Next generation sequencing demonstrates association between tumor suppressor gene aberrations and poor outcome in patients with cancer

Synthesis and Antineoplastic Activity of a Dimer, Spiroindolinone Pyrrolidinecarboxamide

The mutation or function loss of tumour suppressor p53 plays an important role in abnormal cell proliferation and cancer generation. Murine Double Minute 2 (MDM2) is one of the key negative regulators of p53. p53 reactivation by inhibiting MDM2-p53 interaction represents a promising therapeutic option in cancer treatment. Here, to develop more effective MDM2 inhibitors with lower off-target toxicities, we synthesized a dimer, spiroindolinone pyrrolidinecarboxamide XR-4, with potent MDM2-p53 inhibition activity. Western blotting and qRT-PCR were performed to detect the impact of XR-4 on MDM2 and p53 protein levels and p53 downstream target gene levels in different cancers. Cancer cell proliferation inhibition and clonogenic activity were also investigated via the CCK8 assay and colony formation assay. A subcutaneous 22Rv1-derived xenografts mice model was used to investigate the in vivo anti-tumour activity of XR-4. The results reveal that XR-4 can induce wild-type p53 accumulation in cancer cells, upregulate the levels of the p53 target genes p21 and PUMA levels, and then inhibit cancer cell proliferation and induce cell apoptosis. XR-4 can also act as a homo-PROTAC that induces MDM2 protein degradation. Meanwhile, the in vivo study results show that XR-4 possesses potent antitumour efficacy and a favourable safety property. In summary, XR-4 is an interesting spiroindolinone pyrrolidinecarboxamide-derivative dimer with effective p53 activation activity and a cancer inhibition ability.

Integrated analysis of cell cycle-related genes in HR+/HER2- breast cancer

PURPOSE

This study aimed to explore the mutational characteristics and significance of cell cycle-related genes (CCGs) in hormone-receptor positive, human epidermal growth factor receptor 2 negative breast cancer (HR+/HER2- BC).

METHODS

A total of 1668 HR+/HER2- BC patients from the Guangdong Provincial People's Hospital (GDPH) cohort (n = 321) and METABRIC cohort (n = 1347) were included. Tumor samples from HR+/HER2- BC patients were collected for a next-generation sequencing assay in GDPH cohort, including 15 key CCGs. The association between CCGs alterations and overall survival were identified via the Cox regression analysis. The functional roles of the CCGs were explored via the Metascape database.

RESULTS

Based on multivariate Cox regression analysis, a set of five key CCGs (CDK4, CCND1, CDKN1A, CDKN1C, and CHEK2) were identified as independent prognostic variables in HR+/HER2- BC patients. Besides, the five-CCGs-based risk score was used to effectively classify patients into the low-risk and high-risk groups (P < 0.0001). The potential functional pathways of the CCGs included cell cycle, cyclin D associated events in G1, and regulation of G1/S transition of mitotic cell cycle.

CONCLUSION

We performed the integrated analysis of the CCGs in HR+/HER2- BC patients. It has the potential to guide individualized precision oncology therapeutic schemes in HR+/HER2- BC patients.

Telomerase reverse transcriptase promoter alterations across cancer types as detected by next-generation sequencing: A clinical and molecular analysis of 423 patients

BACKGROUND

Telomerase reverse transcriptase (TERT) promoter mutations that may affect telomerase activity have recently been described in human malignancies. The purpose of this study was to investigate the clinical correlates of TERT promoter abnormalities in a large cohort of patients with diverse cancers.

METHODS

This study analyzed TERT promoter alterations and clinical characteristics of 423 consecutive patients for whom molecular testing by next-generation sequencing was performed between August 2014 and July 2015.

RESULTS

Of the 423 patients, 61 (14.4%) had TERT promoter mutations, and this placed TERT promoter alterations among the most prevalent aberrations after tumor protein 53 (TP53; 39%) and KRAS and cyclin-dependent kinase inhibitor 2A/B (CDKN2A/B) alterations (15% each) in this population. TERT promoter alterations were more frequent in men (P = .031) and were associated with brain cancers (P = .001), skin cancers/melanoma (P = .001), and a higher number of aberrations (P = .0001). A co-alteration analysis found that TERT promoter alterations were significantly correlated with CDKN2A/B (P = .001) and BRAF abnormalities (P = .0003). Patients harboring TERT promoter alterations or TP53 or CDKN2A/B alterations and those with 4 or more alterations demonstrated shorter survival (hazard ratio for normal TERT promoters vs aberrant ones, 0.44; P = .017). However, only a higher number of alterations remained significant in the multivariate analysis.

CONCLUSIONS

Overall, TERT promoter alterations were among the most prevalent aberrations in this population, with very high rates in brain cancers (48% of patients) and melanomas (56% of patients). These aberrations frequently coexist with a high number of other aberrations, with the latter feature also significantly associated with poorer overall survival. Therapeutic options for targeting tumors with TERT promoter mutations are currently limited, although a variety of novel approaches are under development. Cancer 2018;124:1288-96. © 2017 American Cancer Society.

