Biomedical subjects

Martin Schuler

Publications and source records attributed to Martin Schuler.

16 recordsLinked to original sources

PubMed2026

Patient-reported outcomes with tarlatamab in extensive-stage small cell lung cancer after platinum-based chemotherapy: results from the phase 3 DeLLphi-304 trial.

BACKGROUND: Extensive-stage small cell lung cancer (ES-SCLC) is associated with a high symptom burden and impaired health-related quality of life (HRQoL). This prespecified analysis from the phase 3 DeLLphi-304 trial evaluated patient-reported outcomes (PROs) for tarlatamab versus standard-of-care (SoC) chemotherapy following first-line platinum-based therapy. METHODS: DeLLphi-304 is a multicenter, open-label, randomized phase 3 study in adults with ES-SCLC. PROs were assessed using validated instruments, including the EORTC QLQ-C30, EORTC QLQ-LC13, FACT-G GP5, BPI-SF, and the EQ-5D-5L visual analogue scale. Change from baseline, response rates, and time to deterioration in these PROs were analyzed. RESULTS: PRO data from all 509 patients enrolled were evaluated. Compliance with QLQ-C30 and QLQ-LC13 assessments remained above 69% through 19 weeks. A higher proportion of patients receiving tarlatamab achieved symptom or functional improvement at 19 weeks compared with SoC in chest pain (19% vs 10%), cough (35% vs 26%), dyspnea (22% vs 7%), physical functioning (13% vs 8%), and global health status (23% vs 15%), respectively. Tarlatamab also delayed deterioration in symptoms, physical functioning, and pain at worst relative to SoC. FACT-G GP5 results indicated that patients receiving tarlatamab were less bothered by treatment side effects over time. CONCLUSIONS: In addition to its previously reported antitumor activity, tarlatamab demonstrated clinically meaningful improvements in symptoms and HRQoL compared with SoC. These findings support a favorable benefit-risk profile of tarlatamab in patients previously treated for ES-SCLC.

Humans↗

PubMed2026

Long-term follow-up of a phase 1/2 trial of anti-GDF-15 antibody visugromab plus anti-PD-1 antibody nivolumab in anti-PD-1/-L1 relapsed/refractory solid tumors.

BACKGROUND: Resistance to anti-PD-1/PD-L1 therapy is a major unmet need. Growth Differentiation Factor 15 (GDF-15) has been identified as a key resistance factor for anti-PD-1/PD-L1 immunotherapy. Visugromab, a neutralizing anti-GDF-15 antibody, plus the anti-PD-1 antibody nivolumab (V+N) was evaluated in the first-in-human phase 1/2a GDFATHER-01 trial in heavily pretreated participants with locally advanced/metastatic non-squamous non-small-cell lung cancer (nsq NSCLC), urothelial carcinoma (UC), or hepatocellular carcinoma (HCC), stringently defined as anti-PD-1/PD-L1-relapsed/refractory, and showed encouraging objective responses. This analysis reports long-term follow-up of these three phase 2 expansion cohorts of the GDFATHER-01 trial. METHODS: Seventy-seven participants with nsq NSCLC (N=22), UC (N=27), and HCC (N=28) received visugromab (10 mg/kg) plus nivolumab (240 mg) every two weeks until disease progression or unacceptable toxicity. RESULTS: Objective response rates (RECIST v1.1) were 18.2% for nsq NSCLC (4/22; 95%CI 5.2-40.3), 18.5% for UC (5/27; 95%CI 6.3-38.1), and 14.3% for HCC (4/28; 95%CI 4.0-32.7). Median duration of response (DoR) was 32.2 months (95%CI 5.5-38.0), 28.8 months (95%CI 7.4-39.4), and 19.4 months (95%CI 5.8-39.7; with protracted recruitment), respectively, with 7/13 responses (53.8%) ongoing. Confirmed complete response or complete metabolic response (CR or CMR) among responders was 61.5% (8/13), with 7/8 ongoing. In addition, 46.2% (6/13) of responders achieved a deeper response on V+N per RECIST v1.1 than with the prior anti-PD-(L)1 therapy; median DoR on V+N was 28.8 months (95%CI 7.4-38.0) versus 12.0 months (95%CI 8.0-24.0) on initial anti-PD-1/PD-L1 treatment. V+N was generally well tolerated. CONCLUSIONS: In heavily pretreated, advanced/metastatic participants with nsq NSCLC, UC, or HCC who were anti-PD-1/PD-L1-relapsed/refractory, V+N achieved deep and durable objective responses. The observed DoR, depth of response, and CR+CMR rate among responders exceeded those reported for their initial anti-PD-1/PD-L1 therapy. These findings suggest that GDF-15 blockade with visugromab can overcome resistance and enhance the magnitude and durability of anti-PD-1/PD-L1 responses, and warrant further exploration in randomized trials. REGISTRY: ClinicalTrials.gov, TRN: NCT04725474, Registration date: 25 January 2021; EudraCT, TRN: 2020-002103-19, Registration date 16 Dec 2020.

