The Potential of Combining Tubulin-Targeting Anticancer Therapeutics and Immune Therapy

Discovery of novel thiophene[3,2-d]pyrimidine-based tubulin inhibitors with enhanced antitumor efficacy for combined use with anti-pd-l1 immunotherapy in melanoma

Herein, we designed and synthesized a series of novel 2-methylthieno [3,2-d]pyrimidine analogues as tubulin inhibitors with antiproliferative activities at low nanomolar levels. Among them, compound DPP-21 displayed the most potent anti-proliferative activity against six cancer cell lines with an average IC50 of ∼6.23 nM, better than that of colchicine (IC50 = 9.26 nM). DPP-21 exerted its anti-cancer activity by suppressing the polymerization of tubulin with an IC50 of 2.4 μM. Furthermore, the crystal structure of DPP-21 in complex with tubulin was solved by X-ray crystallography to 2.94 Å resolution, confirming the direct binding of DPP-21 to the colchicine site. Moreover, DPP-21 arrested the cell cycle in the G2/M phase of mitosis, subsequently inducing tumor cell apoptosis. Additionally, DPP-21 was able to effectively inhibit the migration of cancer cells. Besides, DPP-21 exhibited significant in vivo anti-tumor efficacy in a B16-F10 melanoma tumor model with a TGI of 63.3 % (7 mg/kg) by intraperitoneal (i.p.) injection. Notably, the combination of DPP-21 with NP-19 (a PD-L1-targeting small molecule inhibitor reported by our group before) demonstrated enhanced anti-cancer efficacy in vivo. These results suggest that DPP-21 is a promising lead compound deserving further investigation as a potential anti-cancer agent.

Platinum/taxane/pembrolizumab vs platinum/5FU/pembrolizumab in recurrent/metastatic head and neck squamous cell carcinoma (r/m HNSCC)

OBJECTIVES

Pembrolizumab +/- chemotherapy is standard therapy for r/m HNSCC. Despite regulatory approval of platinum/5FU/pembrolizumab, a taxane is often substituted for 5FU for convenience and tolerability. We aimed to characterize nationwide use patterns and compare outcomes between platinum/taxane/pembrolizumab vs platinum/5FU/pembrolizumab.

METHODS

Patients in a US nationwide database with r/m HNSCC treated from 2017 to 2022 with pembrolizumab plus platinum chemotherapy were included. Demographic and cancer-specific characteristics were summarized. Overall survival (OS) was estimated using Kaplan-Meier methodology, and compared between groups using log-rank test and multivariable Cox regression. Time on treatment, number of cycles, receipt of second-line therapy, and toxicities were compared between groups.

RESULTS

Of 438 patients, 320 (73 %) received 5FU and 118 (27 %) received a taxane. Taxane use became more frequent over time and was higher in academic vs community practices (51 % vs 23 %, p < 0.001). OS did not differ between taxane and 5FU groups (mOS 12.2 vs 13.4 months, p = 0.662). On multivariable Cox regression, HR for death associated with taxane vs 5FU was 0.99 (95 %CI 0.71-1.38). Receipt of 2L therapy was numerically higher for 5FU patients (46 %) compared to taxane patients (35 %, p = 0.071). Grade ≥ 3 anemia was more common in taxane patients (33 % vs 20 %, p = 0.003), whereas grade ≥ 3 lymphopenia and thrombocytopenia were numerically higher in 5FU patients.

CONCLUSION

In patients with r/m HNSCC undergoing chemoimmunotherapy, taxane vs 5FU use varies by practice setting and geographical region. Platinum/taxane/pembrolizumab was associated with similar survival as platinum/5FU/pembrolizumab; these results suggest that chemoimmunotherapy with taxane is a reasonable alternative to 5FU.

Participation of T cells in generating immune protection against cancers

T cells are essential to the immune system's reaction. The major job of the immune system is to identify and get rid of any abnormal or malignant cells in the body. White blood cells called T cells coordinate and carry out immunological responses, including identifying and eliminating cancer cells. It mostly consists of two types called helper T-cells and cytotoxic T-cells. Together, they create an efficient reaction against cancer. Both the primary T cell subtype - CD4+ and CD8+ Tcells have specific role to play in our immune system.CD4+ T cells are limited to MHC-II molecules and acts as helper cell by activating and enhancing other immune cells. On the other side CD8+ T cells are called the killer cells as they eradicate the abnormal and contaminated cells and are limited to MHC-I molecules. The malignant cells are destroyed when cytotoxic T cells come into direct contact with them. This happens via number of processes, including TCR recognition, the release of cytotoxic chemicals, and finally the activation of the immune system. T cell receptors on the surface of cytotoxic T cells allow them to identify tumour cells and these T cells release harmful chemicals like perforins and granzymes when they connect to malignant cells. T-cells that have been stimulated release cytokines such as gamma interferon. T-cells can also acquire memory responses that improve their capacity for recognition and response. Helper T-cells contribute to the development of an immune response. It entails coordination and activation as well as the enlistment of additional immune cells, including macrophages and natural killer cells, to assist in the eradication of cancer cells. Despite the fact that the cancer frequently creates defence systems to circumvent their immune response. Together, these activities support the immune surveillance and T-cell-mediated regulation of cancer cells. Treatments like chemotherapy, radiation, and surgery are main ways to treat cancer but immunotherapy has been emerging since last few decades. These immune specific treatments have shown huge positive result. CAR T cell therapy is a promising weapon to fight again blood cancer and it works by focusing on our immune system to fight and eliminate cancer.

Advances in and prospects of immunotherapy for prostate cancer

Immunotherapy has shown promising therapeutic effects in hematological malignancies and certain solid tumors and has emerged as a critical and highly potential treatment modality for cancer. However, prostate cancer falls under the category of immune-resistant cold tumors, for which immunotherapy exhibits limited efficacy in patients with solid tumors. Thus, it is important to gain a deeper understanding of the tumor microenvironment in prostate cancer to facilitate immune system activation and overcome immune suppression to advance immunotherapy for prostate cancer. In this review, we discuss the immunosuppressive microenvironment of prostate cancer, which is characterized by the presence of few tumor-infiltrating lymphocytes, abundant immunosuppressive cells, low immunogenicity, and a noninflammatory phenotype, which significantly influences the efficacy of immunotherapy for prostate cancer. Immunotherapy is mainly achieved by activating the host immune system and overcoming immunosuppression. In this regard, we summarize the therapeutic advances in immune checkpoint blockade, immunogenic cell death, reversal of the immunosuppressive tumor microenvironment, tumor vaccines, immune adjuvants, chimeric antigen receptor T-cell therapy, and overcoming penetration barriers in prostate cancer, with the aim of providing novel research insights and approaches to enhance the effectiveness of immunotherapy for prostate cancer.

