Potential Therapeutic Target In Cancer Research Articles

The mechanism of USP43 in the development of tumor: a literature review.

Ubiquitination of the proteins is crucial for governing protein degradation and regulating fundamental cellular processes. Deubiquitinases (DUBs) have emerged as significant regulators of multiple pathways associated with cancer and other diseases, owing to their capacity to remove ubiquitin from target substrates and modulate signaling. Consequently, they represent potential therapeutic targets for cancer and other life-threatening conditions. USP43 belongs to the DUBs family involved in cancer development and progression. This review aims to provide a comprehensive overview of the existing scientific evidence implicating USP43 in cancer development. Additionally, it will investigate potential small-molecule inhibitors that target DUBs that may have the capability to function as anti-cancer medicines.

Comprehensive pan-cancer analysis: essential role of ABCB family genes in cancer.

The adenosine triphosphate-binding-cassette (ABC) transporter orchestrates the transmembrane transport of diverse substrates with the aid of ATP as an energy source. ABC transporter constitutes a widespread superfamily of transporters prominently present on the cellular membrane of organisms. Advancements in understanding have unveiled additional roles beyond mere intracellular or extracellular transport functions for the ABC protein family, encompassing involvement in DNA repair, protein translation, and gene expression regulation. Yet its role in tumors is still unknown. This study drew support from multiple databases, including Gene Expression Omnibus (GEO), European Genome-phenome Archive (EGA), The Cancer Genome Atlas (TCGA), and employed multidimensional bioinformatics analyses, incorporating online databases and the R-project. Through a comprehensive analysis, we seek to discern transcriptional-level disparities among genes and their consequential impacts on prognosis, tumor microenvironment (TME), stemness score, immune subtypes, clinical characteristics, and drug sensitivity across human cancers. ABC transporter subfamily B (ABCB) family genes exhibited heightened expression across diverse tumors, demonstrating a significant correlation with overall prognosis in pan-cancer contexts. Notably, gene expression levels manifested substantial associations with TME, stemness score, immune subtypes, clinical characteristics, and drug sensitivity in specific cancers, including kidney renal papillary cell carcinoma (KIRP), liver hepatocellular carcinoma (LIHC), and pancreatic adenocarcinoma (PAAD). Within this subset, transporter associated with antigen processing 1 (TAP1), TAP2, and ABCB6 emerged as noteworthy oncogenes. The outcomes of this study contribute to a comprehensive understanding of the implications of ABCB family genes in tumor progression, offering insights into potential therapeutic targets for cancer. Notably, the identification of ABCB6 as a significant oncogene suggests promising avenues for targeted therapies in KIRP, LIHC, and PAAD.

CK2 Inhibitors Targeting Inside and Outside the Catalytic Box

CK2 is a protein kinase that plays an important role in numerous cellular pathways involved in cell growth, differentiation, proliferation, and death. Consequently, upregulation of CK2 is implicated in many disease types, in particular cancer. As such, CK2 has gained significant attention as a potential therapeutic target in cancer, and over 40 chemical probes targeting CK2 have been developed in the past decade. In this review, we highlighted several chemical probes that target sites outside the conventional ATP-binding site. These chemical probes belong to different classes of molecules, from small molecules to peptides, and possess different mechanisms of action. Many of the chemical probes discussed in this review could serve as promising new candidates for drugs selectively targeting CK2.

Abstract 1670: Mechanistic insight into mTOR signaling identifies RNA splicing machinery as a potential therapeutic target for cancer

