The utility of circulating tumor DNA (ctDNA) as a biomarker in patients with advanced cancers receiving immunotherapy is uncertain. We therefore analyzed pretreatment (n=978) and on-treatment (n=171) ctDNA samples across 16 advanced stage tumor types from three phase I/II trials of durvalumab (± anti-CTLA-4 therapy tremelimumab).Higher pretreatment variant allele frequencies (VAF) were associated with poorer overall survival and other known prognostic factors, but not objective response, suggesting a prognostic role for patient outcomes. On-treatment reductions in VAF and lower on-treatment VAF were independently associated with longer PFS and OS, and increased ORR, but not prognostic variables, suggesting that on-treatment ctDNA dynamics are predictive of benefit from immune checkpoint blockade. Accordingly, we propose a concept of "molecular response" using ctDNA, incorporating both pretreatment and on-treatment VAF that predicted long-term survival similarly to initial radiological response, while also permitting early differentiation of responders among patients with initially radiologically stable disease. SignificanceIn a pan-cancer analysis of immune checkpoint blockade, pretreatment ctDNA levels appeared prognostic and on-treatment dynamics predictive. A "molecular response" metric identified long-term responders and adjudicated benefit among patients with initial radiologically stable disease. Changes in ctDNA may be more dynamic than radiographic changes and could complement existing trial endpoints.

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The combination of reactive oxygen species‐involved chemodynamic therapy (CDT) and photothermal therapy (PTT) holds great promise in enhancing anticancer effects. Herein, a multifunctional Fe‐doped polyoxometalate (Fe‐POM) cluster is fabricated via a simple method. The Fe‐POM can not only be utilized as PTT agents to generate a hyperthermia effect for cancer cell killing under near‐infrared (NIR) II laser (1060 nm) irradiation, but also can be used as CDT agents to convert endogenous less‐reactive H2O2 into harmful ·OH and simultaneously deplete glutathione for an amplified CDT effect. Notably, the hyperthermia induced by PTT can further enhance the CDT effect, achieving a synergistic PTT/CDT effect. Owing to the self‐assembling properties at lowered pH values, the Fe‐POM exhibits high tumor accumulation as revealed by photoacoustic imaging. More importantly, Fe‐POM enables effective destruction of tumors without inducing noticeable damage to normal tissues under 1060 nm laser irradiation. The work presents a new type of multifunctional agent with high PTT/CDT efficacy, providing promising methods for PTT‐enhanced CDT in a NIR‐II biowindow.

BackgroundMultidrug resistance (MDR) in gastric cancer remains a major challenge to clinical treatment. Activating transcription factor 4 (ATF4) is a stress response gene involved in homeostasis and cellular protection. However, the expression and function of ATF4 in gastric cancer MDR remains unknown. In this study, we investigate whether ATF4 play a role in gastric cancer MDR and its potential mechanisms.Methodology/Principal FindingsWe demonstrated that ATF4 overexpression confered the MDR phenotype to gastric cancer cells, while knockdown of ATF4 in the MDR variants induced re-sensitization. In this study we also showed that the NAD+-dependent histone deacetylase SIRT1 was required for ATF4-induced MDR effect in gastric cancer cells. We demonstrated that ATF4 facilitated MDR in gastric cancer cells through direct binding to the SIRT1 promoter, resulting in SIRT1 up-regulation. Significantly, inhibition of SIRT1 by small interfering RNA (siRNA) or a specific inhibitor (EX-527) reintroduced therapeutic sensitivity. Also, an increased Bcl-2/Bax ratio and MDR1 expression level were found in ATF4-overexpressing cells.Conclusions/SignificanceWe showed that ATF4 had a key role in the regulation of MDR in gastric cancer cells in response to chemotherapy and these findings suggest that targeting ATF4 could relieve therapeutic resistance in gastric cancer.

