The role of photodynamic therapy in overcoming cancer drug resistance

Multifunctional and Scalable Nanoparticles for Bimodal Image-Guided Phototherapy in Bladder Cancer Treatment

Rational design of multifunctional nanoplatforms capable of combining therapeutic effects with real-time monitoring of drug distribution and tumor status is emerging as a promising approach in cancer nanomedicine. Here, we introduce pyropheophorbide a-bisaminoquinoline conjugate lipid nanoparticles (PPBC LNPs) as a bimodal system for image-guided phototherapy in bladder cancer treatment. PPBC LNPs not only demonstrate both powerful photodynamic and photothermal effects upon light activation, but also exhibit potent autophagy blockage, effectively inducing bladder cancer cell death. Furthermore, PPBC LNPs possess remarkable photoacoustic (PA) and fluorescence (FL) imaging capabilities, enabling imaging with high-resolution, deep tissue penetration and high sensitivity for tracking drug biodistribution and phototherapy efficacy. Specifically, PA imaging confirms the efficient accumulation of PPBC LNPs within tumor and predicts therapeutic outcomes of photodynamic therapy, while FL imaging confirms their prolonged retention at the tumor site for up to 6 days. PPBC LNPs significantly suppress bladder tumor growth, with several tumors completely ablated following just two doses of the nanoparticles and laser treatment. Additionally, PPBC LNPs were formulated with lipid-based excipients and assembled using microfluidic technology to enhance biocompatibility, stability, and scalability, showing potential for clinical translation. This versatile nanoparticle represents a promising candidate for further development in bladder cancer therapy.

Rationally Designed Ir(III) Complex with an Exceptionally Strong Binding to Human Serum Albumin for Targeted Photodynamic Therapy

The application of iridium(III) complexes in photodynamic therapy (PDT) is often limited by their poor selectivity for cancerous cells, necessitating high drug doses that increase the risk of side effects. The development of efficient drug delivery systems such as albumin conjugation is therefore crucial to enhance the tumor-targeted delivery of photosensitizers. To date, the vast majority of metal complexes exhibit weak to moderate binding with human serum albumin, limiting the feasibility of this approach. To overcome this limitation, the rational design through molecular docking and density functional theory calculations of a novel Ir(III) complex as a strong albumin-binding photosensitizer is described. The herein reported compound has the highest albumin binding constant ever reported for an iridium complex, and it showed to photocatalytically produce reactive oxygen species upon blue light irradiation. The presented compound as well as structural derivatives could have high potential in tumor-targeted photodynamic therapy.

Activatable Photosensitizers: From Fundamental Principles to Advanced Designs

Photodynamic therapy (PDT) is a promising treatment that uses light to excite photosensitizers in target tissue, producing reactive oxygen species and localized cell death. It is recognized as a minimally invasive, clinically approved cancer therapy with additional preclinical applications in arthritis, atherosclerosis, and infection control. A hallmark of ideal PDT is delivering disease-specific cytotoxicity while sparing healthy tissue. However, conventional photosensitizers often suffer from non-specific photoactivation, causing off-target toxicity. Activatable photosensitizers (aPS) have emerged as more precise alternatives, offering controlled activation. Unlike traditional photosensitizers, they remain inert and photoinactive during circulation and off-target accumulation, minimizing collateral damage. These photosensitizers are designed to "turn on" in response to disease-specific biostimuli, enhancing therapeutic selectivity and reducing off-target effects. This review explores the principles of aPS, including quenching mechanisms stemming from activatable fluorescent probes and applied to activatable photosensitizers (RET, PeT, ICT, ACQ, AIE), as well as pathological biostimuli (pH, enzymes, redox conditions, cellular internalization), and bioresponsive constructs enabling quenching and activation. We also provide a critical assessment of unresolved challenges in aPS development, including limitations in targeting precision, selectivity under real-world conditions, and potential solutions to persistent issues (dual-lock, targeting moieties, biorthogonal chemistry and artificial receptors). Additionally, it provides an in-depth discussion of essential research design considerations needed to develop translationally relevant aPS with improved therapeutic outcomes and specificity.

Optical Microneedle-Enhanced Transdermal Light Scattering for In Situ Photothermal Therapy Targeting Basal-Layer Psoriasis

Near-infrared (NIR) light-mediated photothermal and photodynamic therapies are promising for nonsurgical treatment of skin diseases. However, the skin's inherent light absorption, especially from melanin in the epidermis, attenuates NIR energy penetration, limiting photothermal efficacy and potentially causing off-target tissue damage. In this context, we developed subcutaneous light response-enhanced microneedles (SLE MNs) that allow basal layer-localized seeding of therapeutics and leverage physical channels to efficiently transmit light transdermally, facilitating in situ scattered light activation for enhanced photothermal and photodynamic therapy outcomes. Such ultraoptical SLE MNs facilitated NIR light penetration, achieving up to 80% of initial light power at 500 μm subcutaneously, representing an approximate 160% increase compared to the control groups. Additionally, we conceptualized a two-segmented MN structure integrating light-guiding channels with photoresponsive therapeutics to enable precise in situ basal-layer treatment, effectively mitigating local hyperenergy on the skin surface and energy attenuation within tissues. This optical SLE MN patch offers a transformative platform for transdermal light therapy with significant clinical potential.