Abstract Aberrant signal transduction regulating cell growth and proliferation is a hallmark of many cancers. Activation of mTOR signaling is common and is an attractive therapeutic target with mechanistically different mTOR inhibitors in clinical use. One consequence of exposure to the mTOR inhibitor rapamycin is an alteration of gene expression through a global increase in alternative exon inclusion (Cheng et al. 2022, doi.org/10.3390/ijms232012416). To examine the mechanisms underlying this effect, we utilized the TempO-Seq targeted sequencing platform to profile both the whole transcriptome and a selection of alternatively spliced RNA targets in the rapamycin sensitive and resistant breast cancer cell lines MCF-7 and MDA MB 231 following exposure to 13 mTOR inhibitors, some closely related and some from distinct chemical classes. Recent publications have demonstrated that high quality dose response data can be obtained using this sequencing platform (Harrill et al. 2021, doi: 10.1093/toxsci/kfab009; Ramaiahgari et al. 2019, doi: 10.1093/toxsci/kfz065) and TempO-Seq has been widely adopted in toxicology for deriving compound-specific expression signatures to identify mechanisms of action and long-term toxicity. Treated cells were also profiled using TempO-LINC, a novel high-throughput single-cell assay based on the same platform. We observed that certain mTOR inhibitors induced both common and cell-specific differential expression as well as widespread alternative exon inclusion, as expected. Intriguingly, transcripts with the most significant changes in splicing upon treatment were those encoding members of the SR family of splicing factors, often overexpressed or amplified in breast cancers (Park, et al. 2019, doi: 10.1016/j.celrep.2019.10.110). This is significant because SR protein expression is autoregulated by alternative inclusion of an exon containing a premature stop codon in a feedback loop leading to nonsense-mediated decay (NMD) and lowered protein levels. Indeed, NMD is known to be inhibited by rapamycin (Martinez-Nunez, et al. 2017, doi: 10.1093/nar/gkw1109), which would lead to the observed accumulation of these transcripts. Thus, monitoring a targeted selection of alternative splicing events and regulators revealed mTOR regulation of mRNA isoform abundance consistent with regulation of the NMD RNA turnover process and with overexpression of SR proteins in breast cancers. Importantly, targeted bulk and single-cell TempO-Seq assays enable efficient sequencing and simplified data analysis without the expense and bioinformatic burden of RNAseq, making them particularly well-suited for drug discovery. These results support the use of this approach for further characterization of cell-specific effects of mTOR inhibitors and their mechanisms of action. Citation Format: Gaelle Rondeau, Megan Opichka, Kevin White, Joanne M. Yeakley, Dennis J. Eastburn, Bruce Seligmann. Mechanistic insight into mTOR signaling identifies RNA splicing machinery as a potential therapeutic target for cancer [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2024; Part 1 (Regular Abstracts); 2024 Apr 5-10; San Diego, CA. Philadelphia (PA): AACR; Cancer Res 2024;84(6_Suppl):Abstract nr 1670.

CBP/p300 Degrader: A Promising Therapeutic Strategy for Treatment of Prostate Cancer and Beyond.

Transcriptional coactivators CBP/p300 have emerged as potential targets for cancer therapeutics. This Viewpoint discusses recent results that demonstrate an exceptionally potent and orally efficacious CBP/p300 degrader for the treatment of prostate cancer. This degrader stands out as a promising new candidate for cancer therapy and deserves further research.

Abstract 5604: Modulating DNA repair through endo-exonuclease inhibition: a new therapeutic paradigm in oncology

Abstract DNA damage repair (DDR) mechanisms are crucial for the maintenance of genomic stability and are emerging as potential therapeutic targets for cancer. Endo-exonuclease (EE)1 plays a key role in this process and increase EE expression has been observed in the cancer cells examined. In this context, we identified a dicationic diarylfuran, pentamidine, which is an antiparasitic drug that has been used clinically to treat opportunistic infections such as Pneumocystis carinii. Pentamidine is an inhibitor of the endo-exonuclease as determined by enzyme kinetic assay and is known to be active on cancer cells. In a proof of concept study2, tumor with increased EE expression (determined by IHC) showed the best response to this drug. We have now identified novel mono- and di-amidine analogs of pentamidine that are more effective than the parent drug in both in vitro and in vivo studies. Furthermore, pre-clinical animal studies of our lead candidate, MTDX203, showed an increased anti-cancer activity with a higher safety index than pentamidine. Based on a predictive PK/PD model, a human iv infusion dose administered twice weekly at ~0.4 mpk (i.e. 28 mg/day, ~10% of pentamidine effective iv dose) is expected to be clinically effective. Our work establishes the EE as a therapeutic target for cancer and identifies a new First in Class of novel anti-cancer agents. 1Chow et al. (2004) MCT 3:911-9182 NCT01378143: Pentamidine (OCZ103-OS) in Patients With Unresectable and Locally Recurrent or Metastatic Colorectal Cancer Undergoing Standard Chemotherap Citation Format: Terry Chow, Jianmin Duan, Patrick Colin, Colin Bier. Modulating DNA repair through endo-exonuclease inhibition: a new therapeutic paradigm in oncology [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2024; Part 1 (Regular Abstracts); 2024 Apr 5-10; San Diego, CA. Philadelphia (PA): AACR; Cancer Res 2024;84(6_Suppl):Abstract nr 5604.

