Synergistic effects of Smac mimetic APG-1387 with anti-PD-1 antibody are attributed to increased CD3 + NK1.1 + cell recruitment secondary to induction of cytokines from tumor cells.

BACKGROUND: Immune checkpoint inhibitors are approved for the treatment of various tumors, but the response rate is not satisfactory in certain malignancies. Inhibitor of apoptosis proteins (IAP) ubiquitin-E3 ligase activity is involved in the regulation of immune responses. APG-1387 is a novel second mitochondria-derived activator of caspase (Smac) mimetic IAP inhibitor. The aim of this study was to explore the synergistic effect of APG-1387 when combined with anti-PD-1 antibody in a preclinical setting. METHODS: We utilized syngeneic mouse models of ovarian cancer (ID8), colon cancer (MC38), malignant melanoma (B16), and liver cancer (Hepa1-6) to assess the combination effect of APG-1387 and anti-PD-1 antibody, including immune-related factors, tumor growth, and survival. MSD V-PLEX validated assays were used to measure in vitro and in vivo cytokine release. RESULTS: In ID8 ovarian cancer and MC38 colon cancer models, APG-1387 and anti-PD1 antibody had synergistic antitumor effects. In the MC38 model, the combination of APG-1387 and anti-PD-1 antibody significantly inhibited tumor growth (P < 0.0001) and increased the survival rate of tumor-bearing animals (P < 0.001). Moreover, we found that APG-1387 upregulated tumor-infiltrating CD3 + NK1.1 + cells by nearly 2-fold, by promoting tumor cell secretion of IL-12. Blocking IL-12 secretion abrogated the synergistic effects of APG-1387 and anti-PD-1 antibody in both MC38 and ID8 models. CONCLUSIONS: APG-1387 has the potential to turn "cold tumors" into hot ones by recruiting more CD3 + NK1.1 + cells into certain tumors. Based on these and other data, the safety and therapeutic effect of this combination will be investigated in a phase 1/2 trial in patients with advanced solid tumors or hematologic malignancies (NCT03386526).

Fcγ-Receptor-Independent Controlled Activation of CD40 Canonical Signaling by Novel Therapeutic Antibodies for Cancer Therapy.

The activation of CD40-mediated signaling in antigen-presenting cells is a promising therapeutic strategy to promote immune responses against tumors. Most agonistic anti-CD40 antibodies currently in development require the Fcγ-receptor (FcγR)-mediated crosslinking of CD40 molecules for a meaningful activation of CD40 signaling but have limitations due to dose-limiting toxicities. Here we describe the identification of CD40 antibodies which strongly stimulate antigen-presenting cells in an entirely FcγR-independent manner. These Fc-silenced anti-CD40 antibodies induce an efficient upregulation of costimulatory receptors and cytokine release by dendritic cells. Finally, the most active identified anti-CD40 antibody shows activity in humanized mice. More importantly, there are no signs of obvious toxicities. These studies thus demonstrate the potent activation of antigen-presenting cells with anti-CD40 antibodies lacking FcγR-binding activity and open the possibility for an efficacious and safe combination therapy for cancer patients.

Cell targeting and immunostimulatory properties of a novel Fcγ-receptor-independent agonistic anti-CD40 antibody in rhesus macaques.

Targeting CD40 by agonistic antibodies used as vaccine adjuvants or for cancer immunotherapy is a strategy to stimulate immune responses. The majority of studied agonistic anti-human CD40 antibodies require crosslinking of their Fc region to inhibitory FcγRIIb to induce immune stimulation although this has been associated with toxicity in previous studies. Here we introduce an agonistic anti-human CD40 monoclonal IgG1 antibody (MAB273) unique in its specificity to the CD40L binding site of CD40 but devoid of Fcγ-receptor binding. We demonstrate rapid binding of MAB273 to B cells and dendritic cells resulting in activation in vitro on human cells and in vivo in rhesus macaques. Dissemination of fluorescently labeled MAB273 after subcutaneous administration was found predominantly at the site of injection and specific draining lymph nodes. Phenotypic cell differentiation and upregulation of genes associated with immune activation were found in the targeted tissues. Antigen-specific T cell responses were enhanced by MAB273 when given in a prime-boost regimen and for boosting low preexisting responses. MAB273 may therefore be a promising immunostimulatory adjuvant that warrants future testing for therapeutic and prophylactic vaccination strategies.

