Potential Chemotherapeutic Target Research Articles

FOXP1 phosphorylation antagonizes its O-GlcNAcylation in regulating ATR activation in response to replication stress

AbstractATR signaling is essential in sensing and responding to the replication stress; as such, any defects can impair cellular function and survival. ATR itself is activated via tightly regulated mechanisms. Here, we identify FOXP1, a forkhead-box-containing transcription factor, as a regulator coordinating ATR activation. We show that, unlike its role as a transcription factor, FOXP1 functions as a scaffold and directly binds to RPA–ssDNA and ATR–ATRIP complexes, facilitating the recruitment and activation of ATR. This process is regulated by FOXP1 O-GlcNAcylation, which represses its interaction with ATR, while CHK1-mediated phosphorylation of FOXP1 inhibits its O-GlcNAcylation upon replication stress. Supporting the physiological relevance of this loop, we find pathogenic FOXP1 mutants identified in various tumor tissues with compromised ATR activation and stalled replication fork stability. We thus conclude that FOXP1 may serve as a potential chemotherapeutic target in related tumors.

Crotonylation of MCM6 enhances chemotherapeutics sensitivity of breast cancer via inducing DNA replication stress.

Breast cancer is associated with high morbidity and mortality, which are closely influenced by protein post-translational modifications (PTMs). Lysine crotonylation (Kcr) serves as a newly identified PTM type that plays a role in various biological processes; however, its involvement in breast cancer progression remains unclear. Minichromosome maintenance 6 (MCM6) is a critical component of DNA replication and has been previous confirmed to exhibit a significant role in tumorigenesis. Despite this, a comprehensive analysis of MCM6, particularly regarding its modifications in breast cancer is lacking. In this study, we found MCM6 is upregulated in breast invasive carcinoma (BRCA) and is associated with poorer overall survival by regulating the DNA damage repair mechanisms. Furthermore, MCM6-knockdown resulted in decreased cell proliferation and inhibited the DNA replication, leading to DNA replication stress and sustained DNA damage, thereby enhancing the chemotherapeutic sensitivity of breast cancer. Additionally, SIRT7-mediated crotonylation of MCM6 at K599 (MCM6-K599cr) was significantly upregulated in response to DNA replication stress, primarily due to the disassemebly of the MCM2-7 complex and regulated by RNF8-mediated ubiquitination. Concurrently, kaempferol, which acts as a regulator of SIRT7, was found to enhance the Kcr level of MCM6, reducing tumour weight, particular when combined with paclitaxel, highlighting its potential chemotherapeutic target for BRCA therapy.

The Z isomer of pyridoxilidenerhodanine 5'-phosphate is an efficient inhibitor of human pyridoxine 5'-phosphate oxidase, a crucial enzyme in vitamin B6 salvage pathway and a potential chemotherapeutic target.

Pyridoxal 5'-phosphate (PLP), the catalytically active form of vitamin B6, acts as a cofactor in many metabolic processes. In humans, PLP is produced in the reactions catalysed by pyridox(am)ine 5'-phosphate oxidase (PNPO) and pyridoxal kinase (PDXK). Both PNPO and PDXK are involved in cancer progression of many tumours. The silencing of PNPO and PDXK encoding genes determines a strong reduction in tumour size and neoplastic cell invasiveness in models of acute myeloid leukaemia (in the case of PDXK) and ovarian and breast cancer (in the case of PNPO). In the present work, we demonstrate that pyridoxilidenerhodanine 5'-phosphate (PLP-R), a PLP analogue that has been tested by other authors on malignant cell lines reporting a reduction in proliferation, inhibits PNPO in vitro following a mixed competitive and allosteric mechanism. We also show that the unphosphorylated precursor of this inhibitor (PL-R), which has more favourable pharmacokinetic properties according to our predictions, is phosphorylated by PDXK and therefore transformed into PLP-R. On this ground, we propose the prototype of a novel prodrug-drug system as a useful starting point for the development of new, potential, antineoplastic agents.

