A head-to-head comparison of the first choice and crossover lead extraction tool: laser vs. mechanical

Funding Acknowledgements

Type of funding sources: None.

Background

During transvenous lead extraction (TLE) longer dwelling time often requires the use of powered sheaths.

Purpose

This study aimed to compare outcomes with the laser and mechanical tools.

Methods

Single-center data from consecutive patients undergoing TLE between 2012 and 2021 were retrospectively analyzed. Efficacy and safety of the primary extraction tool were compared. Procedures requiring crossover between powered sheaths were also analyzed. Moreover, we examined the efficacy of each level of the stepwise approach.

Results

Out of 166 patients 142 (age 65.4±13.7 years) underwent TLE requiring advanced techniques with 245 leads (dwelling time 9.4±6.3 years). Laser sheaths were used in 64.9%, mechanical sheaths in 35.1% of the procedures as primary extraction tools. Procedural success rate was 85.5% with laser and 82.5% with mechanical sheaths (p=0.552). Minor and major complications were observed in similar rate. Procedural mortality occurred only in the laser group in case of 3 patients. Crossover was needed in 19.5% after laser and in 12.8% after mechanical extractions (p=0.187). Among crossover procedures only clinical success favored the secondary mechanical arm (87.1% vs. 54.5%, aOR: 0.09, 95%CI: 0.01-0.79, p=0.030). After step-by-step efficacy analysis, procedural success was 64.9% with the first-line extraction tool, 75.1% after crossover, 84.5% with bailout femoral snare, and 91.8% by non-emergency surgery (Figure).

Conclusion

The efficacy and safety of laser and mechanical sheaths were similar in our study, however in the subgroup of crossover procedures mechanical tools had better performance regarding clinical success. Device diversity seems to be indispensable in order to achieve the most optimal outcomes.

Abstract 1863: Correlations of genetic variation R521K of EGF receptor and the in vitro, in vivo and clinical phenotypes of head and neck cancers after cetuximab treatment

Squamous cell carcinomas of the Head and Neck region (HNSCCs) have about 600.000 new cases every year. Advanced disease is treated by radio-chemotherapy, which has ambiguous success. Cetuximab, a monoclonal antibody against EGF receptor, is proven to be useful in combination therapy, thus it is in clinical use in HNSCC. However, a large number of patients show therapy resistance and do not benefit from combined therapy. EGF receptor is a widely used target in the therapy against cancer cells. Antibodies (as cetuximab) and inhibitors (TKI) are in use. However, genetic variations of the receptor are described to influence therapy efficacy. The extracellular missense polymorphism R521K of the receptor is reported to be abundant in HNSCC. However, its role in therapy outcome is yet to be cleared. In the present work, we mapped the possible effects of cetuximab therapy in wild type and mutant genotype HNSCCs. We selected two wild type (Pe/Ca-PJ41, Cal27) and two R521K (Pe/Ca-PJ15, FaDu) cell lines, performed in vitro proliferation tests and antibody binding assays, measured in vitro Antigen-Dependent Cellular Cytotoxicity (ADCC), and quantified receptor phosphorylation inhibition by cetuximb. In our in vivo xenograft experiments, we analyzed subcutaneous tumor growth by cetuximab, in combination with inhibition of NK cell and macrophage activity. Importantly, we analyzed clinical samples in the National Institute of Oncology, originated from 95 relapsed HNSCC patients treated with cetuximab to reveal any connections between EGFR R521K single nucleotide polymorphism and clinical outcome. In cell lines, cetuximab did not show significant cytotoxic effects, but was effective in the ADCC assay. Significantly, it enhanced the killing of cancer cells more effectively in wild type cell line models than on R521K harboring cells. Although antibody binding assay and EGF receptor phosphorylation was not different among the cell lines used, in vivo xenograft models showed strong antitumor effect of cetuximab in wild type models, and only moderate or no response in EGFR R521K models. Our clinical study, showed significantly lower progression-free survival among patients with R521K tumors. Overall survival of the two genotype groups showed only a trend of similar pattern, without statistically significant difference. Immune cell quantification showed no difference between the NK cell and macrophage infiltration in the two groups. Our data suggests the possible effect of EGFR 521 genotype on cetuximab therapy efficacy, but per se is insufficient to explain the dramatic difference between patient responses. Further data collection and analysis might be needed to reassure if R521K should play role in therapy selection for HNSCC, while clinical samples collected after cetuximab treatment would be exceptionally useful in order to track immune cell changes in patients with wild type and EGFR R521K tumors. This work was funded by the National Research, Development and Innovation Office grant K/116295 (2015). Financial support from the 2019 Thematic Excellence Program (TUDFO/51757/2019-ITM) is greatly acknowledged.

