Predictors of treatment initiation and mapping the cancer diagnostic pathway: A retrospective observational cohort study of patients with metastatic non-small cell lung cancer.

BACKGROUND: Health-care providers in the US revealed that a substantial proportion of mNSCLC patients do not receive any first-line therapy and the biggest gaps in care are time inefficiencies in the diagnostic process. The goal of this study was to determine whether such gaps are found in Israel where healthcare is universal and participation in a medical insurance plan is free and compulsory. METHODS: We conducted a retrospective, observational cohort study using the computerized data of Maccabi Healthcare Services, a 2.5 million-member state-mandated health-service. Patients with mNSCLC diagnosed between 2017 and 2018 were followed until December 2019. RESULTS: Among 434 patients (62% male, mean age 68 y, 74% adenocarcinoma), 345 (79%) initiated first-line treatment. Compared to treated, untreated patients (n = 89) were more likely to be older (mean [SD]=71 years [10] vs. 67 [10], p < 0.001), have a higher co-morbidity index (5.6 ([4.4] vs. 4.0 [3.4], p < 0.001), smokers (84% vs. 66%, p = 0.001), and require hospitalization in the year prior to diagnosis (80% vs 61%, p = 0.002). There was no difference in socioeconomic status. Time from first symptom to imaging was longer for untreated than treated patients (6.51 months [4.24, 7.33] vs 3.48 months [2.76, 4.34] respectively, p = 0.22). Predictors of treatment initiation included age< 70 years, non-smokers, EGFR testing performed, ECOG performance status 0-1 and shorter wait from first symptom to imaging. Median time from first symptom to initiation of 1 L, was 7.76 months (6.51-8.75). CONCLUSION: The proportion of untreated mNSCLC patients are comparable to those reported in the US; we did not find health disparities between socioeconomic levels. Our data suggest that the main barrier to effective diagnostic process is the wait between symptom complaint and imaging.

Gene expression signature of human cancer cell lines treated with the ras inhibitor salirasib (S-farnesylthiosalicylic acid).

Deregulation of Ras pathways results in complex abnormalities of multiple signaling cascades that contribute to human malignancies. Ras is therefore considered an appropriate target for cancer therapy. In light of the complexity of the deregulated Ras pathway, it is important to decipher at the molecular level the response of cancer cells to Ras inhibitors that would reregulate it. In the present study, we used gene expression profiling as a robust method for the global dissection of gene expression alterations that resulted from treatment with the Ras inhibitor S-farnesylthiosalicylic acid (FTS; salirasib). Use of a ranking-based procedure, combined with functional analysis and promoter sequence analysis, enabled us to decipher the common and most prominent patterns of the transcriptional response of five different human cancer cell lines to FTS. Remarkably, the analysis identified a distinctive core transcriptional response to FTS that was common to all cancer cell lines tested. This signature fits well to a recently described deregulated Ras pathway signature that predicted sensitivity to FTS. Taken together, these studies provide strong support for the conclusion that FTS specifically reregulates defective Ras pathways in human tumor cells. Ras pathway reregulation by FTS was manifested by repression of E2F-regulated and NF-Y-regulated genes and of the transcription factor FOS (all of which control cell proliferation), repression of survivin expression (which blocks apoptosis), and induction of activating transcription factor-regulated and Bach2-regulated genes (which participate in translation and stress responses). Our results suggest that cancer patients with deregulated Ras pathway tumors might benefit from FTS treatment.

Disruption of cooperation between Ras and MycN in human neuroblastoma cells promotes growth arrest.

PURPOSE: Our aim was to examine whether active Ras and MycN cooperation contributes to the malignant phenotype of human neuroblastoma with amplified MycN gene, an aggressive incurable tumor. EXPERIMENTAL DESIGN: Human neuroblastoma LAN-1 cells, in which the MycN gene is amplified, were used to examine the impact of the Ras inhibitor farnesylthiosalicylic acid on cell growth, on the levels Ras and MycN proteins, and on profiles of gene expression. RESULTS: We show that LAN-1 cells express relatively large amounts of MycN and active Ras-GTP. Inhibition of active Ras by farnesylthiosalicylic acid led to attenuation of the Raf-MEK-ERK and phosphoinositide 3-kinase-Akt-glycogen synthase-3 (GSK-3) pathways, to reduction in cyclin D1, phospho-retinoblastoma, and E2F, and to increase in the cyclin-dependent kinase inhibitor p27 and in retinoblastoma-binding protein-1, an inhibitor of E2F transcriptional activity. Ras inhibition by farnesylthiosalicylic acid or by a dominant-negative Ras also led to complete disappearance of MycN protein from the nuclei of LAN-1 cells. This was a result of blocking of Akt inactivation of GSK-3, leading to GSK-3-dependent phosphorylation with consequent proteosomal degradation of MycN. Loss of active Ras and of MycN in LAN-1 cells was manifested in profiles of gene expression that could be expected from the loss of MycN transcriptional activity and of Ras signaling. These changes explain the farnesylthiosalicylic acid-induced inhibition of LAN-1 cell growth. CONCLUSIONS: Active Ras is needed to block MycN degradation, promoting cooperative Ras- and MycN-dependent cell cycle progression in LAN-1 cells. Ras inhibitors are therefore likely candidates for the treatment of advanced neuroblastoma characterized by high expression of MycN.