Potential Therapeutic Target In Cancer Research Articles

Cancer-keeper genes as therapeutic targets

Finding cancer-driver genes has been a central theme of cancer research. We took a different perspective; instead of considering normal cells, we focused on cancerous cells and genes that maintained abnormal cell growth, which we named cancer-keeper genes (CKGs). Intervening CKGs may rectify aberrant cell growth, making them potential cancer therapeutic targets. We introduced control-hub genes and developed an efficient algorithm by extending network controllability theory. Control hub are essential for maintaining cancerous states and thus can be taken as CKGs. We applied our CKG-based approach to bladder cancer (BLCA). All genes on the cell-cycle and p53 pathways in BLCA were identified as CKGs, showing their importance in cancer. We discovered that sensitive CKGs - genes easily altered by structural perturbation - were particularly suitable therapeutic targets. Experiments on cell lines and a mouse model confirmed that six sensitive CKGs effectively suppressed cancer cell growth, demonstrating the immense therapeutic potential of CKGs.

Bioactivity of recombinant humanized monoclonal antibody against HER2 in-vivo and in-vitro and its mechanism of action in ovarian cancer.

Human epidermal growth factor receptor 2 (HER2) protein is overexpressed on the surface of various epithelial ovarian cancer tissues, mediates the proliferation, differentiation, metastasis, and signal transduction of tumor cells, and thus is a potential cancer therapeutic target. However, its research in ovarian cancer is still limited, and how to quickly obtain a large number of antibodies remains a concern for researchers. In this study, we expressed the recombinant anti-HER2 humanized monoclonal antibody (rhHER2-mAb) in human embryonic kidney 293 (HEK293) cells through transient gene expression (TGE) technology by constructing a mammalian cell expression vector. Firstly, the transfection conditions has been optimized, the ratio of light chain (LC) and heavy chain (HC) was optimized in the range of 4:1 to 1:2 and the ration DNA and polyethyleneimine was optimized in the range of 4:1 to 1:1. The antibody was purified by rProtein A affinity chromatography, and its mediated antibody-dependent cellular cytotoxicity (ADCC) was identified by lactate dehydrogenase release assays. The anti-tumor activity of rhHER2-mAb was evaluated in non-obese diabetic/severe combined immunodeficiency mice. The expression of rhHER2-mAb in the HEK293F cells was at the highest level (100.5 mg/L) when the DNA/polyethyleneimine and light-chain/heavy-chain ratios were 1:4 and 1:2, respectively. The half-maximal inhibitory concentration of the ADCC of the antibodies against the SK-OV-3, OVCAR-3, and A-2780 cells were 12.36, 5.43, and 102.90 ng/mL, respectively. The animal experiments with the mice showed that rhHER2-mAb effectively inhibited the growth (P<0.01) of the SK-OV-3 tumors at a dose of 10 mg/kg. TGE technology allows us to quickly obtain a large number of anti-HER2 antibodies compared to the traditional method of constructing stable cell lines, and its in vitro and in vivo studied shows that our anti-HER2 antibody have higher affinity and better biological activity bioactivity (P<0.01) compared to Herceptin. Our findings provide novel insights into the development and production of future biotechnology-based drugs using the TGE technology of HEK293F.

Structure of the immunoregulatory sialidase NEU1.

Sialic acids linked to glycoproteins and glycolipids are important mediators of cell and protein recognition events. These sugar residues are removed by neuraminidases (sialidases). Neuraminidase-1 (sialidase-1 or NEU1) is a ubiquitously expressed mammalian sialidase located in lysosomes and on the cell membrane. Because of its modulation of multiple signaling processes, it is a potential therapeutic target for cancers and immune disorders. Genetic defects in NEU1 or in its protective protein cathepsin A (PPCA, CTSA) cause the lysosomal storage diseases sialidosis and galactosialidosis. To further our understanding of this enzyme's function at the molecular level, we determined the three-dimensional structure of murine NEU1. The enzyme oligomerizes through two self-association interfaces and displays a wide substrate-binding cavity. A catalytic loop adopts an inactive conformation. We propose a mechanism of activation involving a conformational change in this loop upon binding to its protective protein. These findings may facilitate the development of selective inhibitor and agonist therapies.