Kinesin Family Member C1: Function in liver hepatocellular carcinoma and potential target for chemotherapeutic

MiR-105 exerts inhibitory effects on the development and progression of various cancers, including breast cancer, lung cancer, and gastric cancer. Through GEO data analysis, we observed decreased expression of miR-105 in liver cancer tissues compared to adjacent tissues. Furthermore, miR-105 downregulates KIFC1 expression levels by targeting its 3' UTR. KIFC1 (Kinesin Family Member C1), a Protein Coding gene, may play a role in mitotic metaphase plate polymerization and mitotic spindle assembly. However, our findings suggest that this gene could serve as a potential chemotherapeutic target for Liver hepatocellular carcinoma (LIHC). We obtained the LIHC dataset from the TCGA database and genotype Tissue Expression Project (GTEx) normal tissue data for differential analysis. Additionally, we utilized the cBioPortal database, tumor immune single-cell center (TISCH) database, gene set enrichment analysis (GSEA), and R software to investigate the possible functions and mechanisms of KIFC1. These findings were further validated through experiments such as immunohistochemistry and wound healing assays. Our results indicate that KIFC1 might be involved in DNA repair and cell cycle regulation in LIHC cells which subsequently impacts tumor cell proliferation; moreover, miR-105 influences hepatoma cell line proliferation via its interaction with KIFC1. Collectively, these results highlight the potential therapeutic significance of targeting KIFC1 for chemotherapy treatment in LIHC patients.

Functional genetic variants of GEN1 predict overall survival of Chinese epithelial ovarian cancer patients

BackgroundInherited variations in DNA double-strand break (DSB) repair pathway are known to influence ovarian cancer occurrence, progression and treatment response. Despite its significance, survival-associated genetic variants within the DSB pathway remain underexplored.MethodsIn the present study, we performed a two-phase analysis of 19,290 single-nucleotide polymorphisms (SNPs) in 199 genes in the DSB repair pathway from a genome-wide association study (GWAS) dataset and explored their associations with overall survival (OS) in 1039 Han Chinese epithelial ovarian carcinoma (EOC) patients. After utilizing multivariate Cox regression analysis with bayesian false-discovery probability for multiple test correction, significant genetic variations were identified and subsequently underwent functional prediction and validation.ResultsWe discovered a significant association between poor overall survival and the functional variant GEN1 rs56070363 C > T (CT + TT vs. TT, adjusted hazard ratio (HR) = 2.50, P < 0.001). And the impact of GEN1 rs56070363 C > T on survival was attributed to its reduced binding affinity to hsa-miR-1287-5p and the resultant upregulation of GEN1 mRNA expression. Overexpression of GEN1 aggregated EOC cell proliferation, invasion and migration presumably by influencing the expression of immune inhibitory factors, thereby elevating the proportion of polymorphonuclear myeloid-derived suppressor cells (PMN-MDSCs) and then constructing an immunosuppressive tumor microenvironment.ConclusionsIn conclusion, GEN1 rs56070363 variant could serve as a potential predictive biomarker and chemotherapeutic target for improving the survival of EOC patients.

Abstract 5696: Exploring the association between miR-9-5p levels and the mTORC1/mTORC2 pathway in laryngeal cancer cell lines

