Evaluation of the effect of SMA-pirarubicin micelles on colorectal cancer liver metastases and of hyperbaric oxygen in CBA mice

Lauric acid-based thermosensitive delivery system for the treatment of head and neck squamous cell carcinoma

Traditional treatments for head and neck squamous cell carcinoma (HNSCC) such as surgery, radiation therapy, and chemotherapy, often have severe side effects. Local delivery of chemotherapeutic agents can be a promising approach to minimise systemic toxicity and improve efficacy. Lauric acid (LA), was explored as a novel injectable thermosensitive drug reservoir as a depot for sustained release of anticancer drugs to treat HNSCC. LA was characterised in terms of melting temperature and gelation time. The efficacy of LA-based drug formulations was tested in vitro in a HNSCC cell line and in vivo in a mouse model of HNSCC. LA was modified to have a melting point of 38.5 °C and a gelation time of 40 s at 37.5 °C, rendering it suitable for injection at body temperature. LA- based doxorubicin (DOXO) formulation showed slow release with a maximum of 18% release after 3 days. The in vitro study showed that LA enhanced the cytotoxic effect of DOXO. LA combined with DOXO prevented tumour progression and LA alone significantly reduced the original tumour volume compared to the untreated control group. These findings confirmed that LA can function as practical carrier for the local delivery of chemotherapeutics and provides a safe and simple strategy for the delivery of hydrophobic anticancer drugs and warrant further testing in clinical trials.

Carbonic Anhydrase-IX Guided Albumin Nanoparticles for Hypoxia-mediated Triple-Negative Breast Cancer Cell Killing and Imaging of Patient-derived Tumor

Triple-Negative Breast Cancer (TNBC) is considered as the most onerous cancer subtype, lacking the estrogen, progesterone, and HER2 receptors. Evaluating new markers is an unmet need for improving targeted therapy against TNBC. TNBC depends on several factors, including hypoxia development, which contributes to therapy resistance, immune evasion, and tumor stroma formation. In this study, we studied the curcumin analogue (3,4-Difluorobenzylidene Curcumin; CDF) encapsulated bovine serum albumin (BSA) nanoparticle for tumor targeting. For tumor targeting, we conjugated Acetazolamide (ATZ) with CDF and encapsulated it in the BSA to form a nanoparticle (namely BSA-CDF-ATZ). The in vitro cytotoxicity study suggested that BSA-CDF-ATZ is more efficient when compared to free CDF. The BSA-CDF-ATZ nanoparticles showed significantly higher cell killing in hypoxic conditions compared to normoxic conditions, suggesting better internalization of the nanoparticles into cancer cells under hypoxia. Fluorescent-dye labeled BSA-CDF-ATZ revealed higher cell uptake of the nanoparticle compared to free dye indicative of better delivery, substantiated by a high rate of apoptosis-mediated cell death compared to free CDF. The significantly higher tumor accumulation and low liver and spleen uptake in TNBC patient-derived tumor xenograft models confirm the significant potential of BSA-CDF-ATZ for targeted TNBC imaging and therapy.

Multifunctional nanoparticles for cancer immunotherapy: A groundbreaking approach for reprogramming malfunctioned tumor environment

Several cancer immunotherapy approaches have been recently introduced into the clinics and they have shown remarkable therapeutic potentials. The groundbreaking cancer immunotherapeutic agents function as a stimulant or modulator of the body immune system to fight against or kill cancers. Although targeted immunotherapies such as immune check point inhibitors (CTLA-4 or PD-1/PD-L1), DNA vaccination and CAR-T therapy are revolutionizing cancer treatment, the delivery efficacy can be further improved while their off-target toxicity can be mitigated through nanotechnology approaches. Recent research has demonstrated that nanotechnology has multifaceted role for (i) reeducating tumor associated macrophages (TAM) to function as tumor suppressor agent, (ii) serving as an efficient alternative for Chimeric Antigen Receptor (CAR)-T cell generation and transduction, and (iii) selective knockdown of Kras oncogene addiction by nano-Crisper-Cas9 delivery system. The function of host immune stimulatory signals and tumor immunotherapies can further be improved by repurposing of nanomedicine platform. This review summarizes the role of multifunctional polymeric, lipid, metallic and cell based nanoparticles for improving current immunotherapy.

