LA-ICP-MS has often been applied for the analysis of trace elemental distributions in biological tissues. However, the strong matrix dependence of LA-ICP-MS analyses and highly variable matrix ...conditions aggravate reliable qualitative distribution analyses and thus for obtaining quantitative information elaborate quantification strategies have to be applied. In this work printed patterns on paper with thin gold layers as pseudo-internal standard have been proposed as an alternative approach to the commonly used matrix-matched tissue standards. Besides a major reduction of the workload for standard preparation the presented method allows for compensation of instrumental drifts during measurement as well as a reduction of matrix related effects. The developed method has been verified using matrix-matched tissue standards (deviations from the actual metal content less than 5% with relative standard deviations of less than 7%) and applied to platinum imaging on human malignant pleural mesothelioma samples after administration of individuals with platinum containing cytostatic drugs.
Printed patterns on paper are presented as an alternative quantification method to matrix-matched tissue standards in LA-ICP-MS imaging experiments.
Malignant pleural mesothelioma (MPM) is a rare, but aggressive tumor with dismal prognosis. Platinum-based chemotherapy is regularly used as part of multimodality therapy. The expression of ...metallothioneins (MT) has been identified as a reason for cisplatin resistance, which often leads to early therapy failure or relapse. Thus, knockdown of MT expression may improve response to cisplatin treatment. The MT gene- and protein expression of the MPM-cell lines MSTO-211H, NCI-H2052 and NCI-H2452 and the human fibroblast cell line MRC-5, as well as their sensitivity to cisplatin treatment have been evaluated. Knockdown of MT1A, 1B and 2A expression was induced by RNA interference. MT expression was measured using quantitative real-time PCR. An in vitro Assay based on enzyme activity was used to detect cell viability, necrosis and apoptosis before and after incubation with cisplatin. MT2A gene expression could be detected in all MPM cell lines, showing the highest expression in NCI-H2452 and NCI-H2052, whereas gene expression levels of MT1A and MT1B were low or absent. The immunohistochemically protein expression of MT-I/II reflect MT2A gene expression levels. Especially for MSTO-211H cell presenting low initial MT2A levels, a strong induction of MT2A expression could be observed during cisplatin treatment, indicating a cell line-specific and platin-dependent adaption mechanism. Additionally, a MT2A-dependent cellular evasion of apoptosis during cisplatin could be observed, leading to three different MT based phenotypes. MSTO-211H cells showed lower apoptosis rates at an increased expression level of MT2A after cisplatin treatment (from sixfold to fourfold). NCI-H2052 cells showed no changes in MT2A expression, while apoptosis rate is the highest (8-12-fold). NCI-H2452 cells showed neither changes in alteration rate of MT2A expression nor changes in apoptosis rates, indicating an MT2A-independent resistance mechanism. Knockdown of MT2A expression levels resulted in significantly induced apoptotic rates during cisplatin treatment with strongest induction of apoptosis in each of the MPM cell lines, but in different markedness. A therapeutic meaningful effect of MT2A knockdown and subsequent cisplatin treatment could be observed in MSTO-211H cells. The present study showed MT2A to be part of the underlying mechanism of cisplatin resistance in MPM. Especially in MSTO-211H cells we could demonstrate major effects by knockdown of MT2A expression, verifying our hypothesis of an MT driven resistance mechanism. We could prove the inhibition of MT2A as a powerful tool to boost response rates to cisplatin-based therapy in vitro. These data carry the potential to enhance the clinical outcome and management of MPM in the future.
Background Interleukin-15 has become a promising molecule in the context of eliciting an effective, antitumor immune response because it is able to stimulate cells of the innate and adaptive immune ...system. Methods We generated an interleukin-15-expressing oncolytic influenza A virus for the treatment of an established murine tumor model. Results Our oncolytic influenza A virus produced large amounts of interleukin-15 and induced proliferation and activation of human T cells in vitro. Intraperitoneal administration increased the amount of mouse natural killer cells and effector memory T cells, as well as T cell reactivity in vivo. Moreover, intratumoral injection induced a profound decrease in growth of established tumors in mice and increased the amount of tumor-infiltrating T cells and natural killer cells. Conclusion We established a stable, IL-15-producing oncolytic influenza A virus with promising immunostimulatory and antitumor attributes.