Abstract Background: We previously demonstrated that differing levels of miR-9-5p could predict chemosensitivity to cisplatin, and that miR-9-5p is a regulator of potential chemotherapeutic target MAP1B. As the mTOR/PIK3CA pathway has been implicated in the pathogenesis of laryngeal squamous cell carcinoma (LSCC), we sought to determine an association between differing miR-9-5p levels, mTOR pathway mediators including MAP1B, and methylation. Methods: UM-SCC-98, UM-SCC-12, UM-SCC-11A, UM-SCC-10A (obtained from the University of Michigan) laryngeal cancer cell lines were used in this study. We previously showed UM-SCC-98 and UM-SCC-12 to have significantly lower miR-9-5p levels as compared to UM-SCC-11A and UM-SCC-10A (Northern blot analysis). The IC50 of an mTORC1 inhibitor (Rapamycin) and an mTORC1/C2 inhibitor (AZD-8055) were evaluated using the Cell Titer Blue Viability assay. Cells were treated with the de-methylating agent, 5-Azacytidine (1μM). Gene expression of mTOR pathway mediators- miR-9-5p, PTEN, EGFR, PIK3CA, and MAP1B- were determined in each cell line pre-and post-treatment via qPCR. Results: All cell lines were resistant to treatment with Rapamycin (IC50 &amp;gt; 60μM) with the UM-SCC-12 cell line yielding the highest IC50 (&amp;gt; 150μM). Conversely, decreased cell proliferation was detected with AZD-8055. This was significantly associated with their miR-9-5p levels– a higher AZD-8055 IC50 was associated with cell lines UM-SCC-98 (~40μM) and UM-SCC-12 (~23μM) compared to UM-SCC-10A (~16μM) and UM-SCC-11A (~8μM). Following demethylation treatment, miR-9-5p levels were significantly increased in UM-SCC-12 only (2-fold), and this corresponded to a significant decrease in MAP1B gene expression (2-fold) but not with EGFR, PIK3CA, and PTEN gene expression. Conclusion: In conclusion, our study suggests that miR-9-5p may regulate MAP1B gene expression via the mTORC2 pathway. In addition, methylation may play a role in the regulation of the miR-9-5p gene and its downstream targets in laryngeal cancer tumorigenesis. Future studies will involve exploring epigenetic mechanisms of miR-9-5p inhibition and defining the role of key mediators of the mTOR pathway in LSCC. Citation Format: Christina Gobin, Matthew Chang, Chayil C. Lattimore, Kristianna M. Fredenburg. Exploring the association between miR-9-5p levels and the mTORC1/mTORC2 pathway in laryngeal cancer cell lines [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 5696.

Single-cell integrated transcriptomics reveals the role of keratinocytes in head and neck squamous cell carcinoma.

Head and neck squamous cell carcinoma (HNSCC) is a prevalent malignant tumor with significant morbidity and mortality. Understanding the molecular mechanisms of HNSCC and identifying prognostic markers and therapeutic targets are crucial for improving patient outcomes. In this study, we utilized single-cell RNA sequencing (scRNA-seq) and bulk RNA-seq data to comprehensively analyze HNSCC at the cellular level. We identified keratinocytes as the predominant cell type in tumor samples, suggesting their potential role in HNSCC development. Through hdWGCNA co-expression network analysis, we identified gene modules associated with HNSCC progression. Furthermore, we constructed a prognostic model based on specific genes and demonstrated its robust predictive performance in multiple datasets. The model exhibited strong correlations with immune cell infiltration patterns and signaling pathways related to tumor progression. Additionally, drug sensitivity analysis revealed potential chemotherapeutic targets for HNSCC treatment. Our findings provide valuable insights into the molecular characteristics and immune microenvironment of HNSCC, offering new perspectives for prognosis prediction and therapeutic interventions in clinical practice. Further research is warranted to validate and expand upon these findings, ultimately improving patient outcomes in HNSCC.

Abstract C068: Exploring the relationship between miR-9-5p levels and MAP1B expression in laryngeal cancer cell lines

