P53-Mediated Radiosensitization of 177Lu-DOTATATE in Neuroblastoma Tumor Spheroids.
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SUBMITTER: Lundsten S
PROVIDER: S-EPMC8615514 | biostudies-literature |
REPOSITORIES: biostudies-literature
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Project description:177Lu‑DOTATATE was recently approved for the treatment of somatostatin receptor (SSTR)‑positive neuroendocrine tumors (NETs). However, despite impressive response rates, complete responses are rare. Heat shock protein 90 (HSP90) inhibitors have been suggested as suitable therapeutic agents for NETs, as well as a potential radiosensitizers. Consequently, the aim of this study was to investigate whether the HSP90‑inhibitor onalespib could reduce NET cell growth and act as a radiosensitizer when used in combination with 177Lu‑DOTATATE. The NET cell lines BON, NCI‑H727 and NCI‑H460, were first characterized with regards to 177Lu‑DOTATATE uptake and sensitivity to onalespib treatment in monolayer cell assays. The growth inhibitory effects of the monotherapies and combination treatments were then examined in three‑dimensional multicellular tumor spheroids. Lastly, the molecular effects of the treatments were assessed. 177Lu‑DOTATATE uptake was observed in the BON and NCI‑H727 cells, while the NCI‑H460 cells exhibited no detectable uptake. Accordingly, 177Lu‑DOTATATE reduced the growth of BON and NCI‑H727 spheroids, while no effect was observed in the NCI‑H460 spheroids. Onalespib reduced cell viability and spheroid growth in all three cell lines. Furthermore, the combination of onalespib and 177Lu‑DOTATATE exerted synergistic therapeutic effects on the BON and NCI‑H727 spheroids. Western blot analysis of BON spheroids revealed the downregulation of epidermal growth factor receptor (EGFR) and the upregulation of γ H2A histone family member X (γH2AX) following combined treatment with onalespib and 177Lu‑DOTATATE. Moreover, flow cytometric analyses revealed a two‑fold increase in caspase 3/7 activity in the combination group. In conclusion, the findings of this study demonstrate that onalespib exerts antitumorigenic effects on NET cells and may thus be a feasible treatment option for NETs. Furthermore, onalespib was able to synergistically potentiate 177Lu‑DOTATATE treatment in a SSTR‑specific manner. The radiosensitizing mechanisms of onalespib involved the downregulation of EGFR expression and the induction of apoptosis. Consequently, the combination of onalespib and 177Lu‑DOTATATE may prove to be a promising strategy with which to improve therapeutic responses in patients with NETs. Further studies investigating this strategy in vivo regarding the therapeutic effects and potential toxicities are warranted to expand these promising findings.
| S-EPMC6831206 | biostudies-literature
Project description:PurposeMolecular radiotherapy is a treatment modality that is highly suitable for targeting micrometastases and [177Lu]Lu-DOTATATE is currently being explored as a potential novel treatment option for high-risk neuroblastoma. p53 is a key player in the proapoptotic signalling in response to radiation-induced DNA damage and is therefore a potential target for radiosensitisation.MethodsThis study investigated the use of the p53 stabilising peptide VIP116 and [177Lu]Lu-DOTATATE, either alone or in combination, for treatment of neuroblastoma tumour xenografts in mice. Initially, the uptake of [177Lu]Lu-DOTATATE in the tumours was confirmed, and the efficacy of VIP116 as a monotherapy was evaluated. Subsequently, mice with neuroblastoma tumour xenografts were treated with placebo, VIP116, [177Lu]Lu-DOTATATE or a combination of both agents.ResultsThe results demonstrated that monotherapy with either VIP116 or [177Lu]Lu-DOTATATE significantly prolonged median survival compared to the placebo group (90 and 96.5 days vs. 50.5 days, respectively). Notably, the combination treatment further improved median survival to over 120 days. Furthermore, the combination group exhibited the highest percentage of complete remission, corresponding to a twofold increase compared to the placebo group. Importantly, none of the treatments induced significant nephrotoxicity. Additionally, the therapies affected various molecular targets involved in critical processes such as apoptosis, hypoxia and angiogenesis.ConclusionIn conclusion, the combination of VIP116 and [177Lu]Lu-DOTATATE presents a promising novel treatment approach for neuroblastoma. These findings hold potential to advance research efforts towards a potential cure for this vulnerable patient population.