The Role of Paxillin Aberrant Expression in Cancer and Its Potential as a Target for Cancer Therapy

Paxillin is a multi-domain adaptor protein. As an important member of focal adhesion (FA) and a participant in regulating cell movement, paxillin plays an important role in physiological processes such as nervous system development, embryonic development, and vascular development. However, increasing evidence suggests that paxillin is aberrantly expressed in many cancers. Many scholars have also recognized that the abnormal expression of paxillin is related to the prognosis, metastases, invasion, survival, angiogenesis, and other aspects of malignant tumors, suggesting that paxillin may be a potential cancer therapeutic target. Therefore, the study of how aberrant paxillin expression affects the process of tumorigenesis and metastasis will help to develop more efficacious antitumor drugs. Herein, we review the structure of paxillin and its function and expression in tumors, paying special attention to the multifaceted effects of paxillin on tumors, the mechanism of tumorigenesis and progression, and its potential role in tumor therapy. We also hope to provide a reference for the clinical prognosis and development of new tumor therapeutic targets.

Enhanced mitochondrial fission inhibits triple-negative breast cancer cell migration through an ROS-dependent mechanism

Mitochondria produce reactive oxygen species (ROS), which function in signal transduction. Mitochondrial dynamics, encompassing morphological shifts between fission and fusion, can directly impact ROS levels in cancer cells. In this study, we identified an ROS-dependent mechanism for how enhanced mitochondrial fission inhibits triple negative breast cancer (TNBC) cell migration. We found that enforcing mitochondrial fission in TNBC resulted in an increase in intracellular ROS levels and reduced cell migration and the formation of actin-rich migratory structures. Consistent with mitochondrial fission, increasing ROS levels in cells inhibited cell migration. Conversely, reducing ROS levels with either a global ormitochondrially targeted scavenger overcame the inhibitory effects of mitochondrial fission. Mechanistically, we found that the ROS sensitive SHP-1/2 phosphatases partially regulate inhibitory effects of mitochondrial fission on TNBC migration. Overall, our work reveals the inhibitory effects of ROS in TNBC and supports mitochondrial dynamics as a potential therapeutic target for cancer.

The role of truncated p53 isoforms in the DNA damage response.

The tumour suppressor p53 is activated following genotoxic stress and regulates the expression of target genes involved in the DNA damage response (DDR). The discovery that p53 isoforms alter the transcription of p53 target genes or p53 protein interactions unveiled an alternative DDR. This review will focus on the role p53 isoforms play in response to DNA damage. The expression of the C-terminally truncated p53 isoforms may be modulated via DNA damage-induced alternative splicing, whereas alternative translation plays an important role in modulating the expression of N-terminally truncated isoforms. The DDR induced by p53 isoforms may enhance the canonical p53 DDR or block cell death mechanisms in a DNA damage- and cell-specific manner, which could contribute to chemoresistance in a cancer context. Thus, a better understanding of the involvement of p53 isoforms in the cell fate decisions could uncover potential therapeutic targets in cancer and other diseases.

LncRNA CASC19: a novel oncogene involved in human cancer.

Multiple studies have shown that long non-coding RNAs (lncRNAs) play an important role in the occurrence and development of diverse cancers. Cancer susceptibility candidate 19 (CASC19), encoded by chromosome 8q24.21, is a newly discovered lncRNA that contains 324 nucleotides. CASC19 has been found to be significantly overexpressed in different human cancers, such as non-small cell lung carcinoma, gastric cancer, colorectal cancer, pancreatic cancer, clear cell renal cell carcinoma, glioma, cervical cancer, and nasopharyngeal carcinoma. Moreover, dysregulation of CASC19 was closely associated with clinicopathological parameters and cancer progression. CASC19 regulates a variety of cell phenotypes, including cell proliferation, apoptosis, cell cycle, migration, invasion, epithelial-mesenchymal transition, autophagy, and therapeutic resistance. In this study, we review recent studies on the characteristics and biological function of CASC19, as well as its role in human cancers. These findings suggest that CASC19 may be both a reliable biomarker and a potential therapeutic target in cancers.