Abstract 1651: Targeting intermediates of the PRMT5/BRG1 axis as a combination therapy

Abstract Over 40% of colorectal cancer (CRC) patients harbor a mutation in the KRAS gene, leading to a worse prognosis. PRMT5 and BRG1 are proteins considered potential therapeutic targets for cancer. Our lab has previously reported that both PRMT5 and BRG1 are overexpressed in KRAS mutant CRC when compared to KRAS wild-type CRC. It is therefore proposed that the PRMT5-BRG1 axis may be a strong therapeutic target for CRC. In this study, several key proteins that potentially mediate crosstalk between the PRMT5-BRG1 axis and KRAS were investigated.A literature review was first conducted to determine how the PRMT5-BRG1 axis acts in cancers. Additionally, pathways that may be involved in mediating the potential crosstalk between BRG1 and KRAS were discussed. Initial findings indicated that the PRMT5-BRG1 axis facilitates cancer oncogenesis. At the same time, the axis suppresses Myc/Max/Mad expression, leading to a dual role of the PRMT5-BRG1 axis depending on the tumor status. BRG1 was also found to work alongside mutant KRAS to affect tumor levels, with the effect differing by tumor type. The STRING database to determine the connection between the PRMT5-BRG1 axis and KRAS. It was determined that PRMT5, BRG1, and KRAS all interact with PBRM1, SMARCB1, ARID1A, and ARID2, with a combined interaction score >0.5. The UCSC Xena software was then used to analyze the mRNA data of CRC patients from The Cancer Genome Atlas (TCGA) database. Xena was utilized to determine which proteins are over expressed in CRC patient tumor samples compared to non-cancerous colon and rectum patient samples. Levels of PBRM1 and ARID1A were observed to significantly decrease in CRC patients as compared to non-cancerous samples by approximately 15% (adjp < 0.0001 and 0.05, respectively). However, SMARCB1 expression increased by 12% (adjp < 0.05). The Gene Expression Profiling Interactive Analysis (GEPIA) software was then used to analyze the correlation between the intermediary genes and PRMT5, BRG1, and KRAS in CRC patient tumor samples. PBRM1, SMARCB1, ARID1A, and ARID2 all demonstrated positive correlation with PRMT5, SMARCA4, and KRAS (R greater than 0.75 for nearly all correlations and p =0) in CRC patient tumor samples. Our study thus showcases the possible disrepair of the PRMT5/BRG1 axis in relation to KRAS. Key downstream proteins are decreased in CRC and may lower the potential crosstalk between PRMT5, BRG1, and KRAS. These findings are significant, and these key intermediate proteins may be strong therapeutic targets via inducing expression. Further research is currently in progress to outline the molecular processes behind the therapeutic role of revitalizing the SMARCA4/BRG1 axis when the downstream proteins are induced. Citation Format: Aaron Shaykevich, Isaac Silverman, Alexander Siegman, Radhashree Maitra. Targeting intermediates of the PRMT5/BRG1 axis as a combination therapy [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2024; Part 1 (Regular Abstracts); 2024 Apr 5-10; San Diego, CA. Philadelphia (PA): AACR; Cancer Res 2024;84(6_Suppl):Abstract nr 1651.

Abstract 4730: Pharmacodynamic determinants of anti tumor activity of SHMT2 inhibitors

