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Pancreatic ductal adenocarcinoma (PDAC) is resistant to virtually all chemo- and targeted therapeutic approaches. Epigenetic regulators represent a novel class of drug targets. Among them, BET and HDAC proteins are central regulators of chromatin structure and transcription, and preclinical evidence suggests effectiveness of combined BET and HDAC inhibition in PDAC. Here, we describe that TW9, a newly generated adduct of the BET inhibitor (+)-JQ1 and class I HDAC inhibitor CI994, is a potent dual inhibitor simultaneously targeting BET and HDAC proteins. TW9 has a similar affinity to BRD4 bromodomains as (+)-JQ1 and shares a conserved binding mode, but is significantly more active in inhibiting HDAC1 compared to the parental HDAC inhibitor CI994. TW9 was more potent in inhibiting tumor cell proliferation compared to (+)-JQ1, CI994 alone or combined treatment of both inhibitors. Sequential administration of gemcitabine and TW9 showed additional synergistic antitumor effects. Microarray analysis revealed that dysregulation of a FOSL1-directed transcriptional program contributed to the antitumor effects of TW9. Our results demonstrate the potential of a dual chromatin-targeting strategy in the treatment of PDAC and provide a rationale for further development of multitarget inhibitors., (© 2020 The Authors. International Journal of Cancer published by John Wiley & Sons Ltd on behalf of UICC.)

Background: The protease inhibitor ritonavir (RTV) is a clinical-stage inhibitor of the human immunodeficiency virus. In a drug repositioning approach, we here exhibit the additional potential of RTV to augment current treatment of glioblastoma, the most aggressive primary brain tumour of adulthood., Methods: We explored the antitumour activity of RTV and mechanisms of action in a broad spectrum of short-term expanded clinical cell samples from primary and recurrent glioblastoma and in a cohort of conventional cell lines and non-tumour human neural controls in vitro. To validate RTV efficacy in monotherapeutic and in combinatorial settings, we used patient-derived xenograft models in a series of in vivo studies., Results: RTV monotherapy induced a selective antineoplastic response and demonstrated cytostatic and anti-migratory activity at clinical plasma peak levels. Additional exposure to temozolomide or irradiation further enhanced the effects synergistically, fostered by mechanisms of autophagy and increased endoplasmic reticulum stress. In xenograft models, we consequently observed increasing overall survival under the combinatorial effect of RTV and temozolomide., Conclusions: Our data establish RTV as a valuable repositioning candidate for further exploration as an adjunct therapeutic in the clinical care of glioblastoma., Competing Interests: Conflict of interest statement The authors have declared no conflicts of interest., (Copyright © 2020 Elsevier Ltd. All rights reserved.)

Purpose: Dovitinib (TKI258) is an oral multi-tyrosine kinase inhibitor of FGFR, VEGFR, PDGFR β, and c-Kit. Since dovitinib is able to cross the blood-brain barrier and targets brain tumor-relevant pathways, we conducted a phase I trial to demonstrate its safety in recurrent glioblastoma (GBM)., Patients and Methods: Patients with first or second GBM recurrence started treatment with the maximal tolerated dose (MTD) previously established in systemic cancer patients (500 mg/d, 5 days on/2 days off). A modified 3 + 3 design in three cohorts (500, 400, 300 mg) was used., Results: Twelve patients were enrolled. Seventy-two adverse events (AEs) occurred and 16.7 % of AEs were classified as ≥CTC grade 3 toxicity, mainly including hepatotoxicity and hematotoxicity. Only one out of six patients of the 300-mg cohort showed grade 3 toxicity. The PFS-6 rate was 16.7 %, and it was not associated with detection of the FGFR-TACC gene fusion in the tumor., Conclusion: Dovitinib is safe in patients with recurrent GBM and showed efficacy in only some patients unselected for target expression. The recommended phase II dose of 300 mg would be substantially lower than the recently established MTD in systemic cancer patients. Further personalized trials are recommended.

Leptomeningeal metastasis (LM), i.e. the seeding of tumor cells to the cerebrospinal fluid (CSF) and the leptomeninges, is a devastating and mostly late-stage complication of various solid tumors. Clinical signs and symptoms may include cranial nerve palsies, radicular symptoms, signs of increased intracranial pressure such as headache, nausea and vomiting, and cognitive dysfunction. In cases of suspected LM, the highest diagnostic sensitivity is provided by the combination of CSF cytology and contrast-enhanced MRI (cranial as well as complete spine). The therapeutic spectrum includes radiotherapy of the clinically involved region as well as systemic and intrathecal chemotherapy. The choice of treatment modalities depends on the type of LM (non-adherent tumor cells in the CSF vs. nodular contrast-enhancing tumor growth), additional systemic involvement (uncontrolled vs. controlled systemic disease) and additional involvement of the CNS parenchyma (LM as the only CNS involvement vs. LM+parenchymal CNS metastases). Larger contrast-enhancing nodular LM or symptomatic lesions of the spine may be treated with radiotherapy. In case of uncontrolled systemic disease, the treatment regimen should include systemic chemotherapy. The choice of systemic treatment should take into account the histology of the primary tumor. Intrathecal chemotherapy is most important in cases of LM of the non-adherent type. There are three substances for routine use for intrathecal chemotherapy: methotrexate, cytarabine, and thiotepa. Liposomal cytarabine shows advantages in terms of longer injection intervals, a sufficient distribution in the entire subarachnoid space after lumbar administration and improved quality-of-life. The role of new agents (e.g. rituximab and trastuzumab) for intrathecal therapy is still unclear., (Copyright © 2015 Elsevier Ltd. All rights reserved.)