Improved Photodynamic Therapy of Hepatocellular Carcinoma via Surface-Modified Protein Nanoparticles

Background: Photodynamic therapy (PDT) has evolved as a reliable therapeutic modality for cancer. However, the broad application of the technique is still limited because of poor bioavailability and the non-selective distribution of photosensitizers within host tissues. Herein, zein, a natural corn protein, was functionalized with glycyrrhetinic acid (GA) and polyethylene glycol (Z-PEG-GA) as a targeting platform for liver cancer cells. Parietin, as novel photosensitizer, was successfully encapsulated into zein via nanoprecipitation and used for the therapy of hepatocellular carcinoma. Methods: The in vitro phototoxicity of Z-PEG-GA nanoparticles and their non-functionalized control (Z-PEG) were assessed against hepatocellular carcinoma (HepG2 cells) and the In vivo biodistribution was determined in an adult male CD-1 Swiss albino mice model. Results: The formulated Z-PEG and Z-PEG-GA showed spherical shapes with average sizes of 82.8 and 94.7 nm for unloaded nanoparticles, respectively, and 109.7 and 111.5 nm for loaded nanoparticles carrying more than 70% of parietin, and Quantum yield measurements show that parietin's photodynamic potential is conserved. Moreover, parietin-loaded Z-PEG-GA exhibited three-fold higher toxicity against liver cancer cells than its non-functionalized control and attained more than an eleven-fold enhancement in the generated intracellular reactive oxygen species (ROS) at a 9 J/cm2 radiant exposure. The generated intracellular ROS led to mitochondrial disruption and the release of cytochrome c. In vivo biodistribution studies revealed that fluorescence signals of Z-PEG-GA can persist in the excised animal liver for up to 24 h post-administration. Conclusions: Consequently, tailored zein can hold great potential for delivering several hydrophobic photosensitizers in anticancer PDT.

Self-Assembled Metal Complexes in Biomedical Research

Cisplatin is widely used in clinical cancer treatment; however, its application is often hindered by severe side effects, particularly inherent or acquired resistance of target cells. To address these challenges, an effective strategy is to modify the metal core of the complex and introduce alternative coordination modes or valence states, leading to the development of a series of metal complexes, such as platinum (IV) prodrugs and cyclometalated complexes. Recent advances in nanotechnology have facilitated the development of multifunctional nanomaterials that can selectively deliver drugs to tumor cells, thereby overcoming the pharmacological limitations of metal-based drugs. This review first explores the self-assembly of metal complexes into spherical, linear, and irregular nanoparticles in the context of biomedical applications. The mechanisms underlying the self-assembly of metal complexes into nanoparticles are subsequently analyzed, followed by a discussion of their applications in biomedical fields, including detection, imaging, and antitumor research.

Next-Generation Photosensitizers: Cyanine-Carborane Salts for Superior Photodynamic Therapy of Metastatic Cancer

Photodynamic therapy (PDT) has emerged as a promising targeted treatment for cancer. However, current PDT is limited by low tissue penetration, insufficient phototoxicity (toxicity with light irradiation), and undesirable cytotoxicity (toxicity without light irradiation). Here, we report the discovery of cyanine-carborane salts as potent photosensitizers (PSs) that harness the near-infrared (NIR) absorbing [cyanine+] with the inertness of [carborane-]. The implementation of [cyanine+] [carborane-] salts dramatically enhance cancer targeting of the PSs and decrease cytotoxicity. We characterize the cellular uptake of the cyanine-carborane PSs, organelle localization, generation of reactive oxygen species (ROS) with the ability to cogenerate multiple ROS species, suppression of pro-metastatic pathways, and activation of apoptotic pathways. We further demonstrate the ability of optimized PSs to eliminate tumors in vivo using an orthotopic mouse model of breast cancer. These newly developed [cyanine+] [carborane-] salt PSs introduce a potent therapeutic approach against aggressive breast cancer while decreasing side effects.

Programmable Modular Assembly of Homochiral Ir(III)-Metallohelices to Reverse Metallodrug Resistance by Inhibiting CDK1

Drug resistance is a major cause of cancer recurrence and poor prognosis. The innovative design and synthesis of inhibitors to target drug-resistance-specific proteins is highly desirable. However, challenges remain in precisely adjusting their conformation and stereochemistry to adapt the chiral regions of target proteins. Herein, using a stepwise programmable modular assembly approach, we precisely engineered two pairs of homochiral dinuclear Ir(III) metallohelices (Λ2S4-Hbpy and Δ2R4-Hbpy, Δ2S4-Hbpy and Λ2R4-Hbpy) functionalized with flexible dithiourea linkages. The resulting homochiral metallohelices exhibited significant chirality-dependent photocytotoxicities, and the enhanced structural compatibility of Δ2S4-Hbpy with the target cyclin-dependent kinase 1 (CDK1) contributed to its superior photodynamic therapy efficacy, achieving an outstanding photocytotoxicity index (PI) value of 2.3×104. Interestingly, emerging as a critical mediator in the development of oxaliplatin resistance, CDK1 targeting by Δ2S4-Hbpy achieved enhanced cellular uptake, anticancer activity, and oncosis-mediated cell death in oxaliplatin-resistant HCT-8/L cells. Mechanistic investigations, including proteomic profiling and CDK1 gene silencing, confirmed the pivotal role of chirality-selective CDK1 targeting in reversing metallodrug resistance. This study introduces a promising platform for constructing and customizing flexible metallohelices with precise conformation and stereochemistry to target drug-resistance-specific proteins, offering innovative insights into the designability of metallodrugs to overcome drug resistance.