| S-EPMC10796565 | biostudies-literature
Project description:Introduction: 177Lutetium-[DOTA°,Tyr3]octreotate (177Lu-DOTATATE) is a type of peptide receptor radionuclide therapy that garnered FDA approval in January 2018 for the treatment of somatostatin receptor-positive gastroenteropancreatic (GEP) neuroendocrine tumor (NET) patients. The therapy approval was based on findings from the randomized international phase III NETTER-1 trial as well as outcome data from a large European registry. The mechanism of the drug stems directly from its structure: a somatostatin analog (octreotate) selectively binding to somatostatin receptor expressing cells and being internalized, along with a chelated beta-emitting isotope 177Lu.Areas Covered: Herein we describe the pharmacology, clinical efficacy and adverse event data from prospective and retrospective studies with 177Lu-DOTATATE. We discuss the role of 177Lu-DOTATATE within the current treatment landscape for GEP NET patients.Expert Opinion: 177Lu-DOTATATE represents a unique addition to the treatment armamentarium for GEP NETs because of its potential to elicit tumor cytoreduction, which is rare among other existing treatment options, and prolonged disease control. Where 177Lu-DOTATATE fits into the treatment sequence for GEP NET patients remains an area of active investigation.
| S-EPMC7227421 | biostudies-literature
Project description:BACKGROUND:The role of concomitant peptide receptor radionuclide therapy (PRRT) and capecitabine therapy has shown benefit in gastroenteropancreatic neuroendocrine tumors. However, data reporting its role in paraganglioma (PGL) patients is lacking. The aim of this study was to evaluate the role of combined capecitabine and 177Lu-DOTATATE in malignant PGL patients. METHODS:In this retrospective, single-institutional, single-arm, observational study, data of consecutive advanced stage PGL patients treated with concomitant 177Lu-DOTATATE-capecitabine therapy, between July 2009 and March 2017, were collected and analyzed. RESULTS:Twenty-five PGL patients received an average dose of 22.86 ± 9.54 (14.43-50) GBq 177Lu-DOTATATE and 1250 mg/m2 capecitabine from days 0 to 14, commencing on the morning of PRRT. The median overall survival (OS) was not attained in this patient cohort; however, the median PFS was 32 months. Morphological response according to RECIST 1.1 criteria was achieved in 28% (7/25) patients. Biochemical response with > 50% reduction in chromogranin A levels was observed in 28% of the patients. CONCLUSIONS:Our data confirm that 177Lu-DOTATATE-capecitabine therapy is effective in achieving an objective response in 28% and symptomatic response in 43% patients. In comparison to published PRRT monotherapy outcomes in PGL, we did not observe any great advantage of concomitant therapy; however, it could be due to under-powered study. We recommend a large randomized trial to prove or disprove the utility of capecitabine as a radiosensitizer for PRRT in PGL patients.
| S-EPMC6365580 | biostudies-literature
Project description:BACKGROUND:Patients with advanced midgut neuroendocrine tumors who have had disease progression during first-line somatostatin analogue therapy have limited therapeutic options. This randomized, controlled trial evaluated the efficacy and safety of lutetium-177 (177Lu)-Dotatate in patients with advanced, progressive, somatostatin-receptor-positive midgut neuroendocrine tumors. METHODS:We randomly assigned 229 patients who had well-differentiated, metastatic midgut neuroendocrine tumors to receive either 177Lu-Dotatate (116 patients) at a dose of 7.4 GBq every 8 weeks (four intravenous infusions, plus best supportive care including octreotide long-acting repeatable [LAR] administered intramuscularly at a dose of 30 mg) (177Lu-Dotatate group) or octreotide LAR alone (113 patients) administered intramuscularly at a dose of 60 mg every 4 weeks (control group). The primary end point was progression-free survival. Secondary end points included the objective response rate, overall survival, safety, and the side-effect profile. The final analysis of overall survival will be conducted in the future as specified in the protocol; a prespecified interim analysis of overall survival was conducted and is reported here. RESULTS:At the data-cutoff date for the primary analysis, the estimated rate of progression-free survival at month 20 was 65.2% (95% confidence interval [CI], 50.0 to 76.8) in the 177Lu-Dotatate group and 10.8% (95% CI, 3.5 to 23.0) in the control group. The response rate was 18% in the 177Lu-Dotatate group versus 3% in the control group (P<0.001). In the planned interim analysis of overall survival, 14 deaths occurred in the 177Lu-Dotatate group and 26 in the control group (P=0.004). Grade 3 or 4 neutropenia, thrombocytopenia, and lymphopenia occurred in 1%, 2%, and 9%, respectively, of patients in the 177Lu-Dotatate group as compared with no patients in the control group, with no evidence of renal toxic effects during the observed time frame. CONCLUSIONS:Treatment with 177Lu-Dotatate resulted in markedly longer progression-free survival and a significantly higher response rate than high-dose octreotide LAR among patients with advanced midgut neuroendocrine tumors. Preliminary evidence of an overall survival benefit was seen in an interim analysis; confirmation will be required in the planned final analysis. Clinically significant myelosuppression occurred in less than 10% of patients in the 177Lu-Dotatate group. (Funded by Advanced Accelerator Applications; NETTER-1 ClinicalTrials.gov number, NCT01578239 ; EudraCT number 2011-005049-11 .).
