Effect of bortezomib in combination with cisplatin and 5‑fluorouracil on 4T1 breast cancer cells

pH/H2 O2 Cascade-Responsive Nanoparticles of Lipid-Like Prodrugs through Dynamic-Covalent and Coordination Interactions for Chemotherapy

Traditional lipid nanoparticles (LNPs) suffer from low drug loading capacity (DLC), weak stability, and lack of responsiveness. Conventional approaches to address these issues involve the synthesis of lipid-prodrug by incorporating responsive covalent linkers. However, such approaches often result in suboptimal sensitivity for drug release and undermine therapeutic effectiveness. Herein, the study reports a fundamentally different concept for designing lipid-like prodrugs through boron-nitrogen (B-N) coordination and dynamic covalent interaction. The 5-fluorouracil-based lipid-like prodrugs, featuring a borate ester consisting of a glycerophosphoryl choline head and a boronic acid-modified 5Fu/dodecanamine complex tail, are used to prepare pH/H2 O2 cascade-responsive LNPs (5Fu-LNPs). The 5Fu-LNPs exhibit enhanced DLC and stability in a neutral physiological environment due to the B-N coordination and enhanced hydrophobicity. In tumors, acidic pH triggers the dissociation of B-N coordination to release prodrugs, which further responds to low H2 O2 concentrations to release drugs, showcasing a potent pH/H2 O2 -cascade-responsive property. Importantly, 5Fu-LNPs demonstrate greater antitumor efficiency and lower toxicity compared to the commercial 5Fu. These results highlight 5Fu-LNPs as a safer and more effective alternative to chemotherapy. This work presents a unique LNP fabrication strategy that can overcome the limitations of conventional LNPs and broaden the range of intelligent nanomaterial preparation techniques.

Circadian disruption and cisplatin chronotherapy for mammary carcinoma

Solid tumors are commonly treated with cisplatin, which can cause off-target side effects in cancer patients. Chronotherapy is a potential strategy to reduce drug toxicity. To determine the effectiveness of timed-cisplatin treatment in mammals, we compared two conditions: clock disrupted jet-lag and control conditions. Under normal and disrupted clock conditions, triple-negative mammary carcinoma cells were injected subcutaneously into eight-week-old NOD.Cg-Prkdc^scid/J female mice. Tumor volumes and body weights were measured in these mice before and after treatment with cisplatin. We observed an increase in tumor volumes in mice housed under disrupted clock compared to the normal clock conditions. After treatment with cisplatin, we observed a reduced tumor growth rate in mice treated at ZT10 compared to ZT22 and untreated cohorts under normal clock conditions. However, these changes were not seen with the jet-lag protocol. We also observed greater body weight loss in mice treated with ZT10 compared to ZT22 or untreated mice in the jet-lag protocol. Our observations suggest that the effectiveness of cisplatin in mammary carcinoma treatment is time-dependent in the presence of the circadian clock.

Anticancer effect of sodium metavanadate on murine breast cancer both in vitro and in vivo

Sodium metavanadate (NaVO₃) exhibits important physiological effects including insulin-like, chemoprevention and anticancer activity. However, the effects of NaVO₃ on breast cancer and underlying mechanisms are still unclear. In this study, our results revealed that NaVO₃ was able to inhibit proliferation of murine breast cancer cells 4T1 with IC₅₀ value of 8.19 μM and 1.92 μM at 24 h and 48 h, respectively. The mechanisms underlying the inhibition activity were that NaVO₃ could increase reactive oxygen species (ROS) level in a concentration-dependent way, arrest cells at G2/M phase, diminish the mitochondrial membrane potential (MMP), finally promote the progress of apoptosis. Furthermore, NaVO₃ also exhibited a dose-dependent anticancer activity in breast cancer-bearing mice that led to the shrinkage of tumor volume (about 50%), lower microvessel density, less propagating cells and more apoptotic cells in vivo, as compared to the saline group. Therefore, NaVO₃ may act as a potential chemotherapeutic agent in breast cancer treatment.