Although classic sensitizing mutations of epidermal growth factor receptor (EGFR) are positive predictive markers for EGFR tyrosine kinase inhibitors (TKIs) in lung adenocarcinoma, there are rare ...EGFR mutations with unknown epidemiology and influence on prognosis and TKI response.
Eight hundred and fourteen lung adenocarcinoma patients with KRAS and/or EGFR mutation analyses for TKI therapy indication were identified. Six hundred and forty-five patients were included in the epidemiological analysis. The clinical outcome was analyzed in 419 advanced-stage patients with follow-up data.
Four hundred and eighty (59%) KRAS/EGFR double wild-type, 216 (27%) KRAS mutant, 42 (5%) classic, 49 (6%) rare, and 27 (3%) synonymous EGFR mutant cases were identified. Twenty previously unpublished non-synonymous mutations were found. Rare EGFR mutations were significantly associated with smoking (vs. classic EGFR mutations; p = 0.0062). Classic EGFR mutations but not rare ones were independent predictors of increased overall survival (hazard ratios, 0.45; 95% confidence intervals, 0.25–0.82; p = 0.009). TKI therapy response rate of patients harboring classic EGFR mutations was significantly higher (vs. rare EGFR mutations; 71% vs. 37%; p = 0.039). Patients with classic or sensitizing rare (G719x and L861Q) EGFR mutations had significantly longer progression-free survival when compared with the remaining rare mutation cases (12 vs. 6.2 months; p = 0.048).
The majority of rare EGFR mutations was associated with smoking, shorter overall survival, and decreased TKI response when compared with classic EGFR mutations. However, studies characterizing the TKI sensitizing effect of individual rare mutations are indispensable to prevent the exclusion of patients with sensitizing rare EGFR mutations who may benefit from anti-EGFR therapy.
Oncogenic mutations of BRAF lead to constitutive ERK activity that supports melanoma cell growth and survival. While Ca2+ signaling is a well‐known regulator of tumor progression, the crosstalk ...between Ca2+ signaling and the Ras‐BRAF‐MEK‐ERK pathway is much less explored. Here we show that in BRAF mutant melanoma cells the abundance of the plasma membrane Ca2+ ATPase isoform 4b (PMCA4b, ATP2B4) is low at baseline but markedly elevated by treatment with the mutant BRAF specific inhibitor vemurafenib. In line with these findings gene expression microarray data also shows decreased PMCA4b expression in cutaneous melanoma when compared to benign nevi. The MEK inhibitor selumetinib—similarly to that of the BRAF‐specific inhibitor—also increases PMCA4b levels in both BRAF and NRAS mutant melanoma cells suggesting that the MAPK pathway is involved in the regulation of PMCA4b expression. The increased abundance of PMCA4b in the plasma membrane enhances Ca2+i clearance from cells after Ca2+ entry. Moreover we show that both vemurafenib treatment and PMCA4b overexpression induce marked inhibition of migration of BRAF mutant melanoma cells. Importantly, reduced migration of PMCA4b expressing BRAF mutant cells is associated with a marked decrease in their metastatic potential in vivo. Taken together, our data reveal an important crosstalk between Ca2+ signaling and the MAPK pathway through the regulation of PMCA4b expression and suggest that PMCA4b is a previously unrecognized metastasis suppressor.
What's new?
New results may give researcher another way to attack metastatic melanoma. Commonly, melanomas have a mutated copy of BRAF, and current therapies focus on these mutants. In search of new target molecules, these authors looked at the calcium ion signaling system, which promotes cell migration and invasion. They found that BRAF‐mutant melanoma cells have less of the plasma membrane calcium ion pump molecule PMCA‐4b. Treatment with mutant BRAF inhibitor boosts PMCA‐4b and slows the migration of cancer cells. Furthermore, PMCA‐4b overexpression reduced metastatic potential of cells in vivo. This study is the first to show that PMCA‐4b could hinder metastasis.