Abstract 534: PRMT5 inhibition as a therapeutic strategy for KRAS mutant CRC: downstream mediators of the PRMT5-KRAS crosstalk

Abstract Despite decades of research, there are still no effective targeted treatments for the nearly 45% of colorectal cancer (CRC) patients harboring a mutation in their KRAS gene. Protein Arginine Methyltransferase 5 (PRMT5) is an epigenetic regulator undergoing clinical trials as a potential therapeutic target for cancer. Our group has previously reported that PRMT5 is overexpressed in KRAS mutant CRC when compared to KRAS wild-type (WT) CRC, and that PRMT5 inhibition exhibited greater therapeutic efficacy in KRAS mutant CRC when compared to KRAS WT CRC. We therefore proposed that PRMT5 may be a strong therapeutic target for KRAS mutant CRC, and that PRMT5 and KRAS may crosstalk. In this study, we investigated several key downstream signal transduction proteins that may be involved in mediating the potential crosstalk between PRMT5 and KRAS. This is important, as these key intermediate proteins may be strong therapeutic targets for inhibition, as well as valuable therapeutic targets for combination therapy along with PRMT5 inhibitors. We first conducted a literature review to determine which key downstream proteins may be involved in mediating the potential crosstalk between PRMT5 and KRAS. Our initial findings indicated that MYC, p65/RELA, TP53, P21/CDKN1A, ELF1, E2F1, and EIF4E may be key downstream proteins involved in mediating the potential crosstalk between PRMT5 and KRAS. We next used the STRING database to determine which of the aforementioned proteins have demonstrated interactions with PRMT5 and KRAS. We found that PRMT5 and KRAS both interact with MYC, p65/RELA, TP53, P21/CDKN1A, E2F1, and EIF4E with an interaction score &amp;gt; 0.150. We then used the Gene Expression Profiling Interactive Analysis (GEPIA) database to analyze the RNA-Seq data of CRC patients from The Cancer Genome Atlas (TCGA) database. We first used the GEPIA database to determine which proteins are overexpressed in CRC patient tumor samples compared to normal colon and rectum patient samples. We observed that MYC, TP53, E2F1, and EIF4E are all over 2-fold overexpressed in CRC patient tumor samples compared to normal colon and rectum patient samples (q &amp;lt; 0.01). We next used the GEPIA database to determine which proteins have an expressional correlation with PRMT5 and KRAS in CRC patient tumor samples. We found that MYC, E2F1, and EIF4E are all positively correlated with PRMT5 and KRAS with an R-Value &amp;gt; 0.70 and a P-Value &amp;lt; 0.01 in CRC patient tumor samples. Our study thus showcases the key downstream signal transduction proteins that may be involved in mediating the potential crosstalk between PRMT5 and KRAS. These findings are significant, as these key intermediate proteins may be strong therapeutic targets for inhibition, as well as strong therapeutic targets for a PRMT5 combination therapy. Additional research is currently underway to outline the molecular processes behind MYC, E2F1, and EIF4E’s interactions with both PRMT5 and KRAS. Citation Format: David Shifteh, Tzuriel Sapir, Moshe Pahmer, Sanjay Goel, Radhashree Maitra. PRMT5 inhibition as a therapeutic strategy for KRAS mutant CRC: downstream mediators of the PRMT5-KRAS crosstalk [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2023; Part 1 (Regular and Invited Abstracts); 2023 Apr 14-19; Orlando, FL. Philadelphia (PA): AACR; Cancer Res 2023;83(7_Suppl):Abstract nr 534.