Cell-Cycle Gene Alterations in 4,864 Tumors Analyzed by Next-Generation Sequencing: Implications for Targeted Therapeutics

Alterations in the cyclin-dependent kinase (CDK)-retinoblastoma (RB) machinery disrupt cell-cycle regulation and are being targeted in drug development. To understand the cancer types impacted by this pathway, we analyzed frequency of abnormalities in key cell-cycle genes across 4,864 tumors using next-generation sequencing (182 or 236 genes; Clinical Laboratory Improvement Amendments laboratory). Aberrations in the cell-cycle pathway were identified in 39% of cancers, making this pathway one of the most commonly altered in cancer. The frequency of aberrations was as follows: CDKN2A/B (20.1% of all patients), RB1 (7.6%), CCND1 (6.1%), CCNE1 (3.6%), CDK4 (3.2%), CCND3 (1.8%), CCND2 (1.7%), and CDK6 (1.7%). Rates and types of aberrant cell-cycle pathway genes differed between cancer types and within histologies. Analysis of coexisting and mutually exclusive genetic aberrations showed that CCND1, CCND2, and CCND3 aberrations were all positively associated with CDK6 aberrations [OR and P values, multivariate analysis: CCND1 and CDK6 (OR = 3.5; P < 0.0001), CCND2 and CDK6 (OR = 4.3; P = 0.003), CCND3 and CDK6 (OR = 3.6; P = 0.007)]. In contrast, RB1 alterations were negatively associated with multiple gene anomalies in the cell-cycle pathway, including CCND1 (OR = 0.25; P = 0.003), CKD4 (OR = 0.10; P = 0.001), and CDKN2A/B (OR = 0.21; P < 0.0001). In conclusion, aberrations in the cell-cycle pathway were very common in diverse cancers (39% of 4,864 neoplasms). The frequencies and types of alterations differed between and within tumor types and will be informative for drug development strategies. Mol Cancer Ther; 15(7); 1682-90. ©2016 AACR.

The Conundrum of Genetic "Drivers" in Benign Conditions

Advances in deep genomic sequencing have identified a spectrum of cancer-specific passenger and driver aberrations. Clones with driver anomalies are believed to be positively selected during carcinogenesis. Accumulating evidence, however, shows that genomic alterations, such as those in BRAF, RAS, EGFR, HER2, FGFR3, PIK3CA, TP53, CDKN2A, and NF1/2, all of which are considered hallmark drivers of specific cancers, can also be identified in benign and premalignant conditions, occasionally at frequencies higher than in their malignant counterparts. Targeting these genomic drivers can produce dramatic responses in advanced cancer, but the effects on their benign counterparts are less clear. This benign-malignant phenomenon is well illustrated in studies of BRAF V600E mutations, which are paradoxically more frequent in benign nevi (∼80%) than in dysplastic nevi (∼60%) or melanoma (∼40%-45%). Similarly, human epidermal growth factor receptor 2 is more commonly overexpressed in ductal carcinoma in situ (∼27%-56%) when compared with invasive breast cancer (∼11%-20%). FGFR3 mutations in bladder cancer also decrease with tumor grade (low-grade tumors, ∼61%; high-grade, ∼11%). “Driver” mutations also occur in nonmalignant settings: TP53 mutations in synovial tissue from rheumatoid arthritis and FGFR3 mutations in seborrheic keratosis. The latter observations suggest that the oncogenicity of these alterations may be tissue context–dependent. The conversion of benign conditions to premalignant disease may involve other genetic events and/or epigenetic reprogramming. Putative driver mutations can also be germline and associated with increased cancer risk (eg, germline RAS or TP53 alterations), but germline FGFR3 or NF2 abnormalities do not predispose to malignancy. We discuss the enigma of genetic “drivers” in benign and premalignant conditions and the implications for prevention strategies and theories of tumorigenesis.

Precision Oncology: The UC San Diego Moores Cancer Center PREDICT Experience

By profiling their patients' tumors, oncologists now have the option to use molecular results to match patients with drug(s) based on specific biomarkers. In this observational study, 347 patients with solid advanced cancers and next-generation sequencing (NGS) results were evaluated. Outcomes for patients who received a "matched" versus "unmatched" therapy following their NGS results were compared. Eighty-seven patients (25%) were treated with a "matched" therapy, 93 (26.8%) with an "unmatched" therapy. More patients in the matched group achieved stable disease (SD) ≥ 6 months/partial response (PR)/complete response (CR), 34.5% vs. 16.1%, (P ≤ 0.020 multivariable or propensity score methods). Matched patients had a longer median progression-free survival (PFS; 4.0 vs. 3.0 months, P = 0.039 in the Cox regression model). In analysis using PFS1 (PFS on the prior line of therapy) as a comparator to PFS after NGS, as expected, the unmatched group demonstrated a PFS2 significantly shorter than PFS1 (P = 0.009); however, this shortening was not observed in the matched patients (P = 0.595). Furthermore, 45.3% of the matched patients (24/53) had a PFS2/PFS1 ratio ≥1.3 compared with 19.3% of patients (11/57) in the unmatched group (P = 0.004 univariable and P ≥ 0.057 in multivariable/propensity score analysis). Patients with a "matching-score" (the number of matched drugs divided by the number of aberrations; unmatched patients had a score of zero) > 0.2 had a median overall survival (OS) of 15.7 months compared with 10.6 months when their matching-score was ≤ 0.2, (P = 0.040 in the Cox regression model). Matched versus unmatched patients had higher rates of SD ≥ 6 months/PR/CR and longer PFS, and improvement in OS correlated with a higher matching score in multivariable analysis. Mol Cancer Ther; 15(4); 743-52. ©2016 AACR.