Red light-activated depletion of drug-refractory glioblastoma stem cells and chemosensitization of an acquired-resistant mesenchymal phenotype

Glioblastoma stem cells (GSCs) are potent tumor initiators resistant to radiochemotherapy, and this subpopulation is hypothesized to re-populate the tumor milieu due to selection following conventional therapies. Here, we show that 5-aminolevulinic acid (ALA) treatment-a pro-fluorophore used for fluorescence-guided cancer surgery-leads to elevated levels of fluorophore conversion in patient-derived GSC cultures, and subsequent red light-activation induces apoptosis in both intrinsically temozolomide chemotherapy-sensitive and -resistant GSC phenotypes. Red light irradiation of ALA-treated cultures also exhibits the ability to target mesenchymal GSCs (Mes-GSCs) with induced temozolomide resistance. Furthermore, sub-lethal light doses restore Mes-GSC sensitivity to temozolomide, abrogating GSC-acquired chemoresistance. These results suggest that ALA is not only useful for fluorescence-guided glioblastoma tumor resection, but that it also facilitates a GSC drug-resistance agnostic, red light-activated modality to mop up the surgical margins and prime subsequent chemotherapy.

Methods for assessing and removing non-specific photoimmunotherapy damage in patient-derived tumor cell culture models

Tumor-targeted, activatable photoimmunotherapy (taPIT) has been shown to selectively destroy tumor in a metastatic mouse model. However, the photoimmunoconjugate (PIC) used for taPIT includes a small fraction of non-covalently associated (free) benzoporphyrin derivative (BPD), which leads to non-specific killing in vitro. Here, we report a new treatment protocol for patient-derived primary tumor cell cultures ultrasensitive to BPD photodynamic therapy (BPD-PDT). Based on free BPD efflux dynamics, the updated in vitro taPIT protocol precludes non-specific BPD-PDT by silencing the effect of free BPD. Following incubation with PIC, incubating cells with PIC-free medium allows time for expulsion of free BPD whereas BPD covalently bound to PIC fragments is retained. Administration of the light dose after the intracellular free BPD drops below the threshold for inducing cell death helps to mitigate non-specific damage. In this study, we tested two primary ovarian tumor cell lines that are intrinsically chemoresistant, yet ultrasensitive to BPD-PDT such that small amounts of free BPD (a few percent of the total BPD dose) lead to potent induction of cell death upon irradiation. The modifications in the protocol suggested here improve in vitro taPIT experiments that lack in vivo mechanisms of free BPD clearance (i.e., lymph and blood flow).

Therapeutic Chemoresistance in Ovarian Cancer: Emerging Hallmarks, Signaling Mechanisms and Alternative Pathways

Ovarian cancer is the fifth leading cause of mortality and the most lethal gynecologic malignancy among females. It may arise from atypical borderline tumors (Type I) or serous tubal intraepithelial carcinoma (Type II). The diagnosis of cancer at its early stages is difficult because of non-specific symptoms, most patients are diagnosed at the advanced stage. Several drugs and therapeutic strategies are available to treat ovarian cancer such as surgery, chemotherapy, neoadjuvant therapy, and maintenance therapy. However, the cancer cells have developed resistance to a number of available therapies causing treatment failure. This emerging chemoresistance in ovarian cancer cells is becoming an obstacle due to alterations in multiple cellular processes. These processes involve altered drug target response, drug pumps, detoxification systems, lower sensitivity to apoptosis, and altered proliferation, and are responsible for developing resistance to anticancer medicines. Various research reports have evidenced that these altered processes might play a role in the emergence of resistance. This review addresses the recent advances in understanding the underlying mechanisms of ovarian cancer resistance and covers sophisticated alternative pathways to overcome these resistance mechanisms in patients.

Efficacy of photodynamic therapy using 5-aminolevulinic acid-induced photosensitization is enhanced in pancreatic cancer cells with acquired drug resistance

The use of 5-aminolevulinic acid (ALA) as a precursor for protoporphyrin IX (PpIX) is an established photosensitization strategy for photodynamic therapy (PDT) and fluorescence guided surgery. Ongoing studies are focused on identifying approaches to enhance PpIX accumulation as well as to identify tumor sub-types associated with high PpIX accumulation. In this study, we investigated PpIX accumulation and PDT treatment response with respect to nodule size in 3D cultures of pancreatic cancer cells (Panc1) and a derivative subline (Panc1OR), which has acquired drug resistance and exhibits increased epithelial mesenchymal transition. In monolayer and 3D culture dose response studies the Panc1OR cells exhibit significantly a higher level of photokilling at lower light doses than the drug naïve cells. Panc1OR also exhibits increased PpIX accumulation. Further analysis of cell killing efficiency per molecule of intracellular PpIX indicates that the drug resistant cells are intrinsically more responsive to PDT. Additional investigation using exogenous delivery of PpIX also shows higher cell killing in drug resistant cells, under conditions which achieve approximately the same intracellular PpIX. Overall these results are significant as they demonstrate that this example of drug-resistant cells associated with aggressive disease progression and poor clinical outcomes, show increased sensitivity to ALA-PDT.

