The novel toluidine sulphonamide EL102 shows pre-clinical in vitro and in vivo activity against prostate cancer and circumvents MDR1 resistance

New sulfa drug derivatives and their zinc(II) complexes: synthesis, spectroscopic properties and in vitro cytotoxic activities

Synthesis of four sulfa drug derivatives (L1-L4) and Zn(II) complexes derived from sulfonamide group antibiotic substances was carried out using the hydrothermal technique (HT) and their structures of the obtained compounds were explained using elemental analysis (EA), FT-IR and NMR (1H- and 13C-). Cytotoxic activities of four novel sulfa drug based-Schiff base compounds and their Zn(II) complexes were determined by 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyl-2H-tetrazolium bromide (MTT) assay using MCF-7 (human breast cancer), Caco-2 (human colorectal adenocarcinoma), A2780 (human ovarian cancer) and LNCaP (human prostate adenocarcinoma) cell lines. LogIC50 values of all obtained compounds were computed with the Graphpad Prism 6 program after 24 h of treatment for MCF-7, Caco-2, A2780 and LNCaP cells. Comet assay experiments were performed using LogIC50 concentrations of all compounds to determine DNA damage. Based on the data obtained, all compounds significantly decreased MCF-7, Caco-2, A2780 and LNCaP cell viability compared to the control groups (p < 0.05).

Mechanisms of Taxane Resistance

The taxane family of chemotherapy drugs has been used to treat a variety of mostly epithelial-derived tumors and remain the first-line treatment for some cancers. Despite the improved survival time and reduction of tumor size observed in some patients, many have no response to the drugs or develop resistance over time. Taxane resistance is multi-faceted and involves multiple pathways in proliferation, apoptosis, metabolism, and the transport of foreign substances. In this review, we dive deeper into hypothesized resistance mechanisms from research during the last decade, with a focus on the cancer types that use taxanes as first-line treatment but frequently develop resistance to them. Furthermore, we will discuss current clinical inhibitors and those yet to be approved that target key pathways or proteins and aim to reverse resistance in combination with taxanes or individually. Lastly, we will highlight taxane response biomarkers, specific genes with monitored expression and correlated with response to taxanes, mentioning those currently being used and those that should be adopted. The future directions of taxanes involve more personalized approaches to treatment by tailoring drug-inhibitor combinations or alternatives depending on levels of resistance biomarkers. We hope that this review will identify gaps in knowledge surrounding taxane resistance that future research or clinical trials can overcome.

Targeting the androgen receptor (AR) with AR degradation enhancer ASC-J9® led to increase docetaxel sensitivity via suppressing the p21 expression

Chemotherapy with docetaxel remains the effective therapy to suppress castration resistant prostate cancer (CRPC) in some patients. However, most chemotherapy with docetaxel eventually fails with the development of docetaxel resistance after 18-weeks of treatment. Here we found docetaxel treatment might have an adverse effect of increasing the androgen receptor (AR) protein level in the CRPC cells, and combining docetaxel with anti-AR therapy using AR-shRNA or the AR degradation enhancer ASC-J9® may increase docetaxel sensitivity to better suppress the CRPC cell growth. Mechanism dissection found docetaxel might have the adverse effect of increasing the AR protein stability via suppressing the AR ubiquitination due to the increased AR phosphorylation. The consequence of such increased AR protein may then lead to increase p21 expression via transcriptional regulation. Preclinical studies with in vitro cells lines also demonstrated that targeting AR with ASC-J9® led to suppressing the AR-increased p21 expression to improve the docetaxel sensitivity in the CRPC cells that already developed docetaxel resistance. Together, these results suggest that a combined therapy of docetaxel and ASC-J9® is a novel therapy to better suppress CRPC in patients that already developed docetaxel resistance.

Synthesis and biological evaluation of novel 5-chloro-N-(4-sulfamoylbenzyl) salicylamide derivatives as tubulin polymerization inhibitors

A novel series of sulfonamide derivatives, coupled with a salicylamide scaffold, was designed and synthesized. The structures of the synthesized compounds were established using 1H NMR, 13C NMR and high-resolution mass spectroscopy. The synthesized compounds were tested in vitro against five types of human cell lines. Two were breast adenocarcinoma, including the hormone-dependent MCF-7 and the hormone-independent MDA-MB-231. The others were the colorectal adenocarcinoma Caco-2, the carcinoma HCT-116 and the immortalized retinal-pigmented epithelium, hTERT-RPE1. Nine sulfonamides were able to inhibit the growth of the four tested cancer cells. Compound 33 was the most active against the selected colon cancer (Caco-2 and HCT-116) subtypes, while compound 24 showed the best efficacy against the examined breast cancer (MCF-7 and MDA-MB-231) cells. The selectivity index introduced compounds 24 and 33 as having the best selectivity among the breast and colon subtypes, respectively. In vitro tubulin polymerization experiments and flow cytometric assays showed that compounds 24 and 33 led to cell cycle arrest at the G2/M phase in a dose-dependent manner by effectively inhibiting tubulin polymerization. Furthermore, the results of the molecular docking studies indicate that this class of compounds can bind to the colchicine-binding site of tubulin.