Abstract These studies investigate factors that impact the antitumor activity of SHMT2 targeting including drug accumulation, metabolism, expression of one carbon (C1) related enzymes, and tumor hypoxia. Mitochondrial C1 metabolism is upregulated in a variety of cancer types including leukemias and solid tumors. The mitochondrial C1 enzymes serine hydroxymethyltransferase (SHMT) 2 and 5,10-methylene tetrahydrofolate (THF) dehydrogenase 2 (MTHFD2) are among the top 5 overexpressed metabolic enzymes in tumors vs normal tissues in a wide range of tumor types. Thus, SHMT2 and MTHFD2 are potential therapeutic targets for cancer, sparing normal tissues that are less reliant on mitochondrial C1 metabolism. SHMT2 metabolizes serine and THF to produce glycine and 5,10-methylene THF; MTHFD2 metabolizes 5,10-methylene THF to NADH and 10-formyl THF which is converted to formate by MTHFD1L. Thus, mitochondrial C1 metabolism is the principal source of C1 units for cellular biosynthesis and provides the majority of glycine for protein, purine and glutathione synthesis. We previously discovered novel 5-substituted pyrrolo[3,2-d]pyrimidine antifolate compounds which exhibit primary inhibition at mitochondrial SHMT2 along with cytosolic SHMT1 and de novo purine biosynthesis at glycinamide ribonucleotide and 5-aminoimidazole-4-carboxamide ribonucleotide formyltransferases. The lead compound AGF347 is taken up into cells by the facilitative transporters reduced folate carrier (SLC19A1) and the proton coupled folate transporter (SLC46A1) and like folate cofactors is metabolized to polyglutamate (PG) forms by folylpolyglutamate synthase (FPGS) which promotes retention in cytosolic and mitochondrial compartments and target enzyme engagement. We investigated the impact of folate transporter expression on metabolism to PGs for SHMT2 targeted antifolates. Folate transporter expression inversely correlated with anti-tumor efficacy of SHMT2 targeted antifolates and overexpression of FPGS resulted in dramatically increased sensitivities. However, for pyrazolopyran inhibitors of SHMT2 (e.g. SHIN1) which enter cells by diffusion and are not metabolized to polyglutamates, increased transporter and FPGS levels dramatically decreased anti-tumor activity. As SHMT2 is a target of HIF1α, we studied the impact of multitargeting SHMT2 and purine biosynthesis by pyrrolo[3,2-d]pyrimidine antifolates under hypoxic conditions. Our results establish that multi-targeting SHMT2 and purine biosynthesis preserves anti-tumor activity under hypoxia. Collectively, our results demonstrate that SHMT2 targeted pyrrolo[3,2-d]pyrimidine antifolates exhibit increased antitumor efficacies in cells expressing low folate transporter expression and is further enhanced by increased FPGS activity. Additionally, we find multitargeting of SHMT2 and de novo purine biosynthesis manifests as antitumor activity even under hypoxic conditions. Citation Format: Mathew Joseph Schneider, Carrie O'Connor, Xun Bao, Md. Junayed Nayeen, Zhanjun Hou, Jing Li, Aleem Gangjee, Larry Matherly. Pharmacodynamic determinants of anti tumor activity of SHMT2 inhibitors [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2024; Part 1 (Regular Abstracts); 2024 Apr 5-10; San Diego, CA. Philadelphia (PA): AACR; Cancer Res 2024;84(6_Suppl):Abstract nr 4730.

Abstract 2375: 23ME-01473, a novel anti-ULBP6/2/5 monoclonal antibody, reinvigorates anti-tumor NK cell function through NKG2D and FcγRIIIa activation

Abstract Using genome-wide association studies (GWAS) of the 23andMe genetic and healthy survey database across all phenotypes as part of our unique target discovery platform, we identified immuno-oncology (I/O)-related genetic variants as those with opposing directionality of effects on cancer and immunological phenotypes, which comprise the I/O signature. This I/O signature identified ULBP6 as a potential cancer therapeutic target. ULBP6 is a stress-induced cell surface ligand found on cancer cells, that binds to the activating receptor, NKG2D, on NK and T cells to induce tumor cell killing. However, as a mechanism of immune escape, tumors shed ULBP6 to produce a soluble form that attenuates NKG2D activation and is elevated in cancers. Given that the 2 allelic variants of ULBP6 have the highest binding affinity to NKG2D of all human NKG2D ligands, ULBP6 may be the most immunosuppressive soluble NKG2D ligand and a critical regulator of anti-tumor response. Accordingly, soluble ULBP6 exhibited significant suppression of IFNγ release and detectable cell surface NKG2D expression on healthy donor PBMCs using in vitro cell-based assays. Moreover, the overexpression of human ULBP6 in a genetically modified MC38 murine model resulted in decreased infiltration of NK, NKT, and CD8 T cells in vivo. As such, we developed a novel humanized monoclonal antibody, 23ME-01473, that binds with high affinity to ULBP6, and due to the high sequence homology, to ULBP2 and ULBP5, to block their interaction with NKG2D. By preventing the binding of soluble ULBP6 to NKG2D on PBMCs in vitro, 23ME-01473 restored NKG2D activation as measured by increased detectable cell surface NKG2D expression, IFNγ and granzyme B release, and tumor cell killing by PBMCs. To further leverage the binding of 23ME-01473 to ULBP6/2/5, 23ME-01473 was designed to have an afucosylated Fc domain that enhances its binding affinity to the activating Fc receptor, FcγRIIIa, on NK cells to induce ADCC against tumor cells. The combination of NKG2D and FcγRIIIa activation resulted in synergistic PBMC-mediated IFNγ secretion and enhanced tumor cell killing, compared to activation of either NKG2D or FcγRIIIa. Taken together, these results reveal ULBP6 as a novel cancer therapeutic target, and given the dual activation of NKG2D and FcγRIIIa, suggest the potential of 23ME-01473 to activate NK cells and elicit anti-tumor immunity. Citation Format: Joel Benjamin, Abigail Jarret, Shashank Bharill, Shruti Yadav, Dina Ayupova, Clifford Hom, Zahra Bahrami Dizicheh, I-Ling Chen, Anh Diep, Shi Shi, Caroline Bonnans, Danielle Kellar, Germaine Fuh, Maike Schmidt, Kimberline Gerrick, Patrick Koenig, Mauro Poggio. 23ME-01473, a novel anti-ULBP6/2/5 monoclonal antibody, reinvigorates anti-tumor NK cell function through NKG2D and FcγRIIIa activation [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2024; Part 1 (Regular Abstracts); 2024 Apr 5-10; San Diego, CA. Philadelphia (PA): AACR; Cancer Res 2024;84(6_Suppl):Abstract nr 2375.