Abstract Background: Low miR-9-5p expression has been associated with poor overall survival in head and neck squamous cell carcinoma (HNSCC), whereas higher expression is associated with better outcomes. Our previous studies determined that low miR-9 levels is a significant feature of advanced stage laryngeal squamous cell carcinoma (LSCC) specifically in Black patients. We further showed that low miR-9 is associated with increased cell proliferation and decreased chemosensitivity to cisplatin. In this study, we sought to explore the relationship between low miR-9-5p- and high miR-9-5p-LSCC cell lines and its genomic and potential chemotherapeutic target, microtubule-associated protein 1B (MAP1B). Methods: We used four cell lines derived from patients with advanced stage LSCC: UM-SCC-98, UM-SCC-12, UM-SCC-11A, UM-SCC-10A (University of Michigan). Mature miR-9-5p levels were determined in each cell line via northern blotting. Baseline chemosensitivity (IC50 of cisplatin) as well as cell proliferation of each cell line was assessed using the Cell Titer Blue Viability assay. Baseline MAP1B gene and protein expression were determined in each cell line via qPCR and western blotting, respectively. Results: The lowest mature miR-9-5p levels were found in UM-SCC-98 followed by UM-SCC-12. The highest mature miR-9-5p levels were found in UM-SCC-11A followed by UM-SCC-10A. Cell lines with lower miR-9-5p resulted in increased cell proliferation and higher cisplatin IC50 (p &amp;lt; 0.0001): UM-SCC-98 IC50 = 18.32µM and UM-SCC-12 IC50 = 16.70µM. Conversely, cell lines with higher miR-9-5p levels resulted in lower cell proliferation and lower cisplatin IC50; UM-SCC-11A IC50 = 2.28µM and UM-SCC-10A IC50 = 10.95µM. An inverse relationship between miR-9-5p levels and MAP1B gene expression was seen, wherein the low miR-9-5p expressing cell lines (UM-SCC-98 and UM-SCC-12) had the highest gene expression levels; the high miR-9-5p expressing cell lines (UM-SCC-11A and UM-SCC-10A) had the lowest gene expression levels (p &amp;lt; 0.0001, fold change &amp;gt;2). Lower miR-9-5p levels also corresponded with higher MAP1B protein expression, wherein expression was only seen in cell lines UM-SCC-98 and UM-SCC-12. No MAP1B protein expression was seen in UM-SCC-11A and UM-SCC-10A (p &amp;lt; 0.0001). Conclusion: This study further supports the relevance of low miR-9-5p in the regulation of cisplatin chemosensitivity in LSCC. MAP1B, a described mediator of chemoresistance, may be a future target for intervention. Future studies will involve exploring mechanisms of miR-9-5p inhibition and defining MAP1B regulatory pathways. Citation Format: Christina Gobin, Chayil C. Lattimore, Jai Walker, Kristianna M. Fredenburg. Exploring the relationship between miR-9-5p levels and MAP1B expression in laryngeal cancer cell lines [abstract]. In: Proceedings of the 16th AACR Conference on the Science of Cancer Health Disparities in Racial/Ethnic Minorities and the Medically Underserved; 2023 Sep 29-Oct 2;Orlando, FL. Philadelphia (PA): AACR; Cancer Epidemiol Biomarkers Prev 2023;32(12 Suppl):Abstract nr C068.

A proteasomal β5 subunit of Haemonchus contortus with a role in the growth, development and life span

BackgroundThe proteasome in eukaryotic cells can degrade a variety of proteins and plays an important role in regulating the cell cycle, cell survival and apoptosis. The proteasome receives much attention as a potential chemotherapeutic target for treatment of a variety of infectious parasitic diseases, but few studies of proteasomes have been done on parasitic nematodes.MethodsA proteasomal β5 subunit encoding gene (named Hc-pbs-5) and its inferred product (Hc-PBS-5) in Haemonchus contortus were identified and characterized in this study. Then, the transcriptional profiles and anatomical expression were studied using an integrated molecular approach. Finally, a specific proteasome inhibitor bortezomib (BTZ), together with RNA interference (RNAi), was employed to assess the function of Hc-PBS-5.ResultsBioinformatic analysis revealed that the coding sequence of Hc-pbs-5 was 855 bp long and encoded 284 amino acids (aa). The predicted protein (Hc-PBS-5) had core conservative sequences (65–250 aa) belonging to N-terminal nucleophile (Ntn) family of hydrolases. Real-time PCR results revealed that Hc-pbs-5 was continuously transcribed in eight developmental stages with higher levels at the infective third-stage larvae (L3s) and adult males of H. contortus. Immunohistochemical results revealed that Hc-PBS-5 was expressed in intestine, outer cuticle, muscle cells under the outer cuticle, cervical glands and seminal vesicles of male adults and also in intestine, outer cuticle, cervical glands, uterine wall, eggs and ovaries of female adults of H. contortus. BTZ could reduce proportions of egg hatching, and the fourth-stage larvae (L4s) developed from the exsheathed L3s (xL3s) of H. contortus. In addition, silencing Hc-pbs-5 by soaking the specific double-stranded RNA (dsRNA) could decrease the transcription of Hc-pbs-5 and result in fewer xL3s developing to L4s in vitro.ConclusionsThese results indicate that proteasomal β5 subunit plays an important role in the growth, development and life span of H. contortus.Graphical

Computational benchmarking of putative KIFC1 inhibitors.