Abstract 5341: Data mining of PubChem bioassay data reveals OXPHOS inhibitors with anti-cancer activity

Abstract High Grade Serous Ovarian Cancer (HGSOC) is a fatal disease that is typically detected at an advanced stage when there are limited modalities for effective treatment. Treatment efficacy against cancer is dependent on tumor metabolism and its adaptation for most therapies. Warburg effect is an important adaptation found in tumors where cells primarily catabolize glucose even in presence of sufficient oxygen and nutrients. Nevertheless, recent evidence suggests cells in tumor microenvironments remain dependent on mitochondrial ATP production via oxidative phosphorylation (OXPHOS). OXPHOS also represents a major metabolic pathway in cancer stem cells and tumor cells of relapse patients. Molecular signatures of glycolysis and OXPHOS are both detected in tumors. This points to the OXPHOS pathway as a potential therapeutic target in cancer. Here we apply a data mining approach to identify OXPHOS inhibitors to evaluate as candidates for therapies against HGSOC. High-Throughput Screening (HTS) on mechanistic targets like OXPHOS are cost prohibitive for academic laboratories. As an alternative, we deployed a data mining pipeline to find active chemical classes among 8415 available OXPHOS-related bioassays in the PubChem data repository. Active compound clusters frequently contain α,β-unsaturated carbonyl groups, which are also observed in both endogenous quinone electron carriers and atovaquone–a potent inhibitor of OXPHOS. Out of 312041 unique compounds tested in the assays, we selected 6 representative molecules from each of the 6 largest active chemical clusters to test for OXPHOS inhibition, ROS production, and reduced cancer cell proliferation. We assayed cell viability (MTT) to check for proliferation of human (OVCAR3, OVCAR5, OVISE) and mouse (ID8) ovarian cancer cells against 6 compounds, Oryzalin, Allylyestrenol, Esbiothrin, Lacidipine, Coumatetralyl, and CID929419 (MLS000713029), 72 h post treatment. ID8 and OVCAR5 significantly decreased cell proliferation after Lacidipine and Oryzalin treatment. Significant increase in intracellular ROS, a frequent consequence of OXPHOS inhibition, was observed in all cell lines after Lacidipine treatment. Elevated ROS was also observed in ID8 and OVISE cells after Esbiothrin treatment. To confirm OXPHOS inhibition as the mechanism of action, we performed Mito Stress Test on the Seahorse Analyzer and measured Oxygen Consumption Rate. Treatment with Oryzalin, Allylyestrenol, Esbiothrin, and Lacidipine significantly decreased basal respiration rate and ATP production in ID8 and OVCAR3 cells. This suggests that 4 of the 6 compound classes prioritized by the data mining pipeline inhibits OXPHOS in ovarian cancer cells. Thus, our pipeline provides an efficient alternative to HTS for identifying OXPHOS inhibitors. Next, we plan to test the in-vivo efficacy of these drugs against ovarian tumors in a mouse model and investigate their molecular mechanisms. Citation Format: Sejal T. Sharma, Liping Feng, Nicha Boonpattrawong, Lisa M. Barroilhet, Manish Patankar, Spencer S. Ericksen. Data mining of PubChem bioassay data reveals OXPHOS inhibitors with anti-cancer activity. [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2023; Part 1 (Regular and Invited Abstracts); 2023 Apr 14-19; Orlando, FL. Philadelphia (PA): AACR; Cancer Res 2023;83(7_Suppl):Abstract nr 5341.

Abstract 2690: In vivo CRISPR screen identifies SOAT1 as a chemotherapy chemosensitizing target for non-small cell lung cancer (NSCLC)