Advances in smart nanotechnology-supported photodynamic therapy for cancer

Cancer has emerged as a formidable challenge in the 21st century, impacting society, public health, and the economy. Conventional cancer treatments often exhibit limited efficacy and considerable side effects, particularly in managing the advanced stages of the disease. Photodynamic therapy (PDT), a contemporary non-invasive therapeutic approach, employs photosensitizers (PS) in conjunction with precise light wavelengths to selectively target diseased tissues, inducing the generation of reactive oxygen species and ultimately leading to cancer cell apoptosis. In contrast to conventional therapies, PDT presents a lower incidence of side effects and greater precision in targeting. The integration of intelligent nanotechnology into PDT has markedly improved its effectiveness, as evidenced by the remarkable synergistic antitumor effects observed with the utilization of multifunctional nanoplatforms in conjunction with PDT. This paper provides a concise overview of the principles underlying PS and PDT, while also delving into the utilization of nanomaterial-based PDT in the context of cancer treatment.

PpIX-enabled fluorescence-based detection and photodynamic priming of platinum-resistant ovarian cancer cells under fluid shear stress

Over 75% percent of ovarian cancer patients are diagnosed with advanced-stage disease characterized by unresectable intraperitoneal dissemination and the presence of ascites, or excessive fluid build-up within the abdomen. Conventional treatments include cytoreductive surgery followed by multi-line platinum and taxane chemotherapy regimens. Despite an initial response to treatment, over 75% of patients with advanced-stage ovarian cancer will relapse and succumb to platinum-resistant disease. Recent evidence suggests that fluid shear stress (FSS), which results from the movement of fluid such as ascites, induces epithelial-to-mesenchymal transition and confers resistance to carboplatin in ovarian cancer cells. This study demonstrates, for the first time, that FSS-induced platinum resistance correlates with increased cellular protoporphyrin IX (PpIX), the penultimate downstream product of heme biosynthesis, the production of which can be enhanced using the clinically approved pro-drug aminolevulinic acid (ALA). These data suggest that, with further investigation, PpIX could serve as a fluorescence-based biomarker of FSS-induced platinum resistance. Additionally, this study investigates the efficacy of PpIX-enabled photodynamic therapy (PDT) and the secretion of extracellular vesicles under static and FSS conditions in Caov-3 and NIH:OVCAR-3 cells, two representative cell lines for high-grade serous ovarian carcinoma (HGSOC), the most lethal form of the disease. FSS induces resistance to ALA-PpIX-mediated PDT, along with a significant increase in the number of EVs. Finally, the ability of PpIX-mediated photodynamic priming (PDP) to enhance carboplatin efficacy under FSS conditions is quantified. These preliminary findings in monolayer cultures necessitate additional studies to determine the feasibility of PpIX as a fluorescence-based indicator, and mediator of PDP, to target chemoresistance in the context of FSS.

Overcoming the effects of fluid shear stress in ovarian cancer cell lines: Doxorubicin alone or photodynamic priming to target platinum resistance

Resistance to platinum-based chemotherapies remains a significant challenge in advanced-stage high-grade serous ovarian carcinoma, and patients with malignant ascites face the poorest outcomes. It is, therefore, important to understand the effects of ascites, including the associated fluid shear stress (FSS), on phenotypic changes and therapy response, specifically FSS-induced chemotherapy resistance and the underlying mechanisms in ovarian cancer. This study investigated the effects of FSS on response to cisplatin, a platinum-based chemotherapy, and doxorubicin, an anthracycline, both of which are commonly used to manage advanced-stage ovarian cancer. Consistent with prior research, OVCAR-3 and Caov-3 cells cultivated under FSS demonstrated significant resistance to cisplatin. Examination of the role of mitochondria revealed an increase in mitochondrial DNA copy number and intracellular ATP content in cultures grown under FSS, suggesting that changes in mitochondria number and metabolic activity may contribute to platinum resistance. Interestingly, no resistance to doxorubicin was observed under FSS, the first such observation of a lack of resistance under these conditions. Finally, this study demonstrated the potential of photodynamic priming using benzoporphyrin derivative, a clinically approved photosensitizer that localizes in part to mitochondria and endoplasmic reticula, to enhance the efficacy of cisplatin, but not doxorubicin, thereby overcoming FSS-induced platinum resistance.

Photodynamic therapy with curcumin and near-infrared radiation as an antitumor strategy to glioblastoma cells

Glioblastoma is a malignant neoplasm that develops in the central nervous system and is characterized by high rates of cell proliferation and invasion, presenting resistance to treatments and a poor prognosis. Photodynamic therapy (PDT) is a therapeutic modality that can be applied in oncological cases and stands out for being less invasive. Photosensitizers (PS) of natural origin gained prominence in PDT. Curcumin (CUR) is a natural compound that has been used in PDT, considered a promising PS. In this work, we evaluated the effects of PDT-mediated CUR and near-infrared radiation (NIR) in glioblastoma cells. Through trypan blue exclusion analysis, we chose the concentration of 5 μM of CUR and the dose of 2 J/cm2 of NIR that showed better responses in reducing the viable cell number in the C6 cell line and did not show cytotoxic/cytostatic effects in the HaCat cell line. Our results show that there is a positive interaction between CUR and NIR as a PDT model since there was an increase in ROS levels, a decrease in cell proliferation, increase in cytotoxicity with cell death by autophagy and necrosis, in addition to the presence of oxidative damage to proteins. These results suggest that the use of CUR and NIR is a promising strategy for the antitumor application of PDT.