The centrosome in animal cells is instrumental in spindle pole formation, nucleation, proper alignment of microtubules during cell division, and distribution of chromosomes in each daughter cell. Centrosome amplification involving structural and numerical abnormalities in the centrosome can cause chromosomal instability and dysregulation of the cell cycle, leading to cancer development and metastasis. However, disturbances caused by centrosome amplification can also limit cancer cell survival by activating mitotic checkpoints and promoting mitotic catastrophe. As a smart escape, cancer cells cluster their surplus of centrosomes into pseudo-bipolar spindles and progress through the cell cycle. This phenomenon, known as centrosome clustering (CC), involves many proteins and has garnered considerable attention as a specific cancer cell-targeting weapon. The kinesin-14 motor protein KIFC1 is a minus end-directed motor protein that is involved in CC. Because KIFC1 is upregulated in various cancers and modulates oncogenic signaling cascades, it has emerged as a potential chemotherapeutic target. Many molecules have been identified as KIFC1 inhibitors because of their centrosome declustering activity in cancer cells. Despite the ever-increasing literature in this field, there have been few efforts to review the progress. The current review aims to collate and present an in-depth analysis of known KIFC1 inhibitors and their biological activities. Additionally, we present computational docking data of putative KIFC1 inhibitors with their binding sites and binding affinities. This first-of-kind comparative analysis involving experimental biology, chemistry, and computational docking of different KIFC1 inhibitors may help guide decision-making in the selection and design of potent inhibitors.

Lactate Dehydrogenase as a Potential Therapeutic Drug Target to Control Babesia bigemina

Babesia bigemina is a tick-borne apicomplexan hemoprotozoan responsible for bovine babesiosis. The current drugs used for bovine babesiosis treatment have several drawbacks, including toxicity, the lack of effectiveness to clear the parasite, and potential to develop resistance. Identifying compounds that target essential and unique parasite metabolic pathways is a rational approach toward finding alternative drug treatments. Based on the genome sequence and transcriptomics analysis, it can be inferred that anaerobic glycolysis is the dominant adenosine triphosphate (ATP) supply for Babesia, and lactate dehydrogenase (LDH) is one of the essential enzymes in this pathway. Furthermore, the Babesia LDH sequence is distinct from its bovine homologue and thus a potential chemotherapeutic target that would result in decreasing the ATP supply to the parasite but not to the host. Gossypol is a known efficient specific inhibitor of LDH in the sensu stricto B. bovis and the sensu lato B. microti, among other related parasites, but no such data are currently available in the sensu stricto B. bigemina parasites. Hereby, we show that the LDH amino acid sequence is highly conserved among sensu stricto but not in sensu lato Babesia spp. A predictive structural analysis of B. bigemina LDH showed the conservation of the key amino acids involved in the binding to gossypol compared to B. bovis. Gossypol has a significant (P < 0.0001) inhibitory effect on the in vitro growth of B. bigemina, with IC50 of 43.97 mM after 72 h of treatment. The maximum IC (IC98) was observed at 60 mM gossypol. However, a significant effect on the viability of cattle PBMC was observed when the cells were cultured with 60 mM (IC98) gossypol compared with DMSO-exposed control cells. Interestingly, B. bigemina cultured at 3% oxygen expresses significantly higher levels of LDH and is more resistant to gossypol than the parasites maintained at ambient conditions containing ~20% oxygen. Altogether, the results suggest the potential of gossypol as an effective drug against B. bigemina infection, but the risk of host toxicity at therapeutic doses should be further evaluated in in vivo studies.

Transient Receptor Potential Cation Channel Subfamily V Member 1 Expression Promotes Chemoresistance in Non-Small-Cell Lung Cancer.