Abstract Purpose: To identify druggable gene targets that would sensitize NSCLCs to available chemotherapy agents. Experimental Procedures: We developed a CRISPR-Cas9 lentivirus library of 12,474 sgRNAs targeting 660 FDA proved ‘druggable’ putative proteins (18 guides/gene) and investigated their potential to chemosensitize (“drop out” in the presence of taxane) the NSCLC lung adenocarcinoma (LUAD) line NCI-H2009 (TP53 and KRAS mutant) in parallel studies in vitro (tissue culture) &amp; in vivo (xenografts). Key elements of our experiments were: the use low doses of paclitaxel (IC10 values for in vitro and in vivo doses that barely affected tumor growth) compared to control treatment; treatment schedules in vitro and in vivo that mirrored those used in patients; multiple biologic replicates for each transfection and drug selection; and large representation (2,000 cells/sgRNA) for each guide. At the end time point (1 month) we harvested multiple replicates of the taxane and control treatments and sequenced each to identify each guide that “remained” or “dropped out.” Data Summary: We were looking for guides that selectively dropped out in the setting of low dose taxane exposure comparing taxane to control treatment and in vitro to in vivo results. Of importance, we found little overlap between guides that dropped out during taxane exposure in tissue culture vs those that dropped out in xenografts. From the top 10 gene “sensitizers” that selectively dropped out only with taxane treatment and selectively dropped out in xenografts compared to 2D mass tissue culture, we focused on SOAT1 (Sterol O-Acyltransferase 1). SOAT1 is a key enzyme for lipid metabolism which mediates conversion of intracellular free cholesterol to cholesteryl esters which are then stored as lipid droplets. SOAT1 is a potential cancer therapeutic target with a clinically available inhibitor, avasimibe. H2009 cells with SOAT1 hemizygously removed (CRISPR) grew well in vitro and in vivo in the absence of chemotherapy treatment, but were dramatically sensitized to taxanes compared to parental H2009 cells. While avasimibe treatment, at concentrations achievable in patients, sensitized NSCLC to taxanes, this sensitization was not as dramatic as hemizygous removal by CRISPR. Of equal importance, SOAT1 H2009 hemizygous knockout (KO) cells were also dramatically sensitized to etoposide, pemetrexed, and gemcitabine, other chemotherapy agents used in NSCLC treatment. Mechanistically, RNAseq analysis identified G2/M cell cycle related gene sets as enriched in the H2009 SOAT1 KO xenografts compared to SOAT1 wildtype xenografts with paclitaxel treatment. Conclusions: Our results using CRISPR screening in vivo, identified SOAT1 as a critical therapeutic chemosensitizing target requiring only 50% inhibition of activity for sensitizing NSCLC to several chemotherapy agents routinely used in the clinic. Citation Format: Long Shan Li, Kenneth Huffman, Huiyu Li, Michael Peyton, Hyunsil Park, Kimberley Avila, Luc Girard, Mathew Augustine, Joshua T. Mendell, John D. Minna. In vivo CRISPR screen identifies SOAT1 as a chemotherapy chemosensitizing target for non-small cell lung cancer (NSCLC) [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2023; Part 1 (Regular and Invited Abstracts); 2023 Apr 14-19; Orlando, FL. Philadelphia (PA): AACR; Cancer Res 2023;83(7_Suppl):Abstract nr 2690.

The tumor suppressor functions of ubiquitin ligase KPC1: from cell cycle control to NF-κB regulator.

The ubiquitin-proteasome system (UPS) is responsible for up to 90% of intracellular protein degradation. Alterations in UPS are extensively involved in the development and advancement of malignant pathologies. Thus, the components of the UPS can become potential targets for cancer therapeutics. KPC1 is an E3 ubiquitin ligase component of the UPS that regulates key pathways and processes in cancer. KPC1 sustains the ubiquitination of cytoplasmic p27, determining its elimination and transition between cell cycle phases. KPC1 also regulates NF-κB signaling by inducing ubiquitination of p105 to allow subsequent proteasomal processing to the functional form p50. It has been shown that the KPC1-p50 duo is reduced or absent in multiple malignancies and that therapeutic reinforcement of the functional axis can exhibit significant tumor suppressor activity. Here, we highlight the potential role of KPC1 as a tumor-suppressor by fully describing its crucial role in p27 signaling and the canonical NF-κB pathway.

Subtle Immunoreactivity Differences in the Fractal Patterns of Membrane E-Cadherin in Gastric Adenocarcinoma.