Abstract 4695: Effect of fully human anti-PTGFRN antibody drug conjugate on head neck cancer cells and patient derived xenografts

Abstract Prostaglandin F2 Receptor Negative regulator, or PTGFRN, also known as FPRP is a 175 kDa transmembrane protein associated with metastatic characteristics of certain cancer types and a member of the tetraspanin family. PTGFRN expression is undetectable to low in normal tissues whereas it is elevated in several cancers such as head and neck, mesothelioma and medulloblastoma. PTGFRN has also been reported to be upregulated in many different types of cancer, increasingly so in metastatic cancer cells, compared to their non-metastatic counterparts PTGFRN expression has been reported to be a poor prognostic factor for glioblastoma making it a potential novel cancer therapeutic target. We have previously shown that PTGFRN is an internalizable cell surface protein making it suitable for targeting by antibody drug conjugate (ADC). We have developed fully human monoclonal antibodies to PTGFRN by immunizing humanized transgenic TC mice with human PTGFRN. Within 60 days from the start of immunization we were able to select several fully human anti-PTGFRN monoclonal antibodies that were examined by several functional assays that included flow binding, internalization, affinity determination and cell killing as antibody drug conjugates. Several monoclonal antibodies were selected and evaluated for their ability to inhibit tumor formation in several cancers. Selected antibodies were then conjugated to duocarmycin by a cleavable linker. The present study proposed to examine the effect of one such anti-PTGFRN ADC on head and neck cancer cell lines and patient derived xenografts that had been analyzed for their PTGFRN expression by western blot analysis using anti-PTGFRN antibody. Cells lines and PDX that were positive for PTGFRN expression were used to examine the effect of anti-PTGFRN ADC on their in vitro and in vivo proliferation. The data show that anti-PTGFRN ADC inhibits tumor formation in a dose-dependent fashion. These data also establish PTGFRN as cancer druggable target and the selected fully human anti-PTGFRN antibody as an attractive antibody for the development of new antibody drug conjugate in Oncology. These data also emphasize the potential of humanized transgenic TC mice for the development of fully human monoclonal antibodies, thus bypassing the need for humanization and affinity maturation required by other humanized mice or phase display. Citation Format: Jorge Marquez, Jianping Dong, Mitsuo Oshimura, Jun Hayashi, Ginette Serrero. Effect of fully human anti-PTGFRN antibody drug conjugate on head neck cancer cells and patient derived xenografts [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2024; Part 1 (Regular Abstracts); 2024 Apr 5-10; San Diego, CA. Philadelphia (PA): AACR; Cancer Res 2024;84(6_Suppl):Abstract nr 4695.

The pleiotropic nature of NONO, a master regulator of essential biological pathways in cancers.