N-Phenyl-2-Pyridone-Derived Endoperoxide Suppressing both Lung Cancer and Idiopathic Pulmonary Fibrosis Progression by Three-Pronged Action

We report an endoperoxide compound (E5) which can deliver three therapeutic components by a thermal cycloreversion, namely, singlet oxygen, triplet oxygen and 3-methyl-N-phenyl-2-pyridone (P5), thus targeting multiple mechanisms for treating non-small cell lung cancer and idiopathic pulmonary fibrosis. In aqueous environment, E5 undergoes clean reaction to afford three therapeutic components with a half-life of 8.3 hours without the generation of other by-products, which not only achieves good cytotoxicity toward lung cancer cells and decreases the levels of hypoxia-inducible factor 1α (HIF-1α) protein, but also inhibits the transforming growth factor β1 (TGF-β1) induced fibrosis in vitro. In vivo experiments also demonstrated the efficacy of E5 in inhibiting tumor growth and relieving idiopathic pulmonary fibrosis, while exhibiting good biocompatibility. Many lines of evidence reveal the therapeutic efficacy of singlet oxygen and 3-methyl-N-phenyl-2-pyridone for these two lung diseases, and triplet oxygen could downregulate HIF-1α and relieve tumor hypoxia which is a critical issue in photodynamic therapy (PDT). Unlike other combination therapies, in which multiple therapeutic agents are given in independent formulations, our work demonstrates single molecule endoperoxide prodrugs could be developed as new platforms for treatment of cancers and related diseases.

Reactive oxygen species produced by photodynamic therapy enhance docosahexaenoic acid lipid peroxidation and induce the death of breast cancer cells

Breast cancer remains a serious threat to women's physical and emotional health. The combination therapies can overcome the deficiency of single therapy, enhance the therapeutic effects and reduce the side effects at the same time. In this study, we synthesize a novel nanomedicine that enhanced the therapeutic effects of breast cancer treatment by combining photodynamic therapy and chemotherapy. The doxorubicin (DOX) and photosensitizer methyl pyropheophorbide-a (MPPa) are loaded into the nano-drug delivery system as DPSPFA/MPPa/DOX. In response to near-infrared (NIR) laser, the drugs were quickly released to the cancer cells. The MPPa produces reactive oxygen species (ROS) under the action of photodynamics. Unsaturated fatty acids with ROS promotes lipid peroxidation and the combination of chemotherapy and photodynamic therapy. The data shows that the DPSPFA/MPPa/DOX has a spherical shape, good dispersibility and stability, and the particle size is roughly 200 nm. The drug loading capability of DOX is about 13 %. Both of MCF7 cell model in vitro and breast cancer model in vivo, DPSPFA/MPPa/DOX showed an excellent anti-tumor effect of 86.9 % and without any obvious side effects. These findings might offer potential for a new approach for breast cancer treatment.

ROS-Responsive Nanoprobes for Bimodal Imaging-Guided Cancer Targeted Combinatorial Therapy

Purpose

Chemotherapy mediated by Reactive oxygen species (ROS)-responsive drug delivery systems can potentially mitigate the toxic side effects of chemotherapeutic drugs and significantly enhance their therapeutic efficacy. However, achieving precise targeted drug delivery and real-time control of ROS-responsive drug release at tumor sites remains a formidable challenge. Therefore, this study aimed to describe a ROS-responsive drug delivery system with specific tumor targeting capabilities for mitigating chemotherapy-induced toxicity while enhancing therapeutic efficacy under guidance of Fluorescence (FL) and Magnetic resonance (MR) bimodal imaging.

Methods

Indocyanine green (ICG), Doxorubicin (DOX) prodrug pB-DOX and Superparamagnetic iron oxide (SPIO, Fe3O4) were encapsulated in poly(lactic-co-glycolic acid) (PLGA) by double emulsification method to prepare ICG/ pB-DOX/ Fe3O4/ PLGA nanoparticles (IBFP NPs). The surface of IBFP NPs was functionalized with mammaglobin antibodies (mAbs) by carbodiimide method to construct the breast cancer-targeting mAbs/ IBFP NPs (MIBFP NPs). Thereafter, FL and MR bimodal imaging ability of MIBFP NPs was evaluated in vitro and in vivo. Finally, the combined photodynamic therapy (PDT) and chemotherapy efficacy evaluation based on MIBFP NPs was studied.

Results

The multifunctional MIBFP NPs exhibited significant targeting efficacy for breast cancer. FL and MR bimodal imaging clearly displayed the distribution of the targeting MIBFP NPs in vivo. Upon near-infrared laser irradiation, the MIBFP NPs loaded with ICG effectively generated ROS for PDT, enabling precise tumor ablation. Simultaneously, it triggered activation of the pB-DOX by cleaving its sensitive moiety, thereby restoring DOX activity and achieving ROS-responsive targeted chemotherapy. Furthermore, the MIBFP NPs combined PDT and chemotherapy to enhance the efficiency of tumor ablation under guidance of bimodal imaging.

