[Efficacy and safety of dexcitabine combined with HAAG regimen in the treatment of recurrent acute myeloid leukemia].

Objective: To investigate the efficacy and safety of dexithabine (DAC) combined with HAAG regimen [harringtonine (HHT), cytarabine (Ara-C), aclarubicin (Acla) and recombinant human granulocyte colony stimulating factor (G-CSF)] in the treatment of acute myeloid leukemia (AML). Methods: The clinical data of 89 AML patients in People's Hospital Affiliated to Shandong First Medical University from January 2019 to January 2021 were retrospectively analyzed. The patients were divided into observation group (n=48) and control group (n=41) according to the treatment plan. The observation group included 25 males and 23 females, aged (44.4±9.3) years old, and was treated with DAC combined with HAAG. The control group included 24 males and 17 females, aged (42.2±10.1) years old, and was treated with DAC regimen. After 3 cycles of treatment, the treatment efficacy of the two groups was judged, including complete remission, partial remission and no remission. The level of serum P-glycoprotein (P-gp) in the two groups was detected by direct immunofluorescence-labeled monoclonal antibody flow cytometry. The enzyme-linked immunosorbent assay was used to detect the level of soluble urokinase-type plasminogen activator receptor (suPAR). Meanwhile, the incidence of adverse reactions such as digestive tract reaction, liver and kidney dysfunction, hemorrhage and infection during treatment were recorded. Results: After 3 cycles of treatment, the observation group had complete remission, partial remission and no remission in 10 cases, 21 cases and 17 cases, respectively, and the control group had 3 cases, 11 cases and 27 cases, respectively. The overall efficacy of the observation group was better than that of the control group (Z=-2.919, P=0.004). The levels of serum P-gp and suPAR in the observation group were (5.2±1.8) % and (464.4±103.4) ng/L, respectively, which were significantly lower than those in the control group [(8.8±1.9) % and (660.6±110.4) ng/L, respectively] (both P<0.05). During the treatment, the incidence of digestive tract reaction, liver and kidney dysfunction, hemorrhage and infection in the observation group was 29.2% (14/48), 22.9% (11/48), 16.7% (8/48) and 33.3% (16/48), respectively, while in the control group was 26.8% (11/41), 21.9% (9/41), 14.6% (6/41) and 24.4% (10/41), respectively, with no statistically significant difference (all P>0.05). Conclusions: The overall efficacy of DAC combined with HAAG in the treatment of AML is better than that of DAC alone. Moreover, the incidence of adverse reactions in DAC combined with HAAG is similar to that of DAC alone, with a high safety profile.

Surface-enhanced Raman spectroscopy (SERS) nanoprobes for ratiometric detection of cancer cells.

We report a ratiometric strategy for detection of different types of breast cancer cells by surface-enhanced Raman spectroscopy (SERS), which simultaneously quantifies the levels of dual biomarkers distinctly expressed on cancer cells to consequently achieve their expression ratio. Two SERS nanoprobes that are encoded with distinct SERS signatures are conjugated with urokinase plasminogen activation receptor (uPAR)- and epidermal growth factor receptor (EGFR)-targeting peptides. The SERS imaging of single live cells can accurately quantify the cellular biomarker expression difference from the SERS intensity ratio and is further employed for cancer cell screening. The results show that MDA-MB-231 and MCF-7 exhibit distinct expression of the uPAR and EGFR and they can be respectively discriminated by the intensity ratio of SERS signals from uPAR- and EGFR-targeting SERS nanoprobes. The ratiometric strategy permits background-free SERS detection of cancer cells and dramatically improves the signal-to-noise ratio of targeted cellular SERS imaging, thus enabling accurate cancer cell screening without the need for additional references. It is believed that the present ratiometric method should be a promising avenue for breast cancer diagnostics and screening, which can be easily extended for detection of other cancer cell types.

The urokinase receptor-derived cyclic peptide [SRSRY] suppresses neovascularization and intravasation of osteosarcoma and chondrosarcoma cells.