NONO is a member of the Drosophila behavior/human splicing (DBHS) family of proteins. NONO is a multifunctional protein that acts as a "molecular scaffold" to carry out versatile biological activities in many aspects of gene regulation, cell proliferation, apoptosis, migration, DNA damage repair, and maintaining cellular circadian rhythm coupled to the cell cycle. Besides these physiological activities, emerging evidence strongly indicates that NONO-altered expression levels promote tumorigenesis. In addition, NONO can undergo various post-transcriptional or post-translational modifications, including alternative splicing, phosphorylation, methylation, and acetylation, whose impact on cancer remains largely to be elucidated. Overall, altered NONO expression and/or activities are a common feature in cancer. This review provides an integrated scenario of the current understanding of the molecular mechanisms and the biological processes affected by NONO in different tumor contexts, suggesting that a better elucidation of the pleiotropic functions of NONO in physiology and tumorigenesis will make it a potential therapeutic target in cancer. In this respect, due to the complex landscape of NONO activities and interactions, we highlight caveats that must be considered during experimental planning and data interpretation of NONO studies.

Biological role and regulation of circular RNA as an emerging biomarker and potential therapeutic target for cancer.

Circular RNAs (circRNAs) are a unique family of endogenous RNAs devoid of 3' poly-A tails and 5' end caps. These single-stranded circRNAs, found in the cytoplasm, are synthesized via back-splicing mechanisms, merging introns, exons, or both, resulting in covalently closed circular loops. They are profusely expressed across the eukaryotic transcriptome and offer heightened stability against exonuclease RNase R compared to linear RNA counterparts. This review endeavors to provide a comprehensive overview of circRNAs' characteristics, biogenesis, and mechanisms of action. Furthermore, aimed to shed light on the potential of circRNAs as significant biomarkers in various cancer types. It has been performed an exhaustive literature review, drawing on recent studies and findings related to circRNA characteristics, synthesis, function, evaluation techniques, and their associations with oncogenesis. CircRNAs are intricately associated with tumor progression and development. Their multifaceted roles encompass gene regulation through the sponging of proteins and microRNAs, controlling transcription and splicing, interacting with RNA binding proteins (RBPs), and facilitating gene translation. Due to these varied roles, circRNAs have become a focal point in tumor pathology investigations, given their promising potential as both biomarkers and therapeutic agents. CircRNAs, due to their unique biogenesis and multifunctionality, hold immense promise in the realm of oncology. Their stability, widespread expression, and intricate involvement in gene regulation underscore their prospective utility as reliable biomarkers and therapeutic targets in cancer. As our understanding of circRNAs deepens, advanced techniques for their detection, evaluation, and manipulation will likely emerge. These advancements might catalyze the translation of circRNA-based diagnostics and therapeutics into clinical practice, potentially revolutionizing cancer care and prognosis.

FPFT-2216, a Novel Anti-lymphoma Compound, Induces Simultaneous Degradation of IKZF1/3 and CK1α to Activate p53 and Inhibit NFκB Signaling.

We found potential vulnerability to CK1α degradation in certain lymphoma cells refractory to IKZF1/3 degraders. Targeting CK1α with FPFT-2216 could inhibit the growth of these cells by activating p53 signaling. Our study demonstrates the potential therapeutic application of CK1α degraders, such as FPFT-2216, for treating lymphoma.

Transmembrane pH gradient imaging in rodent glioma models.

A unique feature of the tumor microenvironment is extracellular acidosis in relation to intracellular milieu. Metabolic reprogramming in tumors results in overproduction of H+ ions (and lactate), which are extruded from the cells to support tumor survival and progression. As a result, the transmembrane pH gradient (ΔpH), representing the difference between intracellular pH (pHi) and extracellular pH (pHe), is posited to be larger in tumors compared with normal tissue. Controlling the transmembrane pH difference has promise as a potential therapeutic target in cancer as it plays an important role in regulating drug delivery into cells. The current study shows successful development of an MRI/MRSI-based technique that provides ΔpH imaging at submillimeter resolution. We applied this technique to image ΔpH in rat brains with RG2 and U87 gliomas, as well as in mouse brains with GL261 gliomas. pHi was measured with Amine and Amide Concentration-Independent Detection (AACID), while pHe was measured with Biosensor Imaging of Redundant Deviation in Shifts (BIRDS). The results indicate that pHi was slightly higher in tumors (7.40-7.43 in rats, 7.39-7.47 in mice) compared with normal brain (7.30-7.38 in rats, 7.32-7.36 in mice), while pHe was significantly lower in tumors (6.62-6.76 in rats, 6.74-6.84 in mice) compared with normal tissue (7.17-7.22 in rats, 7.20-7.21 in mice). As a result, ΔpH was higher in tumors (0.64-0.81 in rats, 0.62-0.65 in mice) compared with normal brain (0.13-0.16 in rats, 0.13-0.16 in mice). This work establishes an MRI/MRSI-based platform for ΔpH imaging at submillimeter resolution in gliomas.