Conclusion

MIBFP NPs constitute a novel dual-modality imaging-guided drug delivery system for targeted breast cancer therapy and offer precise and controlled combined treatment options.

The therapeutic efficacy of 5-ALA based photodynamic therapy and chemotherapy combination in triple negative breast cancer cells

Triple negative breast cancer (TNBC) is one of the subtypes of breast cancer characterized by a heterogeneous and aggressive nature. Photodynamic therapy (PDT) has drawn significant attention in cancer treatment. However, solubility of photosensitizer, penetration problems into a target tissue and insufficient oxygen concentration limit the effectiveness of PDT. To overcome these limitations and to reduce the side effects of chemotherapy, combination treatment modalities play an essential role in cancer treatment. In this study, we aimed to investigate the combination efficacy of cisplatin-based chemotherapy and 5-Aminolevulinic acid (5-ALA)/PDT in TNBC cells and healthy breast cells in vitro. To determine the effect of the combination effects of cisplatin and 5-ALA/PDT on TNBC cells, two treatment protocols (simultaneous and sequential combination therapy) were evaluated compared with cisplatin and 5-ALA/PDT monotherapy and WST-1, Annexin V assay, acridine orange (AO) and mitochondrial staining were performed. Our findings showed that MDA-MB-231 TNBC cell viability was significantly decreased following simultaneous combination treatment compared to cisplatin and 5-ALA/PDT monotherapy. Additionally, simultaneous combination treatment was more effective than sequential combination treatment. The simultaneous combination treatment of 2.5 µM cisplatin and 5-ALA/PDT at 6 J/cm2 and 9 J/cm2 induced 46.78% and 53.6% total apoptotic death, respectively in TNBC cells compared with monotherapies (cisplatin (37.88%) and 5-ALA/PDT (6 J/cm2: 31.48% and 9 J/cm2: 37.78%). Additionally, cisplatin and 5-ALA/PDT combination treatment resulted in nuclear fragmentation and mitochondrial damage due to apoptosis. Our results suggest that cisplatin and 5-ALA/PDT simultaneous combination therapy could be a promising new alternative strategy for treating TNBC. However, further studies are required to assess the underlying molecular mechanisms of cisplatin and 5-ALA/PDT combination treatment at the molecular level.

Apoptotic efficiency of Dicoma anomala biosynthesized silver nanoparticles against A549 lung cancer cells

Lung cancer is one of the common forms of cancer that affects both men and women and is regarded as the leading cause of cancer related deaths. It is characterized by unregulated cell division of altered cells within the lung tissues. Green nanotechnology is a promising therapeutic option that is adopted in cancer research. Dicoma anomala (D. anomala) is one of the commonly used African medicinal plant in the treatment of different medical conditions including cancer. In the present study, silver nanoparticles (AgNPs) were synthesized using D. anomala MeOH root extract. We evaluated the anticancer efficacy of the synthesized AgNPs as an individual treatment as well as in combination with pheophorbide a (PPBa) mediated photodynamic therapy (PDT) in vitro. UV-VIS spectroscopy, high-resolution transmission electron microscopy (HR-TEM), Scanning electron microscopy (SEM) and energy dispersive X-ray spectroscopy (EDS) was used to confirm the formation of D.A AgNPs. Post 24 h treatment, A549 cells were evaluated for ATP proliferation, morphological changes supported by LIVE/DEAD assay, and caspase activities. All experiments were repeated four times (n=4), with findings being analysed using SPSS statistical software version 27 set at 0.95 confidence interval. The results from the present study revealed a dose-dependent decrease in cell proliferation in both individual and combination therapy of PPBa mediated PDT and D.A AgNPs on A549 lung cancer cells with significant morphological changes. Additionally, LIVE/DEAD assay displayed a significant increase in the number of dead cell population in individual treatments (i.e., IC50's treated A549 cells) as well as in combination therapy. In conclusion, the findings from this study demonstrated the anticancer efficacy of green synthesized AgNPs as a mono-therapeutic drug as well as in combination with a chlorophyll derivative PPBa in PDT. Taken together, the findings highlight the therapeutic potential of green nanotechnology in medicine.

Specific photodamage on HT-29 cancer cells leads to endolysosomal failure and autophagy blockage by cathepsin depletion

Endolysosomes perform a wide range of cellular functions, including nutrient sensing, macromolecule digestion and recycling, as well as plasma membrane repair. Because of their high activity in cancerous cells, endolysosomes are attractive targets for the development of novel cancer treatments. Light-activated compounds termed photosensitizers (PS) can catalyze the oxidation of specific biomolecules and intracellular organelles. To selectively damage endosomes and lysosomes, HT-29 colorectal cancer cells were incubated with nanomolar concentrations of meso-tetraphenylporphine disulfonate (TPPS2a), an amphiphilic PS taken up via endocytosis and activated by green light (522 nm, 2.1 J.cm-1). Several cellular responses were characterized by a combination of immunofluorescence and immunoblotting assays. We showed that TPPS2a photosensitization blocked autophagic flux without extensive endolysosomal membrane rupture. Nevertheless, there was a severe functional failure of endolysosomes due to a decrease in CTSD (cathepsin D, 55%) and CTSB (cathepsin B, 52%) maturation. PSAP (prosaposin) processing (into saposins) was also considerably impaired, a fact that could be detrimental to glycosphingolipid homeostasis. Therefore, photosensitization of HT-29 cells previously incubated with a low concentration of TPPS2a promotes endolysosomal dysfunction, an effect that can be used to improve cancer therapies.