A third dose of the unmodified COVID-19 mRNA vaccine CVnCoV enhances quality and quantity of immune responses.

A third vaccine dose is often required to achieve potent, long-lasting immune responses. We investigated the effect of three 8-µg doses of CVnCoV, CureVac's severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) vaccine candidate containing sequence-optimized unmodified mRNA encoding the spike (S) glycoprotein, administered at 0, 4, and 28 weeks, on immune responses in rhesus macaques. After the third dose, S-specific binding and neutralizing antibodies increased 50-fold compared with post-dose 2 levels, with increased responses also evident in the lower airways and against the SARS-CoV-2 B.1.1.7 (Alpha), B.1.351 (Beta), P.1 (Gamma), and B.1.617.2 (Delta) variants. Enhanced binding affinity of serum antibodies after the third dose correlated with higher somatic hypermutation in S-specific B cells, corresponding with improved binding properties of monoclonal antibodies expressed from isolated B cells. Administration of low-dose mRNA led to fewer cells expressing antigen in vivo at the injection site and in the draining lymph nodes compared with a 10-fold higher dose, possibly reducing engagement of precursor cells with the antigen and resulting in the suboptimal response observed after two-dose vaccination schedules in phase IIb/III clinical trials of CVnCoV. However, when immune memory is established, a third dose efficiently boosts the immunological responses and improves antibody affinity and breadth.

Optical frequency comb assisted denoising for multiple access and capacity enhancement of covert wireless communication.

An optical frequency comb (OFC)-assisted covert wireless communication system with multiple access and enhanced capacity is proposed and experimentally demonstrated. In the scheme, signals in multiple channels are spread and mixed together to use a single transmitter and then received by individual receivers according to multiple access channels. The mixed signal is highly contaminated by noise to achieve high concealment in both the time and frequency domains, and then effectively recovered as different channels using the OFC assisted analog deep denoising technique. In experiments, mixed signals of 16 access channels with a signal-to-noise ratio (SNR) from -18 to -5 dB are accommodated, showing high covertness and 16× capacity enhancement (16×10 Mbit/s). Mutual interference among different channels is also analyzed and greatly eliminated by phases optimization in the spectral-spreading process. This scheme can greatly improve the time and spectrum utilization efficiency, which will be of great significance for enabling multiple access, large capacity, and high security for wireless communications.

Comparison of Immune Microenvironment Between Colon and Liver Metastatic Tissue in Colon Cancer Patients with Liver Metastasis.

BACKGROUND: Liver metastasis is an indicator of unfavorable responses to immunotherapy in colorectal cancer patients. However, the difference of immune microenvironment between primary tumors and liver metastases has not been well understood. PATIENTS AND METHODS: Fifty-four colon cancer with liver metastasis patients who received resection of both primary and metastasis lesions have been analyzed. The immune score is based on the density of infiltrating immune cells (CD3+ cell, CD8+ cell, CD11b+ cell, CD11c+ cell, and CD33+ cell) in the center and margin of the tumor. The expression of immune markers between the primary tumor and hepatic metastases was analyzed using Wilcoxon's signed rank test. RESULTS: All the five markers had higher expression in tumor margins than center tumor in both primary tumor and hepatic metastases lesions. The expression of CD11c and CD11b had no difference between metastatic lesions and primary tumor. In tumor margins, except CD11b, all the other 4 markers expressed significantly higher in hepatic metastases than in primary tumor. Intra-tumor, CD3 had higher expression in primary tumor than in hepatic metastases, while CD33 had higher expression in hepatic metastases than in primary tumor. CD8+ CD3+ cells of the total CD8+ cell population in primary tumor was significantly higher than in hepatic metastases (36.42% vs. 24.88%, p = 0.0069). CONCLUSIONS: The immune microenvironment between primary tumor and hepatic metastasis is different. More immunosuppressing cells in liver may partially explain why immunotherapy in colon cancer is less effective with liver metastatic disease.