Regulation of Fas in response to bortezomib and epirubicin in colorectal cancer cells

Bortezomib is a reversible proteasome inhibitor affects the ubiquitin-proteasome mechanism to kill cancer cells, and inhibition of the proteasome modulates the expression of multiple target genes at the transcriptional level. Epirubicin is known as an anthracycline agent that interferes with DNA and RNA synthesis, and it can be used with other chemotherapeutic drugs in the treatment of post-surgical breast cancer. Epirubicin may have an anti-tumor effect against broad-spectrum tumor cells. However, it is a non-specific chemotherapeutic agent that can cause high toxicity if not used in appropriate doses. Here, we hypothesize that a combination treatment of bortezomib and epirubicin will induce immunogenic cell death in colorectal cancer cells by increasing expression of death receptors such as Fas, which will make these cancer cells more susceptible to Fas/FasL mediated tumor cell killing. Our data demonstrate that a combination of bortezomib and epirubicin significantly increases the sensitivity of colorectal carcinoma cells, but not healthy non-malignant epithelial cells, to apoptosis. The combination treatment significantly upregulates the transcriptional activation of Fas in colorectal cancer cells but not in normal cells. Our results suggest that combining bortezomib and epirubicin may simultaneously enhance tumor immunogenicity and the induction of antitumor immunity.

Single Cell Mass Cytometry Revealed the Immunomodulatory Effect of Cisplatin Via Downregulation of Splenic CD44+, IL-17A+ MDSCs and Promotion of Circulating IFN-γ+ Myeloid Cells in the 4T1 Metastatic Breast Cancer Model

The treatment of metastatic breast cancer remained a challenge despite the recent breakthrough in the immunotherapy regimens. Here, we addressed the multidimensional immunophenotyping of 4T1 metastatic breast cancer by the state-of-the-art single cell mass cytometry (CyTOF). We determined the dose and time dependent cytotoxicity of cisplatin on 4T1 cells by the xCelligence real-time electronic sensing assay. Cisplatin treatment reduced tumor growth, number of lung metastasis, and the splenomegaly of 4T1 tumor bearing mice. We showed that cisplatin inhibited the tumor stroma formation, the polarization of carcinoma-associated fibroblasts by the diminished proteolytic activity of fibroblast activating protein. The CyTOF analysis revealed the emergence of CD11b+/Gr-1+/CD44+ or CD11b+/Gr-1+/IL-17A+ myeloid-derived suppressor cells (MDSCs) and the absence of B220+ or CD62L+ B-cells, the CD62L+/CD4+ and CD62L+/CD8+ T-cells in the spleen of advanced cancer. We could show the immunomodulatory effect of cisplatin via the suppression of splenic MDSCs and via the promotion of peripheral IFN-γ+ myeloid cells. Our data could support the use of low dose chemotherapy with cisplatin as an immunomodulatory agent for metastatic triple negative breast cancer.

Bortezomib sensitivity is tissue dependent and high expression of the 20S proteasome precludes good response in malignant pleural mesothelioma

Background

Bortezomib is an approved proteasome inhibitor for the treatment of certain lymphoma subtypes. Two clinical trials investigated bortezomib in patients with malignant pleural mesothelioma (MPM) and failed to improve outcome. We present a potential explanation for this event.

Methods

171 patients with MPM were analyzed for their mRNA expression of proteasomal subunits PSMA1, PSMA5, PSMB1, PSMB2, PSMB4 and PSMB5 via qPCR (n=84) or sequencing (n=87 TCGA/cBioPortal data set “Mesothelioma”). Outcome and subunit expression were correlated. Four mesothelial and one fibroblast cell line were treated with bortezomib and cisplatin. Cellular response was measured after 0, 6, 12, 24, 48 and 72 hrs. Enzyme activity of proteasomal subunits was assessed via functional enzyme activity assays.

Results

Patients with MPM presented with elevated expression of proteasomal subunits compared to benign controls (p<0.001). PSMB4 correlated with outcome (Cox propotiortional-hazards model (COXPH): p<0.0175, TCGA/cBioPortal data). In cell lines, apoptosis was the main event with a peak after 48 hr incubation for bortezomib or cisplatin. Only two cell lines with comparably low proteasome activity (PSMB2 and PSMB5) responded to 50 nM and 100 nM bortezomib better than to cisplatin (MRC-5, NCI-H2052). MSTO-211H responded to cisplatin only, whereas the other two cell lines were considered therapy resistant (Met-5A, NCI-H2452).

