Reduced Folate Carrier Independent Internalization of PEGylated Pemetrexed: A Potential Nanomedicinal Approach for Breast Cancer Therapy

Tailoring micellar nanocarriers for pemetrexed in breast cancer: design, fabrication and in vitro evaluation

Aim: To investigate the pemetrexed encapsulated polymeric mixed micelles (PMMs) against breast cancer treatment. Methods: We meticulously optimized the formulation and conducted extensive characterizations, including photon correlation spectroscopy for micellization, advanced analytical techniques and in vitro cell line assessments. Results: The PMM exhibited favorable characteristics, with a spherical morphology, hydrodynamic particle size of 19.58 ± 0.89 nm, polydispersity index of 0.245 ± 0.1, and a surface charge of -9.70 ± 0.61 mV. Encapsulation efficiency and drug payload reached 96.16 ± 0.37% and 4.5 ± 0.32%, respectively. Cytotoxicity analysis indicated superior efficacy of the PMM over the drug solution. Conclusion: The PMM formulation exhibited controlled release of the drug, and demonstrated enhanced cytotoxicity against breast cancer cells, highlighting its therapeutic promise.

Dual-drug codelivery nanosystems: An emerging approach for overcoming cancer multidrug resistance

Multidrug resistance (MDR) promotes tumor recurrence and metastasis and heavily reduces anticancer efficiency, which has become a primary reason for the failure of clinical chemotherapy. The mechanisms of MDR are so complex that conventional chemotherapy usually fails to achieve an ideal therapeutic effect and even accelerates the occurrence of MDR. In contrast, the combination of chemotherapy with dual-drug has significant advantages in tumor therapy. A novel dual-drug codelivery nanosystem, which combines dual-drug administration with nanotechnology, can overcome the application limitation of free drugs. Both the characteristics of nanoparticles and the synergistic effect of dual drugs contribute to circumventing various drug-resistant mechanisms in tumor cells. Therefore, developing dual-drug codelivery nanosystems with different multidrug-resistant mechanisms has an important reference value for reversing MDR and enhancing the clinical antitumor effect. In this review, the advantages, principles, and common codelivery nanocarriers in the application of dual-drug codelivery systems are summarized. The molecular mechanisms of MDR and the dual-drug codelivery nanosystems designed based on different mechanisms are mainly introduced. Meanwhile, the development prospects and challenges of codelivery nanosystems are also discussed, which provide guidelines to exploit optimized combined chemotherapy strategies in the future.

Human drug efflux transporter ABCC5 confers acquired resistance to pemetrexed in breast cancer

Aim

Pemetrexed, a new generation antifolate drug, has been approved for the treatment of locally advanced or metastatic breast cancer. However, factors affecting its efficacy and resistance have not been fully elucidated yet. ATP-binding cassette (ABC) transporters are predictors of prognosis as well as of adverse effects of several xenobiotics. This study was designed to explore whether ABC transporters affect pemetrexed resistance and can contribute to the optimization of breast cancer treatment regimen.

Methods

First, we measured the expression levels of ABC transporter family members in cell lines. Subsequently, we assessed the potential role of ABC transporters in conferring resistance to pemetrexed in primary breast cancer cells isolated from 34 breast cancer patients and the role of ABCC5 in mediating pemetrexed transport and apoptotic pathways in MCF-7 cells. Finally, the influence of ABCC5 expression on the therapeutic effect of pemetrexed was evaluated in an in vivo xenograft mouse model of breast cancer.

Results

The expression levels of ABCC2, ABCC4, ABCC5, and ABCG2 significantly increased in the pan-resistant cell line, and the ABCC5 level in the MCF-7-ADR cell line was 5.21 times higher than that in the control group. ABCC5 expression was inversely correlated with pemetrexed sensitivity (IC₅₀, r = 0.741; p < 0.001) in breast cancer cells derived from 34 patients. Furthermore, we found that the expression level of ABCC5 influenced the efflux and cytotoxicity of pemetrexed in MCF-7 cells, with IC₅₀ values of 0.06 and 0.20 μg/mL in ABCC5 knockout and over-expression cells, respectively. In the in vivo study, we observed that ABCC5 affected the sensitivity of pemetrexed in breast tumor-bearing mice, and the tumor volume was much larger in the ABCC5-overexpressing group than in the control group when compared with their own initial volumes (2.7-fold vs. 1.3-fold).

Conclusions

Our results indicated that ABCC5 expression was associated with pemetrexed resistance in vitro and in vivo, and it may serve as a target or biomarker for the optimization of pemetrexed regimen in breast cancer treatment.

