EpCAM Signaling Promotes Tumor Progression and Protein Stability of PD-L1 through the EGFR Pathway

Although epithelial cell adhesion molecule (EpCAM) has previously been shown to promote tumor progression, the underlying mechanisms remain largely unknown. Here, we report that the EGF-like domain I within the extracellular domain of EpCAM (EpEX) binds EGFR, activating both AKT and MAPK signaling to inhibit forkhead transcription factor O3a (FOXO3a) function and stabilize PD-L1 protein, respectively. Treatment with the EpCAM neutralizing antibody, EpAb2-6, inhibited AKT and FOXO3a phosphorylation, increased FOXO3a nuclear translocation, and upregulated high temperature requirement A2 (HtrA2) expression to promote apoptosis while decreasing PD-L1 protein levels to enhance the cytotoxic activity of CD8⁺ T cells. In vivo, EpAb2-6 markedly extended survival in mouse metastasis and orthotopic models of human colorectal cancer. The combination of EpAb2-6 with atezolizumab, an anti-PD-L1 antibody, almost completely eliminated tumors. Moreover, the number of CD8⁺ T cells in combination-treated tumors was increased compared with atezolizumab alone. Our findings suggest a new combination strategy for cancer immunotherapy in patients with EpCAM-expressing tumors. SIGNIFICANCE: This study shows that treatment with an EpCAM neutralizing antibody promotes apoptosis while decreasing PD-L1 protein to enhance cytotoxic activity of CD8⁺ T cells.

Hepatocellular carcinoma-targeted nanoparticles for cancer therapy

Nanocarriers, such as liposomes, have the potential to increase the payload of chemotherapeutic drugs while decreasing toxicity to non-target tissues; such advantageous properties can be further enhanced through surface conjugation of nanocarriers with targeting moieties. We previously reported that SP94 peptides, identified by phage display, exhibited higher binding affinity to human hepatocellular carcinoma (HCC) than to hepatocytes and other normal cells. Here, we confirm the tumor-targeting properties of SP94 peptide by near-infrared fluorescence imaging. Non-targeted PEGylated liposomal doxorubicin (LD) and SP94‑conjugated PEGylated liposomal doxorubicin (SP94‑LD) were compared by assessing pharmacokinetics, tissue distribution, and antitumor efficacy in xenograft-bearing mice, in order to investigate the effectiveness of SP94‑mediated targeting for cancer therapy. SP94‑LD demonstrated a significant increase in drug accumulation in tumors, while its plasma residence time was the same as its non-targeted equivalent. Consistent with this result, conjugation of targeting peptide SP94 enhances the therapeutic efficacy of liposomal doxorubicin in mouse models with hepatocellular carcinoma xenografts. Furthermore, combination targeted therapy exhibited a significant enhancement against orthotopic tumor growth, and markedly extended the survival of mice compared with all other treatments. Our study shows that SP94‑mediated targeting enhances antitumor efficacy by improving tumor pharmacokinetics and tissue distribution, allowing large amounts of antitumor drugs to accumulate in tumors.

Panobinostat sensitizes KRAS-mutant non-small-cell lung cancer to gefitinib by targeting TAZ

Mutation of KRAS in non-small-cell lung cancer (NSCLC) shows a poor response to epidermal growth factor receptor (EGFR) inhibitors and chemotherapy. Currently, there are no direct anti-KRAS therapies available. Thus, new strategies have emerged for targeting KRAS downstream signaling. Panobinostat is a clinically available histone deacetylase inhibitor for treating myelomas and also shows potentiality in NSCLC. However, the therapeutic efficacy of panobinostat against gefitinib-resistant NSCLC is unclear. In this study, we demonstrated that panobinostat overcame resistance to gefitinib in KRAS-mutant/EGFR-wild-type NSCLC. Combined panobinostat and gefitinib synergistically reduced tumor growth in vitro and in vivo. Mechanistically, we identified that panobinostat-but not gefitinib-inhibited TAZ transcription, and the combination of panobinostat and gefitinib synergistically downregulated TAZ and TAZ downstream targets, including EGFR and EGFR ligand. Inhibition of TAZ by panobinostat or short hairpin RNA sensitized KRAS-mutant/EGFR-wild-type NSCLC to gefitinib through abrogating AKT/mammalian target of rapamycin (mTOR) signaling. Clinically, TAZ was positively correlated with EGFR signaling, and coexpression of TAZ/EGFR conferred a poorer prognosis in lung cancer patients. Our findings identify that targeting TAZ-mediated compensatory mechanism is a novel therapeutic approach to overcome gefitinib resistance in KRAS-mutant/EGFR-wild-type NSCLC.

