Human Tumor Research Articles

GHRH and the prostate.

In the late 1960s and early 1970s, hypothalamic regulatory hormones were isolated, characterized and sequenced. Later, it was demonstrated hypothalamic and ectopic production of growth hormone-releasing hormone (GHRH) in normal and tumor tissues, of both humans and animals. Pituitary-type GHRH receptors (pGHRH-R) had been demonstrated to be expressed predominantly in the anterior pituitary gland but also found in other somatic cells, and significantly present in various human cancers; in addition, the expression of splice variants (SVs) of GHRH receptor (GHRH-R) has been found not only in the pituitary but in extrapituitary tissues, including human neoplasms. In relation to the prostate, besides the pGHRH-R, it has been detected the presence of truncated splice variants of GHRH-R (SV1-SV4) in normal human prostate and human prostate cancer (PCa) specimens; lastly, a novel SV of GHRH-R has been detected in human PCa. Signaling pathways activated by GHRH include AC/cAMP/PKA, Ras/Raf/ERK, PI3K/Akt/mTOR and JAK2/STAT3, which are involved in processes such as cell survival, proliferation and cytokine secretion. The neuropeptide GHRH can also transactivate the epidermal growth factor receptor (EGFR) and human epidermal growth factor receptor (HER)-2. Thus, GHRH-Rs have become drug targets for several types of clinical conditions, including prostate-related conditions such as prostatitis, benign hyperplasia and cancer. Over the last fifty years, the development of GHRH-R receptor antagonists has been unstoppable, improving their potency, stability and affinity for the receptor. The last series of GHRH-R antagonists, AVR, exhibits superior anticancer and anti-inflammatory activities in both in vivo and in vitro assays.

A Cancer-Specific Anti-Podoplanin Monoclonal Antibody, PMab-117-mG2a Exerts Antitumor Activities in Human Tumor Xenograft Models

Podoplanin (PDPN) overexpression is associated with poor clinical outcomes in various tumors. PDPN is involved in malignant tumor progression by promoting invasiveness and metastasis. Therefore, PDPN is considered a promising target of monoclonal antibody (mAb)-based therapy. Because PDPN also plays an essential role in normal cells such as kidney podocytes, cancer specificity is required to reduce adverse effects on normal cells. We developed a cancer-specific mAb (CasMab) against PDPN, PMab-117 (rat IgM, kappa), by immunizing rats with PDPN-overexpressed glioblastoma cells. The recombinant mouse IgG2a-type PMab-117 (PMab-117-mG2a) reacted with the PDPN-positive tumor PC-10 and LN319 cells but not with PDPN-knockout LN319 cells in flow cytometry. PMab-117-mG2a did not react with normal kidney podocytes and normal epithelial cells from the lung bronchus, mammary gland, and corneal. In contrast, one of the non-CasMabs against PDPN, NZ-1, showed high reactivity to PDPN in both tumor and normal cells. Moreover, PMab-117-mG2a exerted antibody-dependent cellular cytotoxicity in the presence of effector splenocytes. In the human tumor xenograft models, PMab-117-mG2a exhibited potent antitumor effects. These results indicated that PMab-117-mG2a could be applied to antibody-based therapy against PDPN-expressing human tumors while reducing the adverse effects.

A B7-H3–Targeted CD28 Bispecific Antibody Enhances the Activity of Anti–PD-1 and CD3 T-cell Engager Immunotherapies

Abstract T-cell activation is a multistep process requiring T-cell receptor engagement by peptide–MHC complexes (Signal 1) coupled with CD28-mediated costimulation (Signal 2). Tumors typically lack expression of CD28 ligands, so tumor-specific Signal 1 (e.g., neoepitope presentation) without costimulation may be ineffective or even induce T-cell anergy. We designed the bispecific antibody XmAb808 to co-engage the tumor-associated antigen B7-H3 with CD28 to promote T-cell costimulation within the tumor microenvironment. XmAb808 costimulation was measured by its ability to activate and expand T cells and enhance T cell–mediated cancer cell killing in cocultures of human peripheral blood mononuclear cells and cancer cells and in mice engrafted with human peripheral blood mononuclear cells and tumor xenografts. XmAb808 avidly bound cancer cells and stimulated IL2 and IFNγ secretion from T cells cocultured with cancer cells engineered to deliver Signal 1 to T cells via a surface-expressed anti-CD3 antibody. XmAb808 enhanced expression of the antiapoptotic factor Bcl-xL and CD25, promoting survival and IL2-dependent expansion of T cells coupled with increased T cell–mediated cytotoxicity in vitro. XmAb808 combined with an EpCAM×CD3 bispecific antibody to enhance target cell killing through IL2-dependent expansion of CD25+ T cells. This combination also suppressed pancreatic tumor xenograft growth in mice. Furthermore, XmAb808 combined with an anti–programmed cell death protein 1 antibody to suppress breast tumor xenograft growth in mice. XmAb808 as monotherapy and in combination with an anti–programmed cell death protein 1 antibody is currently in clinical development in patients with advanced solid tumors. Our results suggest that XmAb808 may also combine with tumor antigen–targeted anti-CD3 (Signal 1) T-cell engagers.