Shedding Light on Chemoresistance: The Perspective of Photodynamic Therapy in Cancer Management

The persistent failure of standard chemotherapy underscores the urgent need for innovative and targeted approaches in cancer treatment. Photodynamic therapy (PDT) has emerged as a promising photochemistry-based approach to address chemoresistance in cancer regimens. PDT not only induces cell death but also primes surviving cells, enhancing their susceptibility to subsequent therapies. This review explores the principles of PDT and discusses the concept of photodynamic priming (PDP), which augments the effectiveness of treatments like chemotherapy. Furthermore, the integration of nanotechnology for precise drug delivery at the right time and location and PDT optimization are examined. Ultimately, this study highlights the potential and limitations of PDT and PDP in cancer treatment paradigms, offering insights into future clinical applications.

Nanoparticle-mediated Photodynamic Therapy as a Method to Ablate Oral Cavity Squamous Cell Carcinoma in Preclinical Models

Photodynamic therapy (PDT) is a tissue ablation technique able to selectively target tumor cells by activating the cytotoxicity of photosensitizer dyes with light. PDT is nonsurgical and tissue sparing, two advantages for treatments in anatomically complex disease sites such as the oral cavity. We have previously developed PORPHYSOME (PS) nanoparticles assembled from chlorin photosensitizer-containing building blocks (∼94,000 photosensitizers per particle) and capable of potent PDT. In this study, we demonstrate the selective uptake and curative tumor ablation of PS-enabled PDT in three preclinical models of oral cavity squamous cell carcinoma (OCSCC): biologically relevant subcutaneous Cal-33 (cell line) and MOC22 (syngeneic) mouse models, and an anatomically relevant orthotopic VX-2 rabbit model. Tumors selectively uptake PS (10 mg/kg, i.v.) with 6-to 40-fold greater concentration versus muscle 24 hours post-injection. Single PS nanoparticle-mediated PDT (PS-PDT) treatment (100 J/cm2, 100 mW/cm2) of Cal-33 tumors yielded significant apoptosis in 65.7% of tumor cells. Survival studies following PS-PDT treatments demonstrated 90% (36/40) overall response rate across all three tumor models. Complete tumor response was achieved in 65% of Cal-33 and 91% of MOC22 tumor mouse models 14 days after PS-PDT, and partial responses obtained in 25% and 9% of Cal-33 and MOC22 tumors, respectively. In buccal VX-2 rabbit tumors, combined surface and interstitial PS-PDT (200 J total) yielded complete responses in only 60% of rabbits 6 weeks after a single treatment whereas three repeated weekly treatments with PS-PDT (200 J/week) achieved complete ablation in 100% of tumors. PS-PDT treatments were well tolerated by animals with no treatment-associated toxicities and excellent cosmetic outcomes.

SIGNIFICANCE

PS-PDT is a safe and repeatable treatment modality for OCSCC ablation. PS demonstrated tumor selective uptake and PS-PDT treatments achieved reproducible efficacy and effectiveness in multiple tumor models superior to other clinically tested photosensitizer drugs. Cosmetic and functional outcomes were excellent, and no clinically significant treatment-associated toxicities were detected. These results are enabling of window of opportunity trials for fluorescence-guided PS-PDT in patients with early-stage OCSCC scheduled for surgery.

Advancing Cancer Treatment: Enhanced Combination Therapy through Functionalized Porous Nanoparticles

Cancer remains a major global health challenge, necessitating the development of innovative treatment strategies. This review focuses on the functionalization of porous nanoparticles for combination therapy, a promising approach to enhance cancer treatment efficacy while mitigating the limitations associated with conventional methods. Combination therapy, integrating multiple treatment modalities such as chemotherapy, phototherapy, immunotherapy, and others, has emerged as an effective strategy to address the shortcomings of individual treatments. The unique properties of mesoporous silica nanoparticles (MSN) and other porous materials, like nanoparticles coated with mesoporous silica (NP@MS), metal-organic frameworks (MOF), mesoporous platinum nanoparticles (mesoPt), and carbon dots (CDs), are being explored for drug solubility, bioavailability, targeted delivery, and controlled drug release. Recent advancements in the functionalization of mesoporous nanoparticles with ligands, biomaterials, and polymers are reviewed here, highlighting their role in enhancing the efficacy of combination therapy. Various research has demonstrated the effectiveness of these nanoparticles in co-delivering drugs and photosensitizers, achieving targeted delivery, and responding to multiple stimuli for controlled drug release. This review introduces the synthesis and functionalization methods of these porous nanoparticles, along with their applications in combination therapy.

