Highly potent, orally active novel small-molecule HPK1 inhibitor DS21150768 induces anti-tumor responses in multiple syngeneic tumor mouse models.

Augmenting T-cell activity is a promising approach to enhance the efficacy of cancer immunotherapy treatment. Hematopoietic progenitor kinase 1 (HPK1) is predominantly expressed in immune cells and negatively regulates T-cell receptor signaling. It is reported that inhibition of the kinase function of HPK1 results in tumor growth suppression by enhancing cancer immunity. Thus, developing HPK1 inhibitors has attracted considerable attention as a future cancer immunotherapy approach. However, despite recent progress in HPK1 biology and pharmacology, various challenges still remain, such as developing HPK1 inhibitors with favorable pharmacological profiles and identifying tumor characteristics that can be applied to define susceptibility to HPK1 inhibition. Here, we present the identification and pharmacological evaluation of DS21150768, a potent small-molecule HPK1 inhibitor with a novel chemical scaffold. DS21150768 shows remarkable inhibition of HPK1 kinase activity, and in vitro studies demonstrated its potent activity to enhance T-cell function. DS21150768 is orally bioavailable and shows sustained plasma exposure, which leads to enhanced cytokine responses in vivo. We conducted a comparison of the anti-tumor efficacy of DS21150768 alone or in combination with anti-PD-1 antibody in 12 different mouse cancer cell models, and observed that the treatments suppressed tumor growth in multiple models. Furthermore, Gene Set Enrichment Analysis demonstrated significant enrichment of immune-related gene signatures in the tumor models responsive to DS21150768 treatment. Our results provide a path forward for the future development of HPK1 inhibitors and fundamental insights into biomarkers of HPK1-targeted therapy.

Endoscopic Closure of an Acute Duodenal Perforation Occurring during Endoscopic Ultrasound Using Endoclips and Polyglycolic Acid Sheets with Fibrin Glue.

Acute duodenal perforation during endoscopic ultrasound (EUS) is a serious complication. The conventional endoscopic treatment for duodenal perforations such as endoscopic clipping is unsatisfactory; recently, the effectiveness of over-the-scope clipping (OTSC) has been reported. A 91-year-old woman was referred to our hospital with the chief complaint of jaundice. Contrast-enhanced computed tomography showed a 2-cm mass in the pancreatic head; we planned EUS-guided fine-needle aspiration. During exploration for a puncture route from the duodenal bulb using a linear echoendoscope under carbon dioxide insufflation, the duodenal lumen was suddenly filled with blood. A perforation <15 mm was identified in the superior duodenal horn. We attempted an endoscopic closure with multiple endoclips but could not completely close the perforation site. Strips of bioabsorbable polyglycolic acid (PGA) sheets were placed over the gaps between the endoclips with biopsy forceps and fixed in place with fibrin glue, completely covering the perforation site. Two days after the procedure, the perforation site had closed. Nine days later, endoscopic biliary stenting was performed. The patient was diagnosed with pancreatic cancer through bile cytology, and the optimal supportive care for her age was selected. Endoscopic tissue shielding with PGA sheets and fibrin glue is increasingly being reported for use during gastrointestinal endoscopic procedures. In this case, surgery was avoided due to successful endoscopic treatment using endoclips and PGA sheets with fibrin glue without OTSC. This method may be useful for repairing acute duodenal perforations during EUS and should therefore be known to pancreatobiliary endoscopists.

A case of cytomegalovirus esophagitis during topical steroid therapy for eosinophilic esophagitis.

Systemic immune deficiency is a major cause of cytomegalovirus (CMV) esophagitis. We report a case of CMV esophagitis during topical steroid therapy of eosinophilic esophagitis (EoE) in a non-immunodeficient patient. An 85-year-old man with dysphagia was on a 6-year regimen of oral budesonide (1200 mcg daily) for EoE. He underwent right upper lobectomy and postoperative radiotherapy 25 years ago for lung squamous cell carcinoma. Esophageal cicatricial stenosis due to EoE or previous radiation therapy persisted. Esophagogastroduodenoscopy revealed ulcerating mucosa with a thick white coat originating from the fixed stenotic lesion to the oral side. Histopathological examinations revealed CMV esophagitis. All signs of CMV esophagitis rapidly disappeared after reducing the budesonide dose and initiating anti-viral treatment with ganciclovir and valganciclovir for 12 and 2 days, respectively. The patient continued topical budesonide 400 mcg daily after anti-viral therapy. The clinical course was uneventful and without CMV esophagitis recurrence. This suggests that topical steroid therapy, particularly the local stasis of steroids at stenotic lesions, may induce CMV esophagitis. This is the first report of CMV esophagitis complicating the local steroid therapy of EoE with a stenotic lesion. When EoE patients' clinical symptoms worsen with topical steroid therapy, CMV esophagitis should be considered.