MicroRNA-375 reverses the expression of PD-L1 by inactivating the JAK2/STAT3 signaling pathways in gastric cancer.

BACKGROUND: The mechanism of PD-L1 expression in gastric cancer patients remains unclear. microRNAs (miRs) have been reported to be crucial components of the crosstalk between tumor-immune cells and emerging evidence suggests that microRNA-375 (miR-375) is significantly downregulated in digestive system tumors, but its association with PD-L1 expression in gastric cancer remains to be determined. METHODS: The expression level of miR-375 was first investigated in human gastric cancer tissues and cell lines. Its effect on gastric cancer cell proliferation, migration, invasion, and apoptosis were evaluated in vitro via CCK8, colony formation assays, wound healing assays, transwell assays, and flow cytometry. In vivo experiments using immunodeficient BALB/c nude female mice were also performed. Luciferase reporter assays were employed to identify interactions between miR-375 and its target genes. RESULTS: Quantitative real-time PCR showed that the expression of miR-375 was negatively correlated with PD-L1 in gastric cancer tissues. The overexpression of miR-375 inhibited gastric cancer cell proliferation, migration, invasion, and the knockdown of miR-375 demonstrated opposite effects, both in vitro and in vivo. Luciferase reporter assays showed that miR-375 could bind to the 3'-UTR regions of JAK2 and an inverse association between miR-375 and JAK2/STAT3/PD-L1 expression in gastric cancer cell lines was also observed. In vivo experiments showed that miR-375-overexpression decreased the growth of xenograft tumors in immunodeficient BALB/c mice. CONCLUSIONS: miR-375 negatively regulates PD-L1 expression in gastric cancer via the JAK2/STAT3 signaling pathway and could be a promising novel therapeutic target in gastric cancer.

Bcl-2/Bcl-xl inhibitor APG-1252-M1 is a promising therapeutic strategy for gastric carcinoma.

Gastric carcinoma is the third major cause of cancer-related death in China. Bcl-2 and other BH3 family proteins are critically important in the process of apoptosis pathway, which may be a promising target. APG-1252-M1 specifically connects to Bcl-2 and Bcl-xl. The antitumor effect of APG-1252-M1 in six gastric cancer cells was identified by the Cell Counting Kit-8 assay. The expression level of proapoptotic proteins was evaluated by Western blot. Meanwhile, the cell cycle and apoptosis distributions were analyzed by flow cytometry and JC-1. Xenograft models were used to investigate the roles of APG-1252-M1 in suppressing the growth of tumors and enhancing the chemotherapy antitumor effect. The antitumor effect of APG-1252-M1 was time- and dose-dependent and acted by initiating apoptosis. The change of cell cycle distribution was not discovered in gastric cancer cells treated with APG-1252-M1. APG-1252-M1 also exhibited synergy with chemotherapy in vivo. The combined group inhibited xenograft tumor growth more obviously than the other groups. Moreover, Ki-67 was remarkably decreased in the combination group compared to other groups. In conclusion, APG-1252-M1 had a strong antitumor effect by inducing apoptosis and was synergistic with chemotherapy.

A Novel BCL-2 Inhibitor APG-2575 Exerts Synthetic Lethality With BTK or MDM2-p53 Inhibitor in Diffuse Large B-Cell Lymphoma.