Copper-Free 'Click' Chemistry-Based Synthesis and Characterization of Carbonic Anhydrase-IX Anchored Albumin-Paclitaxel Nanoparticles for Targeting Tumor Hypoxia

Triple negative breast cancer (TNBC) is a difficult to treat disease due to the absence of the three unique receptors estrogen, progesterone and herceptin-2 (HER-2). To improve the current therapy and overcome the resistance of TNBC, there is unmet need to develop an effective targeted therapy. In this regard, one of the logical and economical approaches is to develop a tumor hypoxia-targeting drug formulation platform for selective delivery of payload to the drug-resistant and invasive cell population of TNBC tumors. Toward this, we developed a Carbonic Anhydrase IX (CA IX) receptor targeting human serum albumin (HSA) carriers to deliver the potent anticancer drug, Paclitaxel (PTX). We used Acetazolamide (ATZ), a small molecule ligand of CA IX to selectively deliver HSA-PTX in TNBC cells. A novel method of synthesis involving copper free ‘click’ chemistry (Dibenzocyclooctyl, DBCO) moiety with an azide-labeled reaction partner, known as Strain-Promoted Alkyne Azide Cycloaddition (SPAAC) along with a desolvation method for PTX loading were used in the present study to arrive at the CA IX selective nano-carriers, HSA-PTX-ATZ. The anticancer effect of HSA-PTX-ATZ is higher compared to HSA, PTX and non-targeted HSA-PTX in MDA-MB-231 and MDA-MB-468 cells. The cell killing effect is associated with induction of early and late phases of apoptosis. Overall, our proof-of-concept study shows a promising avenue for hypoxia-targeted drug delivery that can be adapted to several types of cancers.

RIPK1 Inhibition Enhances Pirarubicin Cytotoxic Efficacy through AKT-P21-dependent Pathway in Hepatocellular Carcinoma

Pirarubicin (THP) is a new generation cell cycle nonspecific anthracycline anticancer drug. Pirarubicin and pirarubicin-based combination therapies have been demonstrated to be effective against HCC in TACE. However, the drug resistance limits its therapeutic efficacy. Receptor-interacting protein kinase 1 (RIPK1) displays a critical role in cell death. Here we found that RIPK1 and p21 may participate in the resistance to pirarubicin. In this study, we first found that inhibition of RIPK1 significantly decreased pAKT and increased p21, accompanied by G0/G1 phase cell cycle arrest and cell anti-proliferation in pirarubicin-treated hepatocellular carcinoma cells. Moreover, phosphorylation of AKT reversed the anti-proliferative effect of RIPK1 inhibitor in HCC, which proved that RIPK1-AKT-P21-dependent pathway played a key role in pirarubicin resistance. Using a mouse xenograft model, we further found that RIPK1 inhibitor combined with pirarubicin exerted synergistic anti-tumor effect in vivo. Upon exposure to pirarubicin treatment, xenografts under RIPK1 inhibition maintained higher levels of p21 than control xenografts. In conclusion, the results in our study demonstrated that RIPK1 inhibition enhances the anti-tumor effect of pirarubicin by overcoming drug resistance. RIPK1 inhibitor might be used as an adjuvant to potentiate the inhibitory effect of pirarubicin against primary hepatocellular carcinoma.

A Retrospective 30 Years After Discovery of the Enhanced Permeability and Retention Effect of Solid Tumors: Next-Generation Chemotherapeutics and Photodynamic Therapy--Problems, Solutions, and Prospects