Cellular heterogeneity, for example, the intratumoral coexistence of cancer cells with and without stem cell characteristics, represents a potential root of therapeutic resistance and a significant challenge for modern drug development in glioblastoma (GBM). We propose here that activation of the innate immune system by stimulation of innate immune receptors involved in antiviral and antitumor responses can similarly target different malignant populations of glioma cells. We used short-term expanded patient-specific primary human GBM cells to study the stimulation of the cytosolic nucleic acid receptors melanoma differentiation-associated gene 5 (MDA5) and retinoic acid-inducible gene I (RIG-I). Specifically, we analyzed cells from the tumor core versus "residual GBM cells" derived from the tumor resection margin as well as stem cell-enriched primary cultures versus specimens without stem cell properties. A portfolio of human, nontumor neural cells was used as a control for these studies. The expression of RIG-I and MDA5 could be induced in all of these cells. Receptor stimulation with their respective ligands, p(I:C) and 3pRNA, led to in vitro evidence for an effective activation of the innate immune system. Most intriguingly, all investigated cancer cell populations additionally responded with a pronounced induction of apoptotic signaling cascades revealing a second, direct mechanism of antitumor activity. By contrast, p(I:C) and 3pRNA induced only little toxicity in human nonmalignant neural cells. Granted that the challenge of effective central nervous system (CNS) delivery can be overcome, targeting of RIG-I and MDA5 could thus become a quintessential strategy to encounter heterogeneous cancers in the sophisticated environments of the brain., (Copyright © 2013 AlphaMed Press.)

Amifostine (US Bioscience, West Conshohocken, PA; Ethyol, WR-2721), a phosphorylated thiol developed by the United States Army as a protective agent for military personnel in the event of nuclear warfare, has shown protection of normal tissues from the cytotoxic effects of therapeutic radiation and chemotherapy with preservation of cytotoxic effects on the tumor. The basis of this selective protection derives from the relatively rapid uptake and anabolism of Amifostine into normal tissues and minimal, slower uptake into tumor tissue. Preclinical investigations have demonstrated protection of bone marrow stem cells from the toxic effects of radiation and chemotherapy. Several controlled clinical trials demonstrated this hematoprotective effect. In patients given 1.5 g/m2 cyclophosphamide and month later given Amifostine (740 mg/m2) followed by the same dose of cyclophosphamide, the median nadir neutrophil count was significantly increased and duration of neutropenia was significantly reduced by pretreatment with Amifostine. In women with stage III/IV ovarian cancer treated with 1 g/m2 cyclophosphamide and 100 mg/m2 cisplatin +/- Amifostine 910 mg/m2, treatment with Amifostine before cyclophosphamide and cisplatin resulted in a significant decrease in both the incidence and duration of hospital stays for neutropenic fever compared to cyclophosphamide and cisplatin alone. There were equivalent rates of response and duration of survival in both groups. Other studies have shown Amifostine protects bone marrow purged in vitro with 4-hydroperoxycyclophosphamide before autologous bone marrow transplantation. This preservation of marrow stem cells resulted in a statistically significant decrease in time to marrow engraftment, need for platelet transfusions and antibiotics, and duration of hospital stay. Amifostine-mediated protection of normal bone marrow illustrated in preclinical experiments is also evident in clinical trials. Amifostine preserves trilineage stem cells (red blood cells, platelets, and white blood cells) in contrast to the lineage-specific effects of the colony-stimulating factors. Theoretically, Amifostine and the colony-stimulating factors should provide complementary benefits to bone marrow recovery and function after cytotoxic therapies. These observations offer the promise of using high doses of chemotherapy to exploit antitumor, dose-response relationships in clinical trials.

After failure of temozolomide, there is no established standard salvage chemotherapy for patients with recurrent glioblastoma (GBM). Two phase II trials combining ifosfamide, carboplatin and etoposide chemotherapy (ICE) showed favorable results. We therefore applied the ICE protocol to 13 patients (10 GBM, 3 anaplastic astrocytomas). Partial or complete remissions were not observed. None of the 13 patients survived progression-free for 6 months. Our retrospective analysis suggests that the ICE regimen is not effective in patients with recurrent high-grade glioma if applied at second or third relapse. Copyright © 2011 S. Karger AG, Basel [ABSTRACT FROM AUTHOR]