A case of esophageal cancer with human immunodeficiency virus infection that progressed rapidly after neoadjuvant chemoradiotherapy.

While antiretroviral therapy has improved mortality in patients with human immunodeficiency virus (HIV) infections, deaths caused by non-acquired immunodeficiency syndrome-defining malignancies are increasing. A woman in her 70s with HIV infection who was receiving antiretroviral therapy presented with dysphagia. She was diagnosed with esophageal cancer (cT3N2M0, stage III). She received neoadjuvant chemotherapy (cisplatin and 5-fluorouracil) and radiotherapy. During treatment, we continued administering antiretroviral therapy and prophylaxis for opportunistic infections, with due attention to side effects and drug-drug interactions. No severe adverse events occurred. The primary lesion and metastatic lymph nodes decreased in size after treatment; however, 1 month later, her cancer spread to other organs; thus, surgery was canceled. Her general condition rapidly worsened. She eventually died of cancer cachexia and aspiration pneumonia. No previous reports have mentioned the treatment plan and management of esophageal cancer in HIV-positive patients. This report presents a case of esophageal cancer with HIV infection that progressed rapidly after neoadjuvant chemoradiotherapy.

Novel orally bioavailable EZH1/2 dual inhibitors with greater antitumor efficacy than an EZH2 selective inhibitor.

Polycomb repressive complex 2 (PRC2) methylates histone H3 lysine 27 and represses gene expression to regulate cell proliferation and differentiation. Enhancer of zeste homolog 2 (EZH2) or its close homolog EZH1 functions as a catalytic subunit of PRC2, so there are two PRC2 complexes containing either EZH2 or EZH1. Tumorigenic functions of EZH2 and its synthetic lethality with some subunits of SWItch/Sucrose Non-Fermentable (SWI/SNF) chromatin remodeling complexes have been observed. However, little is known about the function of EZH1 in tumorigenesis. Herein, we developed novel, orally bioavailable EZH1/2 dual inhibitors that strongly and selectively inhibited methyltransferase activity of both EZH2 and EZH1. EZH1/2 dual inhibitors suppressed trimethylation of histone H3 lysine 27 in cells more than EZH2 selective inhibitors. They also showed greater antitumor efficacy than EZH2 selective inhibitor in vitro and in vivo against diffuse large B-cell lymphoma cells harboring gain-of-function mutation in EZH2. A hematological cancer panel assay indicated that EZH1/2 dual inhibitor has efficacy against some lymphomas, multiple myeloma, and leukemia with fusion genes such as MLL-AF9, MLL-AF4, and AML1-ETO. A solid cancer panel assay demonstrated that some cancer cell lines are sensitive to EZH1/2 dual inhibitor in vitro and in vivo. No clear correlation was detected between sensitivity to EZH1/2 dual inhibitor and SWI/SNF mutations, with a few exceptions. Severe toxicity was not seen in rats treated with EZH1/2 dual inhibitor for 14 days at drug levels higher than those used in the antitumor study. Our results indicate the possibility of EZH1/2 dual inhibitors for clinical applications.

Discovery of novel Thieno[2,3-d]pyrimidin-4-yl hydrazone-based cyclin-dependent kinase 4 inhibitors: synthesis, biological evaluation and structure-activity relationships.

The design, synthesis, and evaluation of novel thieno[2,3-d]pyrimidin-4-yl hydrazone analogues as cyclin-dependent kinase 4 (CDK4) inhibitors are described. In continuing our program aim to search for potent CDK4 inhibitors, the introduction of a thiazole group at the hydrazone part has led to marked enhancement of chemical stability. Furthermore, by focusing on the optimization at the C-4' position of the thiazole ring and the C-6 position of the thieno[2,3-d]pyrimidine moiety, compound 35 has been identified with efficacy in a xenograft model of HCT116 cells. In this paper, the potency, selectivity profile, and structure-activity relationships of our synthetic compounds are discussed.