Targeting TACC3 Induces Immunogenic Cell Death and Enhances T-DM1 Response in HER2-Positive Breast Cancer

Trastuzumab emtansine (T-DM1) was the first and one of the most successful antibody-drug conjugates (ADC) approved for treating refractory HER2-positive breast cancer. Despite its initial clinical efficacy, resistance is unfortunately common, necessitating approaches to improve response. Here, we found that in sensitive cells, T-DM1 induced spindle assembly checkpoint (SAC)-dependent immunogenic cell death (ICD), an immune-priming form of cell death. The payload of T-DM1 mediated ICD by inducing eIF2α phosphorylation, surface exposure of calreticulin, ATP and HMGB1 release, and secretion of ICD-related cytokines, all of which were lost in resistance. Accordingly, ICD-related gene signatures in pretreatment samples correlated with clinical response to T-DM1-containing therapy, and increased infiltration of antitumor CD8+ T cells in posttreatment samples was correlated with better T-DM1 response. Transforming acidic coiled-coil containing 3 (TACC3) was overexpressed in T-DM1-resistant cells, and T-DM1 responsive patients had reduced TACC3 protein expression whereas nonresponders exhibited increased TACC3 expression during T-DM1 treatment. Notably, genetic or pharmacologic inhibition of TACC3 restored T-DM1-induced SAC activation and induction of ICD markers in vitro. Finally, TACC3 inhibition in vivo elicited ICD in a vaccination assay and potentiated the antitumor efficacy of T-DM1 by inducing dendritic cell maturation and enhancing intratumoral infiltration of cytotoxic T cells. Together, these results illustrate that ICD is a key mechanism of action of T-DM1 that is lost in resistance and that targeting TACC3 can restore T-DM1-mediated ICD and overcome resistance.

SIGNIFICANCE

Loss of induction of immunogenic cell death in response to T-DM1 leads to resistance that can be overcome by targeting TACC3, providing an attractive strategy to improve the efficacy of T-DM1.

rpoS involved in immune response of Macrobrachium nipponens to Vibrio mimicus infection

Vibrio mimicus is a pathogenic bacterium that cause red body disease in Macrobrachium nipponense, leading to high mortality and financial loss. Based on previous studies, rpoS gene contribute to bacterial pathogenicity during infection, but the role of RpoS involved in the immune response of M. nipponense under V. mimicus infection remains unclear. In this study, the pathogen load and the RNA-seq of M. nipponense under wild-type and ΔrpoS strain V. mimicus infection were investigated. Over the entire infection period, the ΔrpoS strain pathogen load was always lower than that of the wild-type strain in the M. nipponense hemolymph, hepatopancreas, gill and muscle. Furthermore, the expression level of rpoS gene in the hepatopancreas was the highest at 24 hours post infection (hpi), then the samples of hepatopancreas tissue infected with the wild type and ΔrpoS strain at 24 hpi were selected for RNA-seq sequencing. The results revealed a significant change in the transcriptomes of the hepatopancreases infected with ΔrpoS strain. In contrast to the wild-type infected group, the ΔrpoS strain infected group exhibited differentially expressed genes (DEGs) enriched in 181 KEGG pathways at 24 hpi. Among these pathways, 8 immune system-related pathways were enriched, including ECM-receptor interaction, PI3K-Akt signaling pathway, Rap1 signaling pathway, Gap junction, and Focal adhesion, etc. Among these pathways, up-regulated genes related to Kazal-type serine protease inhibitors, S-antigen protein, copper zinc superoxide dismutase, tight junction protein, etc. were enriched. This study elucidates that rpoS can affect tissue bacterial load and immune-related pathways, thereby impacting the survival rate of M. nipponense under V. mimicus infection. These findings validate the potential of rpoS as a promising target for the development of a live attenuated vaccine against V. mimicus.

Analysis of the prognostic value of uric acid on the efficacy of immunotherapy in patients with primary liver cancer

PURPOSE

Uric acid (UA) plays a dual role as an antioxidant and a prooxidant in patients with malignant tumors; however, the relationship between serum UA and malignancy is currently unclear. This study aims to investigate the prognostic value of serum uric acid level before immunotherapy on the efficacy of primary liver cancer (PLC) immunotherapy, which might provide a basis for optimizing the comprehensive treatment scheme.

METHODS

Patients with PLC who were admitted to the First Affiliated Hospital of Gannan Medical College from January 2019 to June 2022 and underwent immunotherapy were collected retrospectively. The difference between serum UA levels in patients with PLC, the correlation between serum UA levels, and the clinical characteristics of patients with PLC were analyzed using the chi-square test, and the survival was estimated using the Kaplan-Meier analysis. To further assess the prognostic significance of UA concentrations, univariate and multivariate Cox regression analyses were performed.

RESULTS

Ninety-nine patients were included in this study cohort. The median follow-up was 7 months (range: 1-29 months), and 76 (76.8%) of the 99 patients with PLC died as of December 31, 2022. Serum UA concentrations ranged from 105 to 670 μmol/l, with a median of 269 μmol/l. The results showed that the serum UA level of patients with PLC was higher than that of healthy subjects (P < 0.001). After subgroup analyses, only male patients with liver cancer had higher serum UA levels than healthy men (P = 0.001). The results of the Kaplan-Meier analysis showed that higher UA levels were associated with poor overall survival (OS) (P = 0.005). In univariate analysis, the OS rate of patients with elevated serum UA levels was significantly lower than the cut-off value (hazard ratio [HR]: 3.191, 95% confidence interval [CI]: 1.456-6.993, P = 0.004), with a median survival time of 151 and 312 days in the high and low serum UA groups, respectively. The results of multivariate analysis showed that the UA level was an independent prognostic factor for immunotherapy in patients with PLC (HR: 3.131, 95% CI: 1.766-5.553, P < 0.001).

CONCLUSIONS

The serum UA level is a reliable biomarker for predicting the prognosis of patients undergoing immunotherapy for PLC, and might provide a basis for the individualized treatment of these patients. Dynamic monitoring of the serum UA level may compensate for the deficiency of the current liver cancer staging system.

Discovery of Novel Isoquinoline Analogues as Dual Tubulin Polymerization/V-ATPase Inhibitors with Immunogenic Cell Death Induction

Cancer immunotherapy has revolutionized clinical advances in a variety of cancers. Due to the low immunogenicity of the tumor, only a few patients can benefit from it. Specific microtubule inhibitors can effectively induce immunogenic cell death and improve immunogenicity of the tumor. A series of isoquinoline derivatives based on the natural products podophyllotoxin and diphyllin were designed and synthesized. Among them, F10 showed robust antiproliferation activity against four human cancer cell lines, and it was verified that F10 exerted antiproliferative activity by inhibiting tubulin and V-ATPase. Further studies indicated that F10 is able to induce immunogenic cell death in addition to apoptosis. Meanwhile, F10 inhibited tumor growth in an RM-1 homograft model with enhanced T lymphocyte infiltration. These results suggest that F10 may be a promising lead compound for the development of a new generation of microtubule drugs.