Supplementary Information

The online version contains supplementary material available at 10.1186/s12935-021-01842-x.

Diselenide-Pemetrexed Assemblies for Combined Cancer Immuno-, Radio-, and Chemotherapies

Immunotherapy has emerged as a promising new approach for cancer treatment. However, clinically available drugs have been limited until recently, and the antitumor efficacy of most cancer immunotherapies still needs to be improved. Herein, we develop diselenide-pemetrexed assemblies that combine natural killer (NK) cell-based cancer immunotherapy with radiotherapy and chemotherapy in a single system. The assemblies are prepared by co-assembly between pemetrexed and cytosine-containing diselenide through hydrogen bonds. Under γ-radiation, the hydrogen bonds are cleaved, resulting in the release of pemetrexed. At the same time, diselenide can be oxidized to seleninic acid, which suppresses the expression of human leukocyte antigen E (HLA-E) in cancer cells, thus activating the immune response of NK cells. In this way, cancer immunotherapy is combined with radiotherapy and chemotherapy, providing a new strategy for cancer treatment.

The stilbene derivatives, nucleosides, and nucleosides modified by stilbene derivatives

In this short review, including 187 references, the issues of biological activity of stilbene derivatives and nucleosides and the biological and medicinal potential of fusion of these two classes are discussed. The stilbenes, especially the stilbenoids, and nucleosides are both biologically active. Hybrids formed from binding of these compounds have not yet been broadly studied. However, those that have been investigated exhibit desirable medicinal properties. The review is divided in such parts: I. Derivative of stilbene (biomedical investigations, biological activities in cells, enzymes and hazard), parts II. naturally occurred nucleoside and its derivatives: uridine, thymidine and 5-methyluridine, cytidine, adenosine, guanosine and part III. hybrid molecules- drugs and hybrid molecules- nucleoside - stilbene and its derivative.

Gemcitabine-loaded DSPE-PEG-PheoA liposome as a photomediated immune modulator for cholangiocarcinoma treatment

To improve the therapeutic efficacy of gemcitabine (GEM) as an anticancer drug for bile duct cancer, GEM-loaded liposomes (GDPPL) prepared from a photosensitizer-conjugated lipid were investigated regarding the drug release kinetics, photodynamic therapy (PDT) efficacy, and immunomodulatory effects. The release rate of GEM from the liposomes was improved approximately 2-fold compared to non-laser irradiation groups due to lipid disruption by reactive oxygen species produced from the activated photosensitizer upon laser irradiation. Through in vitro testing using a human liver bile duct carcinoma cell line (HuCCT-1), the cytotoxicity of GDPPL with laser irradiation was enhanced due to rapid GEM release and PDT effects. Furthermore, the results of in vivo tests using a HuCCT-1 tumor-bearing xenograft mice model showed that GDPPL exhibited approximately 3-fold antitumoral effects compared to control group. Additionally, immunohistochemical analysis demonstrated the recruitment of immunostimulatory cells in tumor tissues. IHC tests in BALB/c mice indicated that GDPPL under laser irradiation dramatically enhanced the quantities of various immune cells for effective antitumoral immunotherapy against biliary tract cancer. From these results, it was concluded that GDPPL with rapid drug release behavior, PDT efficacy, and immunomodulatory effects upon laser irradiation has potential as an antitumor therapeutic agent for biliary tract cancer.

Thymidylate synthase predicts poor response to pemetrexed chemotherapy in patients with advanced breast cancer

Pemetrexed is a candidate chemotherapy regimen for anthracycline- and taxane-pretreated advanced breast cancer. However, to the best of our knowledge, no efficient treatment efficacy biomarkers have been identified. In the present study, the potential correlation between thymidylate synthase (TYMS) expression and clinical response to pemetrexed was examined in advanced breast cancer. A retrospective collection was performed by using 77 advanced breast cancer subjects, who received at least three cycles of pemetrexed treatment in the Second Hospital of Shandong University hospital. TYMS expression was detected using immunohistopathological staining. The correlations between TYMS and therapeutic efficacies of different chemotherapy treatment were analyzed. The objective response rate (ORR) and disease control was 31.17 and 64.94%, respectively. Immunohistochemical staining demonstrated that TYMS expression was observed in the cytoplasm and nuclei of breast cancer cells. High TYMS expression was observed in 32 specimens. Elevated TYMS expression was correlated with higher histological grade and lymph node metastasis (P<0.05). Furthermore, significantly higher TYMS expression was observed in treatment-resistant patients than response ones (P<0.05). Patients with low expression level of TYMS exhibit significantly higher ORR. Cox regression analysis indicated that elevated TYMS expression was a detrimental factor for pemetrexed treatment for advanced breast cancer patients. The present results suggested that TYMS expression levels predicts therapeutic sensitivity of pemetrexed chemotherapy in advanced breast cancer, indicating that it may be a useful biomarker to choose chemotherapy regimens.