Solid tumor has unique vascular architecture, excessive production of vascular mediators, and extravasation of macromolecules from blood vessels into the tumor tissue interstitium. These features comprise the phenomenon named the EPR effect of solid tumors, described in 1986. Our investigations on the EPR revealed that many mediators, such as bradykinin, NO, and prostaglandins, are involved in the EPR effect, which is now believed to be the most important element for cancer-selective drug delivery. However, tumors in vivo manifest great diversity, and some demonstrate a poor EPR effect, for example, because of impaired vascular flow involving thrombosis, with poor drug delivery and therapeutic failure. Another important element of this effect is that it operates in metastatic cancers. Because few drugs are currently effective against metastases, the EPR effect offers a great advantage in nanomedicine therapy. The EPR effect can also be augmented two to three times via nitroglycerin, ACE inhibitors, and angiotensin II-induced hypertension. The delivery of nanomedicines to tumors can thereby be enhanced. In traditional PDT, most PSs had low MW and little tumor-selective accumulation. Our hydroxypropylmetacrylamide-polymer-conjugated-PS, zinc protoporphyrin (apparent MW >50 kDa) showed tumor-selective accumulation, as revealed by fluorescent imaging of autochthonous cancers. After one i.v. injection of polymeric PS followed by two or three xenon light irradiation/treatments, most tumors regressed. Thus, nanoprobes with the EPR effect seem to have remarkable effects. Enhancing the EPR effect by using vascular modulators will aid innovations in PDT for greater tumor-targeted drug delivery.

Hyperbaric oxygen as an adjunctive therapy in treatment of malignancies, including brain tumours

Hyperbaric oxygen (HBO) therapy is widely used as an adjunctive treatment for various pathological states, predominantly related to hypoxic and/or ischaemic conditions. It also holds promise as an approach to overcoming the problem of oxygen deficiency in the poorly oxygenated regions of the neoplastic tissue. Occurrence of local hypoxia within the central areas of solid tumours is one of the major issues contributing to ineffective medical treatment. However, in anti-cancer therapy, HBO alone gives a limited curative effect and is typically not applied by itself. More often, HBO is used as an adjuvant treatment along with other therapeutic modalities, such as radio- and chemotherapy. This review outlines the existing data regarding the medical use of HBO in cancer treatment, with a particular focus on the use of HBO in the treatment of brain tumours. We conclude that the administration of HBO can provide many clinical benefits in the treatment of tumours, including management of highly malignant gliomas. Applied immediately before irradiation, it is safe and well tolerated by patients, causing rare and limited side effects. The results obtained with a combination of HBO/radiotherapy protocol proved to be especially favourable compared to radiation treatment alone. HBO can also increase the cytostatic effect of certain drugs, which may render standard chemotherapy more effective. The currently available data support the legitimacy of conducting further research on the use of HBO in the treatment of malignancies.

Hyaluronic Acid Engineered Nanomicelles Loaded with 3,4-Difluorobenzylidene Curcumin for Targeted Killing of CD44+ Stem-Like Pancreatic Cancer Cells

Cancer stem-like cells (CSLCs) play a pivotal role in acquiring multidrug resistant (MDR) phenotypes. It has been established that pancreatic cancers overexpressing CD44 receptors (a target of hyaluronic acid; HA) is one of the major contributors for causing MDR. Therefore, targeted killing of CD44 expressing tumor cells using HA based active targeting strategies may be beneficial for eradicating MDR-pancreatic cancers. Here, we report the synthesis of a new HA conjugate of copoly(styrene maleic acid) (HA-SMA) that could be engineered to form nanomicelles with a potent anticancer agent, 3,4-difluorobenzylidene curcumin (CDF). The anticancer activity of CDF loaded nanomicelles against MiaPaCa-2 and AsPC-1 human pancreatic cancer cells revealed dose-dependent cell killing. Results of cellular internalization further confirmed better uptake of HA engineered nanomicelles in triple-marker positive (CD44+/CD133+/EpCAM+) pancreatic CSLCs compared with triple-marker negative (CD44-/CD133-/EpCAM-) counterparts. More importantly, HA-SMA-CDF exhibited superior anticancer response toward CD44+ pancreatic CSLCs. Results further confirmed that triple-marker positive cells treated with HA-SMA-CDF caused significant reduction in CD44 expression and marked inhibition of NF-κB that in-turn can mitigate their proliferative and invasive behavior. Conclusively, these results suggest that the newly developed CD44 targeted nanomicelles may have great implications in treating pancreatic cancers including the more aggressive pancreatic CSLCs.