Gastric cancer continues to be a significant malignancy worldwide, accounting for approximately one million new cases in 2020. Scientists are focusing on the cancerous cells' plasma membrane (PM) as a potential therapeutic target in cancer because it functions as the cell's interface with its environment through a variety of mechanisms. The capacity of membrane shape and its structures to influence biological processes frequently occurs through the regulation of enzymes or preferential protein binding to membranes via membrane shape changes. We aimed here to assess the morphological irregularities of the cellular membranes in gastric adenocarcinoma tumors, and to find any putative differences from normal gastric mucosae epithelial cells. We analyzed the pattern of E-cadherin at the level of the cell membrane using the fractal dimension (FD) analysis on fluorescence immunohistochemistry samples labeled with E-cadherin in gastric well/moderate and solid gastric adenocarcinoma from patients without any associated chemotherapeutic treatment or radiotherapy. Images were binarized based on a fixed threshold of the E-cadherin fluorescence channel, and then the FD of the binarized image outlines has been calculated in order to assess the ruggedness of the cellular membranes. Overall assessment of the FD revealed that the subtle membrane variations were evident enough to deem a statistically significant difference and the complexity of the membrane roughness was clearly higher for adenocarcinoma cases. We intended to evaluate if separating adenocarcinoma cases as low grade (G1 and G2) and high grade (G3 and solid), FD analysis could still differentiate membrane patterns and check if the available clinical parameters like age, gender, tumor location, lymph ganglia involved might correlate with FD values for adenocarcinoma patients. Altogether, the morphological analysis of a simple marker for the cell membrane can identify and distinguish tumor cells. Although there was a limited correlation between this analysis and the main clinical and pathological indicators of the disease, it will be very useful in the future for automatic computer-assisted diagnosis on slides, as well as for evaluating cellular adhesion and inter-cellular trafficking in cancer cells.

Construction of cuproptosis‑associated prognostic signature in colon adenocarcinoma based on bioinformatics and RT‑qPCR analysis.

Colon adenocarcinoma (COAD) is the most common pathological subtype of colon cancer with a high degree of malignancy. Cuproptosis is a newly discovered copper-dependent cell death pattern distinguished from all the other known programmed cell death. Hence, it can be used as a potential therapeutic target for cancer. The present study aimed to clarify the relationship between cuproptosis and prognosis of COAD. The variations of 12 cuproptosis-associated genes based on 623 patients with COAD were comprehensively identified. It was found that 8 out of 12 were differentially expressed in tumors and normal tissues and CDKN2A showed a higher prognostic value. Therefore, two molecular subtypes were explored and the subtype A, with higher expression of cuproptosis-associated genes, showed more enrichment of immune pathways and survival advantage over those with lower cuproptosis-associated genes expression. The risk score and a nomogram predicting pattern were constructed to quantify a single patient and the risk score could serve as an independent prognostic factor by multivariate Cox regression analysis (P<0.001, HR: 1.350, 95% CI: 1.189-1.534). The expression levels of key prognostic genes (PMM2, ACOX1, KDM3A, HSPB1, PPARGC1A, UPK3B and EPHB2) was analyzed by HCT-116 colon cancer cells and HT-29 colorectal cancer cells using reverse transcription-quantitative PCR. The high-risk group, characterized by higher immune infiltration, increased microsatellite instability-high, high tumor mutation burden and high expression level of immune checkpoints, indicated higher drug sensitivity. In conclusion, our analysis confirms the potential role of cuproptosis-associated genes in the prognosis of COAD and it will provide new ideas for immunotherapy.

A New Potential Therapeutic Target for Cancer in Ubiquitin-Like Proteins-UBL3.

Ubiquitin-like proteins (Ubls) are involved in a variety of biological processes through the modification of proteins. Dysregulation of Ubl modifications is associated with various diseases, especially cancer. Ubiquitin-like protein 3 (UBL3), a type of Ubl, was revealed to be a key factor in the process of small extracellular vesicle (sEV) protein sorting and major histocompatibility complex class II ubiquitination. A variety of sEV proteins that affects cancer properties has been found to interact with UBL3. An increasing number of studies has implied that UBL3 expression affects cancer cell growth and cancer prognosis. In this review, we provide an overview of the relationship between various Ubls and cancers. We mainly introduce UBL3 and its functions and summarize the current findings of UBL3 and examine its potential as a therapeutic target in cancers.

