High affinity and covalent-binding microtubule stabilizing agents show activity in chemotherapy-resistant acute myeloid leukemia cells

High Expression of Microtubule-associated Protein TBCB Predicts Adverse Outcome and Immunosuppression in Acute Myeloid Leukemia

Acute myeloid leukemia (AML) is a devastating blood cancer with high heterogeneity and ill-fated outcome. Despite numerous advances in AML treatment, the prognosis remains poor for a significant proportion of patients. Consequently, it is necessary to accurately and comprehensively identify biomarkers as soon as possible to enhance the efficacy of diagnosis, prognosis and treatment of AML. In this study, we aimed to identify prognostic markers of AML by analyzing the cohorts from TCGA-LAML database and GEO microarray datasets. Interestingly, the transcriptional level of microtubule-associated protein TBCB in AML patients was noticeably increased when compared with normal individuals, and this was verified in two independent cohorts (GSE9476 and GSE13159) and with our AML patients. Furthermore, univariate and multivariate regression analysis revealed that high TBCB expression was an independent poor prognostic factor for AML. GO and GSEA enrichment analysis hinted that immune-related signaling pathways were enriched in up-regulated DEGs between two populations separated by the median expression level of TBCB. By constructing a protein-protein interaction network, we obtained six hub genes, all of which are immune-related molecules, and their expression levels were positively linked to that of TBCB. In addition, the high expression of three hub genes was significantly associated with a poor prognosis in AML. Moreover, we found that the tumor microenvironment in AML with high TBCB expression tended to be infiltrated by NK cells, especially CD56^bright NK cells. The transcriptional levels of NK cell inhibitory receptors and their ligands were positively related to that of TBCB, and their high expression levels also predicted poor prognosis in AML. Notably, we found that the down-regulation of TBCB suppressed cell proliferation in AML cell lines by enhancing the apoptosis and cell cycle arrest. Finally, drug sensitivity prediction illustrated that cells with high TBCB expression were more responsive to ATRA and midostaurin but resistant to cytarabine, dasatinib, and imatinib. In conclusion, our findings shed light on the feasibility of TBCB as a potential predictor of poor outcome and to be an alternative target of treatment in AML.

In Vivo Evaluation of (-)-Zampanolide Demonstrates Potent and Persistent Antitumor Efficacy When Targeted to the Tumor Site

Microtubule-stabilizing agents (MSAs) are a class of compounds used in the treatment of triple-negative breast cancer (TNBC), a subtype of breast cancer where chemotherapy remains the standard-of-care for patients. Taxanes like paclitaxel and docetaxel have demonstrated efficacy against TNBC in the clinic, however new classes of MSAs need to be identified due to the rise of taxane resistance in patients. (−)-Zampanolide is a covalent microtubule stabilizer that can circumvent taxane resistance in vitro but has not been evaluated for in vivo antitumor efficacy. Here, we determine that (−)-zampanolide has similar potency and efficacy to paclitaxel in TNBC cell lines, but is significantly more persistent due to its covalent binding. We also provide the first reported in vivo antitumor evaluation of (−)-zampanolide where we determine that it has potent and persistent antitumor efficacy when delivered intratumorally. Future work on zampanolide to further evaluate its pharmacophore and determine ways to improve its systemic therapeutic window would make this compound a potential candidate for clinical development through its ability to circumvent taxane-resistance mechanisms.

SNX10 and PTGDS are associated with the progression and prognosis of cervical squamous cell carcinoma

Background

Cervical cancer (CC) is the primary cause of death in women. This study sought to investigate the potential mechanism and prognostic genes of CC.

Methods

We downloaded four gene expression profiles from GEO. The RRA method was used to integrate and screen differentially expressed genes (DEGs) between CC and normal samples. Functional analysis was performed by clusterprofiler. We built PPI network by Search Tool for the Retrieval of Interacting Genes Database (STRING) and selected hub modules via Molecular COmplex Detection (MCODE). CMap database was used to find molecules with therapeutic potential for CC. The hub genes were validated in GEO datasets, Gene Expession Profiling Interactive Analysis (GEPIA), immunohistochemistry, Cox regression analysis, TCGA methylation analysis and ONCOMINE were carried out. ROC curve analysis and GSEA were also performed to describe the prognostic significance of hub genes.