TMEM206 Contributes to Cancer Hallmark Functions in Colorectal Cancer Cells and Is Regulated by p53 in a p21-Dependent Manner

Acid-induced ion flux plays a role in pathologies where tissue acidification is prevalent, including cancer. In 2019, TMEM206 was identified as the molecular component of acid-induced chloride flux. Localizing to the plasma membrane, TMEM206 contributes to cellular processes like acid-induced cell death. Since over 50% of human cancers carry loss of function mutations in the p53 gene, we aimed to analyze how TMEM206 is regulated by p53 and its role in cancer hallmark function and acid-induced cell death in HCT116 colorectal cancer (CRC) cells. We generated p53-deficient HCT116 cells and assessed TMEM206-mediated Cl− currents and transcriptional regulation using the patch-clamp and a dual-luciferase reporter assay, respectively. To investigate the contribution of TMEM206 to cancer hallmark functions, we performed migration and metabolic activity assays. The role of TMEM206 in p53-mediated acid-induced cell death was assessed with cell death assays. The TMEM206 mRNA level was significantly elevated in human primary CRC tumors. TMEM206 knockout increased acid-induced cell death and reduced proliferation and migration, indicating a role for TMEM206 in these cancer hallmark functions. Furthermore, we observed increased TMEM206 mRNA levels and currents in HCT116 p53 knockout cells. This phenotype can be rescued by transient overexpression of p53 but not by overexpression of dysfunctional p53. In addition, our data suggest that TMEM206 may mediate cancer hallmark functions within p53-associated pathways. TMEM206 promoter activity is not altered by p53 overexpression. Conversely, knockout of p21, a major target gene of p53, increased TMEM206-mediated currents, suggesting expression control of TMEM206 by p21 downstream signaling. Our results show that in colorectal cancer cells, TMEM206 expression is elevated, contributes to cancer hallmark functions, and its regulation is dependent on p53 through a p21-dependent mechanism.

PPM1D/Wip1 is amplified, overexpressed, and mutated in human non-Hodgkin's lymphomas.

Wip1, is a p53-dependent Ser/Thr phosphatase involved in the timely termination of DDR. The PPM1D gene encoding Wip1 is deregulated and thus gained an oncogene character in common human solid tumors and cell lines. This study assessed the oncogenic potential of the PPM1D gene in human non- Hodgkin's lymphomas (NHL), the most common hematological malignancy worldwide. FFPE human lymphoid hyperplasia (LH) (n = 17) and NHL tumor lymph node samples (n = 65) and human NHL cell lines were used to assess the oncogenic potential of the PPM1D gene in the present study. Copy number gain and mRNA expression analysis of the PPM1D/Wip1 gene were assessed by qRT-PCR analysis. Mutational analysis of Exon 6 of the PPM1D gene was performed by PCR amplification and Sanger sequencing. Expressions of Wip1 and p53 proteins were assessed by immunohistochemistry and Western blot analysis. We found that PPM1D gained gene copy number in NHL tumors by 0.7-8 times compared to the control (p < 0.01). Increased PPM1D/Wip1 gene copy number was associated with higher mRNA and protein expression in human NHL samples (p < 0.01). Overexpression of Wip1 in NHL tumors and NHL cell lines was associated with amplification level and was unaffected by p53 status. Furthermore, a heterozygous type insertion mutation was detected in exon 6 (c.1553_1554insA) of the PPM1D gene particularly in DLBCL samples. Wip1 may have oncogenic potential, perhaps playing a role in the onset and progression of human NHL. The possible significance of Wip1 overexpression to chemotherapy response in NHL remains an intriguing question that requires more exploration.

