%) of 135 patients in the control group; these events were treatment-related in two (1%) patients in the switch maintenance group (pulmonary embolism) and two (1%) patients in the control group (mucositis and anaemia). No treatment-related deaths occurred. Paclitaxel and ramucirumab switch maintenance could be a potential treatment strategy in patients with advanced HER2-negative gastric or gastro-oesophageal junction cancer who are not eligible for immunotherapy or targeted agents. Partly funded by Eli Lilly.