Humans↗

PubMed2006

Effect of rituximab on the long-term outcome after high-dose therapy for relapsed B-cell non-Hodgkin's lymphoma.

To better define the role of rituximab in salvage and high-dose therapy (HDT) for relapsed or refractory non-Hodgkin's lymphoma (NHL), patients treated before the implementation of rituximab in salvage and HDT (n = 57, control group) were compared with patients with rituximab included in this procedure (n = 36, study group). All patients had been antibody-naive at this point, and analyses were performed separately for 22 and 31 patients with aggressive, and 14 and 26 patients with indolent NHL, respectively. All patients received two courses of salvage therapy, predominantly dexamethasone, BCNU, etoposide, cytosine arabinoside, melphalan. Conditioning regimens included BCNU, etoposide, cytosine arabinoside, melphalan; BCNU, etoposide, cytosine arabinoside, cyclophosphamide or total body irradiation and cyclophosphamide, with rituximab added for patients in the study group. Despite the absence of differences in stem cell collection, haematopoietic recovery was delayed in patients with aggressive NHL treated in the study group: median days to absolute neutrophil count more than 0.5 x 10(9)/l, 11 vs 10 (p = 0.01), and platelets more than 20 x 10(9)/l, 14 vs 11 (p = 0.0005), with an increased requirement for platelet transfusions. No similar observations were made in indolent lymphoma patients. Remission rates were superior for patients with aggressive NHL in the study group. With a median follow-up of 7.25 and 4.5 years, this resulted in an improvement in OS at 4.5 years: 67 vs 45% (95% confidence interval, 47-87% vs 28-64%; p = 0.0468). For patients with indolent lymphoma, no comparable benefit was detectable. Our data support the use of rituximab in HDT for patients with aggressive NHL. For patients with indolent NHL, only longer follow-up and/or randomized trials may help to fully determine the impact of rituximab on the outcome after HDT.

Adult↗

PubMed2006

Biomimetic modification of titanium dental implant model surfaces using the RGDSP-peptide sequence: a cell morphology study.

Surface topography and (bio)chemistry are key factors in determining cell response to an implant. We investigated cell adhesion and spreading patterns of epithelial cells, fibroblasts and osteoblasts on biomimetically modified, smooth and rough titanium surfaces. The RGD bioactive peptide sequence was immobilized via a non-fouling poly(L-lysine)-graft-poly(ethylene glycol) (PLL-g-PEG) molecular assembly system, which allowed exploitation of specific cell-peptide interactions even in the presence of serum. As control surfaces, bare titanium and bio-inactive surfaces (scrambled RDG and unfunctionalized PLL-g-PEG) were used. Our findings demonstrated that surface topography and chemistry directly influenced the attachment and morphology of all cell types tested. In general, an increase in cell number and more spread cells were observed on bioactive substrates (containing RGD) compared to bio-inactive surfaces. More fibroblasts were present on smooth than on rough topographies, whereas for osteoblasts the opposite tendency was observed. Epithelial cell attachment did not follow any regular pattern. Footprint areas for all cell types were significantly reduced on rough compared to smooth surfaces. Osteoblast attachment and footprint areas increased with increasing RGD-peptide surface density. However, no synergy (interaction) between RGD-peptide surface density and surface topography was observed for osteoblasts neither in terms of attachment nor footprint area.