Structurally Diverse Limonoids from Trichilia connaroides and Their Antitumor Activities

Comprehensive SummaryTwelve new limonoids (1—12), named trichilitins A—L, were isolated from the leaves and twigs of Trichilia connaroides, together with ten known compounds (13—22). The structures were elucidated by extensive spectroscopic investigations, X‐ray diffraction analyses, and ECD calculations. Compound 1, which belongs to a unique class of ring B‐seco limonoid, has been identified as 6/7/6/5 tetracyclic due to a key Baeyer‐Villiger oxidation. Compounds 2—7 were identified as ring intact limonoids, while compounds 8—10 were established as ring D‐seco ones, and 11 and 12 were determined to be rearranged ones. All of the compounds were tested for cytotoxicity against three human tumor cell lines (HCT‐116, NCl‐H1975, and SH‐SY5Y). Compounds 6, 7, 13, 14, and 19 exhibited significant cytotoxic effects, especially 7 exhibited significant cytotoxic effects against HCT‐116 with an IC50 value of 0.035 μmol·L–1 and was more active than the positive control, doxorubicin with an IC50 value of 0.20 μmol·L–1. Compound 7 effectively induced apoptosis of HCT‐116, which was associated with S‐phase cell cycle arrest. Furthermore, the Western blot analysis showed that compound 7 could induce cell cycle arrest by promoting the expression levels of p53 and p21.

Genomic and transcriptomic landscape of human gastrointestinal stromal tumors

Gastrointestinal stromal tumor (GISTs) are clinically heterogenous exhibiting varying degrees of disease aggressiveness in individual patients. We comprehensively describe the genomic and transcriptomic landscape of a cohort of 117 GISTs including 31 low-risk, 18 intermediate-risk, 29 high-risk, 34 metastatic and 5 neoadjuvant GISTs from 105 patients. GISTs have notably low tumor mutation burden but widespread copy number variations. Aggressive GISTs harbor remarkably more genomic aberrations than low-/intermediate-risk GISTs. Complex genomic alterations, chromothripsis and kataegis, occur selectively in aggressive GISTs. Despite the paucity of mutations, recurrent inactivating YLPM1 mutations are identified (10.3%, 7 of 68 patients), enriched in high-risk/metastatic GIST and functional study further demonstrates YLPM1 inactivation promotes GIST proliferation, growth and oxidative phosphorylation. Spatially and temporally separated GISTs from individual patients demonstrate complex tumor heterogeneity in metastatic GISTs. Finally, four prominent subtypes are proposed with different genomic features, expression profiles, immune characteristics, clinical characteristics and subtype-specific treatment strategies. This large-scale analysis depicts the landscape and provides further insights into GIST pathogenesis and precise treatment.

Ly6E on tumor cells impairs anti-tumor T-cell responses: a novel mechanism of tumor-induced immune exclusion

BackgroundLymphocyte antigen 6 complex, locus E (Ly6E) has been initially demonstrated to involve in T cell activity and impair viral infectivity. Recently, high expression levels of Ly6E have been reported in tumor microenvironment (TME) of various types of cancers. However, the immunoregulatory mechanism of Ly6E manipulating TME remains unknown.MethodsTCGA database and Kaplan–Meier plotter database were used to evaluate the correlation between Ly6E expression levels and cancer patient survival. After analyzing Ly6E expression levels in human breast cancer tissues and tumor cell lines, we generated Ly6E knockout (KO) and overexpression (OE) mouse cell lines. Cell proliferation ability in vitro and the ability of growth and metastasis in mouse tumor models were compared between KO/OE and wild-type tumor cells. On day 7 after tumor implantation, tumor tissues were separated for flow cytometric assay, bulk RNA sequencing and single-cell RNA sequencing (ScRNA-seq). The role of Ly6E-expressing tumor cell on macrophage was analyzed in vitro.ResultsOur result surprisingly found that high Ly6E expression levels were associated with CD8+ T cell exclusion in tumor tissues and resistance to immunotherapy. Our data showed that knockout of Ly6E in tumor cells prompts tumor regression and inhibits tumor metastases, and Ly6E-OE tumor cells vice versa. The enhanced anti-tumor effect of Ly6E knockout in tumor cells was dependent on T cell response and formed long-lasting memory. The increase in the CD8+ T-cell infiltration into the tumor islet of Ly6E-KO tumors confirmed the role of Ly6E on T cell exclusion. ScRNA-seq analysis showed that M2 macrophages are particularly abundant in the Ly6E-expressing tumor tissues, especially M2-4 macrophage cluster identified by high levels of Arg-1, indicates that Ly6E-expressing tumor cells might restrict T cell infiltration via M2 macrophages. Moreover, in vitro assay showed that cell culture media derived from Ly6E-positive tumor cells promoted macrophage migration and M2 polarization.ConclusionOur study illuminated that Ly6E-expressing tumor cells facilitated the accumulation of M2 macrophages in TME, which contributes to CD8+ T cell exclusion and provides new insights for improving efficacy of cancer immunotherapy.

