TLD-1, a novel liposomal doxorubicin, in patients with advanced solid tumors: Dose escalation and expansion part of a multicenter open-label phase I trial (SAKK 65/16).

BACKGROUND: TLD-1 is a novel liposomal doxorubicin that compared favorably to conventional doxorubicin liposomal formulations in preclinical models. This phase I first-in-human study aimed to define the maximum tolerated dose (MTD), recommended phase 2 dose (RP2D), safety and preliminary activity of TLD-1 in patients with advanced solid tumors. PATIENTS AND METHODS: We recruited patients with advanced solid tumors who failed standard therapy and received up to 3 prior lines of palliative systemic chemotherapy. TLD-1 was administered intravenously every 3 weeks up to a maximum of 9 cycles (6 for patients with prior anthracyclines) from a starting dose of 10 mg/m2, according to an accelerated titration design followed by a modified continual reassessment method. RESULTS: 30 patients were enrolled between November 2018 and May 2021. No dose-limiting toxicities (DLT) were observed. Maximum administered dose of TLD-1 was 45 mg/m2, RP2D was defined at 40 mg/m2. Most frequent treatment-related adverse events (TRAE) of any grade included palmar-plantar erythrodysesthesia (PPE) (50% of patients), oral mucositis (50%), fatigue (30%) and skin rash (26.7%). Most common G3 TRAE included PPE in 4 patients (13.3%) and oral mucositis in 2 (6.7%). Overall objective response rate was 10% in the whole population and 23.1% among 13 patients with breast cancer; median time-to-treatment failure was 2.7 months. TLD-1 exhibit linear pharmacokinetics, with a median terminal half-life of 95 h. CONCLUSIONS: The new liposomal doxorubicin formulation TLD-1 showed a favourable safety profile and antitumor activity, particularly in breast cancer. RP2D was defined at 40 mg/m2 administered every 3 weeks. (NCT03387917).

Combined therapy with ibrutinib and bortezomib followed by ibrutinib maintenance in relapsed or refractory mantle cell lymphoma and high-risk features: a phase 1/2 trial of the European MCL network (SAKK 36/13).

Background: The Bruton's tyrosine kinase inhibitor ibrutinib and the proteasome inhibitor bortezomib have single-agent activity, non-overlapping toxicities, and regulatory approval in mantle cell lymphoma (MCL). In vitro, their combination provides synergistic cytotoxicity. In this investigator-initiated phase 1/2 trial, we established the recommended phase 2 dose of ibrutinib in combination with bortezomib, and assessed its efficacy in patients with relapsed or refractory MCL. Methods: In this phase 1/2 study open in 15 sites in Switzerland, Germany and Italy, patients with relapsed or refractory MCL after ≤2 lines of chemotherapy and both ibrutinib-naïve and bortezomib-naïve received six cycles of ibrutinibb and bortezomib, followed by ibrutinib maintenance. For the phase 1 study, a standard 3 + 3 dose escalation design was used to determine the recommended phase 2 dose of ibrutinib in combination with bortezomib. The primary endpoint in phase 1 was the dose limiting toxicities in cycle 1. The phase 2 study was an open-label, single-arm trial with a Simon's two-stage min-max design, with a primary endpoint of overall response rate (ORR) assessed by CT/MRI. This study was registered with ClinicalTrials.gov, NCT02356458. Findings: Between August 2015 and September 2016, nine patients were treated in the phase 1 study, and 49 patients were treated between November 2016 and March 2020 in the phase 2 of the trial. The ORR was 81.8% (90% CI 71.1, 89.8%, CR(u) 21.8%) which increased with continued ibrutinib (median 10.6 months) to 87.3%, (CR(u) 41.8%). 75.6% of patients had at least one high-risk feature (Ki-67 > 30%, blastoid or pleomorphic variant, p53 overexpression, TP53 mutations and/or deletions). In these patients, ibrutinib and bortezomib were also effective with an ORR of 74%, increasing to 82% during maintenance. With a median follow-up of 25.4 months, the median duration of response was 22.7, and the median PFS was 18.6 months. PFS reached 30.8 and 32.9 months for patients with a CR or Cru, respectively. Interpretation: The combination of ibrutinib and bortezomib shows durable efficacy in patients with relapsed or refractory MCL, also in the presence of high-risk features. Funding: SAKK (Hubacher Fund), Swiss State Secretariat for Education, Research and Innovation, Swiss Cancer Research Foundation, and Janssen.