Animals↗

PubMed2006

Therapeutic targeting of apoptotic pathways in cancer.

Programmed cell death (apoptosis) is a key tumor suppressor mechanism. Consequently, most if not all cancers develop mechanisms to abolish or circumvent this genetic program. Besides enabling malignant transformation and tumor progression, defects in apoptosis can result in resistance to cytotoxic cancer therapies. Much progress has been made in the delineation of the molecular pathways leading to apoptosis. This allows the identification of target molecules and lead compounds to develop novel therapies, which make use of this intrinsic death program for the treatment of cancer. Here, we review the current understanding of apoptotic signal transduction pathways, and strategies of their therapeutic modulation in relation to lymphoma and other cancers.

Animals↗

PubMed2005

Subcutaneous injection of interleukin 12 induces systemic inflammatory responses in humans: implications for the use of IL-12 as vaccine adjuvant.

Interleukin 12 (IL-12) is a cytokine with important regulatory functions bridging innate and adaptive immunity. It has been proposed as an immune adjuvant for vaccination therapy of infectious diseases and malignancies. The inflammatory properties of IL-12 play an important role in the adjuvant effect. We studied the effect of s.c. injections of recombinant human IL-12 (rHuIL-12) in 26 patients with renal cell cancer and demonstrated dose-dependent systemic activation of multiple inflammatory mediator systems in humans. rHuIL-12 at a dose of 0.5 microg/kg induced degranulation of neutrophils with a significant increase in the plasma levels of elastase (p < 0.05) and lactoferrin (p = 0.01) at 24 h. Additionally, rHuIL-12 injection mediated the release of lipid mediators, as demonstrated by a sharp increase in the plasma secretory phospholipase A2 (sPLA2) level (p = 0.003). rHuIL-12, when administered at a dose of 0.1 microg/kg, showed minimal systemic effects. In conclusion, when IL-12 is used as an adjuvant, doses should not exceed 0.1 microg/kg, in order to avoid severe systemic inflammatory responses.

Adjuvants, Immunologic↗

PubMed2005

Transcription, apoptosis and p53: catch-22.

The tumor suppressor p53 is a transcription factor and is activated in response to DNA damage or oncogenic transformation through modification of its interaction with regulatory proteins. The transcription factor activity of p53 is thought to mediate its primary functions of cell-cycle arrest and apoptosis through the gene expression it regulates, and evidence to support this interpretation continues to accumulate. However, reports of transcription-independent activities of p53, especially in the induction of apoptosis, persist. In particular, recent studies suggest that cytosolic p53 directly interacts with members of the BCL-2 family of apoptosis regulators, thereby triggering mitochondrial outer membrane permeabilization and apoptosis. In this article, we examine the possible relationships between the transcription-dependent activity of p53 and its transcription-independent activity, and we propose ways in which both might regulate apoptosis.

Animals↗

PubMed2004

Smac induces cytochrome c release and apoptosis independently from Bax/Bcl-x(L) in a strictly caspase-3-dependent manner in human carcinoma cells.