Tubulin inhibitors. Selected scaffolds and main trends in the design of novel anticancer and antiparasitic agents

Design of tubulin inhibitors as anticancer drugs dynamically developed over the past 20 years. The modern arsenal of potential tubulin-targeting anticancer agents is represented by small molecules, monoclonal antibodies, and antibody-drug conjugates. Moreover, targeting tubulin has been a successful strategy in the development of antiparasitic drugs. In the present review, an overall picture of the research and development of potential tubulin-targeting agents using small molecules between 2018 and 2023 is provided. The data about some most often used and prospective chemotypes of small molecules (privileged heterocycles, moieties of natural molecules) and synthetic methodologies (analogue-based, fragment-based drug design, molecular hybridization) applied for the design of novel agents with an impact on the tubulin system are summarized. The design and prospects of multi-target agents with an impact on the tubulin system were also highlighted. Reported in the review data contribute to the "structure-activity" profile of tubulin-targeting small molecules as anticancer and antiparasitic agents and will be useful for the application by medicinal chemists in further exploration, design, improvement, and optimization of this class of molecules.

Identification of acetylshikonin as a novel tubulin polymerization inhibitor with antitumor activity in human hepatocellular carcinoma cells

Background

Microtubules are attractive targets for anticancer drugs. However, the microtubule-targeting agents (MTAs) currently in clinical use exhibit inevitable drug resistance. Therefore, there is an urgent need to discover novel MTAs for the clinical treatment of cancer.

Methods

Bioactive compounds extracted from Lithospermum erythrorhizon were assessed for in vitro anti-proliferative activities against a panel of human cancer cell lines using cell counting kit-8 (CCK-8) assay. Tubulin polymerization inhibition assay, colchicine competitive binding site assay, and immunofluorescence were used to validate the tubulin inhibition effect of acetylshikonin. Flow cytometry, Hoechst staining, and caspase-3 activity evaluation were performed to assess cell cycle arrest and cell apoptosis. 5,5',6,6'-tetrachloro-1,1',3,3'-tetramethylbenzimidazolylcarbocyanine iodide (JC-1) staining and dichloro-dihydro-fluorescein diacetate (DCFH-DA) staining were used to evaluate mitochondrial membrane potential (MMP) and reactive oxygen species (ROS), respectively.

Results

Acetylshikonin exhibited potent anti-proliferative activities against a panel of human cancer cell lines (IC50 values: 1.09-7.26 µM) and displayed comparable cytotoxicity against several drug-resistant cell lines. Further mechanism studies revealed that acetylshikonin induced cell cycle arrest of MHCC-97H cells at G2/M phase, and significantly promoted apoptosis marked by a collapse of MMP and abnormal ROS accumulation.

Conclusions

In this study, acetylshikonin was identified as MTA against hepatocellular carcinoma and can serve as a promising lead compound for further development of anti-cancer drug, underscoring its potential clinical significance.

PD-1 inhibitors combined with paclitaxel and cisplatin in first-line treatment of esophageal squamous cell carcinoma (ESCC): a network meta-analysis

BACKGROUND

The combinations of PD-1 inhibitors with paclitaxel/cisplatinum (PD-1 + TP) and fluoropyrimidine/cisplatinum (PD-1 + FP) both have been shown to improve overall survival (OS) and progression-free survival (PFS) in patients with previously untreated, advanced esophageal squamous cell carcinoma (ESCC). However, there is no consensus on which chemotherapy regimen combined with PD-1 has better efficacy. To deal with this important issue in the first-line treatment of patients with ESCC, a network meta-analysis (NMA) was performed.

METHODS

Data were collected from eligible studies searched in Medline, Web of Science, PubMed, the Cochrane Library and Embase. The pooled hazard ratio (HR) for the OS, and PFS, odds ratio (OR) for the objective response rate (ORR) and ≥ 3 grade treatment-related adverse events (≥ 3TRAEs) were estimated to evaluate the efficacy of PD-1 inhibitors combined with TP or FP.

RESULTS

Five RCTs and one retrospective study involving 3685 patients and evaluating four treatments were included in this NMA. Compared to other treatments, PD-1 + TP was better. For the PFS, the HRs for PD-1 + TP compared to PD-1 + FP, TP and FP were 0.59 (0.44, 0.80), 0.56 (0.51, 0.61) and 0.45 (0.37, 0.56) respectively. For the OS, PD-1 + TP was also a better treatment compared to other treatments. The HRs were 0.74 (0.56, 0.96), 0.64 (0.57, 0.71), 0.53 (0.43, 0.67) respectively. For the ORR, there was no significant difference between PD-1 + TP and PD-1 + FP, and the ORs were 1.2 (0.69, 2.11). Compare with TP and FP, PD-1 + TP had an obvious advantage, ORs were 2.5 (2.04, 3.04) and 2.95 (1.91, 4.63). For ≥ 3TRAEs, PD-1 + TP compared to other treatments, ORs were 1.34 (0.74, 2.46) and 1.13 (0.92, 1.38) and 2.23 (1.35, 3.69).

CONCLUSION

PD-1 + TP significantly improved both PFS and OS compared to PD-1 + FP. Taking into account both efficacy and safety, PD-1 + TP may be a superior first-line treatment option for ESCC.

Integrated Multimodal Analyses of DNA Damage Response and Immune Markers as Predictors of Response in Metastatic Triple-Negative Breast Cancer in the TNT Trial (NCT00532727)

PURPOSE

The TNT trial (NCT00532727) showed no evidence of carboplatin superiority over docetaxel in metastatic triple-negative breast cancer (mTNBC), but carboplatin benefit was observed in the germline BRCA1/2 mutation subgroup. Broader response-predictive biomarkers are needed. We explored the predictive ability of DNA damage response (DDR) and immune markers.

EXPERIMENTAL DESIGN

Tumor-infiltrating lymphocytes were evaluated for 222 of 376 patients. Primary tumors (PT) from 186 TNT participants (13 matched recurrences) were profiled using total RNA sequencing. Four transcriptional DDR-related and 25 immune-related signatures were evaluated. We assessed their association with objective response rate (ORR) and progression-free survival (PFS). Conditional inference forest clustering was applied to integrate multimodal data. The biology of subgroups was characterized by 693 gene expression modules and other markers.

RESULTS

Transcriptional DDR-related biomarkers were not predictive of ORR to either treatment overall. Changes from PT to recurrence were demonstrated; in chemotherapy-naïve patients, transcriptional DDR markers separated carboplatin responders from nonresponders (P values = 0.017; 0.046). High immune infiltration was associated with docetaxel ORR (interaction P values < 0.05). Six subgroups were identified; the immune-enriched cluster had preferential docetaxel response [62.5% (D) vs. 29.4% (C); P = 0.016]. The immune-depleted cluster had preferential carboplatin response [8.0% (D) vs. 40.0% (C); P = 0.011]. DDR-related subgroups were too small to assess ORR.

CONCLUSIONS

High immune features predict docetaxel response, and high DDR signature scores predict carboplatin response in treatment-naïve mTNBC. Integrating multimodal DDR and immune-related markers identifies subgroups with differential treatment sensitivity. Treatment options for patients with immune-low and DDR-proficient tumors remains an outstanding need. Caution is needed using PT-derived transcriptional signatures to direct treatment in mTNBC, particularly DDR-related markers following prior chemotherapy.