Approximately 85% of lung cancer cases are non-small-cell lung cancer (NSCLC). Chemoresistance is a leading cause of chemotherapy failure in NSCLC treatment. Transient receptor potential cation channel subfamily V, member 1 (TRPV1), a non-selective cation channel, plays multiple roles in tumorigenesis and tumor development, including tumor cell proliferation, death, and metastasis as well as the response to therapy. In this study, we found TRPV1 expression was increased in NSCLC. TRPV1 overexpression induced cisplatin (DDP) and fluorouracil (5-FU) resistance in A549 cells independent of its channel function. TRPV1 expression was upregulated in A549-DDP/5-FU resistant cells, and DDP/5-FU sensitivity was restored by TRPV1 knockdown. TRPV1 overexpression mediated DDP and 5-FU resistance by upregulation of ABCA5 drug transporter gene expression, thereby increasing drug efflux, enhancing homologous recombination (HR) DNA repair pathway to alleviate apoptosis and activating IL-8 signaling to promote cell survival. These findings demonstrate an essential role of TRPV1 in chemoresistance in NSCLC and implicate TRPV1 as a potential chemotherapeutic target.

OLFM4 depletion sensitizes gallbladder cancer cells to cisplatin through the ARL6IP1/caspase-3 axis

BackgroundGallbladder cancer (GBC) is a highly lethal malignancy that carries an extremely poor prognosis due to its chemoresistant nature. Cisplatin (CDDP) is a first-line chemotherapeutic for GBC; however, patients experienced no benefit when treated with CDDP alone. The underlying mechanisms of CDDP resistance in GBC remain largely unknown. MethodsAgilent mRNA microarray analysis was performed between paired GBC and paracarcinoma to explore differentially expressed genes that might underlie drug resistance. Gene Set Enrichment Analysis (GSEA) was employed to identify key genes mediating CDDP resistance in GBC, and immunohistochemistry was performed to validate protein expression and test correlations with clinicopathological features. In vitro and in vivo functional assays were performed to investigate the proteins’ roles in CDDP resistance. ResultsOlfactomedin 4 (OLFM4) was differentially expressed between GBC and paracarcinoma and had the highest rank metric score in the GSEA. OLFM4 expression was increasingly upregulated from chronic cholecystitis to GBC in clinical tissue samples, and OLFM4 depletion decreased GBC cell proliferation and invasion. Interestingly, downregulation of OLFM4 reduced ARL6IP1 (antiapoptotic factor) expression and sensitized GBC cells to CDDP both in vitro and in vivo. The evidence indicated that CDDP could significantly increase Bax and Bad expression and activate caspase-3 cascade in OLFM4-depleted GBC cells through ARL6IP1. Clinically, lower OLFM4 expression was associated with good prognosis of GBC patients. ConclusionsOur results suggest that OLFM4 is an essential gene that contributes to GBC chemoresistance and could serve as a prognostic biomarker for GBC. Importantly, OLFM4 could be a potential chemotherapeutic target.

SATB1 enhances gastric cancer progression and metastasis via upregulation of CLIP4/DZIP1/ PRICKLE2 axis in gastric cancer patients

SATB1 (Special AT-rich sequence binding protein 1) plays key role in chromatin remodeling and geneexpression. SATB1 has been shown to promote invasion, migration and metastasis. However, the underlying molecular mechanisms, function and clinicopathological features of SATB1 in gastric cancer (GC) remains poorly understood. Here, we show that SATB1 plays critical role in GC progression. SATB1 upregulates in GC patients’ samples and shows co-apmlification with a subset of oncogenic proteins (PRICKLE2, ZEB1, CBWX7, WWTR1, ENAH, DZIP1, IGSF11, ZSCAN18, GFRA2, GFRA1, FGFR1, HDAC4, GHR, TIMP3, CLIP4, TAGLN and ILK) in different subtypes of GC. SATB1 shows positive correlation with GC promoting oncogenes and enhances the expression of metastasis associated genes in GC samples to potentiate GC progression. SATB1 enhances WNT/NOTCH signaling axis in GC samples. In contrast, STAB1 suppresses a network of tumor suppressor genes in GC samples. Moreover, SATB1 expression negatively correlates with GC patient’s survival. Importantly, we found that SATB1 co-amplified genes CLIP4, DZIP1 and PRICKLE2 independently involve in GC progression. Overexpression of CLIP4, DZIP1 and PRICKLE2 show poor survival rates in GC patients. DZIP1 empowers AKT3/FGF2/FGFR1 and CXCR3/CXCR6 in GC patients. PRICKLE2 enhances GC progression by targeting FGFR1/NOTCH3/WNT4 signaling. Taken together, these results identified novel roles of SATB1, CLIP4, DZIP1 and PRICKLE2 in the GC invasion, migration and metastasis using cancer bioinformatics approach. These results highlights clinical significance of SATB1, CLIP4, DZIP1 and PRICKLE2 in GC patients and furthermore, these proteins may serve as prognostic markers in GC. These results also provide SATB1, CLIP4, DZIP1 and PRICKLE2 as potential chemotherapeutic targets in treatment of gastric cancer patients.

