Assessing the Combinatorial Chemo-Photothermal Therapy Mediated by Sulfobetaine Methacrylate-Functionalized Nanoparticles in 2D and 3D In Vitro Cancer Models

Nanoparticle-mediated thermal Cancer therapies: Strategies to improve clinical translatability

Despite significant advances, cancer remains a leading global cause of death. Current therapies often fail due to incomplete tumor removal and nonspecific targeting, spurring interest in alternative treatments. Hyperthermia, which uses elevated temperatures to kill cancer cells or boost their sensitivity to radio/chemotherapy, has emerged as a promising alternative. Recent advancements employ nanoparticles (NPs) as heat mediators for selective cancer cell destruction, minimizing damage to healthy tissues. This approach, known as NP hyperthermia, falls into two categories: photothermal therapies (PTT) and magnetothermal therapies (MTT). PTT utilizes NPs that convert light to heat, while MTT uses magnetic NPs activated by alternating magnetic fields (AMF), both achieving localized tumor damage. These methods offer advantages like precise targeting, minimal invasiveness, and reduced systemic toxicity. However, the efficacy of NP hyperthermia depends on many factors, in particular, the NP properties, the tumor microenvironment (TME), and TME-NP interactions. Optimizing this treatment requires accurate heat monitoring strategies, such as nanothermometry and biologically relevant screening models that can better mimic the physiological features of the tumor in the human body. This review explores the state-of-the-art in NP-mediated cancer hyperthermia, discussing available nanomaterials, their strengths and weaknesses, characterization methods, and future directions. Our particular focus lies in preclinical NP screening techniques, providing an updated perspective on their efficacy and relevance in the journey towards clinical trials.

Development of Thiol-Maleimide hydrogels incorporating graphene-based nanomaterials for cancer chemo-photothermal therapy

Nano-sized materials have been widely explored in the biomedicine field, especially due to their ability to encapsulate drugs intended to be delivered to cancer cells. However, systemically administered nanomaterials face several barriers that can hinder their tumor-homing capacity. In this way, researchers are now focusing their efforts in developing technologies that can deliver the nanoparticles directly into the tumor tissue. Particularly, hydrogels assembled using Thiol-Maleimide Michael type additions are emerging for this purpose due to their capacity to incorporate high nanoparticles' doses in a compact 3D structure as well as good chemical selectivity, biocompatibility, and straightforward preparation. Nevertheless, such hydrogels have been mostly prepared using synthetic polymers, which is not ideal due to their poor biodegradability. In this work, a novel natural polymer-based Thiol-Maleimide hydrogel was produced for application in breast cancer chemo-photothermal therapy. To obtain natural polymers compatible with this crosslinking chemistry, Hyaluronic acid was endowed with Thiol groups and deacetylated Chitosan was grafted with Maleimide groups. Parallelly, Doxorubicin loaded Dopamine-reduced graphene oxide (DOX/DOPA-rGO) was prepared for attaining Near Infrared (NIR) light responsive chemo-photothermal nanoagents. By simply mixing Hyaluronic Acid-Thiol, deacetylated Chitosan-Maleimide and DOX/DOPA-rGO, Thiol-Maleimide crosslinked hydrogels incorporating this nanomaterial could be assembled (DOX/DOPA-rGO@TMgel). When breast cancer cells were incubated with DOPA-rGO@TMgel and exposed to NIR light (photothermal therapy), their viability was reduced to about 59 %. On the other hand, DOX/DOPA-rGO@TMgel (chemotherapy) reduced cancer cells' viability to 50 %. In stark contrast, the combined action of DOX/DOPA-rGO@TMgel and NIR light decreased breast cancer cells' viability to just 21 %, highlighting its chemo-photothermal potential.