Reviving immunogenic cell death upon targeting TACC3 enhances T-DM1 response in HER2-positive breast cancer

Immunogenic cell death (ICD), an immune-priming form of cell death, has been shown to be induced by several different anti-cancer therapies. Despite being the first and one of the most successful antibody-drug conjugates (ADCs) approved for refractory HER2-positive breast cancer, little is known if response and resistance to trastuzumab emtansine (T-DM1) involves ICD modulation that can be leveraged to enhance T-DM1 response. Here, we report that T-DM1 induces spindle assembly checkpoint (SAC)-dependent ICD in sensitive cells by inducing eIF2α phosphorylation, surface exposure of calreticulin, ATP and HMGB1 release, and secretion of ICD-related cytokines, all of which are lost in resistance. Accordingly, an ICD-related gene signature correlates with clinical response to T-DM1-containing therapy. We found that transforming acidic coiled-coil containing 3 (TACC3) is overexpressed in T-DM1 resistant cells, and that T-DM1 responsive patients have reduced TACC3 protein while the non-responders exhibited increased TACC3 expression during T-DM1 treatment. Notably, genetic or pharmacological inhibition of TACC3 revives T-DM1-induced SAC activation and induction of ICD markers in vitro. Finally, TACC3 inhibition elicits ICD in vivo shown by vaccination assay, and it potentiates T-DM1 by inducing dendritic cell (DC) maturation and enhancing infiltration of cytotoxic T cells in the human HER2-overexpressing MMTV.f.huHER2#5 (Fo5) transgenic model. Together, our results show that ICD is a key mechanism of action of T-DM1 which is lost in resistance, and that targeting TACC3 restores T-DM1-mediated ICD and overcomes resistance.

TUBA1C is a potential new prognostic biomarker and promotes bladder urothelial carcinoma progression by regulating the cell cycle

BACKGROUND

TUBA1C is an α-tubulin isoform involved in mitosis, and its dysregulation has been implicated in tumor progression. There is still no clear understanding of its role in bladder urothelial carcinoma (BLCA).

METHODS

This study examined the differential expression of TUBA1C and its prognostic significance in bladder cancer based on data from The Cancer Genome Atlas (TCGA) and Gene Expression Omnibus (GEO) and also assessed the correlation of TUBA1C expression level with immune cell infiltration and immune checkpoint gene expression levels and the half-inhibitory concentration (IC50) of different chemotherapeutic agents. Immunotherapy response was estimated using the Tumor Immune Dysfunction and Exclusion (TIDE) algorithm. We detected TUBA1C expression in BLCA cells using PCR and Western blotting. Functional assays, including CCK-8, colony formation, transwell, apoptosis and cell cycle assays, were also performed to assess the oncogenic role of TUBA1C in BLCA.

RESULT

In three independent public cohorts, TUBA1C was significantly upregulated in bladder tumor tissues, and high TUBA1C expression in bladder cancer was associated with a poorer outcome than low expression. TUBA1C was an independent prognostic risk factor for bladder cancer, and numerous immune checkpoint genes and infiltrating immune cells were associated with TUBA1C. TIDE analysis revealed that TUBA1C showed great potential for predicting the immunotherapy response in bladder cancer patients. In addition, drug sensitivity analysis revealed that high TUBA1C expression indicated sensitivity to multiple chemotherapeutic agents. Functional assays revealed that silencing TUBA1C significantly inhibited the proliferation, migration and invasion of BLCA cells and induced apoptosis and cell cycle arrest.

CONCLUSION

The overexpression of TUBA1C in bladder cancer predicts a poor prognosis and may also be a potential immunotherapeutic target. As a prognostic marker, TUBA1C influences tumor progression by regulating the cell cycle.

Antiproliferative and Tubulin-Destabilising Effects of 3-(Prop-1-en-2-yl)azetidin-2-Ones and Related Compounds in MCF-7 and MDA-MB-231 Breast Cancer Cells

A series of novel 3-(prop-1-en-2-yl)azetidin-2-one, 3-allylazetidin-2-one and 3-(buta-1,3-dien-1-yl)azetidin-2-one analogues of combretastatin A-4 (CA-4) were designed and synthesised as colchicine-binding site inhibitors (CBSI) in which the ethylene bridge of CA-4 was replaced with a β-lactam (2-azetidinone) scaffold. These compounds, together with related prodrugs, were evaluated for their antiproliferative activity, cell cycle effects and ability to inhibit tubulin assembly. The compounds demonstrated significant in vitro antiproliferative activities in MCF-7 breast cancer cells, particularly for compounds 9h, 9q, 9r, 10p, 10r and 11h, with IC₅₀ values in the range 10-33 nM. These compounds were also potent in the triple-negative breast cancer (TBNC) cell line MDA-MB-231, with IC₅₀ values in the range 23-33 nM, and were comparable with the activity of CA-4. The compounds inhibited the polymerisation of tubulin in vitro, with significant reduction in tubulin polymerization, and were shown to interact at the colchicine-binding site on tubulin. Flow cytometry demonstrated that compound 9q arrested MCF-7 cells in the G₂/M phase and resulted in cellular apoptosis. The antimitotic properties of 9q in MCF-7 human breast cancer cells were also evaluated, and the effect on the organization of microtubules in the cells after treatment with compound 9q was observed using confocal microscopy. The immunofluorescence results confirm that β-lactam 9q is targeting tubulin and resulted in mitotic catastrophe in MCF-7 cells. In silico molecular docking supports the hypothesis that the compounds interact with the colchicine-binding domain of tubulin. Compound 9q is a novel potent microtubule-destabilising agent with potential as a promising lead compound for the development of new antitumour agents.

X-ray Crystal Structure-Guided Discovery of Novel Indole Analogues as Colchicine-Binding Site Tubulin Inhibitors with Immune-Potentiating and Antitumor Effects against Melanoma

A series of novel indole analogues were discovered as colchicine-binding site inhibitors of tubulin. Among them, 3a exhibited the highest antiproliferative activity (average IC₅₀ = 4.5 nM), better than colchicine (IC₅₀ = 65.3 nM). The crystal structure of 3a in complex with tubulin was solved by X-ray crystallography, which explained the improved binding affinity of 3a to tubulin and thus its higher anticancer activity (IC₅₀ = 4.5 nM) than the lead compound 12b (IC₅₀ = 32.5 nM). In vivo, 3a (5 mg/kg) displayed significant antitumor efficacy against B16-F10 melanoma with a TGI of 62.96% and enhanced the antitumor efficacy of a small-molecule PD-1/PD-L1 inhibitor NP19 (TGI = 77.85%). Moreover, 3a potentiated the antitumor immunity of NP19 by activating the tumor immune microenvironment, as demonstrated by the increased tumor-infiltrating lymphocytes (TIL). Collectively, this work shows a successful example of crystal structure-guided discovery of a novel tubulin inhibitor 3a as a potential anticancer and immune-potentiating agent.

The Role of Colchicine in Different Clinical Phenotypes of Behcet Disease

PURPOSE

Behcet disease (BD) is a multisystemic disorder characterized by variable clinical manifestations that affect nearly all systems and organs. Colchicine, an alkaloid plant extract, is considered as the first-line therapy for gout, pericarditis, and familial Mediterranean fever. However, the role of colchicine in the treatment of different clinical phenotypes of BD has not been clearly described. This narrative review summarizes the clinical use of colchicine in BD.