Stafiba: A STAT5-Selective Small-Molecule Inhibitor.

The transcription factors STAT5a and STAT5b are constitutively active in many human tumors. Combined inhibition of both STAT5 proteins is a valuable approach with promising applications in tumor biology. We recently reported resorcinol bisphosphate as a moderately active inhibitor of the protein-protein interaction domains, the SH2 domains, of both STAT5a and STAT5b. Here, we describe the development of resorcinol bisphosphate to Stafiba, a phosphatase-stable inhibitor of STAT5a and STAT5b with activity in the low micromolar concentration range. Our data provide insights into the structure-activity relationships of resorcinol bisphosphates and the corresponding bisphosphonates for use as inhibitors of both STAT5a and STAT5b.

SAKK 35/15: a phase 1 trial of obinutuzumab in combination with venetoclax in patients with previously untreated follicular lymphoma.

This phase 1 study evaluated safety, tolerability, and preliminary efficacy of obinutuzumab in combination with venetoclax in patients with previously untreated grade 1-3a follicular lymphoma in need of systemic therapy. Two DLs of venetoclax were evaluated with an expansion cohort at the recommended phase 2 dose. Twenty-five patients were enrolled. The recommended phase 2 dose was venetoclax 800 mg OD continuously for 6 cycles starting on day 2 of cycle 1, with obinutuzumab 1000 mg on days 1, 8, and 15 of cycle 1 and on day 1 of cycles 2 to 6, followed by obinutuzumab maintenance every 2 months for 2 years. Only 1 patient had a DLT consisting of grade 4 thrombocytopenia after the first obinutuzumab infusion. Neutropenia was the most common adverse event of grade ≥3 at least possibly attributed to study treatment. Twenty-four patients were evaluable for response after cycle 6 by computed tomography (CT) and 19 by positron emission tomography/CT (PET/CT): overall and complete response rates were 87.5% (95% CI, 67.6% to 97.3%) and 25% (95% CI, 9.8% to 46.7%) in the CT-evaluated patients and 84.2% (95% CI, 60.4% to 96.6%) and 68.4% (95% CI, 43.4% to 87.4%), respectively, in the PET/CT-evaluated patients. One-year progression-free survival was 77.8% (95% CI, 54.6% to 90.1%) and 79% (95% CI, 47.9% to 92.7%) for CT and PET/CT-evaluable patients, respectively, whereas progression-free survival at 30 months was 73.2% (95% CI, 49.8%, 87.0%) as assessed by CT and 79.0% (95% CI, 47.9%, 92.7%) by PET/CT. Despite the activity observed, our results do not support further development of the combination in this patient population. This trial was registered at www.clinicaltrials.gov as #NCT02877550.

Rituximab, bendamustine and lenalidomide in patients with aggressive B-cell lymphoma not eligible for anthracycline-based therapy or intensive salvage chemotherapy - SAKK 38/08.

An increasing number of older patients are suffering from aggressive lymphoma. Effective and more tolerable treatment regimens are urgently needed for this growing patient population. Patients with aggressive lymphoma not eligible for anthracycline-based first-line therapy or intensive salvage regimens were treated with the rituximab-bendamustine-lenalidomide (R-BL) regimen (rituximab 375 mg/m(2)  day 1, bendamustine 70 mg/m(2)  d 1, 2, lenalidomide 10 mg d 1-21) for six cycles every 4 weeks. Forty-one patients with a median age of 75 (range 40-94) years were enrolled: 33 patients had substantial co-morbidities. 13 patients were not eligible for anthracycline-based first-line chemotherapy, 28 patients had relapsed/refractory disease. The primary endpoint, overall response, was achieved by 25 (61%) patients (95% confidence interval 45-76%). Grade ≥ 3 toxicity comprised haematological (59%), skin (15%), constitutional (15%) and neurological (12%) events. 9 patients died during trial treatment: 5 from lymphoma progression, 2 from toxicity, 2 with sudden death. After a median follow-up of 25·9 (interquartile range 20·4-31·6) months, 13 patients were still alive. Median overall survival was 14·5 months. In conclusion, R-BL can be considered a treatment option for elderly patients with treatment naïve or relapsed/refractory aggressive lymphoma not eligible for standard aggressive regimens.