Despite therapeutic advances, the effective treatment for relapsed or refractory diffuse large B-cell lymphoma (DLBCL) remains a major clinical challenge. Evasion of apoptosis through upregulating antiapoptotic B-cell lymphoma-2 (BCL-2) family members and p53 inactivation, and abnormal activation of B-cell receptor signaling pathway are two important pathogenic factors for DLBCL. In this study, our aim is to explore a rational combination of BCL-2 inhibitor plus Brutons tyrosine kinase (BTK) blockade or p53 activation for treating DLBCL with the above characteristics. We demonstrated that a novel BCL-2 selective inhibitor APG-2575 effectively suppressed DLBCL with BCL-2 high expression via activating the mitochondrial apoptosis pathway. BTK inhibitor ibrutinib combined with BCL-2 inhibitors showed synergistic antitumor effect in DLBCL with mean expression of BCL-2 and myeloid cell leukemia-1 (MCL-1) through upregulating the expression level of BIM and modulating MCL-1 and p-Akt expression. For p53 wild-type DLBCL with high expression of BCL-2, APG-2575 showed strong synergic effect with mouse double minute 2 (MDM2)p53 inhibitor APG-115 that can achieve potent antitumor effect and markedly prolong survival in animal models. Collectively, our data provide an effective and precise therapeutic strategy through rational combination of BCL-2 and BTK or MDM2p53 inhibitors for DLBCL, which deserves further clinical investigation.

Preclinical development of HQP1351, a multikinase inhibitor targeting a broad spectrum of mutant KIT kinases, for the treatment of imatinib-resistant gastrointestinal stromal tumors.

BACKGROUND: Imatinib shows limited efficacy in patients with gastrointestinal stromal tumors (GISTs) carrying secondary KIT mutations. HQP1351, an orally bioavailable multikinase BCR-ABL inhibitor, is currently in clinical trials for the treatment of T315I mutant chronic myelogenous leukemia (CML), but the potential application in imatinib-resistant GISTs carrying secondary KIT mutations has not been explored. METHODS: The binding activities of HQP1351 with native or mutant KIT were first analyzed. Imatinib-sensitive GIST T1 and imatinib-resistant GIST 430 cells were employed to test the in vitro antiproliferative activity. Colony formation assay, cell migration assay and cell invasion assay were performed to evaluate the clonogenic, migration and invasion ability respectively. Flow cytometry and western blot analysis were used to detect cell apoptosis, cell cycle and signaling pathway. In vivo antitumor activity was evaluated in mouse xenograft models derived from GIST cell lines. RESULTS: HQP1351 potently inhibited both wild-type and mutant KIT kinases. In both imatinib-resistant and sensitive GIST cell lines, HQP1351 exhibited more potent or equivalent antiproliferative activity compared with ponatinib, a third generation BCR-ABL and KIT inhibitor. HQP1351 led to more profound inhibition of cell colony formation, cell migration and invasion, cell cycle arrest and cell apoptosis than ponatinib. Furthermore, HQP1351 also inhibited p-KIT, p-AKT, p-ERK1/2, and p-STAT3 to a higher extent than ponatinib. Finally, in xenograft tumor models derived from imatinib-resistant GIST cancer cell lines, HQP1351 exhibited antitumor activity superior to ponatinib. CONCLUSIONS: Collectively, our in vitro and in vivo results suggest that the therapeutic application of HQP1351 in imatinib-resistant GIST patients deserves further investigation in clinical trials.

More attention should be paid to adult gastric cancer patients younger than 35 years old: extremely poor prognosis was found.

