In vivo fluorescence imaging in the near-infrared region between 1500–1700 nm (NIR-IIb window) affords high spatial resolution, deep-tissue penetration, and diminished auto-fluorescence due to the suppressed scattering of long-wavelength photons and large fluorophore Stokes shifts. However, very few NIR-IIb fluorescent probes exist currently. Here, we report the synthesis of a down-conversion luminescent rare-earth nanocrystal with cerium doping (Er/Ce co-doped NaYbF₄ nanocrystal core with an inert NaYF₄ shell). Ce doping is found to suppress the up-conversion pathway while boosting down-conversion by ~9-fold to produce bright 1550 nm luminescence under 980 nm excitation. Optimization of the inert shell coating surrounding the core and hydrophilic surface functionalization minimize the luminescence quenching effect by water. The resulting biocompatible, bright 1550 nm emitting nanoparticles enable fast in vivo imaging of blood vasculature in the mouse brain and hindlimb in the NIR-IIb window with short exposure time of 20 ms for rare-earth based probes.

Purpose: This study assessed the safety and efficacy of SHR-1210 (anti-PD-1 antibody) and apatinib (VEGFR2 inhibitor) as combination therapy in patients with advanced hepatocellular carcinoma (HCC), gastric, or esophagogastric junction cancer (GC/EGJC). Patients and Methods: This was an open-label, dose-escalation (phase Ia) and expansion study (phase Ib). In phase Ia, patients (n = 15) received SHR-1210 200 mg every 2 weeks and apatinib 125–500 mg once daily until unacceptable toxicity or disease progression. In phase Ib, patients (n = 28) received apatinib at the phase Ia–identified recommended phase II dose (RP2D) plus SHR-1210. The primary objectives were safety and tolerability and RP2D determination. Results: At data cutoff, 43 patients were enrolled. In phase Ia, four dose-limiting toxicity events were observed (26.7%): one grade 3 lipase elevation (6.7%) in the apatinib 250 mg cohort and three grade 3 pneumonitis events (20%) in the apatinib 500 mg cohort. The maximum tolerated RP2D for apatinib was 250 mg. Of the 33 patients treated with the R2PD combination, 20 (60.6%) experienced a grade ≥3 treatment-related adverse event; adverse events in ≥10% of patients were hypertension (15.2%) and increased aspartate aminotransferase (15.2%). The objective response rate in 39 evaluable patients was 30.8% (95% CI: 17.0%–47.6%). Eight of 16 evaluable HCC patients achieved a partial response (50.0%, 95% CI: 24.7%–75.4%). Conclusions: SHR-1210 and apatinib combination therapy demonstrated manageable toxicity in patients with HCC and GC/EGJC at recommended single-agent doses of both drugs. The RP2D for apatinib as combination therapy was 250 mg, which showed encouraging clinical activity in patients with advanced HCC.

Exosomes are endosome-derived membrane vesicles carrying proteins and nucleic acids that are involved in cellular functions such as intercellular communication, protein and RNA secretion, and antigen presentation. Therefore, exosomes serve as potential biomarkers for many diseases including cancer. Because exosomes are difficult to enrich or purify from biofluids, quantification of exosomes is tedious and inaccurate. Here, we present a real-time, label-free, and quantitative method to detect and characterize tumor-derived exosomes without enrichment or purification. Utilizing surface plasmon resonance imaging (SPRi) in combination with antibody microarrays specific to the extracellular domains of exosome membrane proteins, exosomes in tumor cell culture medium can be quantitatively detected. We found a positive correlation between the metastatic potential of tumor cell lines and exosome secretion. This method provides an easy, efficient, and novel way to detect exosome secretion and thus an avenue toward the diagnosis and prognosis prediction of cancer.

Background: Tumor PD-L1 levels have predictive value in PD-1/PD-L1 checkpoint blockade therapies, yet biopsies can only provide baseline information. Whether PD-L1 expression on circulating tumor cells (CTCs) could serve as an alternative biomarker is of great interest. Design: We established an immunofluorescence assay for semi-quantitative assessment of the PD-L1 expression levels on CTCs with four categories (PD-L1^negative, PD-L1^low, PD-L1^medium and PD-L1^high). 35 patients with different advanced gastrointestinal tumors were enrolled in a phase 1 trial of a PD-1 inhibitor, IBI308. The CTC numeration and the PD-L1 expression levels were analyzed. Results: Prior the treatment of IBI308, 97% (34/35) patients had CTCs, ranging from1 to 70 (median 7). 74% (26/35) had PD-L1^positive CTCs, and 60% (21/35) had at least one PD-L1^high CTCs. The disease control (DC) rate in PD-L1^high patients (48%) is much higher than the others (14%). The group with at least 20% abundance of PD-L1^high CTCs had even higher DC rate of 64% (9/14), with only 14% DC rate for the rest (3/21). We also observed that the count changes of total CTC, PD-L1^postive CTC and PD-L1^high CTC correlate quite well with disease outcome (P<0.001, P = 0.002 and 0.007, respectively). In addition, the abundance of PD-L1^high CTCs at baseline had predicative significance for progression free survival (PFS). Conclusions: We revealed that the abundance of PD-L1^high CTCs at baseline might serve as a predictor to screen patients for PD-1/PD-L1 blockade therapies and measuring the dynamic changes of CTC could indicate the therapeutic response at early time.