Specific Inhibitors of Mitochondrial Deacylase Sirtuin 4 Endowed with Cellular Activity.

Sirtuins are NAD+-dependent protein lysine deacylases implicated in aging-related diseases. Mammalian Sirtuin 4 (Sirt4) is located in mitochondria and a potential therapeutic target for cancer and metabolic diseases, but no potent and selective Sirt4 inhibitors have been reported. Here, we describe the identification of potent Sirt4-specific small-molecule inhibitors. Testing hits from a target-based virtual screen revealed 12 active compounds. A focused screen based on two top compounds, followed by structure-assisted design of derivatives, yielded four first-in-class potent Sirt4 inhibitors. Kinetic analyses indicate compound competition with the acyl peptide substrate, consistent with the docking models and implicating Sirt4's unique acyl binding site. The compounds indeed show preference for Sirt4 over other isoforms, with one of them (69) being highly isoform selective, and they are active in cells. Our results provide first lead compounds and mechanistic insights for optimization toward Sirt4-specific inhibitors useful as experimental tools and potential therapeutics.

Photochemically Controlled Release of the Glucose Transporter 1 Inhibitor for Glucose Deprivation Responses and Cancer Suppression Research.

Cancer cells need a greater supply of glucose mainly due to their aerobic glycolysis, known as the Warburg effect. Glucose transport by glucose transporter 1 (GLUT1) is the rate-limiting step for glucose uptake, making it a potential cancer therapeutic target. However, GLUT1 is widely expressed and performs crucial functions in a variety of cells, and its indiscriminate inhibition will cause serious side effects. In this study, we designed and synthesized a photocaged GLUT1 inhibitor WZB117-PPG to suppress the growth of cancer cells in a spatiotemporally controllable manner. WZB117-PPG exhibited remarkable photolysis efficiency and substantial cytotoxicity toward cancer cells under visible light illumination with minimal side effects, ensuring its safety as a potential cancer therapy. Furthermore, our quantitative proteomics data delineated a comprehensive portrait of responses in cancer cells under glucose deprivation, underlining the mechanism of cell death via necrosis rather than apoptosis. We reason that our study provides a potentially reliable cancer treatment strategy and can be used as a spatiotemporally controllable trigger for studying nutrient deprivation-related stress responses.

PDE3B regulates KRT6B and increases the sensitivity of bladder cancer cells to copper ionophores.

Cuproptosis is a new Cu-dependent programmed cell death manner that has shown regulatory functions in many tumor types, however, its mechanism in bladder cancer remains unclear. Here, we reveal that Phosphodiesterase 3B (PDE3B), a cuproptosis-associated gene, could reduce the invasion and migration of bladder cancer. PDE3B is downregulated in bladder cancer tissues, which is correlated with better prognosis. Conversely, overexpression of PDE3B in bladder cancer cell could significantly resist invasion and migration, which is consistent with the TCGA database results. Future study demonstrate the anti-cancer effect of PDE3B is mediated by Keratin 6B (KRT6B) which leads to the keratinization. Therefore, PDE3B can reduce KRT6B expression and inhibit the invasion and migration of bladder cancer. Meanwhile, increased expression of PDE3B was able to enhance the sensitivity of Cuproptosis drug thiram. This study show that PDE3B/KRT6B is a potential cancer therapeutic target and PDE3B activation is able to increase the sensitivity of bladder cancer cells to copper ionophores.

Identification of approved drugs with ALDH1A1 inhibitory potential aimed at enhancing chemotherapy sensitivity in cancer cells: an in-silico drug repurposing approach