METHODS

All relevant literature from 1980 to March 2021 was searched in PubMed, MEDLINE, and Cochrane Library. The Medical Subject Heading terms and related words that were searched are as follows: Behcet's disease, Behcet's syndrome, BD, colchicine, management, treatment, and therapy.

FINDINGS

BD is an autoimmune systemic vasculitis with various clinical phenotypes, with involvement of skin mucosa, joints, eyes, and gastrointestinal, vascular, and neurologic systems. Colchicine has been used for centuries, acts by binding to tubulin to prevent the mitotic process, and has anti-inflammatory, antitumor, and antifibrotic properties. Colchicine has been reported to be an effective option for the treatment of skin, mucosal, and joint involvement in patients with certain BD clinical phenotypes.

IMPLICATIONS

Colchicine reduces the severity of certain clinical phenotypes and may improve the overall disease activity index in patients with BD. More randomized clinical trials are needed to confirm the value of colchicine in the treatment of BD, and further elucidation of the mechanisms is also needed, which may reveal new application of colchicine that has been used for centuries.

Discovery of Novel Acridane-Based Tubulin Polymerization Inhibitors with Anticancer and Potential Immunomodulatory Effects

A series of novel acridane-based tubulin polymerization inhibitors were designed, synthesized, and bioevaluated as anticancer agents. The most potent compound NT-6 exhibited high tubulin polymerization inhibitory activity (IC50 = 1.5 μM) and remarkable antiproliferative potency against four cancer cell lines with an average IC50 of 30 nM, better than colchicine and the hit compound 1f (IC50 of 65 and 126 nM, respectively). In addition, NT-6 (10 mg/kg) exerted excellent antitumor efficacy in a melanoma tumor model with a tumor growth inhibition (TGI) of 65.1% without apparent toxicity. Importantly, the combination of NT-6 with a small-molecule PD-L1 inhibitor NP-19 decreased tumor burden significantly (TGI% = 77.6%). Moreover, the combination of NT-6 with NP-19 enhanced the antitumor immune response, mediated by a decrease of PD-L1 expression levels and increased infiltration of antitumor CD8+ effector T cells in tumor tissues. Collectively, NT-6 represents a novel tubulin polymerization inhibitor with immunopotentiating effects.

cGAS-dependent proinflammatory and immune homeostatic effects of the microtubule-targeting agent paclitaxel

Taxanes are Microtubule-Targeting Agents (MTAs) that exert potent anticancer activity by directly killing cancer cells. However, recent evidence suggests that they may also stimulate inflammation and anticancer adaptive immunity and that these actions strongly contribute to their therapeutic efficacy. Details on how Taxanes may modulate inflammation and anticancer immunity are, nevertheless, still missing. We show here that at very low doses the Taxane Paclitaxel (Pxl) indeed induces a potent proinflammatory response in various cancer cell types in a cyclic GMP-AMP (cGAMP) synthase (cGAS)- and Stimulator of Interferon Genes (STING)-dependent manner, leading to interferon (IFN) signaling. However, we find that Pxl treatment also strongly upregulates the expression of the immune checkpoint protein Programmed Death-Ligand 1 (PD-L1) in cancer cells, therefore, inducing an inhibitory response to adaptive immunity potentially attenuating anticancer immunity and therapeutic success. These observations provide a mechanistic explanation of why clinical benefit may derive from the combination of Pxl with Immune Checkpoint Inhibitors (ICIs) and suggest that more accurately tailoring dosage and schedule of this combination therapy may provide benefit in the management of a larger number of cancer types and stages.

Phytochemicals as Chemo-Preventive Agents and Signaling Molecule Modulators: Current Role in Cancer Therapeutics and Inflammation

Cancer is one of the deadliest non communicable diseases. Numerous anticancer medications have been developed to target the molecular pathways driving cancer. However, there has been no discernible increase in the overall survival rate in cancer patients. Therefore, innovative chemo-preventive techniques and agents are required to supplement standard cancer treatments and boost their efficacy. Fruits and vegetables should be tapped into as a source of compounds that can serve as cancer therapy. Phytochemicals play an important role as sources of new medication in cancer treatment. Some synthetic and natural chemicals are effective for cancer chemoprevention, i.e., the use of exogenous medicine to inhibit or impede tumor development. They help regulate molecular pathways linked to the development and spread of cancer. They can enhance antioxidant status, inactivating carcinogens, suppressing proliferation, inducing cell cycle arrest and death, and regulating the immune system. While focusing on four main categories of plant-based anticancer agents, i.e., epipodophyllotoxin, camptothecin derivatives, taxane diterpenoids, and vinca alkaloids and their mode of action, we review the anticancer effects of phytochemicals, like quercetin, curcumin, piperine, epigallocatechin gallate (EGCG), and gingerol. We examine the different signaling pathways associated with cancer and how inflammation as a key mechanism is linked to cancer growth.

Two Important Anticancer Mechanisms of Natural and Synthetic Chalcones

ATP-binding cassette subfamily G and tubulin pharmacological mechanisms decrease the effectiveness of anticancer drugs by modulating drug absorption and by creating tubulin assembly through polymerization. A series of natural and synthetic chalcones have been reported to have very good anticancer activity, with a half-maximal inhibitory concentration lower than 1 µM. By modulation, it is observed in case of the first mechanism that methoxy substituents on the aromatic cycle of acetophenone residue and substitution of phenyl nucleus by a heterocycle and by methoxy or hydroxyl groups have a positive impact. To inhibit tubulin, compounds bind to colchicine binding site. Presence of methoxy groups, amino groups or heterocyclic substituents increase activity.

The New Microtubule-Targeting Agent SIX2G Induces Immunogenic Cell Death in Multiple Myeloma

Microtubule-targeting agents (MTAs) are effective drugs for cancer treatment. A novel diaryl [1,2]oxazole class of compounds binding the colchicine site was synthesized as cis-restricted-combretastatin-A-4-analogue and then chemically modified to have improved solubility and a wider therapeutic index as compared to vinca alkaloids and taxanes. On these bases, a new class of tricyclic compounds, containing the [1,2]oxazole ring and an isoindole moiety, has been synthetized, among which SIX2G emerged as improved MTA. Several findings highlighted the ability of some chemotherapeutics to induce immunogenic cell death (ICD), which is defined by the cell surface translocation of Calreticulin (CALR) via dissociation of the PP1/GADD34 complex. In this regard, we computationally predicted the ability of SIX2G to induce CALR exposure by interacting with the PP1 RVxF domain. We then assessed both the potential cytotoxic and immunogenic activity of SIX2G on in vitro models of multiple myeloma (MM), which is an incurable hematological malignancy characterized by an immunosuppressive milieu. We found that the treatment with SIX2G inhibited cell viability by inducing G2/M phase cell cycle arrest and apoptosis. Moreover, we observed the increase of hallmarks of ICD such as CALR exposure, ATP release and phospho-eIF2α protein level. Through co-culture experiments with immune cells, we demonstrated the increase of (i) CD86 maturation marker on dendritic cells, (ii) CD69 activation marker on cytotoxic T cells, and (iii) phagocytosis of tumor cells following treatment with SIX2G, confirming the onset of an immunogenic cascade. In conclusion, our findings provide a framework for further development of SIX2G as a new potential anti-MM agent.