Interpretation

Two clinical trials testing bortezomib in MPM failed, although MPM presents with high proteasome expression, which predicts bortezomib sensitivity in several tumors. Bortezomib induced apoptosis in MPM cell lines with low proteasome activity only. Bortezomib is not suitable for the treatment of MPM, and biomarker-based stratification could have improved both clinical trials.

Trial registration

NCT00513877 and NCT00458913

Ixazomib in combination with carboplatin in pretreated women with advanced triple-negative breast cancer, a phase I/II trial of the AGMT (AGMT MBC-10 trial)

Background

Triple-negative breast cancer (TNBC) comprises a heterogeneous group of diseases which are generally associated with poor prognosis. Up to now, no targeted treatment beyond anti-VEGF therapy has been approved for TNBC and cytotoxic agents remain the mainstay of treatment. Ixazomib is a selective and reversible inhibitor of the proteasome, which has been mainly investigated in the treatment of multiple myeloma. In a preclinical study TNBC cells were treated with the first-generation proteasome inhibitor bortezomib in combination with cisplatin and synergistic efficacy was demonstrated. Clinical data are available for carboplatin plus bortezomib in metastatic ovarian and lung cancers showing remarkable antitumor activity and good tolerability (Mol Cancer 11:26 2012, J Thorac Oncol 4:87–92 2009, J Thorac Oncol 7:1032–1040, 2012). Based on this evidence, the phase I/II MBC-10 trial will evaluate the toxicity profile and efficacy of the second-generation proteasome inhibitor ixazomib in combination with carboplatin in patients with advanced TNBC.

Methods

Patients with metastatic TNBC pretreated with at least one prior line of chemotherapy for advanced disease with a confirmed disease progression and measurable disease according to RECIST criteria 1.1 are eligible for this study. Patients will receive ixazomib in combination with carboplatin on days 1, 8, and 15 in a 28-day cycle. The phase I part of this study utilizes an alternate dose escalation accelerated titration design. After establishing the maximum tolerated dose (MTD), the efficacy and safety of the combination will be further evaluated (phase II, including 41 evaluable patients). All patients will continue on study drugs until disease progression, unacceptable toxicity or discontinuation for any other reason. Primary endpoint of the phase II is overall response rate, secondary endpoints include progression-free survival, safety, and quality of life. This trial is open for patient enrollment since November 2016 in six Austrian cancer centers. Accrual is planned to be completed within 2 years.

Discussion

Based on preclinical and clinical findings an ixazomib and carboplatin combination is thought to be effective in metastatic TNBC patients. The MBC-10 trial is accompanied by a broad biomarker program investigating predictive biomarkers for treatment response and potential resistance mechanisms to the investigational drug combination.

Trial registration

EudraCT Number: 2016–001421-13 received on March 31, 2016, ClinicalTrials.gov Identifier: NCT02993094 first posted on December 15, 2016. This trial was registered prospectively.

Chemoresistance to Cancer Treatment: Benzo-α-Pyrene as Friend or Foe?

Background: Environmental pollution such as exposure to pro-carcinogens including benzo-α-pyrene is becoming a major problem globally. Moreover, the effects of benzo-α-pyrene (BaP) on drug pharmacokinetics, pharmacodynamics, and drug resistance warrant further investigation, especially in cancer outpatient chemotherapy where exposure to environmental pollutants might occur. Method: We report here on the effects of benzo-α-pyrene on esophageal cancer cells in vitro, alone, or in combination with chemotherapeutic drugs cisplatin, 5-flurouracil, or paclitaxel. As the study endpoints, we employed expression of proteins involved in cell proliferation, drug metabolism, apoptosis, cell cycle analysis, colony formation, migration, and signaling cascades in the WHCO1 esophageal cancer cell line after 24 h of treatment. Results: Benzo-α-pyrene had no significant effect on WHCO1 cancer cell proliferation but reversed the effect of chemotherapeutic drugs by reducing drug-induced cell death and apoptosis by 30−40% compared to drug-treated cells. The three drugs significantly reduced WHCO1 cell migration by 40−50% compared to control and BaP-treated cells. Combined exposure to drugs was associated with significantly increased apoptosis and reduced colony formation. Evaluation of survival signaling cascades showed that although the MEK-ERK and Akt pathways were activated in the presence of drugs, BaP was a stronger activator of the MEK-ERK and Akt pathways than the drugs. Conclusion: The present study suggest that BaP can reverse the effects of drugs on cancer cells via the activation of survival signaling pathways and upregulation of anti-apoptotic proteins such as Bcl-2 and Bcl-xL. Our data show that BaP contribute to the development of chemoresistant cancer cells.

