Dissecting signaling regulators driving AXL-mediated bypass resistance and associated phenotypes by phosphosite perturbations.

Receptor tyrosine kinase (RTK)-targeted therapies are often effective but invariably limited by drug resistance. A major mechanism of acquired resistance involves "bypass" switching to alternative pathways driven by non-targeted RTKs that restore proliferation. One such RTK is AXL whose overexpression, frequently observed in bypass resistant tumors, drives both cell survival and associated malignant phenotypes such as epithelial-to-mesenchymal (EMT) transition and migration. However, the signaling molecules and pathways eliciting these responses have remained elusive. To explore these coordinated effects, we generated a panel of mutant lung adenocarcinoma PC9 cell lines in which each AXL intracellular tyrosine residue was mutated to phenylalanine. By integrating measurements of phosphorylation signaling and other phenotypic changes associated with resistance through multivariate modeling, we mapped signaling perturbations to specific resistant phenotypes. Our results suggest that AXL signaling can be summarized into two clusters associated with progressive disease and poor clinical outcomes in lung cancer patients. These clusters displayed favorable Abl1 and SFK motifs and their phosphorylation was consistently decreased by dasatinib. High-throughput kinase specificity profiling showed that AXL likely activates the SFK cluster through FAK1 which is known to complex with Src. Moreover, the SFK cluster overlapped with a previously established focal adhesion kinase (FAK1) signature conferring EMT-mediated erlotinib resistance in lung cancer cells. Finally, we show that downstream of this kinase signaling, AXL and YAP form a positive feedback loop that sustains drug tolerant persister cells. Altogether, this work demonstrates an approach for dissecting signaling regulators by which AXL drives erlotinib resistance-associated phenotypic changes.

Role of surgery to the primary tumor in metastatic anaplastic thyroid carcinoma: pooled analysis and SEER-based study.

PURPOSE: Anaplastic thyroid carcinoma (ATC) is an orphan disease with a fatal outcome. Surgery to the primary tumor in metastatic ATC is controversial. Determination of specific surgical techniques may help facilitate local control and, hence, beneficial overall and disease-specific survival. METHODS: Using individualized patient data derived from our systematic review of literature and our single center study (n = 123), conducting a Surveillance, Epidemiology, and End Results register (SEER)-based study (n = 617) we evaluated surgery, its combination with systemic and local therapies in metastatic ATC. RESULTS: Pooled cohort study showed surgery (p < 0.001), RT ≥ 30 Gy (p < 0.001), ChT (p < 0.001) and multimodal treatment (p = 0.014) to result in improved OS univariately. In the multivariate analysis, surgery (1.997 [1.162-3.433], p = 0.012) and RT ≥ 30 Gy (1.877 [1.232-2.843], p = 0.012) were independent predictors for OS. In SEER-based study of patients undergoing any tumor-directed treatment (n = 445) total thyroidectomy (p = 0.031), administration of ChT (p = 0.007), RT (p < 0.001), combination of surgery and RT ± ChT (p < 0.001) and multimodal treatment (p < 0.001) correlated with an improved DSS univariately. On the multivariate analysis, debulking surgery was an independent predictor for a worse outcome (HR 0.535, 95%CI 0.332-0.862, p = 0.010), whereas RT administration correlated with a longer DSS (HR 2.316, 95%CI 1.362-3.939, p = 0.002). Among operated patients from SEER register total thyroidectomy (p = 0.031), ChT (p = 0.007), RT (p < 0.001), combination of surgery and RT ± ChT (p < 0.001) and multimodal treatment (p < 0.001) correlated with an improved DSS in the univariate analysis, whereas debulking surgery was inversely correlated with the DSS (p < 0.001). On the multivariate analysis, debulking surgery was an independent predictor for a worse DSS (HR 0.535, 95%CI 0.332-0.862, p = 0.010), whilst RT administration correlated with a longer DSS (HR 2.316, 95%CI 1.362-3.939, p = 0.002). CONCLUSIONS: Surgery to the primary tumor with the aim of R0/R1 resection, but not debulking, is associated with a significant OS and DSS benefit even in systemically metastasized disease.

Radiation to the Primary Tumor in Metastatic Anaplastic Thyroid Cancer.

BACKGROUND/AIM: Metastatic anaplastic thyroid cancer is associated with a dismal prognosis. We evaluated outcome and prognostic factors in patients receiving radiation to the primary tumor in metastatic anaplastic thyroid cancer (ATC). PATIENTS AND METHODS: All consecutive patients with metastatic ATC (n=20) undergoing irradiation between 2009 and 2019 for anaplastic thyroid cancer were investigated. RESULTS: Median survival time and median progression-free survival were 2 (range=1-22) and 2 (1-20) months. In univariate analyses, surgery, concurrent or sequential chemotherapy and higher radiation dose escalation (>39 Gy) were correlated with longer overall survival (p=0.005, p=0.018 and p=0.038), respectively. Karnofsky performance status >70% showed a trend of longer survival time (p=0.062). Limited metastatic disease, surgery and concurrent/sequential chemotherapy are correlated with longer progression-free survival times (p=0.043, p=0.024 and p=0.039), respectively. CONCLUSION: Radiation to the primary tumor in metastatic anaplastic thyroid cancer is safe and offers durable local control. Treatment intensification including concurrent or sequential chemotherapy and radiation dose escalation were associated with longer survival rates and should be considered in selected patients with metastatic disease.