Styrene maleic acid copolymer-pirarubicin induces tumor-selective oxidative stress and decreases tumor hypoxia as possible treatment of colorectal cancer liver metastases

BACKGROUND

Pirarubicin, a derivative of doxorubicin, induces tumor destruction via the production of reactive oxygen species (ROS) but is associated with cardiotoxicity. As a macromolecule (conjugated to styrene-maleic acid [SMA]), SMA-pirarubicin is selective to tumors resulting in improved survival with decreased systemic toxicity. Tumor destruction is, however incomplete, and resistant cells at the periphery of the tumor contribute to recurrence. Tumor hypoxia is a major factor in tumor resistance. Understanding the effect of oxidative stress induced by SMA-pirarubicin on the tumor microenvironment may be key to overcoming resistance. This study investigated the pattern of ROS production and tumor hypoxia after treatment with SMA-pirarubicin in a murine model of colorectal liver metastases.

METHODS

Liver metastases were induced in male, CBA mice using a murine-derived colon cancer cell line. SMA-pirarubicin (maximum tolerated dose, 100 mg/kg) or pirarubicin, (maximum tolerated dose, 10 mg/kg) were administered intravenously 14 days after tumor induction. Systemic oxidative stress in serum, liver, and cardiac tissue was quantified using the thiobarbituric acid reactive substances assay. Flow cytometry and fluorescence microscopy were used to assess ROS production for 48 hours after treatment. Tumor hypoxia was quantified using immunohistochemistry for pimonidazole adducts.

RESULTS

SMA-pirarubicin (100 mg/kg) induced ROS exclusively in tumors with minimal levels in serum and cardiac tissue. ROS levels were induced in a time-dependent and dose-dependent manner optimal between 4 and 24 hours after drug administration. Although tumor hypoxia was decreased overall, residual tumor cells adjacent to patent vessels were hypoxic.

CONCLUSION

This study provides insight into the tumor microenvironment after chemotherapy. SMA-pirarubicin inhibits the growth of colorectal liver metastases by inducing ROS, which seems to be largely tumor selective. The temporal pattern of ROS production can be used to improve future dosing regimens. Furthermore, the observation that residual tumor cells are hypoxic clarifies the need for a multimodal approach with agents that can alter the hypoxic state to effect complete tumor destruction.

Parenterally administrable nano-micelles of 3,4-difluorobenzylidene curcumin for treating pancreatic cancer

Pancreatic cancer remains one of the most devastating diseases in terms of patient mortality rates for which current treatment options are very limited. 3,4-Difluorobenzylidene curcumin (CDF) is a nontoxic analog of curcumin (CMN) developed in our laboratory, which exhibits extended circulation half-life, while maintaining high anticancer activity and improved pancreas specific accumulation in vivo, compared with CMN. CDF however has poor aqueous solubility and its dose escalation for systemic administration remains challenging. We have engineered self-assembling nano-micelles of amphiphilic styrene-maleic acid copolymer (SMA) with CDF by non-covalent hydrophobic interactions. The SMA-CDF nano-micelles were characterized for size, charge, drug loading, release, serum stability, and in vitro anticancer activity. The SMA-CDF nano-micelles exhibited tunable CDF loading from 5 to 15% with excellent aqueous solubility, stability, favorable hemocompatibility and sustained drug release characteristics. The outcome of cytotoxicity testing of SMA-CDF nano-micelles on MiaPaCa-2 and AsPC-1 pancreatic cancer cell lines revealed pronounced antitumor response due to efficient intracellular trafficking of the drug loaded nano-micelles. Additionally, the nano-micelles are administrable via the systemic route for future in vivo studies and clinical translation. The currently developed SMA based nano-micelles thus portend to be a versatile carrier for dose escalation and targeted delivery of CDF, with enhanced therapeutic margin and safety.

Effect of styrene maleic acid WIN55,212-2 micelles on neuropathic pain in a rat model

Cannabinoid receptor agonists are moderately effective at reducing neuropathic pain but are limited by psychoactivity. We developed a styrene maleic acid (SMA) based on the cannabinoid WIN 55,212-2 (WIN) and tested in a rat model of neuropathic pain and in the rotarod test. We hypothesized that miceller preparation can ensure prolonged plasma half-life being above the renal threshold of excretion. Furthermore, SMA-WIN could potentially reduce the central nervous system effects of encapsulated WIN by limiting its transport across the blood-brain barrier. Using the chronic constriction injury model of sciatic neuropathy, the SMA-WIN micelles were efficacious in the treatment of neuropathic pain for a prolonged period compared to control (base WIN). Attenuation of chronic constriction injury-induced mechanical allodynia occurred for up to 8 h at a dose of 11.5 mg/kg of SMA-WIN micelles. To evaluate central effects on motor function, the rotarod assessment was utilized. Results showed initial impairment caused by SMA-WIN micelles to be identical to WIN control for up to 1.5 h. Despite this, the SMA-WIN micelle formulation was able to produce prolonged analgesia over a time when there was decreased impairment in the rotarod test compared with base WIN.