In silico analysis of noscapine compounds as anti-tumor agents targeting the tubulin receptor

Objective

This research aims to develop a mathematical model that relates the structural features of noscapine with anti-tumor activity, to explains the mode of binding between noscapine compounds and the target receptor tubulin by docking analysis. By considering the results of docking analysis and predictions of pharmacokinetic properties/drug likeness, we designed novel noscapine compounds as anti-tumor agents against pancreatic cancer.

Methods

We used an in silico quantitative structure–activity relationship (QSAR) approach, molecular docking analysis and online tools for pharmacokinetics and drug likeness prediction to develop novel compounds.

Results

A QSAR model with good validations parameters and quality of fit (R² = 0.9731, Q²_CV = 0.9434, R²_adj = 0.9647 and R²_{test set} = 0.8343) was built utilizing 70% of the dataset as a training set and the remaining 30% as an external validation to ascertain its predictive capability. Three novel compounds were designed: D3, D4 and D6 with binding scores of −11.2, −10.2 and 10.6 kcal/mol, respectively, exhibiting high affinity towards the tubulin receptor than the template (parent compound) and the co-crystallized ligand (E∗) with a binding score of 9.2 kcal/mol.

Conclusion

The QSAR approach and molecular docking analysis is an important approach for modern drug discovery. Pharmacokinetics studies of the selected novel compounds revealed good drug properties and can be used as candidate compounds for the development of anti-tumor agents for pancreatic cancer.

Tubulin Isotypes: Emerging Roles in Defining Cancer Stem Cell Niche

Although the role of microtubule dynamics in cancer progression is well-established, the roles of tubulin isotypes, their cargos and their specific function in the induction and sustenance of cancer stem cells (CSCs) were poorly explored. But emerging reports urge to focus on the transport function of tubulin isotypes in defining orchestrated expression of functionally critical molecules in establishing a stem cell niche, which is the key for CSC regulation. In this review, we summarize the role of specific tubulin isotypes in the transport of functional molecules that regulate metabolic reprogramming, which leads to the induction of CSCs and immune evasion. Recently, the surface expression of GLUT1 and GRP78 as well as voltage-dependent anion channel (VDAC) permeability, regulated by specific isotypes of β-tubulins have been shown to impart CSC properties to cancer cells, by implementing a metabolic reprogramming. Moreover, βIVb tubulin is shown to be critical in modulating EphrinB1signaling to sustain CSCs in oral carcinoma. These tubulin-interacting molecules, Ephrins, GLUT1 and GRP78, are also important regulators of immune evasion, by evoking PD-L1 mediated T-cell suppression. Thus, the recent advances in the field implicate that tubulins play a role in the controlled transport of molecules involved in CSC niche. The indication of tubulin isotypes in the regulation of CSCs offers a strategy to specifically target those tubulin isotypes to eliminate CSCs, rather than the general inhibition of microtubules, which usually leads to therapy resistance.

Activation of the chemokine receptor 3 pathway leads to a better response to immune checkpoint inhibitors in patients with metastatic urothelial carcinoma

Immune checkpoint inhibitors (ICIs) have made important breakthrough in anti-tumor therapy, however, no single biomarker can accurately predict their efficacy. Studies have found that tumor microenvironment is a key factor for determining the response to ICI therapy. Cytokine receptor 3 (C-X-C Motif Chemokine Receptor 3, CXCR3) pathway has been reported to play an important role in the migration, activation, and response of immune cells. We analyzed survival data, genomics, and clinical data from patients with metastatic urothelial carcinoma (mUC) who received ICI treatment to explore the relationship between CXCR3 pathway activation and the effectiveness of ICIs. The Cancer Genome Atlas Bladder Urothelial Carcinoma cohort and six other cohorts receiving ICI treatment were used for mechanism exploration and validation. In the ICI cohort, we performed univariate and multivariate COX analyses and discovered that patients in the CXCR3-high group were more sensitive to ICI treatment. A Kaplan–Meier analysis demonstrated that patients in the high CXCR3-high group had a better prognosis than those in the CXCR3-low group (P = 0.0001, Hazard Ratio = 0.56; 95% CI 0.42−0.75). CIBERSORT analysis found that mUC patients in the CXCR3-high group had higher levels of activated CD8+ T cells, M1 macrophages, and activated NK cells and less regulatory T cell (Treg) infiltration. Immunogenicity analysis showed the CXCR3-high group had higher tumor neoantigen burden (TNB). Our study suggests that CXCR3 pathway activation may be a novel predictive biomarker for the effectiveness of immunotherapy in mUC patients.

Molecular Evolution of Tubulins in Diatoms

Microtubules are formed by α- and β-tubulin heterodimers nucleated with γ-tubulin. Tubulins are conserved eukaryotic proteins. Previously, it was shown that microtubules are involved in diatom silica frustule morphogenesis. Diatom frustules are varied, and their morphology is species-specific. Despite the attractiveness of the problem of elucidating the molecular mechanisms of genetically programmed morphogenesis, the structure and evolution of diatom tubulins have not been studied previously. Based on available genomic and transcriptome data, we analyzed the phylogeny of the predicted amino acid sequences of diatom α-, β- and γ-tubulins and identified five groups for α-tubulins, six for β-tubulins and four for γ-tubulins. We identified characteristic amino acids of each of these groups and also analyzed possible posttranslational modification sites of diatom tubulins. According to our results, we assumed what changes occurred in the diatom tubulin structures during their evolution. We also identified which tubulin groups are inherent in large diatom taxa. The similarity between the evolution of diatom tubulins and the evolution of diatoms suggests that molecular changes in α-, β- and γ-tubulins could be one of the factors in the formation of a high morphological diversity of diatoms.

Nivolumab plus docetaxel in patients with chemotherapy-naïve metastatic castration-resistant prostate cancer: results from the phase II CheckMate 9KD trial

BACKGROUND

Docetaxel has immunostimulatory effects that may promote an immunoresponsive prostate tumour microenvironment, providing a rationale for combination with nivolumab (programmed death-1 inhibitor) for metastatic castration-resistant prostate cancer (mCRPC).

METHODS

In the non-randomised, multicohort, global phase II CheckMate 9KD trial, 84 patients with chemotherapy-naive mCRPC, ongoing androgen deprivation therapy and ≤2 prior novel hormonal therapies (NHTs) received nivolumab 360 mg and docetaxel 75 mg/m² every 3 weeks with prednisone 5 mg twice daily (≤10 cycles) and then nivolumab 480 mg every 4 weeks (≤2 years). The co-primary end-points were objective response rate (ORR) and prostate-specific antigen response rate (PSA₅₀-RR; ≥50% decrease from baseline).