Neoadjuvant chemotherapy and extrapleural pneumonectomy of malignant pleural mesothelioma with or without hemithoracic radiotherapy (SAKK 17/04): a randomised, international, multicentre phase 2 trial.

BACKGROUND: Postoperative hemithoracic radiotherapy has been used to treat malignant pleural mesothelioma, but it has not been assessed in a randomised trial. We assessed high-dose hemithoracic radiotherapy after neoadjuvant chemotherapy and extrapleural pneumonectomy in patients with malignant pleural mesothelioma. METHODS: We did this phase 2 trial in two parts at 14 hospitals in Switzerland, Belgium, and Germany. We enrolled patients with pathologically confirmed malignant pleural mesothelioma; resectable TNM stages T1-3 N0-2, M0; WHO performance status 0-1; age 18-70 years. In part 1, patients were given three cycles of neoadjuvant chemotherapy (cisplatin 75 mg/m(2) and pemetrexed 500 mg/m(2) on day 1 given every 3 weeks) and extrapleural pneumonectomy; the primary endpoint was complete macroscopic resection (R0-1). In part 2, participants with complete macroscopic resection were randomly assigned (1:1) to receive high-dose radiotherapy or not. The target volume for radiotherapy encompassed the entire hemithorax, the thoracotomy channel, and mediastinal nodal stations if affected by the disease or violated surgically. A boost was given to areas at high risk for locoregional relapse. The allocation was stratified by centre, histology (sarcomatoid vs epithelioid or mixed), mediastinal lymph node involvement (N0-1 vs N2), and T stage (T1-2 vs T3). The primary endpoint of part 1 was the proportion of patients achieving complete macroscopic resection (R0 and R1). The primary endpoint in part 2 was locoregional relapse-free survival, analysed by intention to treat. The trial is registered with ClinicalTrials.gov, number NCT00334594. FINDINGS: We enrolled patients between Dec 7, 2005, and Oct 17, 2012. Overall, we analysed 151 patients receiving neoadjuvant chemotherapy, of whom 113 (75%) had extrapleural pneumonectomy. Median follow-up was 54·2 months (IQR 32-66). 52 (34%) of 151 patients achieved an objective response. The most common grade 3 or 4 toxic effects were neutropenia (21 [14%] of 151 patients), anaemia (11 [7%]), and nausea or vomiting (eight [5%]). 113 patients had extrapleural pneumonectomy, with complete macroscopic resection achieved in 96 (64%) of 151 patients. We enrolled 54 patients in part 2; 27 in each group. The main reasons for exclusion were patient refusal (n=20) and ineligibility (n=10). 25 of 27 patients completed radiotherapy. Median total radiotherapy dose was 55·9 Gy (IQR 46·8-56·0). Median locoregional relapse-free survival from surgery, was 7·6 months (95% CI 4·5-10·7) in the no radiotherapy group and 9·4 months (6·5-11·9) in the radiotherapy group. The most common grade 3 or higher toxic effects related to radiotherapy were nausea or vomiting (three [11%] of 27 patients), oesophagitis (two [7%]), and pneumonitis (two [7%]). One patient died of pneumonitis. We recorded no toxic effects data for the control group. INTERPRETATION: Our findings do not support the routine use of hemithoracic radiotherapy for malignant pleural mesothelioma after neoadjuvant chemotherapy and extrapleural pneumonectomy. FUNDING: Swiss Group for Clinical Cancer Research, Swiss State Secretariat for Education, Research and Innovation, Eli Lilly.