Simple preparation of POxylated nanomaterials for cancer chemo-PDT/PTT

Near infrared (NIR) light-responsive nanomaterials hold potential to mediate combinatorial therapies targeting several cancer hallmarks. When irradiated, these nanomaterials produce reactive oxygen species (photodynamic therapy) and/or a temperature increase (photothermal therapy). These events can damage cancer cells and trigger the release of drugs from the nanomaterials' core. However, engineering nanomaterials for cancer chemo-photodynamic/photothermal therapy is a complex process. First, nanomaterials with photothermal capacity are synthesized, being then loaded with photosensitizers plus chemotherapeutics, and, finally functionalized with polymers for achieving suitable biological properties. To overcome this limitation, in this work, a novel straightforward approach to attain NIR light-responsive nanosystems for cancer chemo-photodynamic/photothermal therapy was established. Such was accomplished by synthesizing poly(2-ethyl-2-oxazoline)-IR780 amphiphilic conjugates, which can be assembled into nanoparticles with photodynamic/photothermal capabilities that simultaneously encapsulate Doxorubicin (DOX/PEtOx-IR NPs). The DOX/PEtOx-IR NPs presented a suitable size and surface charge for cancer-related applications. When irradiated with NIR light, the DOX/PEtOx-IR NPs produced singlet oxygen as well as a smaller thermic effect that boosted the release of DOX by 1.7-times. In the in vitro studies, the combination of DOX/PEtOx-IR NPs and NIR light could completely ablate breast cancer cells (viability ≈ 4 %), demonstrating the enhanced outcome arising from the nanomaterials' chemo-photodynamic/photothermal therapy.

Poly(2-ethyl-2-oxazoline)-IR780 conjugate nanoparticles for breast cancer phototherapy

Aims: To address the limitations of IR780 by preparing hydrophilic polymer-IR780 conjugates and to employ these conjugates in the assembly of nanoparticles (NPs) intended for cancer photothermal therapy. Materials & methods: The cyclohexenyl ring of IR780 was conjugated for the first time with thiol-terminated poly(2-ethyl-2-oxazoline) (PEtOx). This novel poly(2-ethyl-2-oxazoline)-IR780 (PEtOx-IR) conjugate was combined with D-α-tocopheryl succinate (TOS), leading to the assembly of mixed NPs (PEtOx-IR/TOS NPs). Results: PEtOx-IR/TOS NPs displayed optimal colloidal stability as well as cytocompatibility in healthy cells at doses within the therapeutic range. In turn, the combination of PEtOx-IR/TOS NPs and near-infrared light reduced heterotypic breast cancer spheroid viability to just 15%. Conclusion: PEtOx-IR/TOS NPs are promising agents for breast cancer photothermal therapy.

Poly(2-ethyl-2-oxazoline) functionalized reduced graphene oxide: Optimization of the reduction process using dopamine and application in cancer photothermal therapy

The high near infrared (NIR) absorption displayed by reduced graphene oxide (rGO) nanostructures renders them a great potential for application in cancer photothermal therapy. However, the production of this material often relies on the use of hydrazine as a reductant, leading to poor biocompatibility and environmental-related issues. In addition, to improve rGO colloidal stability, this material has been functionalized with poly(ethylene glycol). However, recent studies have reported the immunogenicity of poly(ethylene glycol)-based coatings. In this work, the production of rGO, by using dopamine as the reducing agent, was optimized considering the size distribution and NIR absorption of the attained materials. The obtained results unveiled that the rGO produced by using a 1:5 graphene oxide:dopamine weight ratio and a reaction time of 4 h (termed as DOPA-rGO) displayed the highest NIR absorption while retaining its nanometric size distribution. Subsequently, the DOPA-rGO was functionalized with thiol-terminated poly(2-ethyl-2-oxazoline) (P-DOPA-rGO), revealing suitable physicochemical features, colloidal stability and cytocompatibility. When irradiated with NIR light, the P-DOPA-rGO could produce a temperature increase (ΔT) of 36 °C (75 μg/mL; 808 nm, 1.7 W/cm², 5 min). The photothermal therapy mediated by P-DOPA-rGO was capable of ablating breast cancer cells monolayers (viability < 3%) and could reduce heterotypic breast cancer spheroids' viability to just 30%. Overall, P-DOPA-rGO holds a great potential for application in breast cancer photothermal therapy.