RESULTS

The confirmed ORR (95% confidence interval [CI]) was 40.0% (25.7-55.7), and the confirmed PSA₅₀-RR (95% CI) was 46.9% (35.7-58.3). The median (95% CI) radiographic progression-free survival (rPFS) and overall survival (OS) were 9.0 (8.0-11.6) and 18.2 (14.6-20.7) months, respectively. In subpopulations with versus without prior NHT, the ORR was 38.7% versus 42.9%, the PSA₅₀-RR was 39.6% versus 60.7%, the median rPFS was 8.5 versus 12.0 months and the median OS was 16.2 months versus not reached. Homologous recombination deficiency status or tumour mutational burden did not appear to impact efficacy. The most common any-grade and grade 3-4 treatment-related adverse events were fatigue (39.3%) and neutropenia (16.7%), respectively. Three treatment-related deaths occurred (1 pneumonitis related to nivolumab; 2 pneumonias related to docetaxel).

CONCLUSIONS

Nivolumab plus docetaxel has clinical activity in patients with chemotherapy-naïve mCRPC. Safety was consistent with the individual components. These results support further investigation in the ongoing phase III CheckMate 7DX trial. CLINICALTRIALS.

GOV REGISTRATION

NCT03338790.

Lead optimization of novel quinolone chalcone compounds by a structure-activity relationship (SAR) study to increase efficacy and metabolic stability

Many agents targeting the colchicine binding site in tubulin have been developed as potential anticancer agents. However, none has successfully made it to the clinic, due mainly to dose limiting toxicities and the emergence of multi-drug resistance. Chalcones targeting tubulin have been proposed as a safe and effective alternative. We have shown previously that quinolone chalcones target tubulin and maintain potent anti-proliferative activity vis-à-vis colchicine, while also having high tolerability and low toxicity in mouse models of cancer and refractivity to multi-drug resistance mechanisms. To identify the most effective anticancer chalcone compound, we synthesized 17 quinolone-chalcone derivatives based on our previously published CTR-17 and CTR-20, and then carried out a structure-activity relationship study. We identified two compounds, CTR-21 [((E)-8-Methoxy-3-(3-(2-methoxyphenyl)-3-oxoprop-1-enyl) quinolin-2(1H)-one)] and CTR-32 [((E)-3-(3-(2-ethoxyphenyl)-3-oxoprop-1-enyl) quinolin-2(1H)-one)] as potential leads, which contain independent moieties that play a significant role in their enhanced activities. At the nM range, CTR-21 and CTR-32 effectively kill a panel of different cancer cells originated from a variety of different tissues including breast and skin. Both compounds also effectively kill multi-drug resistant cancer cells. Most importantly, CTR-21 and CTR-32 show a high degree of selectivity against cancer cells. In silico, both of them dock near the colchicine-binding site with similar energies. Whereas both CTR-21 and CTR-32 effectively prevents tubulin polymerization, leading to the cell cycle arrest at G2/M, CTR-21 has more favorable metabolic properties. Perhaps not surprisingly, the combination of CTR-21 and ABT-737, a Bcl-2 inhibitor, showed synergistic effect in killing cancer cells, since we previously found the "parental" CTR-20 also exhibited synergism. Taken together, CTR-21 can potentially be a highly effective and relatively safe anticancer drug.

Eribulin activates the cGAS-STING pathway via the cytoplasmic accumulation of mtDNA

Microtubule-targeting agents (MTAs), including both microtubule stabilizers and destabilizers are highly effective chemotherapeutic drugs used in the treatment of solid tumors and hematologic malignancies. In addition to the shared ability of all MTAs to block cell cycle progression, growing evidence shows that different agents of this class can also have mechanistically distinct effects on nonmitotic microtubule-dependent cellular processes, including cellular signaling and transport. Herein, we test the biologic hypothesis that MTAs used in the treatment of triple-negative breast cancer (TNBC) can differentially affect innate immune signaling pathways independent of their antimitotic effects. Our data demonstrate that the microtubule destabilizer eribulin, but not the microtubule stabilizer paclitaxel, induces cGAS-STING–dependent expression of interferon-β in both myeloid and TNBC cells. Activation of the cGAS-STING pathway by eribulin was further found to be mediated by the accumulation of cytoplasmic mitochondrial DNA. Together, these findings provide mechanistic insight into how eribulin can induce innate immune signaling independent of its antimitotic or cytotoxic effects.

Structure-activity relationships and antiproliferative effects of 1,2,3,4-4H-quinoxaline derivatives as tubulin polymerization inhibitors

Colchicine binding site inhibitors (CBSIs) hold great potential for the treatment of various tumors and they can overcome multidrug resistance which the existing tubulin inhibitors such as paclitaxel and vinorelbine are faced with. Herein, we report the design, synthesis and biological evaluation of a series of tetrahydro-quinoxaline derivatives as colchicine binding site inhibitors. All the synthesized compounds were evaluated for their in vitro antiproliferative activities against HT-29 and Hela cancer cell lines, and most of the target compounds demonstrated moderate to strong activities towards two tumor cell lines. In addition, the structure-activity relationships of these derivatives were also discussed. Among them, compounds 11a and 11b showed the most potent activities. Moreover, compound 11a inhibited the tubulin polymerization in both cell-free and cellular assays. Further profiling of compound 11a revealed that it arrested cell cycle in G2/M and induced cell apoptosis in a dose-dependent manner. Furthermore, molecular docking study proved that compound 11a acted on the colchicine binding site. Therefore, 11a is a promising candidate for the discovery of colchicine binding site inhibitors.

Taxanes in cancer treatment: Activity, chemoresistance and its overcoming

Since 1984, when paclitaxel was approved by the FDA for the treatment of advanced ovarian carcinoma, taxanes have been widely used as microtubule-targeting antitumor agents. However, their historic classification as antimitotics does not describe all their functions. Indeed, taxanes act in a complex manner, altering multiple cellular oncogenic processes including mitosis, angiogenesis, apoptosis, inflammatory response, and ROS production. On the one hand, identification of the diverse effects of taxanes on oncogenic signaling pathways provides opportunities to apply these cytotoxic drugs in a more rational manner. On the other hand, this may facilitate the development of novel treatment modalities to surmount anticancer drug resistance. In the latter respect, chemoresistance remains a major impediment which limits the efficacy of antitumor chemotherapy. Taxanes have shown impact on key molecular mechanisms including disruption of mitotic spindle, mitosis slippage and inhibition of angiogenesis. Furthermore, there is an emerging contribution of cellular processes including autophagy, oxidative stress, epigenetic alterations and microRNAs deregulation to the acquisition of taxane resistance. Hence, these two lines of findings are currently promoting a more rational and efficacious taxane application as well as development of novel molecular strategies to enhance the efficacy of taxane-based cancer treatment while overcoming drug resistance. This review provides a general and comprehensive picture on the use of taxanes in cancer treatment. In particular, we describe the history of application of taxanes in anticancer therapeutics, the synthesis of the different drugs belonging to this class of cytotoxic compounds, their features and the differences between them. We further dissect the molecular mechanisms of action of taxanes and the molecular basis underlying the onset of taxane resistance. We further delineate the possible modalities to overcome chemoresistance to taxanes, such as increasing drug solubility, delivery and pharmacokinetics, overcoming microtubule alterations or mitotic slippage, inhibiting drug efflux pumps or drug metabolism, targeting redox metabolism, immune response, and other cellular functions.