Citation Format: Mihaly T. Cserepes, Zita Hegedus, Ivan Ranđelović, Istvan Kenessey, Mónika Meilinger-Dobra, Kristóf G. Csikó, Andrea Ladanyi, Éva Remenár, Jozsef Tovari. Correlations of genetic variation R521K of EGF receptor and the in vitro, in vivo and clinical phenotypes of head and neck cancers after cetuximab treatment [abstract]. In: Proceedings of the Annual Meeting of the American Association for Cancer Research 2020; 2020 Apr 27-28 and Jun 22-24. Philadelphia (PA): AACR; Cancer Res 2020;80(16 Suppl):Abstract nr 1863.

Loss of Tribbles pseudokinase-3 promotes Akt-driven tumorigenesis via FOXO inactivation

Tribbles pseudokinase-3 (TRIB3) has been proposed to act as an inhibitor of AKT although the precise molecular basis of this activity and whether the loss of TRIB3 contributes to cancer initiation and progression remain to be clarified. In this study, by using a wide array of in vitro and in vivo approaches, including a Trib3 knockout mouse, we demonstrate that TRIB3 has a tumor-suppressing role. We also find that the mechanism by which TRIB3 loss enhances tumorigenesis relies on the dysregulation of the phosphorylation of AKT by the mTORC2 complex, which leads to an enhanced phosphorylation of AKT on Ser473 and the subsequent hyperphosphorylation and inactivation of the transcription factor FOXO3. These observations support the notion that loss of TRIB3 is associated with a more aggressive phenotype in various types of tumors by enhancing the activity of the mTORC2/AKT/FOXO axis.

Clinical significance of genetic alterations and expression of epidermal growth factor receptor (EGFR) in head and neck squamous cell carcinomas

The significance of epidermal growth factor receptor (EGFR) signaling is well studied in a number of different tumors, but limited data is available with regard to head and neck squamous cell carcinoma (HNSCC). Since anti-EGFR therapies are currently under investigation in these malignancies as well, comprehensive information about the alteration of EGFR in HNSCC is necessary to design the most appropriate therapeutic protocols. We examined retrospectively the gene copy number of EGFR by FISH and the protein expression by immunohistochemistry using different epitope-specific antibodies in paraffin-embedded primary tumors of five different regions, from 71 HNSCC patients who had not been treated with anti-EGFR therapy. In seven cases corresponding lymph node metastases were also available for comparative analyses. We also determined the mutational status of tyrosine kinase (TK) domain (exon 19 and 21) and the extracellular deletion mutation (vIII) of EGFR, the KRAS mutation at codon 12 and the presence of HPV infection. Eight of the 71 cases (11.3%) showed EGFR gene amplification (most of them localized into the hypopharyngeal region) and the increased gene copy number (amplification+polysomy) was 43.7%. Despite pronounced intratumoral heterogeneity of EGFR protein expression being found, the high EGFR expression correlated with poor prognosis. On the other hand, the phosphorylation of EGFR was associated with prolonged survival. No mutations in the TK domain of EGFR were found in any of the HNSCC patients and only two cases were KRAS mutant at codon 12. We detected vIII deletion mutation of EGFR in 21% of the samples, but there was no statistically significant correlation between the presence of vIII mutant form and patient survival. EGFR vIII mutation was, however, associated with increased gene copy number. Fourteen of 71 cases (19.7%) were HPV-positive and the incidence of infection showed a decreasing tendency from the oral cavity towards the larynx. Interestingly, in contrast to previous findings, we could not observe improved survival in HPV-positive patients compared to non-infected patients, most probably due to the fact that the majority of these HNSCC patients were smokers and alcohol consumers. In conclusion, we found that increased EGFR protein levels and gene copy numbers (not gene amplification alone) have prognostic significance in the investigated HNSCC patient population. However, the relatively high incidence of the EGFR-vIII mutant form warrants careful therapeutic decision-making when choosing between different anti-EGFR treatment options.

Tribbles: A family of kinase-like proteins with potent signalling regulatory function

The recent identification of tribbles as regulators of signal processing systems and physiological processes, including development, together with their potential involvement in diabetes and cancer, has generated considerable interest in these proteins. Tribbles have been reported to regulate activation of a number of intracellular signalling pathways with roles extending from mitosis and cell activation to apoptosis and modulation of gene expression. The current review summarises our current understanding of interactions between tribbles and various other proteins. Since our understanding on the molecular basis of tribbles function is far from complete, we also describe a bioinformatic analysis of various segments of tribbles proteins, which has revealed a number of highly conserved peptide motifs with potentially important functional roles.