The mitochondrial apoptosis pathway mediates cell death through the release of various pro-apoptotic factors including cytochrome c and Smac, the second mitochondrial activator of caspases, into the cytosol. Smac was shown previously to inhibit IAP proteins and to facilitate initiation of the caspase cascade upon cytochrome c release. To investigate Smac function during apoptosis and to explore Smac as an experimental cancer therapeutic, we constructed an expression system based on a single adenoviral vector containing Smac under control of the Tet-off system supplied in cis. Conditional expression of Smac induced apoptosis in human HCT116 and DU145 carcinoma cells regardless of the loss of Bax or overexpression of Bcl-x(L). Nevertheless, apoptosis induced by Smac was associated with cytochrome c release and breakdown of the mitochondrial membrane potential. This indicates that Smac acts independently of Bax and Bcl-x(L) during initiation of apoptosis and triggers a positive feedback loop that results in Bax/Bcl-x(L)-independent activation of mitochondria. In caspase-proficient cells, Smac-induced apoptosis could be inhibited partially by cell-permeable LEHD (caspase-9 inhibitor) and DEVD (caspase-3 inhibitor) peptides. Furthermore, loss of caspase-3 expression in MCF-7 cells carrying a caspase-3 null mutation completely abrogated the sensitivity for Smac-induced apoptotic or nonapoptotic, necrosis-like cell death, while re-expression of caspase-3 conferred sensitivity. Altogether, caspase-3 but not caspase-9 activation was necessary for execution of Smac-induced cell death. Notably, Smac did not induce caspase-9 processing in the absence of caspase-3. Thus, caspase-9 processing occurs secondary to caspase-3 activation during Smac-induced apoptosis. Altogether, Smac is capable of circumventing defects in mitochondrial apoptosis signaling such as loss of Bax or overexpression of Bcl-x(L) that are frequently observed in tumor cells resistant to anticancer therapy. Consequently, Smac appears to be a promising therapeutic target in anticancer treatment.

Adenoviridae↗

PubMed2004

Conformational control of Bax localization and apoptotic activity by Pro168.

In healthy cells, Bax resides inactive in the cytosol because its COOH-terminal transmembrane region (TMB) is tucked into a hydrophobic pocket. During apoptosis, Bax undergoes a conformational change involving NH2-terminal exposure and translocates to mitochondria to release apoptogenic factors. How this process is regulated remains unknown. We show that the TMB of Bax is both necessary and sufficient for mitochondrial targeting. However, its availability for targeting depends on Pro168 located within the preceding loop region. Pro168 mutants of Bax lack apoptotic activity, cannot rescue the apoptosis-resistant phenotype of Bax/Bak double knockout cells, and are retained in the cytosol even in response to apoptotic stimuli. Moreover, the mutants have their NH2 termini exposed. We propose that Pro168 links the NH2 and the COOH terminus of Bax and is required for COOH-terminal release and mitochondrial targeting once this link is broken.

Amino Acid Sequence↗

PubMed2004

Direct activation of Bax by p53 mediates mitochondrial membrane permeabilization and apoptosis.

The tumor suppressor p53 exerts its anti-neoplastic activity primarily through the induction of apoptosis. We found that cytosolic localization of endogenous wild-type or trans-activation-deficient p53 was necessary and sufficient for apoptosis. p53 directly activated the proapoptotic Bcl-2 protein Bax in the absence of other proteins to permeabilize mitochondria and engage the apoptotic program. p53 also released both proapoptotic multidomain proteins and BH3-only proteins [Proapoptotic Bcl-2 family proteins that share only the third Bcl-2 homology domain (BH3)] that were sequestered by Bcl-xL. The transcription-independent activation of Bax by p53 occurred with similar kinetics and concentrations to those produced by activated Bid. We propose that when p53 accumulates in the cytosol, it can function analogously to the BH3-only subset of proapoptotic Bcl-2 proteins to activate Bax and trigger apoptosis.

Animals↗

PubMed2004

Apaf-1 and caspase-9 do not act as tumor suppressors in myc-induced lymphomagenesis or mouse embryo fibroblast transformation.

Based on experiments with cultured fibroblasts, the apoptosis regulators caspase-9 and Apaf-1 are hypothesized to function as tumor suppressors. To investigate their in vivo role in lymphomagenesis, an IgH enhancer-driven c-myc transgene was crossed onto Apaf-1(-/-) and caspase-9(-/-) mice. Due to perinatal lethality, Emu-myc transgenic Apaf-1(-/-) or caspase-9(-/-) fetal liver cells were used to reconstitute lethally irradiated recipient mice. Surprisingly, no differences were seen in rate, incidence, or severity of lymphoma with loss of Apaf-1 or caspase-9, and Apaf-1 was not a critical determinant of anticancer drug sensitivity of c-myc-induced lymphomas. Moreover, loss of Apaf-1 did not promote oncogene-induced transformation of mouse embryo fibroblasts. Thus, Apaf-1 and caspase-9 do not suppress c-myc-induced lymphomagenesis and embryo fibroblast transformation.