Inhibition of mutant KRAS challenged cancer research for decades. Recently, allele-specific inhibitors were approved for the treatment of KRAS-G12C mutant lung cancer. However, de novo and acquired ...resistance limit their efficacy and several combinations are in clinical development. Our study shows the potential of combining G12C inhibitors with farnesyl-transferase inhibitors.
Combinations of clinically approved farnesyl-transferase inhibitors and KRAS G12C inhibitors are tested on human lung, colorectal and pancreatic adenocarcinoma cells in vitro in 2D, 3D and subcutaneous xenograft models of lung adenocarcinoma. Treatment effects on migration, proliferation, apoptosis, farnesylation and RAS signaling were measured by histopathological analyses, videomicroscopy, cell cycle analyses, immunoblot, immunofluorescence and RAS pulldown.
Combination of tipifarnib with sotorasib shows synergistic inhibitory effects on lung adenocarcinoma cells in vitro in 2D and 3D. Mechanistically, we present antiproliferative effect of the combination and interference with compensatory HRAS activation and RHEB and lamin farnesylation. Enhanced efficacy of sotorasib in combination with tipifarnib is recapitulated in the subcutaneous xenograft model of lung adenocarcinoma. Finally, combination of additional KRAS G1C and farnesyl-transferase inhibitors also shows synergism in lung, colorectal and pancreatic adenocarcinoma cellular models.
Our findings warrant the clinical exploration of KRAS-G12C inhibitors in combination with farnesyl-transferase inhibitors.
The RAS/RAF and PI3K/Akt pathways play a key regulatory role in cancer and are often hit by oncogenic mutations. Despite molecular targeting, the long-term success of monotherapy is often hampered by ...de novo or acquired resistance. In the case of concurrent mutations in both pathways, horizontal combination could be a reasonable approach. In our study, we investigated the MEK inhibitor selumetinib and PI3K/mTOR dual inhibitor BEZ235 alone and in combination in BRAF-only mutant and BRAF + PI3K/PTEN double mutant cancer cells using short- and long-term 2D viability assays, spheroid assays, and immunoblots. In the 2D assays, selumetinib was more effective on BRAF-only mutant lines when compared to BRAF + PI3K/PTEN double mutants. Furthermore, combination therapy had an additive effect in most of the lines while synergism was observed in two of the double mutants. Importantly, in the SW1417 BRAF + PI3K double mutant cells, synergism was also confirmed in the spheroid and in the in vivo model. Mechanistically, p-Akt level decreased only in the SW1417 cell line after combination treatment. In conclusion, the presence of concurrent mutations alone did not predict a stronger response to combination treatment. Therefore, additional investigations are warranted to identify predictive factors that can select patients who can benefit from the horizontal combinational inhibition of these two pathways.
Acquired resistance during BRAF inhibitor therapy remains a major challenge for melanoma treatment. Accordingly, we evaluated the phenotypical and molecular changes of isogeneic human V600E ...BRAF-mutant melanoma cell line pairs pre- and post-treatment with vemurafenib. Three treatment naïve lines were subjected to in vitro long-term vemurafenib treatment while three pairs were pre- and post-treatment patient-derived lines. Molecular and phenotypical changes were assessed by Sulforhodamine-B (SRB) assay, quantitative RT-PCR (q-RT-PCR), immunoblot, and time-lapse microscopy. We found that five out of six post-treatment cells had higher migration activity than pretreatment cells. However, no unequivocal correlation between increased migration and classic epithelial-mesenchymal transition (EMT) markers could be identified. In fast migrating cells, the microphthalmia-associated transcription factor (MITF) and epidermal growth factor receptor (EGFR) mRNA levels were considerably lower and significantly higher, respectively. Interestingly, high EGFR expression was associated with elevated migration but not with proliferation. Cells with high EGFR expression showed significantly decreased sensitivity to vemurafenib treatment, and had higher Erk activation and FRA-1 expression. Importantly, melanoma cells with higher EGFR expression were more resistant to the EGFR inhibitor erlotinib treatment than cells with lower expression, with respect to both proliferation and migration inhibition. Finally, EGFR-high melanoma cells were characterized by higher PD-L1 expression, which might in turn indicate that immunotherapy may be an effective approach in these cases.