BaxΔ2 sensitizes colorectal cancer cells to proteasome inhibitor-induced cell death

Proteasome inhibitors, such as bortezomib and carfilzomib, are FDA approved for the treatment of hemopoietic cancers, but recent studies have shown their great potential for treatment of solid tumors. BaxΔ2, a unique proapoptotic Bax isoform, promotes non-mitochondrial cell death and sensitizes cancer cells to chemotherapy. However, endogenous BaxΔ2 proteins are unstable and susceptible to proteasomal degradation. Here, we screened a panel of proteasome inhibitors in colorectal cancer cells with different Bax statuses. We found that all proteasome inhibitors tested were able to block BaxΔ2 degradation without affecting the level of Baxα or Bcl-2 proteins. Among the inhibitors tested, only bortezomib and carfilzomib were able to induce differential cell death corresponding to the distinct Bax statuses. BaxΔ2-positive cells had a significantly higher level of cell death at low nanomolar concentrations than Baxα-positive or Bax-negative cells. Furthermore, bortezomib-induced cell death in BaxΔ2-positive cells was predominantly dependent on the caspase 8/3 pathway, consistent with our previous studies. These results imply that BaxΔ2 can selectively sensitize cancer cells to proteasome inhibitors, enhancing their potential to treat colon cancer and other solid tumors.

Synergistic effects of combining proteasome inhibitors with chemotherapeutic drugs in lung cancer cells

Background

The prognosis for patients with disseminated lung cancer is poor and current treatments have limited survival benefit as resistance often occurs, and is often associated with significant toxicity. A possible strategy to improve treatment and evade chemoresistance may be to find new combinations of drugs. The aim of this study was to analyze the potential of combining proteasome inhibitors (PIs) with chemotherapeutic drugs used in the routine treatment for lung cancer patients.

Results

The median-effect method was applied to the Fluorometric Microculture Cytotoxicity Assay (FMCA) to evaluate effects of combining two different PIs (bortezomib and b-AP15) with clinically used chemotherapeutic drugs representing different mechanisms of action (cisplatin, gefitinib, gemcitabine and vinorelbine) in two lung cancer cell lines (one sensitive and one resistant). Proteasome inhibition in combination with cisplatin, gemcitabine or vinorelbine had synergistic effects in at least one of the tested cell lines. Furthermore, the effect of gefitinib appeared strongly potentiated by the PI in the least resistant lung cancer cell line, although the level of synergy could not be determined with the median-effect method.

Conclusions

Combining PIs with cisplatin, gefitinib, gemcitabine or vinorelbine show potential as new combination chemotherapy for the treatment of lung cancer.

Electronic supplementary material

The online version of this article (10.1186/s13104-017-2842-z) contains supplementary material, which is available to authorized users.

Sageone, a diterpene from Rosmarinus officinalis, synergizes with cisplatin cytotoxicity in SNU-1 human gastric cancer cells

BACKGROUND AND PURPOSE

Chemotherapy resistance is a major obstacle for the effective treatment of cancers. Although several studies have described the anticancer properties of rosemary extract and its components, the detailed mechanisms of action are poorly understood.