Discovery of aminothiazole derivatives as a chemical scaffold for glutaminase inhibition

Cancer cells rely on different mechanisms to maintain their dysregulated metabolism and high proliferation. Metabolic rewiring with an increased dependency on glutamine, the most abundant amino acid in the blood, is a common feature of several types of cancers, including triple-negative breast cancer (TNBC). The enzyme glutaminase (GLS) converts glutamine to glutamate, a reaction that provides α-ketoglutarate for the tricarboxylic/citric acid cycle (TCA) and chromatin-modifying enzymes, thus impacting proliferation and cell differentiation. Glutamine metabolism also impacts the redox balance and synthesis of nucleotides, lipids, and other amino acids. Glutaminase is a potential therapeutic target for cancer, with inhibitors in clinical trials. We previously performed high-throughput screening (HTS) to look for GLS inhibitors. Here, we present the structure–activity relationship (SAR) study of one of the hits, C12, a moleculecontaining the heteroaromatic nucleus 2-amino-thiazole. The SAR investigation was carried out through modifications of the substituents from the main 3 rings present at the C12 prototype, rings A-C.The combination of 4-F and phenylacetic substitutions on ring A, the incorporation of a 1,3,4-thiadiazole moiety on ring B, and a 4-CN substituent on ring C were the best options to improve specific GLS inhibition. In this series, three compounds exhibited suitable enzyme (GAC vs GLS2) and cell (MDA-MB-231 vs SKBR3) selectivity and, thus, could be useful for the development of new glutaminase inhibitors.

ATPase family AAA domain-containing protein 2 (ATAD2): From an epigenetic modulator to cancer therapeutic target.

ATPase family AAA domain-containing protein 2 (ATAD2) has been widely reported to be a new emerging oncogene that is closely associated with epigenetic modifications in human cancers. As a coactivator of transcription factors, ATAD2 can participate in epigenetic modifications and regulate the expression of downstream oncogenes or tumor suppressors, which may be supported by the enhancer of zeste homologue 2. Moreover, the dominant structure (AAA + ATPase and bromine domains) can make ATAD2 a potential therapeutic target in cancer, and some relevant small-molecule inhibitors, such as GSK8814 and AZ13824374, have also been discovered. Thus, in this review, we focus on summarizing the structural features and biological functions of ATAD2 from an epigenetic modulator to a cancer therapeutic target, and further discuss the existing small-molecule inhibitors targeting ATAD2 to improve potential cancer therapy. Together, these inspiring findings would shed new light on ATAD2 as a promising druggable target in cancer and provide a clue on the development of candidate anticancer drugs.

Role of CD36 in cancer progression, stemness, and targeting.

CD36 is highly expressed in diverse tumor types and its expression correlates with advanced stages, poor prognosis, and reduced survival. In cancer cells, CD36: 1) increases fatty acid uptake, reprogramming lipid metabolism; 2) favors cancer cell proliferation, and 3) promotes epithelial-mesenchymal transition. Furthermore, CD36 expression correlates with the expression of cancer stem cell markers and CD36+ cancer cells display increased stemness functional properties, including clonogenicity, chemo- and radioresistance, and metastasis-initiating capability, suggesting CD36 is a marker of the cancer stem cell population. Thus, CD36 has been pointed as a potential therapeutic target in cancer. At present, at least three different types of molecules have been developed for reducing CD36-mediated functions: blocking monoclonal antibodies, small-molecule inhibitors, and compounds that knock-down CD36 expression. Herein, we review the role of CD36 in cancer progression, its participation in stemness control, as well as the efficacy of reported CD36 inhibitors in cancer cell cultures and animal models. Overall, the evidence compiled points that CD36 is a valid target for the development of new anti-cancer therapies.

Discovery of Orally Bioavailable N-Benzylpiperidinol Derivatives as Potent and Selective USP7 Inhibitors with In Vivo Antitumor Immunity Activity against Colon Cancer.

USP7 emerges as a potential therapeutic target for cancers, as it plays an important role in the development of tumorigenesis by stabilizing multiple cancer-relevant proteins. Nevertheless, the discovery of drug-like USP7 inhibitors remains challenging. Herein, we report a series of N-benzylpiperidinol derivatives as potent and selective USP7 inhibitors (e.g., X20 and X26: IC50 = 7.6 and 8.2 nM), whose binding modes were revealed by crystallographic studies to be distinct from the known N-acylpiperidinol USP7 inhibitors. Among them, X36 with good oral PK profiles (rat: F = 40.8% and T1/2 = 3.5 h) exhibited significant antitumor efficacy in the MC38 colon cancer syngeneic mouse model, at least partly through upregulating the tumor infiltration of CD8+ T, NK, and NKT cells and downregulating that of Tregs and MDSCs. These findings may further pave the way for the development of USP7 inhibitors as novel cancer immunotherapy drugs.