The aldehyde dehydrogenase 1A1 (ALDH1A1) also known as retinal dehydrogenase, is an enzyme normally involved in the cellular metabolism, development and detoxification processes in healthy cells. However, it’s also considered a cancer stem cell marker and its high levels of expression in several cancers, including breast, lung, ovarian, and colon cancer have been associated with poor prognosis and resistance to chemotherapy. Given its crucial role in chemotherapy resistance by detoxification of chemotherapeutic drugs, ALDH1A1 has attracted significant research interest as a potential therapeutic target for cancer. Though a few synthetic inhibitors of ALDH1A1 have been synthesized and their efficacy has been proved in-vitro and in-vivo studies, none of them have passed clinical trials so far. In this scenario, we have performed an in-silico study to verify whether any of the already approved drugs used for various purposes has the ability to inhibit catalytic activity of ALDH1A1, so that they can be repurposed for cancer therapy. Keeping in mind the feasibility of repurposing in a larger population we have selected the approved drugs from five widely used drug categories such as antibiotic, antiviral, antifungal, anti diabetic and antihypertensive for screening. Computational techniques like molecular docking, molecular dynamics simulations and MM-PBSA binding energy calculation have been used in this study to screen the approved drugs. Based on the logical analysis of results, we propose that three drugs – telmisartan, irbesartan and maraviroc can inhibit the catalytic activity of ALDH1A1 and thus can be repurposed to increase chemotherapy sensitivity in cancer cells. Communicated by Ramaswamy H. Sarma

Structural optimization of a lysine demethylase 5 inhibitor for improvement of its cellular activity

Lysine demethylase 5 (KDM5) subfamily proteins are important in epigenetic gene regulation. They are involved in the growth and drug resistance of cancer cells. Therefore, KDM5s are potential cancer therapeutic targets, and their inhibitors hold promise as anti-cancer drugs. Several KDM5 inhibitors, including KDM5-C49 (2a), have exhibited potent KDM5-inhibitory activities in in vitro enzyme assays. However, they do not show enough cellular activity despite being converted to their prodrugs. We hypothesized that their poor lipophilicity should prevent them from sufficiently penetrating the cell membrane, and introducing more lipophilic groups should improve cellular activities. In this study, we investigated 2a and KDM5-C70 (3a), a prodrug of 2a, and attempted to improve its cellular activity by replacing the N,N-dimethyl amino group of 3a with more lipophilic groups. N-Butyl, N-methyl amino compound 2e exhibited potent and selective KDM5-inhibitory activity equal to that of 2a. Furthermore, the cell membrane permeability of 3e, an ethyl ester prodrug of 2e, was six times higher than that of 3a in a parallel artificial membrane permeation assay. In addition, western blot analysis indicated that treating human lung cancer A549 cells with 3e increased histone methylation levels more strongly than that with 3a. Thus, we identified compound 3e as a more cell-active KDM5 inhibitor that has sufficient cell membrane permeability.

Pan-cancer analysis reveals the characteristics and roles of tooth agenesis mutant genes.

Tooth development is regulated by numerous genes and signaling pathways. Some studies suggest that mutations in these genes may be associated with several cancer types. However, the tooth agenesis mutated genes role in the prognosis and their clinical therapeutic potentials in pan-cancer have not been elaborately explored. Moreover, the intrinsic correlation between tooth agenesis and cancers also needs to be further verified. We preliminarily analyzed expression levels and prognostic values of causative genes of tooth agenesis, and explored the correlation between the expression of tooth agenesis mutated genes and TME, Stemness score, clinical characteristic, immune subtype, and drug sensitivity in pan-cancer, which based on updated public databases and integrated some bioinformatics analysis methods. In addition, we conducted the enrichment analysis of tooth agenesis mutant genes from KOBAS database. We observed that TA mutant genes had significant gene expression differences in multiple cancer types compared with normal tissues. The expression of causative genes of TA is associated with the prognosis in several cancers from different databases. For example, AXIN2 and MSX1 were correlated to the overall survival (OS) of uterine corpus endometrial carcinoma. PAX9 and TP63 were related to OS of lung squamous cell carcinoma. And TP63 was associated with OS in breast invasive carcinoma and pancreatic adenocarcinoma. Furthermore, the expression of TA mutant genes also has a significant correlation with stromal and immune scores, and RNA stemness score and DNA stemness score in pan-cancer. Besides, we observed that all causative genes of TA were significantly correlated with immune subtypes. Moreover, KEGG pathway analysis showed that causative genes of TA were associated with the development and progression of breast cancer, basal cell carcinoma, gastric cancer, and hepatocellular carcinoma. Finally, AXIN2 expression has a significantly positive or negative correlation with drug sensitivity. Our study indicates the great potential of TA mutant genes as biomarkers for prognosis and provides valuable strategies for further investigation of TA mutant genes as potential therapeutic targets in cancers. Our study can further verify that there may be an intrinsic correlation between tooth agenesis and the occurrence of multiple cancers.