Structure-activity relationships of 1,3-benzoxazole-4-carbonitriles as novel antifungal agents with potent in vivo efficacy.

A series of 1,3-benzoxazole-4-carbonitriles was synthesized and evaluated for its antifungal activity, solubility, and metabolic stability. Among those compounds, 4-cyano-N,N,5-trimethyl-7-[(3S)-3-methyl-3-(methylamino)pyrrolidin-1-yl]-6-phenyl-1,3-benzoxazole-2-carboxamide (16b) exhibited potent in vitro activity against Candida species, higher water solubility, and improved metabolic stability compared to lead compound 1. Compound 16b showed potent in vivo efficacy against mice Candida infection models and good bioavailability in rats.

1,3-Benzoxazole-4-carbonitrile as a novel antifungal scaffold of ß-1,6-glucan synthesis inhibitors.

Synthesis and in vitro antifungal evaluations of 1,3-benzoxazole-7-carbonitrile 3, 1,3-benzoxazole-4-carbonitrile 4, benzofuran 5, benzoxazine 7, and benzimidazole 8 were reported. Among them, 1,3-benzoxazole-4-carbonitrile was found to be a superior scaffold structure with moderate growth inhibition against Candida species. 1,3-Benzoxazole-4-carbonitrile 6 showed potent activity against Candida species compared to 5-desmethyl compound 4 and triazolopyridine 2. Compound 6 was efficiently prepared from versatile intermediate 24, which possessed six different substituents on the benzene ring. Conversion of benzene 24 into various 1,3-benzoxazole derivatives such as 2-aliphatic 34, 2-amino 35, and lactone 38 was demonstrated.

Severe duodenal hemorrhage induced by Lugol's solution administered for thyroid crisis treatment.

Lugol's solution is an iodinated agent used for treating thyroid crisis. It is primarily used in diagnostic tests for esophageal diseases. However, Lugol's solution can cause local mucosal injury and hemorrhage. We report, for the first time, a case of 34-year-old man who exhibited severe duodenal hemorrhage induced by Lugol's solution that was used to treat thyroid crisis. The quantity of Lugol's solution used for treating thyroid crisis is much higher than that used for mucosal disease investigation. Clinical practitioners should be aware of gastrointestinal hemorrhage when using Lugol's solution for the treatment of thyroid crisis.

Discovery of novel thieno[2,3-d]pyrimidin-4-yl hydrazone-based inhibitors of cyclin D1-CDK4: synthesis, biological evaluation and structure-activity relationships. Part 2.

The design, synthesis and evaluation of novel thieno[2,3-d]pyrimidin-4-yl hydrazone analogues as cyclin-dependent kinase 4 (CDK4) inhibitor are described. Focusing on the optimization of the heteroaryl moiety at the hydrazone with substituted phenyl groups, 4-[(methylamino)methyl]benzaldehyde (22) and 5-isoindolinecarbaldehyde (24) (6-tert-butylthieno[2,3-d]pyrimidin-4-yl)hydrazone derivatives have been identified. In this paper, the potency, selectivity profile and structure-activity relationships of our synthetic compounds are discussed.

Discovery of novel thieno[2,3-d]pyrimidin-4-yl hydrazone-based inhibitors of Cyclin D1-CDK4: synthesis, biological evaluation, and structure-activity relationships.

The synthesis and evaluation of new analogues of thieno[2,3-d]pyrimidin-4-yl hydrazones are described. 2-Pyrdinecarboxaldehyde [6-(tert-butyl)thieno[2,3-d]pyrimidine-4-yl]hydrazone derivatives have been identified as cyclin-dependent kinase 4 (CDK4) inhibitors. The potency, selectivity profile, and structure-activity relationship of this series of compounds are discussed.

4-(Pyrrolidinyl)methoxybenzoic acid derivatives as a potent, orally active VLA-4 antagonist.

A novel series of benzoic acid derivatives as VLA-4 antagonists were synthesized. Optimization, focusing on activity and lipophilicity needed for cell permeability, resulted in the identification of 15b and 15e with good activity (IC50 = 1.6 nM each) and moderate lipophilicity (Log D = 2.0, 1.8). Furthermore, 15e demonstrated efficacy in murine asthma model by an oral dose of 30 mg/kg.

Dark-field transmission electron microscopy for a tilt series of ordering alloys: toward electron tomography.