Purpose: Several studies have reported controversial results about prognosis of gastric cancer in young age patients. The difference may partially result from variable definitions of young age. The aim of this study was to find out the relation between age and prognosis of gastric cancer patients, and to analyze the clinicopathological features and prognostic factors in young gastric cancer patients. Methods: Data queried for this analysis included GC patients from the Surveillance, Epidemiology, and End Results Program database from 1973 to 2014. Gastric cancer patients (N=79,505) diagnosed with an age≥18 were included. By combining patients with similar prognosis, we figured out 3 cutoff values of age, 35 years old, 65 years old and 75 years old. We divided patients into 4 groups: young age patients: 18-34 years; middle-age patients: 35-64 years; elderly patients: 65-74 years; extremely elderly patients: >74 years. GC patients from Sun Yat-sen University Cancer Center (SYSUCC) were used as external validation data. Results: The clinicopathological features of young age gastric cancer patients included: poor-differentiated, diffuse type of cancer, and advanced stage at diagnosis. The median survival of patients <35 years old was significantly lower than middle-age patients (35-64 years) and elderly patients (65-74 years) (12 months vs. 15 and 16 months, respectively, both p <0.001). Location of tumor, ethnicity, tumor size, surgery and TNM stage were independent prognostic factors by multivariate analysis in young patients. The poor prognosis for young patients remained valid in the SYSUCC database. Conclusions: Our results demonstrated that gastric cancer patients <35 years old had an extremely poor prognosis. Early detection of gastric cancer is of paramount importance in young age people.

Correction to: Novel smac mimetic APG-1387 elicits ovarian cancer cell killing through TNF-alpha, Ripoptosome and autophagy mediated cell death pathway.

In the publication of this article [1], there was an error in Figs. 2, 3 and 6.

A novel small molecule inhibitor of MDM2-p53 (APG-115) enhances radiosensitivity of gastric adenocarcinoma.

BACKGROUND: Gastric cancer is the leading cause of cancer related death worldwide. Radiation alone or combined with chemotherapy plays important role in locally advanced and metastatic gastric adenocarcinoma. MDM2-p53 interaction and downstream signaling affect cellular response to DNA damage which leads to cell cycle arrest and apoptosis. Therefore, restoring p53 function by inhibiting its interaction with MDM2 is a promising therapeutic strategy for cancer. APG-115 is a novel small molecule inhibitor which blocks the interaction of MDM2 and p53. In this study, we investigated that the radiosensitivity of APG-115 in gastric adenocarcinoma in vitro and in vivo. METHODS: The role of APG-115 in six gastric cancer cells viability in vitro was determined by CCK-8 assay. The expression level of MDM2, p21, PUMA and BAX in AGS and MKN45 cell lines was measured via real-time PCR (RT-PCR). The function of treatment groups on cell cycle and cell apoptosis were detected through Flow Cytometry assay. Clonogenic assays were used to measure the radiosensitivity of APG-115 in p53 wild type gastric cancer cell lines. Western blot was conducted to detect the protein expressions of mdm2-p53 signal pathway. Xenograft models in nude mice were established to explore the radiosensitivity role of APG-115 in gastric cancer cells in vivo. RESULTS: We found that radiosensitization by APG-115 occurred in p53 wild-type gastric cancer cells. Increasing apoptosis and cell cycle arrest was observed after administration of APG-115 and radiation. Radiosensitivity of APG-115 was mainly dependent on MDM2-p53 signal pathway. In vivo, APG-115 combined with radiation decreased xenograft tumor growth much more significantly than either single treatment. Moreover, the number of proliferating cells (Ki-67) significantly decreased in combination group compared with single treatment group. CONCLUSIONS: In summary, we found that combination of MDM2-p53 inhibitor (APG-115) and radiotherapy can enhance antitumor effect both in vitro and in vivo. This is the first report on radiosensitivity of APG-115 which shed light on clinical trial of the combination therapy of radiation with APG-115 in gastric adenocarcinoma.

A novel SMAC mimetic APG-1387 exhibits dual antitumor effect on HBV-positive hepatocellular carcinoma with high expression of cIAP2 by inducing apoptosis and enhancing innate anti-tumor immunity.