Lipoic Acid Metabolism as a Potential Chemotherapeutic Target Against Plasmodium falciparum and Staphylococcus aureus

Lipoic acid (LA) is an organic compound that plays a key role in cellular metabolism. It participates in a posttranslational modification (PTM) named lipoylation, an event that is highly conserved and that occurs in multimeric metabolic enzymes of very distinct microorganisms such as Plasmodium sp. and Staphylococcus aureus, including pyruvate dehydrogenase (PDH) and α-ketoglutarate dehydrogenase (KDH). In this mini review, we revisit the recent literature regarding LA metabolism in Plasmodium sp. and Staphylococcus aureus, by covering the lipoate ligase proteins in both microorganisms, the role of lipoate ligase proteins and insights for possible inhibitors of lipoate ligases.

Induction of Divergent Cell Death Pathways by Urea and Carbohydrazide Derivatives.

The complexity of cancer biology and the development of chemotherapy resistance are two main obstacles to cancer treatment and necessitate novel anticancer molecules that target different cell death pathways. Modulation of Endoplasmic Reticulum (ER) stress and subsequent activation of the Unfolded Protein Response (UPR) has been proposed as a potential chemotherapeutic target, as prolonged ER stress can lead to cell death via apoptosis or necrosis. The present study aims to evaluate the molecular mechanism underlying the cytotoxic activity of selected urea and carbohydrazide derivatives. Cell proliferation assays were performed on HeLa, Capan-1, MCF-7, HCC-1937, and MRC-5 cell lines by WST-1 assay. The expression levels of selected ER stress, autophagy, and apoptosis marker proteins were compared by immunoblotting to characterize the underlying mechanism of cytotoxicity. Flow cytometry was used to detect apoptosis. Of the tested cytotoxic compounds, 3a, 4a, 5a, 6a, and 1b dramatically and 5b moderately increased ER stress-related CHOP protein levels. Interestingly, 5b but not 3a, 4a, 5a, 6a, or 1b increased the expression of proapoptotic proteins such as cleaved PARP-1 and cleaved caspase-3 and -7. The flow-cytometry analysis further confirmed that the cytotoxic activity of 5b but not the other compounds is mediated by apoptosis, demonstrated by a significant increase in the percentage of late apoptotic cells (7-AAD/annexin V double-positive cells). Our results suggest that changing a substituent from trifluoromethyl to nitro in urea and carbohydrazide core structure alters the cell death mechanism from apoptosis to an apoptosis-independent cell death pathway. This study shows an example of how such simple modifications of a core chemical structure could cause the induction of divergent cell death pathways.

Exploiting the HSP60/10 chaperonin system as a chemotherapeutic target for colorectal cancer

Over the past few decades, an increasing variety of molecular chaperones have been investigated for their role in tumorigenesis and as potential chemotherapeutic targets; however, the 60 kDa Heat Shock Protein (HSP60), along with its HSP10 co-chaperone, have received little attention in this regard. In the present study, we investigated two series of our previously developed inhibitors of the bacterial homolog of HSP60/10, called GroEL/ES, for their selective cytotoxicity to cancerous over non-cancerous colorectal cells. We further developed a third “hybrid” series of analogs to identify new candidates with superior properties than the two parent scaffolds. Using a series of well-established HSP60/10 biochemical screens and cell-viability assays, we identified 24 inhibitors (14%) that exhibited > 3-fold selectivity for targeting colorectal cancer over non-cancerous cells. Notably, cell viability EC50 results correlated with the relative expression of HSP60 in the mitochondria, suggesting a potential for this HSP60-targeting chemotherapeutic strategy as emerging evidence indicates that HSP60 is up-regulated in colorectal cancer tumors. Further examination of five lead candidates indicated their ability to inhibit the clonogenicity and migration of colorectal cancer cells. These promising results are the most thorough analysis and first reported instance of HSP60/10 inhibitors being able to selectively target colorectal cancer cells and highlight the potential of the HSP60/10 chaperonin system as a viable chemotherapeutic target.