Synergistic inhibitory effect of hyperbaric oxygen combined with sorafenib on hepatoma cells

OBJECTIVES

Hypoxia is a common phenomenon in solid tumors, associated with chemotherapy and radiotherapy resistance, recurrence and metastasis. Hyperbaric oxygen (HBO) therapy can increase tissue oxygen pressure and content to prevent the resistance, recurrence and metastasis of cancer. Presently, Sorafenib is a first-line drug, targeted for hepatocellular carcinoma (HCC) but effective in only a small portion of patients and can induce hypoxia. The purpose of this study is to investigate the effect of HBO in combination with sorafenib on hepatoma cells.

METHODS

Hepatoma cell lines (BEL-7402 and SK-Hep1) were treated with HBO at 2 atmosphere absolute pressure for 80 min per day or combined with sorafenib or cisplatin. At different time points, cells were tested for cell growth, colony formation, apoptosis, cell cycle and migration. Finally, miRNA from the hepatoma cells was detected by microRNA array and validated by qRT-PCR.

RESULTS

Although HBO, sorafenib or cisplatin alone could inhibit growth of hepatoma cells, HBO combined with sorafenib or cisplatin resulted in much greater synergistic growth inhibition (cell proliferation and colony formation) in hepatoma cells. Similarly, the synergistic effect of HBO and sorafenib on induction of apoptosis was also observed in hepatoma cells. HBO induced G1 arrest in SK-Hep1 not in BEL-7402 cells, but enhanced cell cycle arrest induced by sorafenib in BEL-7402 treated cells. However, HBO had no obvious effect on the migration of hepatoma cells, and microRNA array analysis showed that hepatoma cells with HBO treatment had significantly different microRNA expression profiles from those with blank control.

CONCLUSIONS

We show for the first time that HBO combined with sorafenib results in synergistic growth inhibition and apoptosis in hepatoma cells, suggesting a potential application of HBO combined with sorafenib in HCC patients. Additionally, we also show that HBO significantly altered microRNA expression in hepatoma cells.

Self/co-assembling peptide, EAR8-II, as a potential carrier for a hydrophobic anticancer drug pirarubicin (THP)--characterization and in-vitro delivery

A short ionic-complementary peptide, EAR8-II, was employed to encapsulate the hydrophobic anticancer drug pirarubicin (THP). EAR8-II was designed to inherit advantages from two previously introduced peptides, AAP8 and EAK16-II, in their self/co-assembly. This peptide is short, simple, and inexpensive to synthesize, while possessing a low critical assembly concentration (CAC). The choice of alanine (A) residues in the peptide sequence provides moderate hydrophobic interactions, causing a minimal degree of aggregation, compared with other more hydrophobic residues. EAR8-II is an ionic-complementary peptide, similar to EAK16-II, can self/co-assemble with hydrophobic compounds such as THP, and forms a stable fibular nanostructure in aqueous solution. Physiochemical properties and cellular activities of the EAR8-II and THP complexes were evaluated and show dependency on the peptide-to-drug ratio. The complex at the peptide-to-drug mass ratio of 5:1 provides a stable solution, uniform nanostructure, and highly effective anticancer activity against various cancer cell lines. This work forms the basis for detailed studies on EAR8-II and THP formulations in vitro and in vivo, for future development of peptide-based delivery systems for hydrophobic anticancer drugs.