Novel Small-Molecule Scaffolds as Candidates against the SARS Coronavirus 2 Main Protease: A Fragment-Guided in Silico Approach.

The ongoing pandemic caused by the novel coronavirus has been the greatest global health crisis since the Spanish flu pandemic of 1918. Thus far, severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) has resulted in over 1 million deaths, and there is no cure or vaccine to date. The recently solved crystal structure of the SARS-CoV-2 main protease has been a major focus for drug-discovery efforts. Here, we present a fragment-guided approach using ZINCPharmer, where 17 active fragments known to bind to the catalytic centre of the SARS-CoV-2 main protease (SARS-CoV-2 Mpro) were used as pharmacophore queries to search the ZINC databases of natural compounds and natural derivatives. This search yielded 134 hits that were then subjected to multiple rounds of in silico analyses, including blind and focused docking against the 3D structure of the main protease. We scrutinised the poses, scores, and protein-ligand interactions of 15 hits and selected 7. The scaffolds of the seven hits were structurally distinct from known inhibitor scaffolds, thus indicating scaffold novelty. Our work presents several novel scaffolds as potential candidates for experimental validation against SARS-CoV-2 Mpro.

Clinical Outcome and Toxicity in the Treatment of Anaplastic Thyroid Cancer in Elderly Patients.

BACKGROUND: The present study aims to evaluate the outcomes and toxicity of elderly anaplastic thyroid cancer (ATC) patients receiving (chemo)radiotherapy, as well as to identify prognostic factors. PATIENTS AND METHODS: A systematic review using the MEDLINE/PubMed and Cochrane databases was performed. Individual data from all eligible studies were extracted, and a pooled analysis (n = 186) was conducted to examine patient characteristics and treatment. All consecutive ATC patients (≥65 years) treated between 2009 and 2019 at our institution were evaluated for outcomes concerning progression-free survival (PFS), overall survival (OS) probabilities and treatment-related toxicity. RESULTS: The systematic review and pooled analysis identified age as a prognostic factor. The median OS of our patient cohort (n = 26) was three months (range = 0-125). The 6-, 12- and 24-month survival rates were 35%, 22% and 11%, respectively. In the univariate analysis, a Karnofsky performance status of >70%, the Union for International Cancer Control Tumor-Node-Metastasis classification, multimodal therapy and an EQD2 of >49 Gy were correlated with longer OS and PFS. The acute grade 3 toxicity of dysphagia, dyspnea, dermatitis, mucositis and dysphonia was found in 23%, 15%, 12%, 12% and 8% of patients. CONCLUSION: Age appears to be a prognostic factor in ATC. Elderly ATC patients can tolerate multimodal treatment and achieve a promising outcome. Prospective studies need to confirm our findings.

Hypofractionated Radiotherapy for Anaplastic Thyroid Cancer: Systematic Review and Pooled Analysis.

Anaplastic thyroid carcinoma (ATC) is associated with a poor prognosis due to aggressive tumor growth and high treatment resistance. Hypofractionated treatment concepts may be more effective and less time consuming compared to normofractionated radiotherapy (RT). In this retrospective study, we aim to evaluate the outcome of hypofractionated regimens and perform a systematic review concerning hypofractionated RT and pooled analysis of this treatment modality. A systematic review using the MEDLINE/Pubmed and Cochrane databases was performed. Data from all eligible studies were extracted, and a pooled analysis of literature and our cohort (n = 60) was carried out to examine patient characteristics, toxicity, and outcomes of patients with ATC. As a result, median overall survival (OS) of the single center cohort was four (range 1-12) months. Survival rates at one, three, and six months were 82%, 55%, and 36%, respectively. In univariate analyses, multimodal treatment (p = 0.006) and gender (p = 0.04) were correlated with an improved OS. Six studies with a total number of 152 patients undergoing hypofractionated RT treatment were analyzed. The pooled analysis included four patient cohorts with 60 patients and showed median OS of 5.3 (range: 1-24) months. Multimodal treatment (p < 0.001) and a cumulative radiation dose ≥50 Gy in equivalent dose in 2 Gy fractions (EQD2) (p = 0.014) correlated with an improved OS. On multivariate analysis, multimodal treatment (p = 0.003, hazard ratio (HR): 0.636, 95% confidence interval (CI): 0.469-0.861) was an independent predictor for longer OS. After propensity score matching (PSM), hypofractionated RT appears to be non-inferior compared to normofractionated RT concerning OS. In conclusion, hypofractionated RT is effective with manageable toxicity. A dose escalation with ≥50 Gy (EQD2) correlated with a longer OS. Hypofractionated RT could be an integral part in multimodal treatment with a promising outcome.