Lung cancer specific and reduction-responsive chimaeric polymersomes for highly efficient loading of pemetrexed and targeted suppression of lung tumor in vivo

Lung cancer is one of the worldwide leading and fast-growing malignancies. Pemetrexed disodium (PEM, Alimta®), a small hydrophilic drug, is currently used for treating lung cancer patients. However, PEM suffers from issues like fast elimination, low bioavailability, poor tumor cell selectivity and penetration. Here, we report on lung cancer specific CSNIDARAC (CC₉) peptide-functionalized reduction-responsive chimaeric polymersomes (CC₉-RCPs) for efficient encapsulation and targeted delivery of PEM to H460 human lung cancer cells in vitro and in vivo. PEM-loaded CC₉-RCPs (PEM-CC₉-RCPs) was obtained from co-self-assembly of poly(ethylene glycol)-b-poly(trimethylene carbonate-co-dithiolane trimethylene carbonate)-b-polyethylenimine (PEG-P(TMC-DTC)-PEI) and CC₉-functionalized PEG-P(TMC-DTC) in the presence of PEM followed by self-crosslinking. PEM-CC₉-RCPs displayed an optimal CC₉ density of 9.0% in targeting H460 cells, a high PEM loading content of 14.2 wt%, a small hydrodynamic size of ca. 60 nm and glutathione-triggered PEM release. MTT assays showed that PEM-CC₉-RCPs was 2.6- and 10- fold more potent to H460 cells than the non-targeting PEM-RCPs and free PEM controls, respectively. Interestingly, PEM-CC₉-RCPs exhibited 22-fold longer circulation time and 9.1-fold higher accumulation in H460 tumor than clinical formulation Alimta®. Moreover, CC₉-RCPs showed obviously better tumor penetration than RCPs. Remarkably, PEM-CC₉-RCPs at 12.5 mg PEM equiv./kg effectively suppressed growth of H460 xenografts and significantly prolonged mouse survival time as compared to PEM-RCPs and Alimta® controls. These lung cancer specific and reduction-responsive chimaeric polymersomes provide a unique pemetrexed nanoformulation for targeted lung cancer therapy.

STATEMENT OF SIGNIFICANCE

Multitargeted antifolate agent pemetrexed (PEM, Alimta®) is currently used for treating lung cancer patients and has low side-effects. However, PEM suffers from issues like fast elimination, low bioavailability, poor tumor cell selectivity and penetration. Scarce work on targeted delivery of PEM has been reported, partly because most conventional nanocarriers show a low and instable loading for hydrophilic, negatively charged drugs like PEM. Herewith, we report on lung cancer specific CSNIDARAC (CC₉) peptide-functionalized reduction-responsive chimaeric polymersomes (CC₉-RCPs) which showed efficient PEM encapsulation (14.2 wt%, 60 nm) and targeted delivery of PEM to H460 human lung cancer cells, leading to effective suppression of H460 tumor xenografts and significantly prolonged survival rates of mice than Alimta®. To the best of our knowledge, this represents a first report on targeted nanosystems that are capable of efficient loading and targeted delivery of PEM to lung tumors.

Therapeutic applications of betulinic acid nanoformulations

Betulinic acid (BA), a naturally occurring plant-derived pentacyclic triterpenoid, has gained attention in recent years owing to its broad-spectrum biological and medicinal properties. Despite the pharmacological activity of BA, it has been associated with some drawbacks, such as poor aqueous solubility and short half-life in vivo, which limit therapeutic application. To solve these problems, much work in recent years has focused on enhancing BA's aqueous solubility, half-life, and efficacy by using nanoscale drug delivery systems. Several different kinds of nanoscale delivery systems-including polymeric nanoparticles, magnetic nanoparticles, liposomes, polymeric conjugates, nanoemulsions, cyclodextrin complexes, and carbon nanotubes-have been developed for the delivery of BA. Here, we focus on the recent developments of novel nanoformulations used to deliver BA in order to improve its efficacy.

