Time interval from diagnosis to treatment of brain metastases with stereotactic radiosurgery is not associated with radionecrosis or local failure.

Introduction: Brain metastases are the most common intracranial tumor diagnosed in adults. In patients treated with stereotactic radiosurgery, the incidence of post-treatment radionecrosis appears to be rising, which has been attributed to improved patient survival as well as novel systemic treatments. The impacts of concomitant immunotherapy and the interval between diagnosis and treatment on patient outcomes are unclear. Methods: This single institution, retrospective study consisted of patients who received single or multi-fraction stereotactic radiosurgery for intact brain metastases. Exclusion criteria included neurosurgical resection prior to treatment and treatment of non-malignant histologies or primary central nervous system malignancies. A univariate screen was implemented to determine which factors were associated with radionecrosis. The chi-square test or Fisher's exact test was used to compare the two groups for categorical variables, and the two-sample t-test or Mann-Whitney test was used for continuous data. Those factors that appeared to be associated with radionecrosis on univariate analyses were included in a multivariable model. Univariable and multivariable Cox proportional hazards models were used to assess potential predictors of time to local failure and time to regional failure. Results: A total of 107 evaluable patients with a total of 256 individual brain metastases were identified. The majority of metastases were non-small cell lung cancer (58.98%), followed by breast cancer (16.02%). Multivariable analyses demonstrated increased risk of radionecrosis with increasing MRI maximum axial dimension (OR 1.10, p=0.0123) and a history of previous whole brain radiation therapy (OR 3.48, p=0.0243). Receipt of stereotactic radiosurgery with concurrent immunotherapy was associated with a decreased risk of local failure (HR 0.31, p=0.0159). Time interval between diagnostic MRI and first treatment, time interval between CT simulation and first treatment, and concurrent immunotherapy had no impact on incidence of radionecrosis or regional failure. Discussion: An optimal time interval between diagnosis and treatment for intact brain metastases that minimizes radionecrosis and maximizes local and regional control could not be identified. Concurrent immunotherapy does not appear to increase the risk of radionecrosis and may improve local control. These data further support the safety and synergistic efficacy of stereotactic radiosurgery with concurrent immunotherapy.

Corrigendum: Time interval from diagnosis to treatment of brain metastases with stereotactic radiosurgery is not associated with radionecrosis or local failure.

[This corrects the article DOI: 10.3389/fonc.2023.1132777.].

Chromosomal instability accelerates the evolution of resistance to anti-cancer therapies.

Aneuploidy is a ubiquitous feature of human tumors, but the acquisition of aneuploidy typically antagonizes cellular fitness. To investigate how aneuploidy could contribute to tumor growth, we triggered periods of chromosomal instability (CIN) in human cells and then exposed them to different culture environments. We discovered that transient CIN reproducibly accelerates the acquisition of resistance to anti-cancer therapies. Single-cell sequencing revealed that these resistant populations develop recurrent aneuploidies, and independently deriving one chromosome-loss event that was frequently observed in paclitaxel-resistant cells was sufficient to decrease paclitaxel sensitivity. Finally, we demonstrated that intrinsic levels of CIN correlate with poor responses to numerous therapies in human tumors. Our results show that, although CIN generally decreases cancer cell fitness, it also provides phenotypic plasticity to cancer cells that can allow them to adapt to diverse stressful environments. Moreover, our findings suggest that aneuploidy may function as an under-explored cause of therapy failure.

Single-Chromosomal Gains Can Function as Metastasis Suppressors and Promoters in Colon Cancer.

High levels of cancer aneuploidy are frequently associated with poor prognosis. To examine the relationship between aneuploidy and cancer progression, we analyzed a series of congenic cell lines that harbor single extra chromosomes. We found that across 13 different trisomic cell lines, 12 trisomies suppressed invasiveness or were largely neutral, while a single trisomy increased metastatic behavior by triggering a partial epithelial-mesenchymal transition. In contrast, we discovered that chromosomal instability activates cGAS/STING signaling but strongly suppresses invasiveness. By analyzing patient copy-number data, we demonstrate that specific aneuploidies are associated with distinct outcomes, and the acquisition of certain aneuploidies is in fact linked with a favorable prognosis. Thus, aneuploidy is not a uniform driver of malignancy, and different aneuploidies can uniquely influence tumor progression. At the same time, the gain of a single chromosome is capable of inducing a profound cell state transition, thereby linking genomic plasticity, phenotypic plasticity, and metastasis.

COP1/DET1/ETS axis regulates ERK transcriptome and sensitivity to MAPK inhibitors.

Aberrant activation of MAPK signaling leads to the activation of oncogenic transcriptomes. How MAPK signaling is coupled with the transcriptional response in cancer is not fully understood. In 2 MAPK-activated tumor types, gastrointestinal stromal tumor and melanoma, we found that ETV1 and other Pea3-ETS transcription factors are critical nuclear effectors of MAPK signaling that are regulated through protein stability. Expression of stabilized Pea3-ETS factors can partially rescue the MAPK transcriptome and cell viability after MAPK inhibition. To identify the players involved in this process, we performed a pooled genome-wide RNAi screen using a fluorescence-based ETV1 protein stability sensor and identified COP1, DET1, DDB1, UBE3C, PSMD4, and COP9 signalosome members. COP1 or DET1 loss led to decoupling between MAPK signaling and the downstream transcriptional response, where MAPK inhibition failed to destabilize Pea3 factors and fully inhibit the MAPK transcriptome, thus resulting in decreased sensitivity to MAPK pathway inhibitors. We identified multiple COP1 and DET1 mutations in human tumors that were defective in the degradation of Pea3-ETS factors. Two melanoma patients had de novo DET1 mutations arising after vemurafenib treatment. These observations indicate that MAPK signaling-dependent regulation of Pea3-ETS protein stability is a key signaling node in oncogenesis and therapeutic resistance to MAPK pathway inhibition.