Here we show a technique to obtain a tilt series of dark-field (DF) transmission electron microscopy (TEM) images in ordering alloys for tomographic three-dimensional (3D) observations. A tilt series of DF TEM images of D1a-ordered Ni4Mo precipitates in a Ni-Mo alloy was successfully obtained by adjusting a diffraction condition for a superlattice reflection from the Ni4Mo precipitates. Since the superlattice reflection usually has a long extinction distance, dynamic diffraction effects such as thickness fringes can be suppressed to some extent with precise realignment of the diffraction condition. By using the tilt series of the DF TEM images, we attempted a computed TEM tomography to visualize 3D shapes and positions of the precipitates.

[An abdominal follicular dendritic cell tumor in Castleman's disease].

A 57-year-old man was referred to our hospital because of elevated ALP. CT and MRI scans together with abdominal angiography showed multiple masses in his abdomen and portal vein obstruction. A diagnostic laparoscopic examination revealed a tumor of 3 cm x 3 cm near the portal vein and para-aortic lymphadenopathy. Histopathological examination of the tumor showed abnormal follicles with poorly formed germinal centers, scattered large spindle cells with proliferation of small lymphocytes, and hypervascular interfollicular tissue. The spindle cells were positive for follicular dendritic cell markers CD21, CD35, and epithelial membrane antigen. The diagnosis was made of a follicular dendritic cell (FDC) tumor in Castleman's disease (CD) of the hyaline-vascular type. Although the portal vein was obstructed by the FDC tumor, blood flow to the liver was retained by collateral vein. The patient did not show any response to four courses of CHOP therapy and died of obstructive jaundice, biliary tract infection and sepsis. So far, 17 cases of FDC tumor complicating CD have been reported, with a poor prognosis in all cases.

New highly active taxoids from 9beta-dihydrobaccatin-9,10-acetals. Part 4.

It was shown that a new taxane analogue 3, which exhibited both in vitro antitumor activity and in vivo efficacy by both i.v. and p.o. administration, was prone to be metabolized by human liver microsomes. We identified a major metabolite, M-1, generated by human liver microsomes as 20a, a hydroxylated compound at the pyridine ring of 3. To improve the metabolic stability of 3, we designed and synthesized new taxane analogues based on the structure of M-1, and obtained some compounds that maintained excellent antitumor activity and were scarcely metabolized by human liver microsomes.

Cutting edge: role of Toll-like receptor 1 in mediating immune response to microbial lipoproteins.

The Toll-like receptor (TLR) family acts as pattern recognition receptors for pathogen-specific molecular patterns (PAMPs). TLR2 is essential for the signaling of a variety of PAMPs, including bacterial lipoprotein/lipopeptides, peptidoglycan, and GPI anchors. TLR6 associates with TLR2 and recognizes diacylated mycoplasmal lipopeptide along with TLR2. We report here that TLR1 associates with TLR2 and recognizes the native mycobacterial 19-kDa lipoprotein along with TLR2. Macrophages from TLR1-deficient (TLR1(-/-)) mice showed impaired proinflammatory cytokine production in response to the 19-kDa lipoprotein and a synthetic triacylated lipopeptide. In contrast, TLR1(-/-) cells responded normally to diacylated lipopeptide. TLR1 interacts with TLR2 and coexpression of TLR1 and TLR2 enhanced the NF-kappaB activation in response to a synthetic lipopeptide. Furthermore, lipoprotein analogs whose acylation was modified were preferentially recognized by TLR1. Taken together, TLR1 interacts with TLR2 to recognize the lipid configuration of the native mycobacterial lipoprotein as well as several triacylated lipopeptides.

Small anti-viral compounds activate immune cells via the TLR7 MyD88-dependent signaling pathway.

The imidazoquinoline compounds imiquimod and R-848 are low-molecular-weight immune response modifiers that can induce the synthesis of interferon-alpha and other cytokines in a variety of cell types. These compounds have potent anti-viral and anti-tumor properties; however, the mechanisms by which they exert their anti-viral activities remain unclear. Here we show that the imidazoquinolines activate immune cells via the Toll-like receptor 7 (TLR7)-MyD88-dependent signaling pathway. In response to the imidazoquinolines, neither MyD88- nor TLR7-deficient mice showed any inflammatory cytokine production by macrophages, proliferation of splenocytes or maturation of dendritic cells. Imidazoquinoline-induced signaling events were also abolished in both MyD88- and TLR7-deficient mice.