| S-EPMC5895095 | biostudies-literature
Project description:Pancreatic neuroendocrine tumors (PNET) express high levels of somatostatin receptor type 2 (SSTR2), a unique target for both tumor imaging and therapy. This surface expression is lost in metastatic high-grade PNETs, making patients ineligible for SSTR2-targeted 177 Lutetium (Lu)-DOTATATE peptide receptor radionuclide therapy (PRRT), and represents an unmet clinical need. Here, we aimed to restore SSTR2 expression through the reversal of inhibitory epigenetic gene silencing to improve tumor responsiveness to PRRT. We first assessed human SSTR2 promoter methylation and expression levels in 96 patient samples. We then used three NET cell lines (QGP-1, BON-1, GOT-1) with variable SSTR2 expression profiles for functional in vitro studies using histone deacetylase inhibitors (HDACi). Finally, the QGP-1 xenograft mouse model, with low basal SSTR2 expression, was used to assess the therapeutic efficacy of combined HDACi and 177Lu-DOTATATE therapies. We confirm that SSTR expression is decreased and correlates with SSTR2 promoter methylation in patients with high-grade NETs. When exposed to HDACis, SSTR2 surface expression is increased in three NET cell lines in vitro. In an in vivo PNET xenograft model with low basal SSTR2 expression, our studies demonstrate significantly higher tumor uptake of SSTR2-targeted 177Lu-DOTATATE in animals pretreated with HDACis compared with controls. For the first time, we show that this higher tumor uptake results in significant antitumor response when compared with standard PRRT alone. These preclinical results provide a rationale for utilizing HDACi pretreatment to improve targeted radionuclide therapy in patients with SSTR2-negative, metastatic PNETs.
| S-EPMC10477832 | biostudies-literature
Project description:Targeted radiotherapy of metastatic neuroblastoma using the somatostatin receptor (SSTR)-targeted octreotide analogue DOTATATE radiolabelled with lutetium-177 (177Lu-DOTATATE) is a promising strategy. This study evaluates whether its effectiveness may be enhanced by combination with radiosensitising drugs. The growth rate of multicellular tumour spheroids, derived from the neuroblastoma cell lines SK-N-BE(2c), CHLA-15 and CHLA-20, was evaluated following treatment with 177Lu-DOTATATE, nutlin-3 and topotecan alone or in combination. Immunoblotting, immunostaining and flow cytometric analyses were used to determine activation of p53 signalling and cell death. Exposure to 177Lu-DOTATATE resulted in a significant growth delay in CHLA-15 and CHLA-20 spheroids, but not in SK-N-BE(2c) spheroids. Nutlin-3 enhanced the spheroid growth delay induced by topotecan in CHLA-15 and CHLA-20 spheroids, but not in SK-N-BE(2c) spheroids. Importantly, the combination of nutlin-3 with topotecan enhanced the spheroid growth delay induced by X-irradiation or by exposure to 177Lu-DOTATATE. The efficacy of the combination treatments was p53-dependent. These results indicate that targeted radiotherapy of high risk neuroblastoma with 177Lu-DOTATATE may be improved by combination with the radiosensitising drugs nutlin-3 and topotecan.