Comprehensive description of the N-glycoproteome of mouse pancreatic ß-cells and human islets.

Cell surface N-glycoproteins provide a key interface of cells to their environment and therapeutic entry points for drug and biomarker discovery. Their comprehensive description denotes therefore a formidable challenge. The ß-cells of the pancreas play a crucial role in blood glucose homeostasis, and disruption of their function contributes to diabetes. By combining cell surface and whole cell capturing technologies with high-throughput quantitative proteomic analysis, we report on the identification of a total of 956 unique N-glycoproteins from mouse MIN6 ß-cells and human islets. Three-hundred-forty-nine of these proteins encompass potential surface N-glycoproteins and include orphan G-protein-coupled receptors, novel proteases, receptor protein kinases, and phosphatases. Interestingly, stimulation of MIN6 ß-cells with glucose and the hormone GLP1, known stimulators of insulin secretion, causes significant changes in surface N-glycoproteome expression. Taken together, this ß-cell N-glycoproteome resource provides a comprehensive view on the composition of ß-cell surface proteins and expands the scope of signaling systems potentially involved in mediating responses of ß-cells to various forms of (patho)physiologic stress and the extent of dynamic remodeling of surface N-glycoprotein expression associated with metabolic and hormonal stimulation. Moreover, it provides a foundation for the development of diabetes medicines that target or are derived from the ß-cell surface N-glycoproteome.

Substrate preference and phosphatidylinositol monophosphate inhibition of the catalytic domain of the Per-Arnt-Sim domain kinase PASKIN.

The Per-Arnt-Sim (PAS) domain serine/threonine kinase PASKIN, or PAS kinase, links energy flux and protein synthesis in yeast, regulates glycogen synthesis and protein translation in mammals, and might be involved in insulin regulation in the pancreas. According to the current model, binding of a putative ligand to the PAS domain disinhibits the kinase domain, leading to PASKIN autophosphorylation and increased kinase activity. To date, only synthetic but no endogenous PASKIN ligands have been reported. In the present study, we identified a number of novel PASKIN kinase targets, including ribosomal protein S6. Together with our previous identification of eukaryotic elongation factor 1A1, this suggests a role for PASKIN in the regulation of mammalian protein translation. When searching for endogenous PASKIN ligands, we found that various phospholipids can bind PASKIN and stimulate its autophosphorylation. Interestingly, the strongest binding and autophosphorylation was achieved with monophosphorylated phosphatidylinositols. However, stimulated PASKIN autophosphorylation did not correlate with ribosomal protein S6 and eukaryotic elongation factor 1A1 target phosphorylation. Although autophosphorylation was enhanced by monophosphorylated phosphatidylinositols, di- and tri-phosphorylated phosphatidylinositols inhibited autophosphorylation. By contrast, target phosphorylation was always inhibited, with the highest efficiency for di- and tri-phosphorylated phosphatidylinositols. Because phosphatidylinositol monophosphates were found to interact with the kinase rather than with the PAS domain, these data suggest a multiligand regulation of PASKIN activity, including a still unknown PAS domain binding/activating ligand and kinase domain binding modulatory phosphatidylinositol phosphates.

PVHL is a regulator of glucose metabolism and insulin secretion in pancreatic beta cells.

Insulin secretion from pancreatic beta cells is stimulated by glucose metabolism. However, the relative importance of metabolizing glucose via mitochondrial oxidative phosphorylation versus glycolysis for insulin secretion remains unclear. von Hippel-Lindau (VHL) tumor suppressor protein, pVHL, negatively regulates hypoxia-inducible factor HIF1alpha, a transcription factor implicated in promoting a glycolytic form of metabolism. Here we report a central role for the pVHL-HIF1alpha pathway in the control of beta-cell glucose utilization, insulin secretion, and glucose homeostasis. Conditional inactivation of Vhlh in beta cells promoted a diversion of glucose away from mitochondria into lactate production, causing cells to produce high levels of glycolytically derived ATP and to secrete elevated levels of insulin at low glucose concentrations. Vhlh-deficient mice exhibited diminished glucose-stimulated changes in cytoplasmic Ca(2+) concentration, electrical activity, and insulin secretion, which culminate in impaired systemic glucose tolerance. Importantly, combined deletion of Vhlh and Hif1alpha rescued these phenotypes, implying that they are the result of HIF1alpha activation. Together, these results identify pVHL and HIF1alpha as key regulators of insulin secretion from pancreatic beta cells. They further suggest that changes in the metabolic strategy of glucose metabolism in beta cells have profound effects on whole-body glucose homeostasis.