Glioma is the most frequent form of malignant brain tumors. Surgical debulking is a major strategy for glioma treatment. However, there is a great challenge for the neurosurgeons to intraoperatively identify the true margins of glioma because of its infiltrative nature. Tumor residues or microscopic satellite foci left in the resection bed are the main reasons leading to early recurrence as well as poor prognosis. In this study, a surface-enhanced resonance Raman scattering (SERRS) probe was developed to intraoperatively guide glioma resection. In this probe, molecular reporters with absorptive maxima at the near-infrared wavelength range were covalently functionalized on the surface of gold nanostars. This SERRS probe demonstrated an ultrahigh sensitivity with a detection limit of 5.0 pM in aqueous solution. By the development of glioma xenografts in a mouse dorsal skin window chamber, extravasation of this probe from leaky tumor vasculature as functions of time and distance to tumor boundary was investigated. Importantly, the invasive margin of the tumor xenograft was demarcated by this probe with a high signal-to-background ratio. Preoperative magnetic resonance imaging (MRI) first defined the position of orthotopic glioma xenografts in the brain of rat models, and the craniotomy plan was designed. The brain tumor was then excised intraoperatively step-by-step with the assistance of a handheld Raman scanner till the Raman signals of the probe completely disappeared in the resection bed. Notably, longitudinal MRI showed that SERRS-guided surgery significantly reduced the tumor recurrence rate and improved the overall survival of rat models compared with the white light-guided surgery. Overall, this work demonstrates the prognostic benefit of SERRS-guided glioma surgery in animal models. Because delineation of tumor-invasive margins is a common challenge faced by the surgeons, this SERRS probe with a picomolar detection limit holds the promise in improving the surgical outcome of different types of infiltrated tumors.

High mobility group box (HMGB) consists primarily of HMGB1, HMGB2, and HMGB3 proteins. Although abnormal HMGB expression is associated with various tumors, the relationship with gastric cancer (GC) remains unclear. In this study, HMGB1, HMGB2, and HMGB3 expression was analyzed using the Oncomine and TCGA databases. Correlations between HMGB1, HMGB2, and HMGB3 and clinicopathological factors were analyzed. cBioPortal was used to analyze HMGB1, HMGB2, and HMGB3 genetic alterations and its gene regulation network in GC tissue. HMGB1, HMGB2, and HMGB3 expression was higher in tumor tissues than in normal tissues, especially in GC. High HMGB1, HMGB2, and HMGB3 expression may predict a poor prognosis among patients with GC (hazard ratios [HR] = 1.90; 95% confidence interval [CI]: [1.30−2.78]) and human digestive system neoplasm (HR = 1.85; 95% CI [1.64−2.10]). These findings suggest that HMGB1, HMGB2, and HMGB3 may be useful prognostic indicators for patients with GC.

A novel pH ratiometrically responsive surface-enhanced resonance Raman scattering (SERRS) probe was developed for tumor acidic margin delineation and image-guided surgery.

Glycyrrhizic acid (GA) is the main active ingredient extracted from Chinese herb licorice root, and it shows anti-tumor effects in many cancer types, while its role in gastric cancer (GC) is still unknown. In this study, we evaluated the effects of GA on GC cells and explored the underlying mechanisms. Methods: The anti-proliferation effect of GA on GC cells was assessed by CCK-8, colony formation, and EdU assay. The effects of GA on cell cycle and apoptosis were detected by flow cytometer. Western blotting was performed to explore the underlying mechanisms. Results: Our results showed that GA had a time-and dose-dependent inhibitory effect on proliferation of GC cells. Flow cytometer analysis demonstrated that GA would lead to G1/ S-phase arrest and apoptosis. GA treatment down-regulated the levels of G1 phase-related proteins, including cyclin D1, D2, D3, E1, and E2. In terms of apoptosis, GA treatment upregulated the levels of Bax, cleaved PARP, and pro-caspase-3,-8,-9, but did not influence their cleavage patterns. The expression of Bcl-2, survivin and p65 was attenuated after treatment. Besides, GA would down-regulate the phosphorylation of PI3K/AKT pathway. Conclusion: This study focused on inhibitory effect of GA on GC cells by inducing cell cycle arrest and apoptosis. Several important cyclins-and apoptosis-related proteins were involved in the regulation of GA to GC cells, and phosphorylated PI3K and AKT were attenuated. The results of this study indicated that GA is a potential and promising anticancer drug for GC.