Tribbles: novel regulators of cell function; evolutionary aspects

Identification of rate-limiting steps or components of intracellular second messenger systems holds promise to effectively interfere with these pathways under pathological conditions. The emerging literature on a recently identified family of signalling regulator proteins, called tribbles gives interesting clues for how these proteins seem to link several 'independent' signal processing systems together. Via their unique way of action, tribbles co-ordinate the activation and suppression of the various interacting signalling pathways and therefore appear to be key in determining cell fate while responding to environmental challenges. This review summarises our current understanding of tribbles function and also provides an evolutionary perspective on the various tribbles genes.

Role of calcium-activated potassium channels in the regulation of basal and agonist-elevated tones in isolated conduit arteries

Functional role of calcium-activated potassium (KCa) channels on the basal and agonist-elevated arterial tones was investigated in isolated rabbit aorta, porcine and canine coronary arteries as well as in human internal mammary artery. The vascular tones enhanced by contractile agents were increased further by preincubation of these conduit blood vessels with selective (charybdotoxin or iberiotoxin) or nonselective (tetraethylammonium) inhibitors of KCa channels. The basal tone (without an agonist) was increased only in the canine coronary artery. The results indicate a feed-back regulatory role of KCa channels counteracting the vasospasm of conduit arteries.

The Twisted gastrulation family of proteins, together with the IGFBP and CCN families, comprise the TIC superfamily of cysteine rich secreted factors

AIMS

To analyse the similarities between the Twisted gastrulation (TSG) proteins known to date; in addition, to determine phylogenetic relations among the TSG proteins, and between the TSGs and other protein families--the CCN (for example, CCN2 (CTGF), CCN1 (CYR61), and CCN3 (NOV)) and IGFBP (insulin-like growth factor binding protein) families.

METHODS

TBLASTN and FASTA3 were used to identify new tsg genes and relatives of the TSG family. The sequences were aligned with ClustalW. The predictions of sites for signal peptide cleavage, post-translational modifications, and putative protein domains were carried out with software available at various databases. Unrooted phylogenetic trees were calculated using the UPGMA method.

RESULTS

Several tsg genes from vertebrates and invertebrates were compared. Alignment of protein sequences revealed a highly conserved family of TSG proteins present in both vertebrates and invertebrates, whereas the slightly less well conserved IGFBP and CCN proteins are apparently present only in vertebrates. The TSG proteins display strong homology among themselves and they are composed of a putative signal peptide at the N-terminus followed by a cysteine rich (CR) region, a conserved domain devoid of cysteines, a variable midregion, and a C-terminal CR region. The most striking similarity between the TSGs and the IGFBP and CCN proteins occurs in the N-terminal conserved cysteine rich domain and the characteristic 5' cysteine rich domain(s), spacer region, and 3' cysteine rich domain structure.

CONCLUSION

The family of highly conserved TSG proteins, together with the IGFBP and CCN families, constitute an emerging multigene superfamily of secreted cysteine rich factors. The TSG branch of the superfamily appears to pre-date the others because it is present in all species examined, whereas the CCN and IGFBP genes are found only in vertebrates.

Low sideband guided-mode resonant filter

A guided-mode resonant filter with low sideband reflections is proposed. It is shown that, for serious reduction of out-of band reflectance, the combination of waveguide-grating filter design with conventional antireflective stack design methods is not adequate. To achieve symmetrical low sideband reflectances, independent control of various layer thicknesses is necessary. At a given illumination angle with appropriate control of the waveguide thickness, a specific resonant grating filter is designed whose out-of-band reflectance on both sides of the resonant peak is well below 10(-4). Even 50 nm away from the peak, on both sides, the out-of-band reflectance remains below 10(-3). Analysis of the variation in the main manufacturing parameters indicates that such filters can be reliably produced with present-day technologies.

Effect of phytohaemagglutinin on CD45 in T cells

In this study the effect of PHA activation on the phosphatase activity of CD45 has been investigated in human leukemic T-cell lines. It has been found that in vivo activation of the cells with PHA resulted in 2-4-fold increase in enzyme activity. Addition of PHA to the postnuclear supernatant of cell lysates also resulted in elevation of phosphatase activity. Elevation of enzyme activity resulted from an increase in the amount of antigen in the immunoprecipitates. Elevation of the quantity was not the result of a de novo protein synthesis since the presence of cycloheximide, a protein synthesis inhibitor, did not modulate the effect of PHA. The effect of PHA was specific since ConA, that also bound to the CD45 molecules, or crosslinking of the antigen by antibody did not affect CD45. Since direct binding of PHA to CD45 molecules was shown in immunoblotting analysis, we suggest that the effect of PHA is a consequence of a PHA-induced conformational change of CD45 that results in up-regulation of the analyzed CD45 epitopes.