Treatment with 20(S)-ginsenoside Rg3 reverses multidrug resistance in A549/DDP xenograft tumors

Multidrug resistance (MDR) is an obstacle for cancer chemotherapy. It was reported that 20(S)-ginsenoside Rg3 (hereafter Rg3) was able to regulate MDR in mouse leukemia cells. The present study investigated the effect of Rg3 on the MDR of A549 lung cancer cells. A cell viability assay revealed that Rg3 treatment increased cisplatin (DDP) cytotoxicity in DDP resistant A549 cells (A549/DDP). Furthermore, Rg3 increases the antitumor effect of DDP on A549/DDP xenograft mice. The expression of MDR-mediated proteins, including P-glycoprotein (P-gp), multidrug resistance-associated protein (MPR1) and lung resistance protein 1 (LPR1), was detected in tumor tissue of A549/DDP xenograft mice. The results revealed that Rg3 treatment inhibited the expression of these MDR-associated proteins. Additionally, technetium-99m labeled hexakis-2-methoxyisobutylisonitrile (^99mTc-MIBI) single-photon emission computed tomography was used to monitor the effect of Rg3 on cisplatin sensitivity of A549/DDP xenograft tumors. It was observed that uptake of ^99mTc-MIBI was increased by Rg3 treatment, which indicated that Rg3 is able to effectively enhance chemotherapy sensitivity of A549/DDP xenograft tumors. Taken together, these results revealed that Rg3 may be able to reverse MDR of lung cancer via the downregulation of P-gp, MPR1 and LPR1.

N-(2-methyl-indol-1H-5-yl)-1-naphthalenesulfonamide: A novel reversible antimitotic agent inhibiting cancer cell motility

A series of compounds containing the sulfonamide scaffold were synthesized and screened for their in vitro anticancer activity against a representative panel of human cancer cell lines, leading to the identification of N-(2-methyl-1H-indol-5-yl)-1-naphthalenesulfonamide (8e) as a compound showing a remarkable activity across the panel, with IC50 values in the nanomolar-to-low micromolar range. Cell cycle distribution analysis revealed that 8e promoted a severe G2/M arrest, which was followed by cellular senescence as indicated by the detection of senescence-associated β-galactosidase (SA-β-gal) in 8e-treated cells. Prolonged 8e treatment also led to the onset of apoptosis, in correlation with the detection of increased Caspase 3/7 activities. Despite increasing γ-H2A.X levels, a well-established readout for DNA double-strand breaks, in vitro DNA binding studies with 8e did not support interaction with DNA. In agreement with this, 8e failed to activate the cellular DNA damage checkpoint. Importantly, tubulin staining showed that 8e promoted a severe disorganization of microtubules and mitotic spindle formation was not detected in 8e-treated cells. Accordingly, 8e inhibited tubulin polymerization in vitro in a dose-dependent manner and was also able to robustly inhibit cancer cell motility. Docking analysis revealed a compatible interaction with the colchicine-binding site of tubulin. Remarkably, these cellular effects were reversible since disruption of treatment resulted in the reorganization of microtubules, cell cycle re-entry and loss of senescent markers. Collectively, our data suggest that this compound may be a promising new anticancer agent capable of both reducing cancer cell growth and motility.

Graphene oxide-wrapped PEGylated liquid crystalline nanoparticles for effective chemo-photothermal therapy of metastatic prostate cancer cells

Here, we report the preparation of PEGylated liquid crystalline nanoparticles (LCN) loaded with docetaxel (DTX) and wrapped with graphene oxide (GO), called PEG-GO/LCN/DTX, for effective chemo-photothermal therapy of metastatic prostate cancer cells. The prepared formulation exhibited a small particle size (<250 nm), high drug loading capacity (∼15%), and efficient near infrared (NIR) light-induced thermal heat. Importantly, PEG-GO/LCN/DTX successfully accumulated in prostate cancer cells and exhibited potent apoptotic and antimigration effects, mediated by the combination of the anticancer effects of DTX and the thermal heat induced by exposure of GO to NIR light. Taken together, our findings support that PEG-GO/LCN/DTX may be an effective system for treatment of metastatic prostate cancer. Moreover, the results establish a proof-of-concept for the potential chemo-photothermal functionality of PEG-GO/LCN/DTX. This hybrid system of LCN and GO could provide controlled and targeted drug delivery with enhanced NIR-induced thermal effects for effective treatment of metastatic cancers.

Reversing effect and mechanism of soluble resistance-related calcium-binding protein on multidrug resistance in human lung cancer A549/DDP cells

Lung cancer is the primary malignancy of the lung and is the leading cause of cancer‑associated mortality in China. Multidrug resistance (MDR) is an essential aspect of lung cancer treatment failure and a popular topic of investigation in tumor studies. Previous studies have demonstrated that soluble resistance‑related calcium‑binding protein (Sorcin) is involved in the MDR of various types of human tumor, and that silencing Sorcin was able to reverse the MDR of several types of cultured human cancer cells. However, the effect and potential mechanism underlying the ability of Sorcin to reverse MDR in human lung cancer remains to be fully elucidated. The present study examined the role of Sorcin in the reversal of MDR in human lung cancer A549/DDP cells. The effects included increased drug sensitivity to cisplatin, apoptotic rate, cell cycle arrest in the G2/M phase and intracellular accumulation of rhodamine‑123, and decreased expression of multidrug resistance gene 1, lung resistance protein, multidrug resistance‑associated protein, glutathione S‑transferase π, ATP‑binding cassette transporter A2 (ABCA2), ABCA5, B‑cell lymphoma 2 and P‑glycoprotein, and the depletion of glutathione in Sorcin‑silenced A549/DDP cells. The present study also revealed that there was a downregulation of p‑Akt and phosphorylated extracellular signal‑regulated kinase (p‑ERK), and a decreased transcriptional activation of nuclear factor κB, signal transducer and activator of transcription (STAT)3, STAT5 and nuclear factor of activated T‑cells following silencing of Sorcin. The results indicated that Sorcin may be used as a potential therapeutic target for MDR through inhibiting the Akt and ERK pathways in human lung cancer.