Pan-cancer landscape of disulfidptosis across human tumors

Pan-cancer landscape of disulfidptosis across human tumors

Efficient brain tumor grade classification using ensemble deep learning models

Detecting brain tumors early on is critical for effective treatment and life-saving efforts. The analysis of the brain with MRI scans is fundamental to the diagnosis because it contains detailed structural views of the brain, which is vital in identifying any of its abnormalities. The other option of performing an invasive biopsy is very painful and uncomfortable, which is not the case with MRI as it is free from surgically invasive margins and pieces of equipment. This helps patients to feel more at ease and hasten the diagnostic procedure, allowing physicians to formulate and practice action plans quicker. It is very difficult to locate a human brain tumor by manual because MRI scans produce large numbers of three-dimensional images. Complete applicability of pre-written computerized diagnostics, affords high possibilities in providing areas of interest earlier through the application of machine learning techniques and algorithms. The proposed work in the present study was to develop a deep learning model which will classify brain tumor grade images (BTGC), and hence enhance accuracy in diagnosing patients with different grades of brain tumors using MRI. A MobileNetV2 model, was used to extract the features from the images. This model increases the efficiency and generalizability of the model further. In this study, six standard Kaggle brain tumor MRI datasets were used to train and validate the developed and tested model of a brain tumor detection and classification algorithm into several types. This work consists of two key components: (i) brain tumor detection and (ii) classification of the tumor. The tumor classifications are conducted in both three classes (Meningioma, Pituitary, and glioma) and two classes (malignant, benign). The model has been reported to detect brain tumors with 99.85% accuracy, to distinguish benign and malignant tumors with 99.87% accuracy, and to type meningioma, pituitary, and glioma tumors with 99.38% accuracy. The results of this study indicate that the described technique is useful in the detection and classification of brain tumors.

Trifolirhizin targets PTK6 to induce autophagy and exerts antitumor effects in nasopharyngeal carcinoma.

Trifolirhizin, a natural flavonoid glycoside, has been proved to exert antitumor activities in various human malignant tumors. PTK6 was identified as a direct target of trifolirhizin based on public database SuperPred (https://prediction.charite.de/). Overexpressed PTK6 in a variety of tumors is closely associated with the malignant development of tumors. Herein, this present research was formulated to elaborate the effects of trifolirhizin on the biological behaviors of nasopharyngeal carcinoma (NPC) cells and to probe into the intrinsic mechanisms. The current study firstly elucidated the tumor-inhibiting functions of trifolirhizin in NPC malignant progression from the perspective of targeting inhibition of PTK6. In this work, CCK-8 for cell viability, EdU staining for cell proliferation, terminal deoxynucleotidyl transferase dUTP nick end labeling (TUNEL) staining for cell apoptosis and immunofluorescence staining for LC3 expression were performed. Besides, levels of proliferation-related, apoptosis-related and autophagy-related proteins were detected by western blot analysis. Moreover, molecular docking of trifolirhizin with PTK6 was conducted to seek the compound-protein binding potential. It was demonstrated that trifolirhizin treatment inhibited the proliferation and promoted the apoptosis of NPC cells as well as strengthened autophagy in NPC cells. Furthermore, it was verified that trifolirhizin targeted PTK6 and negatively regulated PTK6 expression. The suppressive effects of trifolirhizin on the malignant behaviors of NPC cells and the enhancing effect of trifolirhizin on autophagy in NPC cells were partly abolished upon upregulation of PTK6. To conclude, findings suggested that trifolirhizin may downregulate PTK6 expression to induce autophagy and exert the antitumor activities in NPC.