| S-EPMC6044389 | biostudies-literature
Project description:IntroductionThe pituitary gland has a high expression of somatostatin receptors and is therefore a potential organ at risk for radiation-induced toxicity after 177Lu-DOTATATE treatment.ObjectiveTo study changes in pituitary function in patients with neuroendocrine tumors (NETs) treated with dosimetry-based 177Lu-DOTATATE to detect possible late toxicity.Methods68 patients from a phase II clinical trial of dosimetry-based, individualized 177Lu-DOTATATE therapy were included in this analysis. Patients had received a median of 5 (range 3-9) treatment cycles of 7.4 GBq/cycle. Median follow-up was 30 months (range 11-89). The GH/IGF-1 axis, gonadotropins, and adrenal and thyroid axes were analyzed at baseline and on a yearly basis thereafter. Percent changes in hormonal levels over time were analyzed statistically using a linear mixed model and described graphically using box plots. The absorbed radiation dose to the pituitary was estimated based on post-therapeutic imaging, and the results analyzed versus percent change in IGF-1 levels over time.ResultsA statistically significant decrease in IGF-1 levels was found (p < 0.005), which correlated with the number of treatment cycles (p = 0.008) and the absorbed radiation dose (p = 0.03). A similar decrease, although non-significant, was seen in gonadotropins in postmenopausal women, while in men there was an increase during the first years after therapy, after which the levels returned to baseline. No change was observed in the adrenal or thyroid axes.ConclusionsNo signs of severe endocrine disorders were detected, although a significant decrease in the GH/IGF-1 axis was found, where dosimetric analyses indicated radiation-induced damage to the pituitary gland as a probable cause.
| S-EPMC8117394 | biostudies-literature
Project description:BackgroundResection of non-functioning pancreatic neuroendocrine tumours (NF-PanNETs) is curative in most patients. The potential benefits of neoadjuvant treatments have, however, never been explored. The primary aim of this study was to evaluate the safety of neoadjuvant 177Lu-labelled DOTA0-octreotate (177Lu-DOTATATE) followed by surgery in patients with NF-PanNETs.MethodsNEOLUPANET was a multicentre, single-arm, phase II trial of patients with sporadic, resectable or potentially resectable NF-PanNETs at high-risk of recurrence; those with positive 68Ga-labelled DOTA PET were eligible. All patients were candidates for neoadjuvant 177Lu-DOTATATE followed by surgery. A sample size of 30 patients was calculated to test postoperative complication rates against predefined cut-offs. The primary endpoint was safety, reflected by postoperative morbidity and mortality within 90 days. Secondary endpoints included rate of objective radiological response and quality of life.ResultsFrom March 2020 to February 2023, 31 patients were enrolled, of whom 26 completed 4 cycles of 177Lu-DOTATATE. A partial radiological response was observed in 18 of 31 patients, and 13 patients had stable disease. Disease progression was not observed. Twenty-four R0 resections and 4 R1 resections were performed in 29 patients who underwent surgery. One tumour was unresectable owing to vascular involvement. There was no postoperative death. Postoperative complications occurred in 21 of 29 patients. Severe complications were observed in seven patients. Quality of life remained stable after 177Lu-DOTATATE and decreased after surgery.ConclusionNeoadjuvant treatment with 177Lu-DOTATATE is safe and effective for patients with NF-PanNETs.
| S-EPMC11364141 | biostudies-literature
Project description:177Lu-DOTATATE for neuroendocrine tumours is considered a low-toxicity treatment and may therefore be combined with other pharmaceuticals to potentiate its efficacy. One approach is to add a poly-[ADP-ribose]-polymerase (PARP) inhibitor to decrease the ability of tumour cells to repair 177Lu-induced DNA damage. To decrease the risk of side effects, the sequencing should be optimized according to the tumour-to-normal tissue enhanced dose ratio (TNED). The aim of this study was to investigate how to enhance 177Lu-DOTATATE by optimal timing of the addition of a PARP inhibitor. Biokinetic modelling was performed based on the absorbed dose to the bone marrow, kidneys and tumour; determined from SPECT/CT and planar images from 17 patients treated with 177Lu-DOTATATE. To investigate the theoretical enhanced biological effect of a PARP inhibitor during 177Lu-DOTATATE treatment, the concept of relative biological effectiveness (RBE) was used, and PARP inhibitor administration was simulated over different time intervals. The absorbed dose rate for the tumour tissue demonstrated an initial increase phase until 12 h after infusion followed by a slow decrease. In contrast, the bone marrow showed a rapid initial dose rate decrease. Twenty-eight days after infusion of 177Lu-DOTATATE, the full absorbed dose to the bone marrow and kidney was reached. Using an RBE value of 2 for both the tumour and normal tissues, the TNED was increased compared to 177Lu-DOTATATE alone. According to the modelling, the PARP inhibitor should be introduced approximately 24 h after the start of 177Lu-DOTATATE treatment and be continued for up to four weeks to optimize the TNED. Based on these results, a phase I trial assessing the combination of olaparib and 177Lu-DOTATATE in somatostatin receptor-positive tumours was launched in 2020 (NCT04375267).
| S-EPMC8615768 | biostudies-literature