Check point inhibitor anti-PD1 antibody produced some efficacy in Hepatocellular Carcinoma (HCC) patients previously treated with sorafenib. Unfortunately, HCC patients with hepatitis B virus (HBV) infection did not respond as well as uninfected patients. Previously, Second mitochondria-derived activator of caspases (SMAC) mimetics-the antagonist for inhibitor of apoptosis proteins (IAPs) can rapidly reduce serum hepatitis B virus DNA in animal model. APG-1387 is a novel SMAC-mimetic, small molecule inhibitor targeting inhibitor of apoptosis proteins (IAPs). In our study, firstly, we found that HCC patients with copy number alteration of cIAP1, cIAP2, and XIAP had a dismal prognosis. Then, we discovered that APG-1387 alone could induce apoptosis of PLC/PRF/5 which was HBV positive both in-vitro and in-vivo. Furthermore, we found that APG-1387 significantly up-regulated the expression of calreticulin and HLA-DR in PLC/PRF/5 via activating non-classic NF-κB pathway. Also, compared to vehicle group, APG-1387 increased NK cell counts by 5 folds in PLC/PRF/5 xenograft model. In-vitro, APG-1387 positively regulated T cells by reducing Treg differentiation and down-regulating PD1 expression in CD4 T cell. Moreover, APG-1387 had no impact on memory T cells. Consequently, our results suggest that APG1387 could be a good candidate to combine with anti-PD1 antibody treatment to overcome low responds of check point inhibitors in HBV positive HCC.

Novel smac mimetic APG-1387 elicits ovarian cancer cell killing through TNF-alpha, Ripoptosome and autophagy mediated cell death pathway.

BACKGROUND: Ovarian cancer is a deadly disease. Inhibitors of apoptosis proteins (IAPs) are key regulators of apoptosis and are frequently dysregulated in ovarian cancer. Overexpression of IAPs proteins has been correlated with tumorigenesis, treatment resistance and poor prognosis. Reinstalling functional cell death machinery by pharmacological inhibition of IAPs proteins may represent an attractive therapeutic strategy for treatment of ovarian cancer. METHODS: CCK-8 and colony formation assay was performed to examine cytotoxic activity. Apoptosis was analyzed by fluorescence microscopy, flow cytometry and TUNEL assay. Elisa assay was used to determine TNFα protein. Caspase activity assay was used for caspase activation evaluation. Immunoprecipitation and siRNA interference were carried out for functional analysis. Western blotting analysis were carried out to test protein expression. Ovarian cancer cell xenograft nude mice model was used for in vivo efficacy evaluation. RESULTS: APG-1387 demonstrated potent inhibitory effect on ovarian cancer cell growth and clonogenic cell survival. APG-1387 induced RIP1- and TNFα-dependent apoptotic cell death in ovarian cancer through downregulation of IAPs proteins and induction of caspase-8/FADD/RIP1 complex, which drives caspase-8 activation. NF-κB signaling pathway was activated upon APG-1387 treatment and RIP1 contributed to NF-κB activation. APG-1387 induced cytoprotective autophagy while triggering apoptosis in ovarian cancer cells and inhibition of autophagy enhanced APG-1387-induced apoptotic cell death. APG-1387 exhibited potent antitumor activity against established human ovarian cancer xenografts. CONCLUSIONS: Our results demonstrate that APG-1387 targets IAPs proteins to potently elicit apoptotic cell death in vitro and in vivo, and provide mechanistic and applicable rationale for future clinical evaluation of APG-1387 in ovarian cancer.

Fully digital programmable optical frequency comb generation and application.

We propose a fully digital programmable optical frequency comb (OFC) generation scheme based on binary phase-sampling modulation, wherein an optimized bit sequence is applied to phase modulate a narrow-linewidth light wave. Programming the bit sequence enables us to tune both the comb spacing and comb-line number (i.e., number of comb lines). The programmable OFCs are also characterized by ultra-flat spectral envelope, uniform temporal envelope, and stable bias-free setup. Target OFCs are digitally programmed to have 19, 39, 61, 81, 101, or 201 comb lines and to have a 100, 50, 20, 10, 5, or 1 MHz comb spacing. As a demonstration, a scanning-free temperature sensing system using a proposed OFC with 1001 comb lines was also implemented with a sensitivity of 0.89°C/MHz.

APG-1252-12A induces mitochondria-dependent apoptosis through inhibiting the antiapoptotic proteins Bcl-2/Bcl-xl in HL-60 cells.