Results

Functional analysis revealed that 147 DEGs were significantly enriched in binding, cell proliferation, transcriptional activity and cell cycle regulation. PPI network screened 30 hub genes, with CDK1 having the strongest connectivity with CC. Cmap showed that apigenin, thioguanine and trichostatin A might be used to treat CC(P < 0.05). Eight genes (APOD, CXCL8, MMP1, MMP3, PLOD2, PTGDS, SNX10 and SPP1) were screened out through GEPIA. Of them, only PTGDS and SNX10 had not appeared in previous studies about CC. The validation in GEO showed that PTGDS showed low expression while SNX10 presented high expression in tumor tissues. Their expression profiles were consistent with the results in immunohistochemistry. ROC curve analysis indicated that the model had a good diagnostic efficiency (AUC = 0.738). GSEA analysis demonstrated that the two genes were correlated with the chemokine signaling pathway (P < 0.05). TCGA methylation analysis showed that patients with lowly-expressed and highly-methylated PTGDS had a worse prognosis than those with highly-expressed and lowly-methylated PTGDS (p = 0.037). Cox regression analysis showed that SNX10 and PTGDS were independent prognostic indicators for OS among CC patients (P = 0.007 and 0.003).

Conclusions

PTGDS and SNX10 showed abnormal expression and methylation in CC. Both genes might have high prognostic value of CC patients.

Supplementary Information

The online version contains supplementary material available at 10.1186/s12885-021-08212-w.

Identification of hub genes associated with adult acute myeloid leukemia progression through weighted gene co-expression network analysis

Acute myeloid leukemia (AML) is a malignancy of hematopoietic stem cells. Although many candidate genes such as CEBPA, FLT3, IDH1, and IDH2 have been associated with AML initiation and prognosis, the molecular mechanisms underlying this disease remain unclear. In this study, we used a systemic co-expression analysis method, namely weighted gene co-expression network analysis (WGCNA), to identify new candidate genes associated with adult AML progression and prognosis. We identified around 5,138 differentially expressed genes (DEGs) between AML samples (from The Cancer Genome Atlas database) and normal control samples (from the Genotype-Tissue Expression database). WGCNA identified nine co-expression modules with significant differences based on the DEGs. Among modules, the turquoise and blue ones were the most relevant to AML (P-value: turquoise 0, blue 4.64E-77). GO term and KEGG pathway analyses revealed that pathways that are commonly dysregulated in AML were all enriched in the blue and turquoise modules. A total of 15 hub genes were identified to be crucial for AML progression. PIVOT analysis revealed non-coding RNAs, transcriptional factors, and drugs associated with the hub genes. Finally, survival analysis revealed that one of the hub genes, CEACAM5, was significantly associated with AML prognosis and could serve as a potential target for AML treatment.

Current advances of tubulin inhibitors as dual acting small molecules for cancer therapy

Microtubule (MT)-targeting agents are highly successful drugs as chemotherapeutic agents, and this is attributed to their ability to target MT dynamics and interfere with critical cellular functions, including, mitosis, cell signaling, intracellular trafficking, and angiogenesis. Because MT dynamics vary in the different stages of the cell cycle, these drugs tend to be the most effective against mitotic cells. While this class of drug has proven to be effective against many cancer types, significant hurdles still exist and include overcoming aspects such as dose limited toxicities and the development of resistance. Newer generations of developed drugs attack these problems and alternative approaches such as the development of dual tubulin and kinase inhibitors are being investigated. This approach offers the potential to show increased efficacy and lower toxicities. This review covers different categories of MT-targeting agents, recent advances in dual inhibitors, and current challenges for this drug target.

BO-1055, a novel DNA cross-linking agent with remarkable low myelotoxicity shows potent activity in sarcoma models

DNA damaging agents cause rapid shrinkage of tumors and form the basis of chemotherapy for sarcomas despite significant toxicities. Drugs having superior efficacy and wider therapeutic windows are needed to improve patient outcomes. We used cell proliferation and apoptosis assays in sarcoma cell lines and benign cells; γ-H2AX expression, comet assay, immunoblot analyses and drug combination studies in vitro and in patient derived xenograft (PDX) models. BO-1055 caused apoptosis and cell death in a concentration and time dependent manner in sarcoma cell lines. BO-1055 had potent activity (submicromolar IC50) against Ewing sarcoma and rhabdomyosarcoma, intermediate activity in DSRCT (IC50 = 2-3μM) and very weak activity in osteosarcoma (IC50 >10μM) cell lines. BO-1055 exhibited a wide therapeutic window compared to other DNA damaging drugs. BO-1055 induced more DNA double strand breaks and γH2AX expression in cancer cells compared to benign cells. BO-1055 showed inhibition of tumor growth in A673 xenografts and caused tumor regression in cyclophosphamide resistant patient-derived Ewing sarcoma xenografts and A204 xenografts. Combination of BO-1055 and irinotecan demonstrated synergism in Ewing sarcoma PDX models. Potent activity on sarcoma cells and its relative lack of toxicity presents a strong rationale for further development of BO-1055 as a therapeutic agent.