Mitoxantrone-loaded lipid nanoparticles for breast cancer therapy - Quality-by-design approach and efficacy assessment in 2D and 3D in vitro cancer models

Breast cancer is the leading cause of cancer-related deaths among women worldwide. The conventional chemotherapeutic regimens used in the treatment of this disease often lead to severe side-effects and reduced efficacy. In this study, a novel drug delivery system for the chemotherapeutic drug mitoxantrone (Mito) was developed using solid lipid nanoparticles (SLN). The production of the SLN was carried out using an organic-solvent-free, low-cost method and optimized using a Box-Behnken design. SLN presented adequate size for cancer-related applications, more than 90% of EE% and remained stable for at least 6 months. A much higher drug release was obtained at acidic pH (mimicking the endosomal compartment) than plasmatic pH, highlighting the potential of the nanosystem for tumor drug delivery. Additionally, SLN were non-hemolytic and cytocompatible, even at high concentrations of lipid. A significantly higher anti-cancer efficacy was obtained for Mito-loaded SLN comparing to the free drug at different concentrations in MCF-7 2D models. Finally, the nanoformulation was evaluated in heterotypic breast cancer spheroids showing capacity to penetrate the tridimensional structure and ability to induce a high anti-tumoral effect, similarly to the free drug. Overall, these results support that the developed SLN are effective Mito nanocarriers for the treatment of breast cancer.

Colorectal Cancer and Immunity: From the Wet Lab to Individuals

Simple Summary

Tackling the current dilemma of colorectal cancer resistance to immunotherapy is puzzling and requires novel therapeutic strategies to emerge. However, characterizing the intricate interactions between cancer and immune cells remains difficult because of the complexity and heterogeneity of both compartments. Developing rationales is intellectually feasible but testing them can be experimentally challenging and requires the development of innovative procedures and protocols. In this review, we delineated useful in vitro and in vivo models used for research in the field of immunotherapy that are or could be applied to colorectal cancer management and lead to major breakthroughs in the coming years.

Abstract

Immunotherapy is a very promising field of research and application for treating cancers, in particular for those that are resistant to chemotherapeutics. Immunotherapy aims at enhancing immune cell activation to increase tumor cells recognition and killing. However, some specific cancer types, such as colorectal cancer (CRC), are less responsive than others to the current immunotherapies. Intrinsic resistance can be mediated by the development of an immuno-suppressive environment in CRC. The mutational status of cancer cells also plays a role in this process. CRC can indeed be distinguished in two main subtypes. Microsatellite instable (MSI) tumors show a hyper-mutable phenotype caused by the deficiency of the DNA mismatch repair machinery (MMR) while microsatellite stable (MSS) tumors show a comparatively more “stable” mutational phenotype. Several studies demonstrated that MSI CRC generally display good prognoses for patients and immunotherapy is considered as a therapeutic option for this type of tumors. On the contrary, MSS metastatic CRC usually presents a worse prognosis and is not responsive to immunotherapy. According to this, developing new and innovative models for studying CRC response towards immune targeted therapies has become essential in the last years. Herein, we review the in vitro and in vivo models used for research in the field of immunotherapy applied to colorectal cancer.

Sulfobetaine methacrylate-albumin-coated graphene oxide incorporating IR780 for enhanced breast cancer phototherapy

Aim: Enhance the colloidal stability and photothermal capacity of graphene oxide (GO) by functionalizing it with sulfobetaine methacrylate (SBMA)-grafted bovine serum albumin (BSA; i.e., SBMA-g-BSA) and by loading IR780, respectively. Materials & methods: SBMA-g-BSA coating and IR780 loading into GO was achieved through a simple sonication process. Results: SBMA-g-BSA-functionalized GO (SBMA-BSA/GO) presented an adequate size distribution and cytocompatibility. When in contact with biologically relevant media, the size of the SBMA-BSA/GO only increased by 8%. By loading IR780 into SBMA-BSA/GO, its photothermal capacity increased by twofold. The combination of near infrared light with SBMA-BSA/GO did not induce photocytotoxicity on breast cancer cells. In contrast, the interaction of IR780-loaded SBMA-BSA/GO with near infrared light caused the ablation of cancer cells. Conclusion: IR780-loaded SBMA-BSA/GO displayed an improved colloidal stability and phototherapeutic capacity.