The receptor for the urokinase-type plasminogen activator (uPAR) is a widely recognized master regulator of cell migration and uPAR88-92 is the minimal sequence required to induce cell motility and angiogenesis by interacting with the formyl peptide receptor type 1 (FPR1). In this study, we present evidence that the cyclization of the uPAR88-92 sequence generates a new potent inhibitor of migration, and extracellular matrix invasion of human osteosarcoma and chondrosarcoma cells expressing comparable levels of FPR1 on cell surface. In vitro, the cyclized peptide [SRSRY] prevents formation of capillary-like tubes by endothelial cells co-cultured with chondrosarcoma cells and trans-endothelial migration of osteosarcoma and chondrosarcoma cells. When chondrosarcoma cells were subcutaneously injected in nude mice, tumor size, intra-tumoral microvessel density and circulating tumor cells in blood samples collected before the sacrifice, were significantly reduced in animals treated daily with i.p-administration of 6 mg/Kg [SRSRY] as compared to animals treated with vehicle only. Our findings indicate that [SRSRY] prevents three key events occurring during the metastatic process of osteosarcoma and chondrosarcoma cells: the extracellular matrix invasion, the formation of a capillary network and the entry into bloodstream.

Evaluation of a bispecific biological drug designed to simultaneously target glioblastoma and its neovasculature in the brain.

OBJECT: The authors of this study aimed to genetically design a bispecific targeted toxin that would simultaneously target overexpressed markers on glioma as well as the tumor vasculature, to mutate certain amino acids to reduce the immunogenicity of this new drug, and to determine whether the drug was able to effectively reduce aggressive human brain tumors in a rat xenograft model via a novel hollow fiber (HF) catheter delivery system. METHODS: A new bispecific ligand-directed toxin (BLT) was created in which 2 human cytokines-epidermal growth factor ([EGF], targeting overexpressed EGF receptor) and amino acid terminal fragment ([ATF], targeting urokinase plasminogen activator receptor)-were cloned onto the same single-chain molecule with truncated Pseudomonas exotoxin with a terminal lysyl-aspartyl-glutamyl-leucine (KDEL) sequence. Site-specific mutagenesis was used to mutate amino acids in 7 key epitopic toxin regions that dictate the B cell generation of neutralizing antitoxin antibodies to deimmunize the drug, now called "EGFATFKDEL 7mut." Bioassays were used to determine whether mutation reduced the drug's potency, and enzyme-linked immunosorbent assay studies were performed to determine whether antitoxin antibodies were decreased. Aggressive brain tumors were intracranially established in nude rats by using human U87 glioma genetically marked with a firefly luciferase reporter gene (U87-luc), and the rats were stereotactically treated with 2 intracranial injections of deimmunized EGFATFKDEL via convection-enhanced delivery (CED). Drug was administered through a novel HF catheter to reduce drug backflow upon delivery. RESULTS: In vitro, EGFATFKDEL 7mut selectively killed the human glioblastoma cell line U87-luc as well as cultured human endothelial cells in the form of the human umbilical vein endothelial cells. Deimmunization did not reduce drug activity. In vivo, when rats with brain tumors were intracranially treated with drug via CED and a novel HF catheter to reduce backflow, there were significant tumor reductions in 2 experiments (p < 0.01). Some rats survived with a tumor-free status until 130 days post-tumor inoculation. An irrelevant BLT control did not protect establishing specificity. The maximal tolerated dose of EGFATFKDEL 7mut was established at 2 µg/injection or 8.0 µg/kg, and data indicated that this dose was nontoxic. Antitoxin antibodies were reduced by at least 90%. CONCLUSIONS: First, data indicated that the BLT framework is effective for simultaneously targeting glioma and its neovasculature. Second, in the rodent CED studies, newly developed HF catheters that limit backflow are effective for drug delivery. Third, by mutating critical amino acids, the authors reduced the threat of the interference of neutralizing antibodies that are generated against the drug. The authors' experiments addressed some of the most urgent limitations in the targeted toxin field.