High sensitivity detection of plasma proteins by multiple reaction monitoring of N-glycosites.

The detection and quantification of plasma (serum) proteins at or below the ng/ml concentration range are of critical importance for the discovery and evaluation of new protein biomarkers. This has been achieved either by the development of high sensitivity ELISA or other immunoassays for specific proteins or by the extensive fractionation of the plasma proteome followed by the mass spectrometric analysis of the resulting fractions. The first approach is limited by the high cost and time investment for assay development and the requirement of a validated target. The second, although reasonably comprehensive and unbiased, is limited by sample throughput. Here we describe a method for the detection of plasma proteins at concentrations in the ng/ml or sub-ng/ml range and their accurate quantification over 5 orders of magnitude. The method is based on the selective isolation of N-glycosites from the plasma proteome and the detection and quantification of targeted peptides in a quadrupole linear ion trap instrument operated in the multiple reaction monitoring (MRM) mode. The unprecedented sensitivity of the mass spectrometric analysis of minimally fractionated plasma samples is the result of the significantly reduced sample complexity of the isolated N-glycosites compared with whole plasma proteome digests and the selectivity of the MRM process. Precise quantification was achieved via stable isotope dilution by adding (13)C- and/or (15)N-labeled reference analytes. We also demonstrate the possibility of significantly expanding the number of MRM measurements during one single LC-MS run without compromising sensitivity by including elution time constraints for the targeted transitions, thus allowing quantification of large sets of peptides in a single analysis.

Male germ cell expression of the PAS domain kinase PASKIN and its novel target eukaryotic translation elongation factor eEF1A1.

PASKIN links energy flux and protein synthesis in yeast, regulates glycogen synthesis in mammals, and has been implicated in glucose-stimulated insulin production in pancreatic beta-cells. Using newly generated monoclonal antibodies, PASKIN was localized in the nuclei of human testis germ cells and in the midpiece of human sperm tails. A speckle-like nuclear pattern was observed for endogenous PASKIN in HeLa cells in addition to its cytoplasmic localization. By yeast two-hybrid screening, we identified the multifunctional eukaryotic translation elongation factor eEF1A1 as a novel interaction partner of PASKIN. This interaction was mapped to the PAS A and kinase domains of PASKIN and to the C-terminus of eEF1A1 using mammalian two-hybrid and GST pull-down assays. Kinase assays, mass spectrometry and site-directed mutagenesis revealed PASKIN auto-phosphorylation as well as eEF1A1 target phosphorylation mainly but not exclusively at Thr432. Wild-type but not kinase-inactive PASKIN increased the in vitro translation of a reporter cRNA. Whereas eEF1A1 did not localize to the nucleus, it co-localizes with PASKIN to the cytoplasm of HeLa cells. The two proteins also showed a remarkably similar localization in the midpiece of the sperm tail. These data suggest regulation of eEF1A1 by PASKIN-dependent phosphorylation in somatic as well as in sperm cells.

Copper-dependent activation of hypoxia-inducible factor (HIF)-1: implications for ceruloplasmin regulation.