Synthesis and Cytotoxic Activity of Quinazoline-benzofuran Conjugates.

In order to study on structure-activity relationships of benzofurans. Benzofuran is a kind of natural compound widely existing in nature with pharmacological effects. The development of new anticancer benzofuran derivatives has attracted more and more attention. We have introduced an active quinazoline unit into piperazine-substituted benzofuran, prepared a series of quinazoline-benzofuran compounds, and evaluated cytotoxic activity against a panel of human tumor cell lines by MTT assay. 48 novel quinazoline-substituted benzofuran derivatives have been prepared, and in vitro, cytotoxic activity against five human tumor cell lines was evaluated. The results indicated that some quinazoline-benzofuran conjugates showed selective inhibitory activity against tumor cell lines. We have found that compound 14x displayed excellent cytotoxic activity, which could be considered a potential anticancer agent.

Mitochondrial double-stranded RNA homeostasis depends on cell-cycle progression.

Mitochondrial gene expression is a compartmentalised process essential for metabolic function. The replication and transcription of mitochondrial DNA (mtDNA) take place at nucleoids, whereas the subsequent processing and maturation of mitochondrial RNA (mtRNA) and mitoribosome assembly are localised to mitochondrial RNA granules. The bidirectional transcription of circular mtDNA can lead to the hybridisation of polycistronic transcripts and the formation of immunogenic mitochondrial double-stranded RNA (mt-dsRNA). However, the mechanisms that regulate mt-dsRNA localisation and homeostasis are largely unknown. With super-resolution microscopy, we show that mt-dsRNA overlaps with the RNA core and associated proteins of mitochondrial RNA granules but not nucleoids. Mt-dsRNA foci accumulate upon the stimulation of cell proliferation and their abundance depends on mitochondrial ribonucleotide supply by the nucleoside diphosphate kinase, NME6. Consequently, mt-dsRNA foci are profuse in cultured cancer cells and malignant cells of human tumour biopsies. Our results establish a new link between cell proliferation and mitochondrial nucleic acid homeostasis.

Prostaglandin E2-EP2/EP4 signaling induces immunosuppression in human cancer by impairing bioenergetics and ribosome biogenesis in immune cells

While prostaglandin E2 (PGE2) is produced in human tumor microenvironment (TME), its role therein remains poorly understood. Here, we examine this issue by comparative single-cell RNA sequencing of immune cells infiltrating human cancers and syngeneic tumors in female mice. PGE receptors EP4 and EP2 are expressed in lymphocytes and myeloid cells, and their expression is associated with the downregulation of oxidative phosphorylation (OXPHOS) and MYC targets, glycolysis and ribosomal proteins (RPs). Mechanistically, CD8+ T cells express EP4 and EP2 upon TCR activation, and PGE2 blocks IL-2-STAT5 signaling by downregulating Il2ra, which downregulates c-Myc and PGC-1 to decrease OXPHOS, glycolysis, and RPs, impairing migration, expansion, survival, and antitumor activity. Similarly, EP4 and EP2 are induced upon macrophage activation, and PGE2 downregulates c-Myc and OXPHOS in M1-like macrophages. These results suggest that PGE2-EP4/EP2 signaling impairs both adaptive and innate immunity in TME by hampering bioenergetics and ribosome biogenesis of tumor-infiltrating immune cells.

Advances in Vulvar Cancer Biology and Management.