METHODS

Activity-guided fractionation and repeated chromatographic separation of the n-hexane fraction of the aqueous methanol extract over silica gel, RP C18, and Sephadex LH-20 led to the isolation of three compounds. The structures of the compounds were determined using ¹H, ¹³C, and two-dimensional nuclear magnetic resonance spectroscopy, mass spectroscopy, and infrared spectroscopy. The 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyl tetrazolium bromide assay was used to evaluate the cytotoxicity of these compounds. Cell cycle, apoptotic cell populations, and mitochondrial membrane potential were analyzed by flow cytometry. Western blot analysis was conducted to detect apoptosis-related proteins.

RESULTS

An abietane diterpenoid, sageone (1), an icetexane diterpenoid, (-)-barbatusol (2), and a monoterpene, (+)-verbenone (3), were identified. Of these compounds, sageone (1) showed cytotoxicity against SNU-1 cells with an IC₅₀ of 9.45 ± 1.33 µM. Sageone reduced the expression of Akt dramatically, as opposed to cisplatin, which increased phosphorylated Akt. Sageone combined with a subtoxic dose of cisplatin had synergistic effects on apoptosis induction in SNU-1 cells, as confirmed by calculating the combination index. Co-treatment was significantly more effective than monotherapy at reducing cell viability and inducing apoptosis, as determined by analyzing DNA fragmentation. The combined treatment of sageone and cisplatin markedly reduced Akt expression and phosphorylation, accompanied by increases in cleaved caspase-3, -9 and PARP.

CONCLUSION

This is the first time compounds 1 and 2 have been isolated from R. officinalis. Sageone induced apoptosis in SNU-1 human gastric cancer cells and notably enhanced the cytotoxicity of cisplatin in SNU-1 cells, which are known to be resistant to cisplatin. These findings suggest that sageone represents a promising anticancer agent against gastric cancer that warrants further study.

Effect of cisplatin on proteasome activity

Cisplatin is a widely used chemotherapy drug which exerts cytotoxic activity by affecting both nuclear and cytosolic pathways. Herewith, we report, for the first time, that cisplatin inhibits proteasome activity in vitro. Cisplatin induces a dose dependent inhibition of the three enzymatic activities of proteasome (i.e., the chymotrypsin-like activity, the trypsin-like activity and the caspase-like activity). Moreover, cisplatin administration to neuroblastoma cells brings about a fast loss of proteasome particle activity, which is followed by a de novo synthesis of proteasome. Lastly, we report that the simultaneous administration of lactacystin and cisplatin enhances the cytotoxicity of cisplatin alone. The overall bulk of data opens to an intriguing scenario, concerning the biological effects of cisplatin in the control of cellular life, which goes beyond the well established genotoxic effect.

Synergistic effects of cisplatin and proteasome inhibitor bortezomib on human bladder cancer cells

The proteasome inhibitor bortezomib is a promising novel agent in bladder cancer therapy; however, inducible cytoprotective mechanisms may limit its potential efficacy. To date, the cellular and molecular effects of proteasome inhibitors on bladder cancer cells have been poorly characterized. Despite the consistent rate of initial responses, cisplatin treatment typically results in the development of chemoresistance, leading to therapeutic failure. Therefore, the present study aimed to characterize the molecular mechanisms underlying the anti-proliferative effects of cisplatin and bortezomib combination therapy on the human T24 bladder cancer cell line, by analyzing the protein expression levels of apoptotic genes. Cytotoxic effects were measured using a water-soluble tetrazolium salt-1 assay, and the apoptosis-associated molecules were examined using western blot analysis and ELISA. It was observed that combined administration of cisplatin and bortezomib induced upregulation of caspase-3, -8 and -9, B-cell lymphoma-2 (Bcl-2)-like 11 and Bcl-2-interacting killer, but downregulated Bcl-2 and Bcl-extra large protein expression levels in T24 cells in a dose-dependent manner. Furthermore, enhanced protein expression of caspase-8 and -9, in line with the significantly increased caspase-3 activation, was detected when the cells were treated with a combination of cisplatin and bortezomib, compared with that of either agent alone. Bortezomib appeared to synergize with cisplatin to promote apoptosis via the extrinsic and intrinsic apoptotic pathways. Taken together, the results of the current study provide the preclinical framework for additional evaluation of the effects of combining bortezomib with other agents to induce apoptosis in bladder cancer cells.