Animals↗

PubMed2003

The DNA damage-induced decrease of Bcl-2 is secondary to the activation of apoptotic effector caspases.

Apoptosis induced by DNA-damaging agents or radiation mainly proceeds through death receptor-independent caspase activation. The release of mitochondrial apoptogenic proteins, such as cytochrome c, into the cytoplasm leading to Apaf1-dependent activation of caspase-9 is a key event in this pathway. The permeability of the mitochondrial outer membrane is regulated by the various pro- and antiapoptotic Bcl-2 family proteins, and it is thought that DNA damage triggers apoptosis through the downregulation of antiapoptotic Bcl-2. Using murine embryonic fibroblasts (MEF) deficient and proficient in Apaf1, we show that DNA-damaging agents and radiation lead to a decline in Bcl-2 protein only in wt MEF, but not in apaf1(-/-) MEF, which are defective in the activation of effector caspases and apoptosis. In contrast, the induction of proapoptotic Noxa, the activation of Bax, the cytoplasmic release of cytochrome c, as well as a drop of the mitochondrial transmembrane potential Deltapsim are equally observed in wt and apaf1(-/-) MEF following DNA damage. Moreover, the loss of Bcl-2 protein occurring in wt MEF can be prevented by caspase inhibition. Hence, the activation of proapoptotic Bcl-2 family proteins rather than the downregulation of antiapoptotic Bcl-2 mediates the primary signal in the DNA damage-induced release of mitochondrial apoptogenic proteins in MEF.

Adenocarcinoma↗

PubMed2003

Pharmacologic activation of p53 elicits Bax-dependent apoptosis in the absence of transcription.

Recent efforts to develop pharmacologic agents that restore function to mutant forms of p53 hold significant promise in cancer therapy. Here, we examine the effects of such pharmacologic activation of p53 function using a small molecule, PRIMA-1, and a model system employing a p53 protein fused to a mutant steroid binding domain of the murine estrogen receptor (p53ERtam) that renders it responsive only in the presence of 4-hydroxytamoxifen. In either case, p53 activation triggered apoptosis that was not inhibited by the presence of macromolecular synthesis inhibitors. This p53-induced, transcription-independent apoptosis is Bax dependent, proceeds in the absence of a nucleus, and involves Bax translocation and cytochrome c release. Hence, pharmacologic p53 modulators can activate a transcription-independent apoptotic program.

Animals↗

PubMed2002

Coupling endoplasmic reticulum stress to the cell death program. An Apaf-1-independent intrinsic pathway.

Accumulation of misfolded proteins and alterations in Ca2+ homeostasis in the endoplasmic reticulum (ER) causes ER stress and leads to cell death. However, the signal-transducing events that connect ER stress to cell death pathways are incompletely understood. To discern the pathway by which ER stress-induced cell death proceeds, we performed studies on Apaf-1(-/-) (null) fibroblasts that are known to be relatively resistant to apoptotic insults that induce the intrinsic apoptotic pathway. While these cells were resistant to cell death initiated by proapoptotic stimuli such as tamoxifen, they were susceptible to apoptosis induced by thapsigargin and brefeldin-A, both of which induce ER stress. This pathway was inhibited by catalytic mutants of caspase-12 and caspase-9 and by a peptide inhibitor of caspase-9 but not by caspase-8 inhibitors. Cleavage of caspases and poly(ADP-ribose) polymerase was observed in cell-free extracts lacking cytochrome c that were isolated from thapsigargin or brefeldin-treated cells. To define the molecular requirements for this Apaf-1 and cytochrome c-independent apoptosis pathway further, we developed a cell-free system of ER stress-induced apoptosis; the addition of microsomes prepared from ER stress-induced cells to a normal cell extract lacking mitochondria or cytochrome c resulted in processing of caspases. Immunodepletion experiments suggested that caspase-12 was one of the microsomal components required to activate downstream caspases. Thus, ER stress-induced programmed cell death defines a novel, mitochondrial and Apaf-1-independent, intrinsic apoptotic pathway.