Acute myeloid leukemia (AML) is the most common acute leukemia in adults. Despite improved remission rates, current treatment regimens for AML are often associated with a very poor prognosis and adverse effects, necessitating more effective and safer agents. B-cell leukemia/lymphoma 2 (Bcl-2) family proteins regulate apoptotic pathway that can be targeted with small molecule inhibitors. APG-1252-12A is a Bcl-2 homology (BH)-3 mimetic that specifically binds to Bcl-2 and Bcl-xl, which has shown efficacy in some Bcl-2 dependent hematological cancers. In this study, we investigated whether APG-1252-12A inhibits the growth of five leukemia cell lines in a concentration- or time-dependent manner by MTS assay. Following treatment of AML cell line HL-60 with this compound, cell apoptosis was detected using flow cytometry and nuclear condensation was observed after Hoechst 33258 dye. Immunoblotting for cytochrome c, cleaved caspase-3 and PARP-1 cleavage was used to demonstrate the mechanism of inducing mitochondria-dependent apoptosis by APG-1252-12A. Our findings showed that this new compound inhibited cell proliferation in five leukemia cell lines and induced apoptotic death. There was a link between the level of Bcl-2 protein and IC50. APG-1252-12A targeted mitochondria and induced caspase-dependent apoptosis by inducing the HL-60 cell cytochrome c released, PARP cleavage and caspase activation. These data suggested that APG-1252-12A is a candidate drug for the in vivo analysis and clinical evaluation in AML.

Restoration of p53 using the novel MDM2-p53 antagonist APG115 suppresses dedifferentiated papillary thyroid cancer cells.

Dedifferentiated papillary thyroid cancer (DePTC) is characterized by aggressive growth, recurrence, distant metastasis, and resistance to radioactive iodine (RAI) therapy. DePTC is also accompanied by poor prognosis and high early-mortality. Nevertheless, most DePTC cells show intact p53 downstream functionality. In cells with wild-type p53, the murine double minute2 (MDM2) protein interacts with p53 and abrogates its activity. Inhibition of the MDM2-p53 interaction restores p53 activity and leads to cell cycle arrest and apoptosis. Restoring p53 function by inhibiting its interaction with p53 suppressors such as MDM2 is thus a promising therapeutic strategy for the treatment of DePTC. The novel MDM2-p53 interaction antagonist APG115 is an analogue of SAR405838, and is being tested in a phase I clinical trial. In this study, we evaluated the efficacy of APG115 as a single-agent to treat DePTC. APG115 diminished the viability of p53 wild-type DePTC cells and induced cell cycle arrest and apoptosis. In a human xenograft mouse model, APG115 elicited robust tumor regression and cell apoptosis. These data demonstrate that further research is warranted to determine whether APG115 can be used to effectively treat DePTC patients.

Wideband Doppler frequency shift measurement and direction ambiguity resolution using optical frequency shift and optical heterodyning.

A photonic approach for both wideband Doppler frequency shift (DFS) measurement and direction ambiguity resolution is proposed and experimentally demonstrated. In the proposed approach, a light wave from a laser diode is split into two paths. In one path, the DFS information is converted into an optical sideband close to the optical carrier by using two cascaded electro-optic modulators, while in the other path, the optical carrier is up-shifted by a specific value (e.g., from several MHz to hundreds of MHz) using an optical-frequency shift module. Then the optical signals from the two paths are combined and detected by a low-speed photodetector (PD), generating a low-frequency electronic signal. Through a subtraction between the specific optical frequency shift and the measured frequency of the low-frequency signal, the value of DFS is estimated from the derived absolute value, and the direction ambiguity is resolved from the derived sign (i.e., + or -). In the proof-of-concept experiments, DFSs from -90 to 90 kHz are successfully estimated for microwave signals at 10, 15, and 20 GHz, where the estimation errors are lower than ±60 Hz. The estimation errors can be further reduced via the use of a more stable optical frequency shift module.