Non-small cell lung cancer (NSCLC)11NSCLC: Non-small cell lung cancer; 18FDG: 18fluorine fluorodeoxyglucose; PET: positron emission tomography; CT: computed tomography; SUV: standardized uptake ...value; TAM: tumor-associated macrophage; CCL18: CC-chemokine ligand 18; SUVmax: maximum standardized uptake value; SQC: squamous carcinoma; AC: adenocarcinoma; FEV1: forced expiratory volume in 1 s; is one of the most common malignancies in the western world 1. Despite multiple therapeutic and diagnostic advances, the overall survival is low and recurrence of NSCLC is a common problem with different treatment regimens. The inclusion of 18fluorine fluorodeoxyglucose (18FDG) positron emission tomography (PET) in combination with computed tomography (CT) in clinical practice was revolutionary for the staging of NSCLC 2. 18FDG-PET/CT provides morphological, functional, and metabolic information about the tumor, which is usually highly, metabolically active. Due to the increased glucose uptake, 18FDG is actively accumulatedin the tumor tissues, resulting in an increased standardized uptake value (SUV). The tumor tissue itself consists of neoplastic cells, extracellular matrix, fibroblasts, and various immune cells. These immune cells include tumor-infiltrating lymphocytes, regulatory T cells, and macrophages. Macrophages have different activation patterns and play an essential role in inflammation and cancer. In particular, tumor-associated macrophages (TAMs) are a specialized group of alternatively activated or M2 macrophages. TAMs release several chemokines that are different from those released by classically activated macrophages found in an inflammatory environment. One of the most important chemokines released by TAMs is CC-chemokine ligand 18 (CCL18). Although CCL18 is present in healthy subjects, its levels are significantly elevated in the serum of patients with NSCLC. It correlates with overall survival and tumor stage in several malignant diseases 3,4. A recurring problem is that increased glucose metabolism can be found in the inflammatory tissue, which can also lead to an increased SUV in 18FDG PET/CT, lowering its oncological specificity 5. In a previous study, we demonstrated that serum CCL18 levels can be used to differentiate between patients with NSCLC and healthy subjects 3. Hence, we investigated the correlation between serum CCL18 levels and the maximum standardized uptake value (SUVmax) of the primary tumor using 18FDG-PET/CT. We found a significant correlation between the SUVmax of the primary tumor and the serum CCL18 level. The data are important because they can be used to draw conclusions about immunometabolism. Furthermore, they can serve as basis for future prospective clinical studies.
Spitzoid melanoma is a rare malignancy with histological characteristics similar to Spitz nevus. It has a diverse genetic background and in adults, a similarly grim clinical outcome as conventional ...malignant melanoma. We established a spitzoid melanoma cell line (PF130) from the pleural effusion sample of a 37-year-old male patient. We found that the cell line carries a rare MEK1 mutation (pGlu102_Lys104delinsGln) that belongs to the RAF- and phosphorylation-independent subgroup of MEK1 alternations supposedly insensitive to allosteric MEK inhibitors. The in vivo tumorigenicity was tested in three different models by injecting the cells subcutaneously, intravenously or into the thoracic cavity of SCID mice. In the intrapleural model, macroscopic tumors formed in the chest cavity after two months, while subcutaneously and intravenously delivered cells showed limited growth. In vitro, trametinib-but not selumentinib-and the ATP-competitive MEK inhibitor MAP855 strongly decreased the viability of the cells and induced cell death. In vivo, trametinib but not MAP855 significantly reduced tumor growth in the intrapleural model. To the best of our knowledge, this is the first patient-derived melanoma model with RAF- and phosphorylation-independent MEK mutation and we demonstrated its sensitivity to trametinib.
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