Vulvar squamous cell carcinoma (VSCC), a rare gynecologic malignancy, has been rising in incidence. Molecular classification on the basis of human papilloma virus (HPV) and tumor protein 53 (p53) status has identified three clinically distinct subtypes, but we still treat all VSCCs the same. Here, we review molecular classification of VSCC, outline treatment landscape, and highlight potential for targeted therapies in advanced VSCC. We conducted a comprehensive review of the literature on treatment of advanced VSCC with particular focus on the implications of molecular stratification on the basis of HPV and p53 status on the treatment landscape of advanced VSCC. Incorporation of HPV and p53 status in locoregional treatment decision making has the potential to advise (de)escalation strategies. The role of immunotherapy, alone and in combination, requires further exploration particularly earlier in the course of the disease. In advanced stages, potential for targeted therapies in VSCCs include inhibitors of vascular endothelial growth factor, endothelial growth factor receptor, cell cycle, and DNA damage response, particularly in HPV-negative (HPV-) VSCCs. Targeting the phosphoinositide 3 kinase/mammalian target of rapamycin pathway is attractive in HPV-positive and HPV-/p53 wildtype VSCCs. Trials incorporating antibody-drug conjugates (eg, trophoblast cell-surface antigen 2, human epidermal growth factor receptor 2) should be considered, and basket trials in perineal squamous cell cancers are warranted. Preclinical models are limited and should be expanded to inform trial design. Like other rare cancers, vulvar cancer lags behind in the identification and optimization of precision medicine strategies. Molecular-based preclinical models and rationally designed clinical trials, incorporating high-quality translational studies, are urgently required. These trials will require international collaboration to ensure feasibility and improvement of outcomes for women diagnosed with this disease.

Single-nucleus RNA-seq dissection of choroid plexus tumor cell heterogeneity.

The genomic, genetic and cellular events regulating the onset, growth and survival of rare, choroid plexus neoplasms remain poorly understood. Here, we examine the heterogeneity of human choroid plexus tumors by single-nucleus transcriptome analysis of 23,906 cells from four disease-free choroid plexus and eleven choroid plexus tumors. The resulting expression atlas profiles cellular and transcriptional diversity, copy number alterations, and cell-cell interaction networks in normal and cancerous choroid plexus. In choroid plexus tumor epithelial cells, we observe transcriptional changes that correlate with genome-wide methylation profiles. We further characterize tumor type-specific stromal microenvironments that include altered macrophage and mesenchymal cell states, as well as changes in extracellular matrix components. This first single-cell dataset resource from such scarce samples should be valuable for divising therapies against these little-studied neoplasms.

An insect cell-derived extracellular vesicle-based gB vaccine elicits robust adaptive immune responses against Epstein-Barr virus.

Epstein-Barr virus (EBV), the first identified human tumor virus, is implicated in various human malignancies, infectious mononucleosis, and more recently, multiple sclerosis. Prophylactic vaccines have the potential to effectively prevent EBV infection. Glycoprotein B (gB) serves as the fusogen and plays a pivotal role in the virus entry process, making it a critical target for EBV vaccine development. Surface membrane proteins of enveloped viruses serve as native conformational antigens, making them susceptible to immune recognition. Utilizing lipid membrane-bound viral antigens is a promising strategy for effective vaccine presentation in this context. In this study, we employed a truncated design for gB proteins, observing that these truncated gB proteins prompted a substantial release of extracellular vesicles (EVs) in insect cells. We verified that EVs exhibited abundant gB proteins, displaying the typical virus particle morphology and extracellular vesicle characteristics. gB EVs demonstrated a more efficient humoral and cellular immune response compared with the gB ectodomain trimer vaccine in mice. Moreover, the antisera induced by the gB EVs vaccine exhibited robust antibody-dependent cytotoxicity. Consequently, gB EVs-based vaccines hold significant potential for preventing EBV infection and offer valuable insights for vaccine design.

Synthesis and Antitumour Activity of Hybrid Compounds Based on 4-Aminophenylarsonic Acid and Spatially Hindered Phenols.

One of the main modern approaches to the creation of effective drugs is the design of new biologically active substances containing two or more pharmacophore groups in their structure. In recent years, there have been many publications on the synthesis and study of biological activity, including antitumour activity, of new organo-arsenic compounds. It is known that spatially hindered phenols can also have antitumor activity, so the synthesis and study of hybrid compounds based on organo-arsenic compounds and spatially hindered phenols is a relevant area of research. In this work, the modification of 4-aminophenylarsonic acid with 3,5-di-tert-butyl-4-hydroxybenzylacetate was carried out. In contrast to a similar transformation of 2-aminophenylarsonic acid, in this case it was possible to obtain both mono- and di-benzyl derivatives of the acid. Using the Zandmeyer method, the oxime isatin containing an arsonic acid fragment in the fifth position of the heterocycle was synthesised. Azo derivatives containing fragments of para-aminophenylarsonic acid and sterically hindered phenols were obtained. 4-((3,5-Di-tert-butyl-2-hydroxyphenyl)diazenyl)phenylarsonic acid was isolated in pure form. At the same time, it was found that the reaction of the diazonium azo salt of 4-aminophenylarsonic acid with 2-hydroxymethyl-4-tert-butylphenol proceeds in two directions. In addition to the classical diazotisation reaction at the 6-position of 2-hydroxymethyl-4-tert-butylphenol, a diazotisation accompanied by a dehydroxymethylation process occurs. The obtained compounds showed cytotoxic activity against human tumor cell lines M-HeLa (cervical epithelioid carcinoma) and HuTu 80 (duodenal adenocarcinoma cells). The most promising is the sodium salt of 4-((3,5-di-tert-butyl-2-hydroxyphenyl)diazenyl)phenylarsonic acid, which is superior to Tamoxifen and 5-fluorouracil in terms of selectivity index towards M-HeLa and HuTu 80 cells.