Hyperbaric oxygen therapy and cancer--a review

Hypoxia is a critical hallmark of solid tumors and involves enhanced cell survival, angiogenesis, glycolytic metabolism, and metastasis. Hyperbaric oxygen (HBO) treatment has for centuries been used to improve or cure disorders involving hypoxia and ischemia, by enhancing the amount of dissolved oxygen in the plasma and thereby increasing O₂ delivery to the tissue. Studies on HBO and cancer have up to recently focused on whether enhanced oxygen acts as a cancer promoter or not. As oxygen is believed to be required for all the major processes of wound healing, one feared that the effects of HBO would be applicable to cancer tissue as well and promote cancer growth. Furthermore, one also feared that exposing patients who had been treated for cancer, to HBO, would lead to recurrence. Nevertheless, two systematic reviews on HBO and cancer have concluded that the use of HBO in patients with malignancies is considered safe. To supplement the previous reviews, we have summarized the work performed on HBO and cancer in the period 2004–2012. Based on the present as well as previous reviews, there is no evidence indicating that HBO neither acts as a stimulator of tumor growth nor as an enhancer of recurrence. On the other hand, there is evidence that implies that HBO might have tumor-inhibitory effects in certain cancer subtypes, and we thus strongly believe that we need to expand our knowledge on the effect and the mechanisms behind tumor oxygenation.

Potential utility of hyperbaric oxygen therapy and propolis in enhancing the leishmanicidal activity of glucantime

In this study we investigated the efficacy of hyperbaric oxygen (HBO) therapy, alone or combined with the pentavalent antimonial glucantime on Leishmania amazonensis infection. In parallel, the effect of Brazilian red propolis gel (propain) alone or combined with glucantime on L. amazonensis infection was evaluated. The inhibition of the infection in macrophages treated with glucantime in combination with HBO exposition was greater than that of macrophages treated with glucantime alone or HBO alone. The susceptible mouse strain BALB/c infected in the shaved rump with L. amazonensis treated with glucantime and exposed to HBO showed: time points in the course of the disease in which lesions were smaller than those of mice treated with glucantime alone and revascularization of the skin in the lesion site; interferon-gamma (IFN-g) levels were not elevated in lymph node cells from these animals. Propain alone was not efficient against lesions, although less exudative lesions were observed in animals treated with propain alone or combined with glucantime. These results reveal the potential value of HBO and red propolis in combination with glucantime for treating cutaneous leishmaniasis and encourage further studies on the effect of more aggressive HBO, propolis and glucantime therapies on different mouse models of leishmaniasis.

In vitro and in vivo evaluation of tumor targeting styrene-maleic acid copolymer-pirarubicin micelles: Survival improvement and inhibition of liver metastases

Pirarubicin is a derivative of doxorubicin with improved intracellular uptake and reduced cardiotoxicity. We have prepared a micellar formulation of pirarubicin using styrene-maleic acid copolymer (SMA) of mean molecular weight of 1.2 kDa, which exhibits a mean diameter of 248 nm in solution. Being a macromolecule, SMA-pirarubicin micelles exhibit excellent tumor targeting capacity due to the enhanced permeability and retention (EPR) effect. Here we report the antitumor activity of SMA-pirarubicin micelles on human colon and breast cancer cell lines in vitro, and a murine liver metastasis model in vivo. Metastatic tumor microvasculature, necrosis, apoptosis, proliferation, and survival were also investigated using immunohistochemistry for Ki-67, active caspase-3, and CD34, respectively. Drug cytotoxicity in vitro was assessed using MTT (3-[4,5-dimethyl-2-thiazolyl]-2, 5-diphenyl-2H-tetrazolium bromide) assay. In vivo, SMA-pirarubicin was administered at 100, 150, or 200 mg/kg (pirarubicin equivalent). Tumor microvasculature was also assessed using scanning electron microscopy. Styrene-maleic acid copolymer (SMA)-pirarubicin micelles were toxic against human colorectal and breast cancer cells in vitro. IC(50) was at or below 1 muM, free pirarubicin equivalent. In vivo, SMA-pirarubicin at 100 mg/kg reduced tumor volume by 80% and achieved a survival rate of 93% at 40 days after tumor inoculation. Styrene-maleic acid copolymer (SMA)-pirarubicin micelles demonstrated potent antitumor activity in this liver metastases model, contributing to prolonged survival. Histological examination of tumor nodules showed significant reduction and proliferation of tumor cells (>90%). The present results suggest that investigation of the effect of multiple dosing at later time points to further improve survival is warranted.