Lung Cancer-Targeting Peptides with Multi-subtype Indication for Combinational Drug Delivery and Molecular Imaging

Lung cancer is the leading cause of cancer-related death worldwide. Most targeted drugs approved for lung cancer treatment are tyrosine kinase inhibitors (TKIs) directed against EGFR or ALK, and are used mainly for adenocarcinoma. At present, there is no effective or tailored targeting agent for large cell carcinoma (LCC) or small cell lung cancer (SCLC). Therefore, we aimed to identify targeting peptides with diagnostic and therapeutic utility that possess broad subtype specificity for SCLC and non-small cell lung cancer (NSCLC). We performed phage display biopanning of H460 LCC cells to select broad-spectrum lung cancer-binding peptides, since LCC has recently been categorized as an undifferentiated tumor type within other histological subcategories of lung cancer. Three targeting phages (HPC1, HPC2, and HPC4) and their respective displayed peptides (HSP1, HSP2, and HSP4) were able to bind to both SCLC and NSCLC cell lines, as well as clinical specimens, but not to normal pneumonic tissues. In vivo optical imaging of phage homing and magnetic resonance imaging (MRI) of peptide-SPIONs revealed that HSP1 was the most favorable probe for multimodal molecular imaging. Using HSP1-SPION, the T2-weighted MR signal of H460 xenografts was decreased up to 42%. In contrast to the tight binding of HSP1 to cancer cell surfaces, HSP4 was preferentially endocytosed and intracellular drug delivery was thereby effected, significantly improving the therapeutic index of liposomal drug in vivo. Liposomal doxorubicin (LD) conjugated to HSP1, HSP2, or HSP4 had significantly greater therapeutic efficacy than non-targeting liposomal drugs in NSCLC (H460 and H1993) animal models. Combined therapy with an HSP4-conjugated stable formulation of liposomal vinorelbine (sLV) further improved median overall survival (131 vs. 84 days; P = 0.0248), even in aggressive A549 orthotopic models. Overall, these peptides have the potential to guide a wide variety of tailored theranostic agents for targeting therapeutics, non-invasive imaging, or clinical detection of SCLC and NSCLC.

Note: Self-biased voltage to suppress secondary electrons by a ZnO varistor in a compact pulsed neutron generator

A large amount of back streaming electrons will bring about a part of current drain on power supply, cause sparking or high-voltage breakdowns, and affect the neutron yield and waveform for a compact sealed-tube pulsed neutron generator. A novel idea which uses a ZnO varistor to provide a constant self-biased voltage to suppress the secondary electrons is introduced. The I-V curve for the ZnO varistor was measured in the experiment. The effects of suppressing the secondary electrons were investigated using a ZnO varistor, linear resistors, and an independent power supply, respectively. The results show that the secondary electrons are suppressed effectively by the compact ZnO varistor, while not increasing the size and the component of the device. It is a promising design for compact sealed-tube neutron generators.

Note: Triggering behavior of a vacuum arc plasma source

Axial symmetry of discharge is very important for application of vacuum arc plasma. It is discovered that the triggering method is a significant factor that would influence the symmetry of arc discharge at the final stable stage. Using high-speed multiframe photography, the transition processes from cathode-trigger discharge to cathode-anode discharge were observed. It is shown that the performances of the two triggering methods investigated are quite different. Arc discharge triggered by independent electric source can be stabilized at the center of anode grid, but it is difficult to achieve such good symmetry through resistance triggering. It is also found that the triggering process is highly correlated to the behavior of emitted electrons.

Operant performance following tail-pinch in the rat: effects of d-amphetamine

To extend the investigation of tail-pinch induced behavioral changes, rats performing on a differential reinforcement of low rates of 10 sec (DRL10), a fixed-interval of 60 sec (F160), and a fixed-ratio of 20 (FR20) schedules were exposed to a paper clip applied to the tail. While a 10 min tail-pinch conducted 1 hr before operant sessions significantly altered the DRL10 behavior, this stressor had little effect on either F160 or FR20 responding. Marked DRL10 behavior performance changes following tail-pinch included increases in the number of lever presses, decreases in the number of the reinforcers, and disruption in the frequency distribution of inter-response times (IRT). These DRL10 operant deficits were diminished when the subject received a tail-pinch pretreatment followed by d-amphetamine treatment (0.2 and 2.0 mg/kg). In combination with biochemical data from others, the present results suggest that catecholamine systems are involved in modulation of DRL10 behavior following tail-pinch.

Distinct accumbal subareas are involved in place conditioning of amphetamine and cocaine

In considering the heterogeneous function of the nucleus accumbens (NAC), the present work evaluated the conditioned place preference (CPP) after local infusion of d-amphetamine (AMP; 10, 15 microg/side) or cocaine (COC; 50, 100 microg/side) into two subareas of NAC, core and shell. A regular two-compartment CPP apparatus was used to test the place conditioning effects after 6 pairings of drug in one compartment and 6 pairings of vehicle in the other one. Significant CPP was observed with either AMP infused in the core area or COC infused into the shell area. Neither AMP in shell nor COC in core significantly produced CPP. These results indicate important differences between two neural substrates within NAC for the rewarding effects of AMP and COC on the CPP task.