Novel Hyaluronic Acid Conjugates for Dual Nuclear Imaging and Therapy in CD44-Expressing Tumors in Mice In Vivo

Hyaluronic acid, a natural CD44 receptor ligand, has attracted attention in the past years as a macromolecular delivery of anticancer agents to cancer. At the same time, the clinical applications of Gemcitabine (Gem) have been hindered by its short biological half-life, high dose and development of drug resistance. This work reports the synthesis of a hyaluronic acid (HA) conjugate for nuclear imaging, and in vivo Gem delivery to CD44-expressing solid tumors in mice. HA was individually conjugated, via amide coupling, to Gem (HA-Gem), 4'-(aminomethyl)fluorescein hydrochloride (HA-4'-AMF) or tris(hydroxypyridinone) amine (HA-THP) for cancer therapy, in vitro tracking or single photon emission computed tomography/computed tomography (SPECT/CT) imaging, respectively. Gem conjugation to HA was directly confirmed by nuclear magnetic resonance (¹H NMR), gel permeation chromatography (GPC) and UV-visible spectrometry, or indirectly by a nucleoside transporter inhibition study. Gem conjugation to HA improved its plasma stability, reduced blood hemolysis and resulted in delayed cytotoxicity in vitro. Uptake inhibition studies in colon CT26 and pancreatic PANC-1 cells, by flow cytometry, revealed that uptake of fluorescent HA conjugate is CD44 receptor and macropinocytosis-dependent. Gamma scintigraphy and SPECT/CT imaging confirmed the relatively prolonged blood circulation profile and uptake in CT26 (1.5 % ID/gm) and PANC-1 (1 % ID/gm) subcutaneous tumors at 24 h after intravenous injection in mice. Four injections of HA-Gem at ~15 mg/kg, over a 28-day period, resulted in significant delay in CT26 tumor growth and prolonged mice survival compared to the free drug. This study reports for the first time dual nuclear imaging and drug delivery (Gem) of HA conjugates to solid tumors in mice. The conjugates show great potential in targeting, imaging and killing of CD44-over expressing cells in vivo. This work is likely to open new avenues for the application of HA-based macromolecules in the field of image-guided delivery in oncology.

Synthesis, characterization and augmented anticancer potential of PEG-betulinic acid conjugate

Betulinic acid (BA), a pentacyclic lupine-type triterpene, is reported to inhibit cell growth in a variety of cancers. However, its efficacy is limited by its poor aqueous solubility and relatively short half-life. In this study, BA-monomethoxy polyethylene glycol (mPEG) conjugate was synthesized by covalent coupling the C-28 carboxylic acid position of BA with amine groups of mPEG, in order to improve its solubility and anticancer efficacy. mPEG-BA conjugate was characterized using various analytical techniques including NMR, FT-IR and MALDI-MS. The mPEG-BA conjugate was cytotoxic, demonstrated internalization and induced cell apoptosis in Hep3B and Huh7 hepatic cancer cells. The western-blot analysis revealed, marked decrease in Bcl-2/Bax ratio, and increase in cleaved-PARP and cleaved-caspase-3 expressions. In vivo studies in Ehrlich ascites tumor (EAT) model following intravenous administration demonstrated significant reduction in tumor volume in case of PEGylated BA as compare to native BA. Furthermore, PEGylated BA treated EAT mice showed no biochemical and histological toxicities. These findings demonstrate the potential of PEGylated BA in cancer therapy, with improved water solubility and efficacy.

Synergistic activity of combination therapy with PEGylated pemetrexed and gemcitabine for an effective cancer treatment

Combination therapy in cancer is now opted as a potential therapeutic strategy for cancer treatment. However, effective delivery of drugs in combination at the tumor site is marred by low bioavailability and systemic toxicity of individual drugs. Polymer therapeutics is indeed an upcoming approach for the combinational drug delivery in favor of better cancer management. Hence, the objective of our investigation was to develop a dual drug PEGylated system that carries two chemotherapeutic drugs simultaneously for effective treatment of cancer. In this regard, we have synthesized Pem-PEG-Gem, wherein pemetrexed (Pem) and gemcitabine (Gem) are conjugated to a heterobifunctional polyethylene glycol (PEG) polymer for the effective treatment of Non-Small Cell Lung Cancer (NSCLC). Our results demonstrate enhanced bioavailability of the individual drugs in Pem-PEG-Gem in comparison with the drugs in their native form. The developed Pem-PEG-Gem showed enhanced cell death with respect to their native counterparts when treated singly or in combination against NSCLC cells. This might be attributed to better cellular internalization through the process of macropinocytosis and synergistic cytotoxic action of Pem-PEG-Gem in NSCLC cells. Hence, we propose the above dual drug based polymer therapeutic approach suitable for better clinical application in the treatment of NSCLC.