Design, Synthesis and Biological Activity Evaluation of β-Carboline Derivatives Containing Nitrogen Heterocycles

A series of β-carboline derivatives containing nitrogen heterocycles were designed and synthesized. All compounds were screened for their antitumor activity against four human tumor cell lines (A549, K562, PC-3, T47D). Notably, compound N-(4-(morpholinomethyl)phenyl)-2-((5-(1-(3,4,5-trimethoxyphenyl)-9H-pyrido[3,4-b]indol-3-yl)-1,3,4-oxadiazol-2-yl)thio)acetamide (8q) exhibited significant inhibitory activity against PC-3 cells with an IC50 value of 9.86 µM. Importantly, compound 8q effectively suppressed both the proliferation and migration of PC-3 cells. Mechanistic studies revealed that compound 8q induced cell apoptosis and caused the accumulation of reactive oxygen species (ROS), leading to cell cycle arrest in the G0/G1 phase in PC-3 cells.

Tumour-intrinsic PDL1 signals regulate the Chk2 DNA damage response in cancer cells and mediate resistance to Chk1 inhibitors

BackgroundAside from the canonical role of PDL1 as a tumour surface-expressed immune checkpoint molecule, tumour-intrinsic PDL1 signals regulate non-canonical immunopathological pathways mediating treatment resistance whose significance, mechanisms, and therapeutic targeting remain incompletely understood. Recent reports implicate tumour-intrinsic PDL1 signals in the DNA damage response (DDR), including promoting homologous recombination DNA damage repair and mRNA stability of DDR proteins, but many mechanistic details remain undefined.MethodsWe genetically depleted PDL1 from transplantable mouse and human cancer cell lines to understand consequences of tumour-intrinsic PDL1 signals in the DNA damage response. We complemented this work with studies of primary human tumours and inducible mouse tumours. We developed novel approaches to show tumour-intrinsic PDL1 signals in specific subcellular locations. We pharmacologically depleted tumour PDL1 in vivo in mouse models with repurposed FDA-approved drugs for proof-of-concept clinical translation studies.ResultsWe show that tumour-intrinsic PDL1 promotes the checkpoint kinase-2 (Chk2)-mediated DNA damage response. Intracellular but not surface-expressed PDL1 controlled Chk2 protein content post-translationally and independently of PD1 by antagonising PIRH2 E3 ligase-mediated Chk2 polyubiquitination and protein degradation. Genetic tumour PDL1 depletion specifically reduced tumour Chk2 content but not ATM, ATR, or Chk1 DDR proteins, enhanced Chk1 inhibitor (Chk1i) synthetic lethality in vitro in diverse human and murine tumour models, and improved Chk1i efficacy in vivo. Pharmacologic tumour PDL1 depletion with cefepime or ceftazidime replicated genetic tumour PDL1 depletion by reducing tumour Chk2, inducing Chk1i synthetic lethality in a tumour PDL1-dependent manner, and reducing in vivo tumour growth when combined with Chk1i.ConclusionsOur data challenge the prevailing surface PDL1 paradigm, elucidate important and previously unappreciated roles for tumour-intrinsic PDL1 in regulating the ATM/Chk2 DNA damage response axis and E3 ligase-mediated protein degradation, suggest tumour PDL1 as a biomarker for Chk1i efficacy, and support the rapid clinical potential of pharmacologic tumour PDL1 depletion to treat selected cancers.