An Overview of Exosomes in Cancer Therapy: A Small Solution to a Big Problem

Exosomes are defined as a type of extracellular vesicle released when multivesicular bodies of the endocytic pathway fuse with the plasma membrane. They are characterized by their role in extracellular communication, partly due to their composition, and present the ability to recognize and interact with cells from the immune system, enabling an immune response. Their targeting capability and nanosized dimensions make them great candidates for cancer therapy. As chemotherapy is associated with cytotoxicity and multiple drug resistance, the use of exosomes targeting capabilities, able to deliver anticancer drugs specifically to cancer cells, is a great approach to overcome these disadvantages. The objective is to assess treatment efficiency in reducing tumor cells, as well as overall safety and response by cancer carriers. So far, results show exosomes as a promising therapeutic strategy in the fight against cancer. This review summarizes the characteristics and composition of exosomes, as well as explaining in detail the involved parties in the origin of exosomes. Furthermore, some considerations about exosome application in immunotherapy are addressed. The main isolation and loading methods are described to give an insight into how exosomes can be obtained and manipulated. Finally, some therapeutic applications of exosomes in cancer therapy are described.

Active metronomic vinorelbine schedules decrease plasma interleukin-2 levels in mice with Lewis lung carcinoma

The aim of our study was to investigate the effects of metronomic vinorelbine (mVNR) in a tumor model of Lewis Lung (LL) cancer in immunocompetent C57BL/6 mice, looking at the plasma levels of interleukin-2 (IL-2) and interleukin-8 (IL-8). mVNR caused a concentration-dependent antiproliferative effect in vitro on LL/2 cells. The in vivo experiment showed the significant antitumor effects of mVNR at the dose of 4 mg/Kg and 5 mg/Kg, 3 times/week, and the significant dose-dependent decrease of IL-2 concentrations in plasma samples. Conversely, such an effect was not observed for IL-8. A significant decrease in microvessel density was also found at both the active mVNR doses. In conclusion, our study confirmed the activity of mVNR in an immunocompetent model of lung carcinoma and suggest multiple mechanisms of action, including the modulation of IL-2 levels.

Friend or Foe? An Unrecognized Role of Uric Acid in Cancer Development and the Potential Anticancer Effects of Uric Acid-lowering Drugs

In recent years, metabolic syndrome (Mets) has been a hot topic among medical scientists. Mets has an intimate relationship with the incidence and development of various cancers. As a contributory factor of Mets, hyperuricemia actually plays an inseparable role in the formation of various metabolic disorders. Although uric acid is classically considered an antioxidant with beneficial effects, mounting evidence indicates that a high serum uric acid (SUA) level may serve as a pro-oxidant to generate inflammatory reactions and oxidative stress. In this review, we describe the unrecognized role of hyperuricemia in cancer development and summarize major mechanisms linking uric acid to carcinogenesis. Furthermore, we also discuss the potential mechanism of liver metastasis of cancer and list some types of uric acid-lowering agents, which may exert anticancer effects.

Colchicine Alkaloids and Synthetic Analogues: Current Progress and Perspectives

Colchicine, the main alkaloid of Colchicum autumnale, is one of the most famous natural molecules. Although colchicine belongs to the oldest drugs (in use since 1500 BC), its pharmacological potential as a lead structure is not yet fully exploited. This review is devoted to the synthesis and structure-activity relationships (SAR) of colchicine alkaloids and their analogues with modified A, B, and C rings, as well as hybrid compounds derived from colchicinoids including prodrugs, conjugates, and delivery systems. The systematization of a vast amount of information presented to date will create a paradigm for future studies of colchicinoids for neoplastic and various other diseases.

Exploiting immune-dependent effects of microtubule-targeting agents to improve efficacy and tolerability of cancer treatment

Microtubule-targeting agents (MTAs), like taxanes and vinca alkaloids, are tubulin-binding drugs that are very effective in the treatment of various types of cancers. In cell cultures, these drugs appear to affect assembly of the mitotic spindle and to delay progression through mitosis and this correlates with their ability to induce cell death. Their clinical efficacy is, however, limited by resistance and toxicity. For these reasons, other spindle-targeting drugs, affecting proteins such as certain kinesins like Eg5 and CENP-E, or kinases like Plk1, Aurora A and B, have been developed as an alternative to MTAs. However, these attempts have disappointed in the clinic since these drugs show poor anticancer activity and toxicity ahead of positive effects. In addition, whether efficacy of MTAs in cancer treatment is solely due to their ability to delay mitosis progression remains controversial. Here we discuss recent findings indicating that the taxane paclitaxel can promote a proinflammatory response by activation of innate immunity. We further describe how this can help adaptive antitumor immune response and suggest, on this basis and on the recent success of immune checkpoint inhibitors in cancer treatment, that a combination therapy based on low doses of taxanes and immune checkpoint inhibitors may be of high clinical advantage in terms of wide applicability, reduced toxicity, and increased antitumor response.

Targeted Nano-Drug Delivery of Colchicine against Colon Cancer Cells by Means of Mesoporous Silica Nanoparticles

Antimitotics are important anticancer agents and include the natural alkaloid prodrug colchicine (COL). However, a major challenge of using COL as an anticancer drug is its cytotoxicity. We developed a novel drug delivery system (DDS) for COL using mesoporous silica nanoparticles (MSNs). The MSNs were functionalized with phosphonate groups, loaded with COL, and coated with folic acid chitosan-glycine complex. The resulting nanoformulation, called MSNsPCOL/CG-FA, was tested for action against cancer and normal cell lines. The anticancer effect was highly enhanced for MSNsPCOL/CG-FA compared to COL. In the case of HCT116 cells, 100% inhibition was achieved. The efficiency of MSNsPCOL/CG-FA ranked in this order: HCT116 (colon cancer) > HepG2 (liver cancer) > PC3 (prostate cancer). MSNsPCOL/CG-FA exhibited low cytotoxicity (4%) compared to COL (~60%) in BJ1 normal cells. The mechanism of action was studied in detail for HCT116 cells and found to be primarily intrinsic apoptosis caused by an enhanced antimitotic effect. Furthermore, a contribution of genetic regulation (metastasis-associated lung adenocarcinoma transcript 1 (MALAT 1), and microRNA (mir-205)) and immunotherapy effects (angiopoietin-2 (Ang-2 protein) and programmed cell death protein 1 (PD-1) was found. Therefore, this study shows enhanced anticancer effects and reduced cytotoxicity of COL with targeted delivery compared to free COL and is a novel method of developing cancer immunotherapy using a low-cost small-molecule natural prodrug.

TUBULIN ROLE IN CANCER DEVELOPMENT AND TREATMENT

This review work is done to show a significance of tubulin in cancer development. Within last decades there are a lot of studies have performed in this area. Now it is clear that there are an enormous number of functions in cell performing by microtubules, a structure unit of which is tubulin. Now it used widely as a predictive factor of tumor aggressiveness, but increasingly it becomes a target for studying and treatment elaboration, since it is well-known that to nowadays tubulin-targeted medicines, such as taxanes or vinca-alkaloids, resistance develops rather quickly, so it consists a large problem in oncology. This work reveals basic microtubule functions, violations that it may undergo and consequences of these. Also it is described here the main modern tendencies in creation of remedy which will make it possible breakthrough treatment resistance barrier.