Cellular oxygen partial pressure is sensed by a family of prolyl-4-hydroxylase domain (PHD) enzymes that modify hypoxia-inducible factor (HIF)alpha subunits. Upon hydroxylation under normoxic conditions, HIFalpha is bound by the von Hippel-Lindau tumor suppressor protein and targeted for proteasomal destruction. Since PHD activity is dependent on oxygen and ferrous iron, HIF-1 mediates not only oxygen- but also iron-regulated transcriptional gene expression. Here we show that copper (CuCl(2)) stabilizes nuclear HIF-1alpha under normoxic conditions, resulting in hypoxia-response element (HRE)-dependent reporter gene expression. In in vitro hydroxylation assays CuCl(2) inhibited prolyl-4-hydroxylation independently of the iron concentration. Ceruloplasmin, the main copper transport protein in the plasma and a known HIF-1 target in vitro, was also induced in vivo in the liver of hypoxic mice. Both hypoxia and CuCl(2) increased ceruloplasmin (as well as vascular endothelial growth factor [VEGF] and glucose transporter 1 [Glut-1]) mRNA levels in hepatoma cells, which was due to transcriptional induction of the ceruloplasmin gene (CP) promoter. In conclusion, our data suggest that PHD/HIF/HRE-dependent gene regulation can serve as a sensory system not only for oxygen and iron but also for copper metabolism, regulating the oxygen-, iron- and copper-binding transport proteins hemoglobin, transferrin, and ceruloplasmin, respectively.

Targeted disruption of the mouse PAS domain serine/threonine kinase PASKIN.

PASKIN is a novel mammalian serine/threonine kinase containing two PAS (Per-Arnt-Sim) domains. PASKIN is related to the Rhizobium oxygen sensor protein FixL and to AMP-regulated kinases. Like FixL, the sensory PAS domain of PASKIN controls the kinase activity by autophosphorylation in a (unknown) ligand-dependent manner. In Saccharomyces cerevisiae, the two PASKIN orthologues PSK1 and PSK2 phosphorylate three translation factors and two enzymes involved in glycogen synthesis, thereby coordinately regulating protein synthesis and glycolytic flux. To elucidate the function of mammalian PASKIN, we inactivated the mouse Paskin gene by homologous recombination in embryonic stem cells. Paskin(-/-) mice showed normal development, growth, and reproduction. The targeted integration of a lacZ reporter gene allowed the identification of the cell types expressing mouse PASKIN. Surprisingly, PASKIN expression is strongly upregulated in postmeiotic germ cells during spermatogenesis. However, fertility and sperm production and motility were not affected by the PASKIN knockout. The Ppp1r7 gene encoding Sds22, a regulatory subunit of protein phosphatase 1, shares the promoter region with the Paskin gene, pointing towards a common transcriptional regulation. Indeed, Sds22 colocalized with the cell types expressing PASKIN in vivo, suggesting a functional role of protein phosphatase-1 in the regulation of PASKIN autophosphorylation.

The antimycotic ciclopirox olamine induces HIF-1alpha stability, VEGF expression, and angiogenesis.

The heterodimeric hypoxia-inducible factor (HIF)-1 is a master regulator of oxygen homeostasis. Protein stability and transactivation function of the alpha subunit are controlled by iron- and oxygen-dependent hydroxylation of proline and asparagine residues. The anti-mycotic ciclopirox olamine (CPX) is a lipophilic bidentate iron chelator that stabilizes HIF-1alpha under normoxic conditions at lower concentrations than other iron chelators, probably by inhibiting HIF-1alpha hydroxylation. As shown by the inhibition of iron-dependent quenching of FITC-labeled deferoxamine (DFX) fluorescence, CPX appears to have an even higher affinity for iron than DFX. Initial observations that treatment with 1% CPX, but not with placebo, occasionally caused reddening of wound margins in a mouse skin wound model prompted us to investigate the capability of CPX to induce angiogenesis. CPX-induced HIF-1-mediated reporter gene activity and endogenous HIF-1 target gene expression, including elevation of transcription, mRNA, and protein levels of the vascular endothelial growth factor (VEGF). In the chick chorioallantoic membrane assay, inert polymer disks containing CPX but not the solvent alone induced angiogenesis. In summary, these results suggest that CPX induces angiogenesis in vivo via HIF-1 and VEGF induction. Therefore, CPX might serve as an alternative to recombinant VEGF treatment or to VEGF gene therapy for therapeutic angiogenesis.