Current Concepts in the Management of Dupuytren Disease of the Hand.

Dupuytren disease is a fibroproliferative disorder of the palmar fascia of the hand. Little agreement and remarkable variability exists in treatment algorithms between surgeons. Because the cellular and molecular etiology of Dupuytren has been elucidated, ongoing efforts have been made to identify potential chemotherapeutic targets that could modulate the phenotypic expression of the disease. Although these efforts may dramatically alter the approach to treating this disease in the future, these approaches are largely experimental at this point. Over the past decade, the mainstay nonsurgical options have continued to be percutaneous needle aponeurotomy and collagenase Clostridium hystoliticum, and the most common surgical option is limited fasciectomy.

Identification of immune-based prostate cancer subtypes using mRNA expression.

Immune infiltration in Prostate Cancer (PCa) was reported to be strongly associated with clinical outcomes. However, previous research could not elucidate the diversity of different immune cell types that contribute to the functioning of the immune response system. In the present study, the CIBERSORT method was employed to evaluate the relative proportions of immune cell profiling in PCa samples, adjacent tumor samples and normal samples. Three types of molecular classification were identified in tumor samples using the ‘CancerSubtypes’ package of the R software. Each subtype had specific molecular and clinical characteristics. In addition, functional enrichment was analyzed in each subtype. The submap and Tumor Immune Dysfunction and Exclusion (TIDE) algorithms were also used to predict clinical response to the immune checkpoint blockade. Moreover, the Genomics of Drug Sensitivity in Cancer (GDSC) database was employed to screen for potential chemotherapeutic targets for the treatment of PCa. The results showed that Cluster I was associated with advanced PCa and was more likely to respond to immunotherapy. The findings demonstrated that differences in immune responses may be important drivers of PCa progression and response to treatment. Therefore, this comprehensive assessment of the 22 immune cell types in the PCa Tumor Environment (TEM) provides insights on the mechanisms of tumor response to immunotherapy and may help clinicians explore the development of new drugs.

Long intergenic non-protein coding RNA 02570 promotes nasopharyngeal carcinoma progression by adsorbing microRNA miR-4649-3p thereby upregulating both sterol regulatory element binding protein 1, and fatty acid synthase

ABSTRACT Our previous studies have elucidated a possible connection between long intergenic non-protein coding RNA 2570 (LINC02570) and nasopharyngeal carcinoma (NPC). However, the precise mechanism by which LINC02570 promotes NPC remains unknown. We used quantitative polymerase chain reaction (qPCR) to detect LINC02570 expression in nasopharyngeal cell lines, NPC tissues, and chronic rhinitis tissues. Subcellular LINC02570 localization was confirmed by fluorescence in situ hybridization (FISH). The effects of LINC02570 stable knockdown and overexpression on viabillity, proliferation, migration, and invasion were analyzed using 3-(4,5-Dimethyl-2-Thiazolyl)-2,5-Diphenyl-2-H-Tetrazolium bromide (MTT), a colorimetric focus-formation assay, a wound healing assay, and transwell assays. RNA crosstalk analysis in silico predicted microRNA-4649-3p (miR-4649-3p) binding to LINC02570 or sterol regulatory element binding transcription factor 1 (SREBF1). A dual luciferase reporter assay was used to confirm potential interactions. Sterol regulatory element binding protein 1 (SREBP1) and fatty acid synthase (FASN) expression were detected by western blotting. The results suggest that LINC02570 is upregulated in late clinical stage NPC patients, and promotes NPC progression by adsorbing miR-4649-3p to up-regulate SREBP1 and FASN. This study elucidates a potential chemotherapeutic target involved in lipid metabolism in NPC.