Recent advances in microtubule-stabilizing agents

Highly dynamic mitotic spindle microtubules are superb therapeutic targets for a group of chemically diverse and clinically successful anticancer drugs. Microtubule-targeted drugs disrupt microtubule dynamics in distinct ways, and they are primarily classified into two groups: microtubule destabilizing agents (MDAs), such as vinblastine, colchicine, and combretastatin-A4, and microtubule stabilizing agents (MSAs), such as paclitaxel and epothilones. Systematic discovery and development of new MSAs have been aided by extensive research on paclitaxel, yielding a large number of promising anticancer compounds. This review focuses on the natural sources, structural features, mechanisms of action, structure-activity relationship (SAR) and chemical synthesis of MSAs. These MSAs mainly include paclitaxel, taccalonolides, epothilones, FR182877 (cyclostreptin), dictyostatin, discodermolide, eleutherobin and sarcodictyins, zampanolide, dactylolide, laulimalides, peloruside and ceratamines from natural sources, as well as small molecular microtubule stabilizers obtained via chemical synthesis. Then we discuss the application prospect and development of these anticancer compounds.

Alectinib (CH5424802) antagonizes ABCB1- and ABCG2-mediated multidrug resistance in vitro, in vivo and ex vivo

Alectinib, an inhibitor of anaplastic lymphoma kinase (ALK), was approved by the Food and Drug Administration (FDA) for the treatment of patients with ALK-positive non-small cell lung cancer (NSCLC). Here we investigated the reversal effect of alectinib on multidrug resistance (MDR) induced by ATP-binding cassette (ABC) transporters, which is the primary cause of chemotherapy failure. We provide the first evidence that alectinib increases the sensitivity of ABCB1- and ABCG2-overexpressing cells to chemotherapeutic agents in vitro and in vivo. Mechanistically, alectinib increased the intracellular accumulation of ABCB1/ABCG2 substrates such as doxorubicin (DOX) and Rhodamine 123 (Rho 123) by inhibiting the efflux function of the transporters in ABCB1- or ABCG2-overexpressing cells but not in their parental sensitive cells. Furthermore, alectinib stimulated ATPase activity and competed with substrates of ABCB1 or ABCG2 and competed with [125I] iodoarylazidoprazosin (IAAP) photolabeling bound to ABCB1 or ABCG2 but neither altered the expression and localization of ABCB1 or ABCG2 nor the phosphorylation levels of AKT and ERK. Alectinib also enhanced the cytotoxicity of DOX and the intracellular accumulation of Rho 123 in ABCB1-overexpressing primary leukemia cells. These findings suggest that alectinib combined with traditional chemotherapy may be beneficial to patients with ABCB1- or ABCG2-mediated MDR.

Microtubule-stabilizing agents: New drug discovery and cancer therapy

Microtubule-stabilizing agents (MSAs) have been highly successful in the treatment of cancer in the past 20years. To date, three classes of MSAs have entered the clinical trial stage or have been approved for clinical anticancer chemotherapy, and more than 10 classes of novel structural MSAs have been derived from natural resources. The microtubule typically contains two MSA-binding sites: the taxoid site and the laulimalide/peloruside site. All defined MSAs are known to bind at either of these sites, with subtle but significant differences. MSAs with different binding sites may produce a synergistic effect. Although having been extensively applied in the clinical setting, paclitaxel and other approved MSAs still pose many challenges such as multidrug resistance, low bioavailability, poor solubility, high toxicity, and low passage through the blood-brain barrier. A variety of studies focus on the structure-activity relationship in order to improve the pharmaceutical properties of these agents. Here, the mechanisms of action, advancements in pharmacological research, and clinical developments of defined MSAs during the past decade are discussed. The latest discovered MSAs are also briefly introduced in this review. The increasing number of natural MSAs indicates the potential discovery of more novel, natural MSAs with different structural bases, which will further promote the development of anticancer chemotherapy.