Cytosolic TGM2 promotes malignant progression in gastric cancer by suppressing the TRIM21-mediated ubiquitination/degradation of STAT1 in a GTP binding-dependent modality.

Previous studies have revealed the critical role of transglutaminase 2 (TGM2) as a potential therapeutic target in cancers, but the oncogenic roles and underlying mechanisms of TGM2 in gastric cancer (GC) are not fully understood. In this study, we examined the role and potential mechanism of TGM2 in GC. Western blotting, immunohistochemistry, CCK8, colony formation and transwell assays were used to measure TGM2 expression in the GC cells and tissues and to examine the in vitro role of TGM2 in GC. Xenograft and in vivo metastasis experiments were performed to examine the in vivo role of TGM2 in GC. Gene set enrichment analysis, quantitative PCR and western blotting were conducted to screen for potential TGM2 targets involved in GC. Gain/loss-of-function and rescue experiments were conducted to detect the biological roles of STAT1 in GC cells in the context of TGM2. Co-immunoprecipitation, mass spectrometry, quantitative PCR and western blotting were conducted to identify STAT1-interacting proteins and elucidate their regulatory mechanisms. Mutations in TGM2 and two molecules (ZM39923 and A23187) were used to identify the enzymatic activity of TGM2 involved in the malignant progression of GC and elucidate the underlying mechanism. In this study, we demonstrated elevated TGM2 expression in the GC tissues, which closely related to pathological grade, and predicted poor survival in patients with GC. TGM2 overexpression or knockdown promoted (and inhibited) cell proliferation, migration, and invasion, which were reversed by STAT1 knockdown or overexpression. Further studies showed that TGM2 promoted GC progression by inhibiting STAT1 ubiquitination/degradation. Then, tripartite motif-containing protein 21 (TRIM21) was identified as a ubiquitin E3 ligase of STAT1 in GC. TGM2 maintained STAT1 stability by facilitating the dissociation of TRIM21 and STAT1 with GTP-binding enzymatic activity. A23187 abolished the role of TGM2 in STAT1 and reversed the pro-tumor role of TGM2 in vitro and in vivo. This study revealed a critical role and regulatory mechanism of TGM2 on STAT1 in GC and highlighted the potential of TGM2 as a therapeutic target, which elucidates the development of medicine or strategies by regulating the GTP-binding activity of TGM2 in GC.

The Expression Patterns of Human Cancer-Testis Genes Are Induced through Epigenetic Drugs in Colon Cancer Cells.

The expression of human germline genes is restricted to the germ cells of the gonads, which produce sperm and eggs. The germline genes involved in testis development and potentially activated in cancer cells are known as cancer-testis (CT) genes. These genes are potential therapeutic targets and biomarkers, as well as drivers of the oncogenic process. CT genes can be reactivated by treatment with drugs that demethylate DNA. The majority of the existing literature on CT gene activation focuses on X-chromosome-produced CT genes. We tested the hypothesis that epigenetic landscape changes, such as DNA methylation, can alter several CT gene expression profiles in cancer and germ cells. Colon cancer (CC) cell lines were treated with the DNA methyltransferase inhibitor (DNMTi) 5-aza-2'-deoxycytidine, or with the histone deacetylase inhibitor (HDACi) trichostatin A (TSA). The effects of these epigenetic treatments on the transcriptional activation of previously published CT genes (CTAG1A, SCP2D1, TKTL2, LYZL6, TEX33, and ACTRT1) and testis-specific genes (NUTM1, ASB17, ZSWIM2, ADAM2, and C10orf82) were investigated. We found that treatment of CC cell lines with 5-aza-2'-deoxycytidine or TSA correlated with activation of X-encoded CT genes and non-X-encoded CT genes in somatic (non-germline) cells. These findings confirm that a subset of CT genes can be regulated by hypomethylating drugs and subsequently provide a potential therapeutic target for cancer.