3T3 Cells↗

PubMed2002

Successful adenovirus-mediated wild-type p53 gene transfer in patients with bladder cancer by intravesical vector instillation.

PURPOSE: To study safety, feasibility, and biologic activity of adenovirus-mediated p53 gene transfer in patients with bladder cancer. PATIENTS AND METHODS: Twelve patients with histologically confirmed bladder cancer scheduled for cystectomy were treated on day 1 with a single intratumoral injection of SCH 58500 (rAd/p53) at cystoscopy at one dose level (7.5 x 10(11) particles) or a single intravesical instillation of SCH 58500 with a transduction-enhancing agent (Big CHAP) at three dose levels (7.5 x 10(11) to 7.5 x 10(13) particles). Cystectomies were performed in 11 patients on day 3, and transgene expression, vector distribution, and biologic markers of transgene activity were assessed by molecular and immunohistochemical methods in tumors and normal bladder samples. RESULTS: Specific transgene expression was detected in tissues from seven of eight assessable patients treated with intravesical instillation of SCH 58500 but in none of three assessable patients treated with intratumoral injection of SCH 58500. Induction of RNA and protein expression of the p53 target gene p21/WAF1 was demonstrated in samples from patients treated with SCH 58500 instillation at higher dose levels. Distribution studies after intravesical instillation of SCH 58500 revealed both high transduction efficacy and vector penetration throughout the whole urothelium and into submucosal tumor cells. No dose-limiting toxicity was observed, and side effects were local and of transient nature. CONCLUSION: Intravesical instillation of SCH 58500 combined with a transduction-enhancing agent is safe, feasible, and biologically active in patients with bladder cancer. Studies to evaluate the clinical efficacy of this treatment in patients with localized high-risk bladder cancer are warranted.

Adenoviridae↗

PubMed2001

Galectin-7 (PIG1) exhibits pro-apoptotic function through JNK activation and mitochondrial cytochrome c release.

Galectin-7 is normally expressed in all types of stratified epithelia, but is significantly down-regulated in squamous cell carcinomas. This protein was recently found to be highly inducible by p53 in a colon carcinoma cell line, DLD-1, and designated as PIG1 (for p53-induced gene 1). We studied transfectants of HeLa and DLD-1 cells ectopically expressing this protein and found that they were more susceptible to apoptosis than control transfectants. This was observed in apoptosis induced by mechanistically distinct stimuli, suggesting that galectin-7 acts on a common point in the apoptosis signaling pathways. Further analyses of actinomycin D-induced apoptosis demonstrated that galectin-7 expression causes enhanced caspase-3 activity and poly(ADP-ribose) polymerase cleavage, and the potentiation of apoptosis by galectin-7 was completely abrogated by a caspase inhibitor, benzyloxycarbonyl-Val-Ala-Asp-fluoromethyl ketone. In addition, galectin-7 transfectants displayed accelerated mitochondrial cytochrome c release and up-regulated JNK activity upon apoptosis induction. Several lines of evidence indicate that the effect on apoptosis is not due to the lectin functioning extracellularly through interactions with cell surface glycoconjugates. In fact, this lectin is found to localize in nuclei and cytoplasm of the transfectants and the transformed keratinocyte line HaCaT. Therefore, galectin-7 is a pro-apoptotic protein that functions intracellularly upstream of JNK activation and cytochrome c release. DNA microarray analysis revealed genes that are differentially expressed between galectin-7 and control transfectants. Some of them are potentially contributory to this lectin's proapoptotic function and these include redox-related genes monoamine oxidase B, ryanodine receptor 2, and glutathione S-transferase Mu 3.

Apoptosis↗