Nano-phototherapy: Favorable prospects for cancer treatment

Nanotechnology-based phototherapies have drawn interest in the fight against cancer because of its noninvasiveness, high flexibility, and precision in terms of cancer targeting and drug delivery based on its surface properties and size. Phototherapy has made remarkable development in recent decades. Approaches to phototherapy, which utilize nanomaterials or nanotechnology have emerged to contribute to advances around nanotechnologies in medicine, particularly for cancers. A brief overviews of the development of photodynamic therapy as well as its mechanism in cancer treatment is provided. We emphasize the design of novel nanoparticles utilized in photodynamic therapy while summarizing the representative progress during the recent years. Finally, to forecast important future research in this area, we examine the viability and promise of photodynamic therapy systems based on nanoparticles in clinical anticancer treatment applications and briefly make mention of the elimination of all reactive metabolites pertaining to nano formulations inside living organisms providing insight into clinical mechanistic processes. Future developments and therapeutic prospects for photodynamic treatments are anticipated. Our viewpoints might encourage scientists to create more potent phototherapy-based cancer therapeutic modalities. This article is categorized under: Therapeutic Approaches and Drug Discovery > Nanomedicine for Oncologic Disease.

Heterogeneous photocatalytic degradation of antiviral drug didanosine mediated by rose bengal and TiO2 nanoparticles

There is a great concern among the researcher to remove the problem of the persistent organic pollutants in wastewater. Pharmaceutical agrochemical and personal care products are generally considered Persistent organic pollutants. Therefore, it is a matter of concern to develop new techniques how to remove these pollutants safely at low cost. This study mainly focuses on the commonly used antiviral drug didanosine and one most commonly used dye rose bengal. In this study, an organic dye rose bengal and TiO2 nanoparticles have been used in combination with UV light to achieve the photodegradation of selected pharmaceutical products and the dye was also degraded by using TiO2 Nanoparticles. The formation of three oxidation products was detected by using a very popular separation technique thin layer and column chromatography. The isolated photoproduct was characterized by using advanced characterization techniques like FTIR (Fourier transform infrared spectroscopy), UV Spectroscopy, and Proton and 13C NMR (Nuclear Magnetic Resonance spectroscopy). The role of singlet oxygen as an active species in this reaction was confirmed by using D2O as a reaction medium. The role of singlet oxygen in this photochemical reaction was also established by the addition of sodium azide. The TiO2 nanophotocatalyst efficiently degrade the didanosine and rose bengal in the presence of the UV light. In the TiO2-induced photocatalytic degradation of didanosine and dyes, the hydroxyl and superoxide radical anion play a prominent role. The finding of this manuscript is very useful to develop an efficient low-cost method for the treatment of wastewater contaminated by antiviral drugs, similar pharmaceutical products and dyes. This study was also very helpful to establish a plausible mechanism behind the phototoxicity of the didanosine.

A Photoactive Supramolecular Complex Targeting PD-L1 Reveals a Weak Correlation between Photoactivation Efficiency and Receptor Expression Levels in Non-Small-Cell Lung Cancer Tumor Models

Photo-immunotherapy uses antibodies conjugated to photosensitizers to produce nanostructured constructs endowed with targeting properties and photo-inactivation capabilities towards tumor cells. The superficial receptor density on cancer cells is considered a determining factor for the efficacy of the photodynamic treatment. In this work, we propose the use of a photoactive conjugate that consists of the clinical grade PD-L1-binding monoclonal antibody Atezolizumab, covalently linked to either the well-known photosensitizer eosin or the fluorescent probe Alexa647. Using single-molecule localization microscopy (direct stochastic optical reconstruction microscopy, dSTORM), and an anti-PD-L1 monoclonal antibody labelled with Alexa647, we quantified the density of PD-L1 receptors exposed on the cell surface in two human non-small-cell lung cancer lines (H322 and A549) expressing PD-L1 to a different level. We then investigated if this value correlates with the effectiveness of the photodynamic treatment. The photodynamic treatment of H322 and A549 with the photo-immunoconjugate demonstrated its potential for PDT treatments, but the efficacy did not correlate with the PD-L1 expression levels. Our results provide additional evidence that receptor density does not determine a priori the level of photo-induced cell death.

Cancer treatment therapies: traditional to modern approaches to combat cancers

As far as health issues are concerned, cancer causes one out of every six deaths around the globe. As potent therapeutics are still awaited for the successful treatment of cancer, some unconventional treatments like radiotherapy, surgery, and chemotherapy and some advanced technologies like gene therapy, stem cell therapy, natural antioxidants, targeted therapy, photodynamic therapy, nanoparticles, and precision medicine are available to diagnose and treat cancer. In the present scenario, the prime focus is on developing efficient nanomedicines to treat cancer. Although stem cell therapy has the capability to target primary as well as metastatic cancer foci, it also has the ability to repair and regenerate injured tissues. However, nanoparticles are designed to have such novel therapeutic capabilities. Targeted therapy is also now available to arrest the growth and development of cancer cells without damaging healthy tissues. Another alternative approach in this direction is photodynamic therapy (PDT), which has more potential to treat cancer as it does minimal damage and does not limit other technologies, as in the case of chemotherapy and radiotherapy. The best possible way to treat cancer is by developing novel therapeutics through translational research. In the present scenario, an important event in modern oncology therapy is the shift from an organ-centric paradigm guiding therapy to complete molecular investigations. The lacunae in anticancer therapy may be addressed through the creation of contemporary and pertinent cancer therapeutic techniques. In the meantime, the growth of nanotechnology, material sciences, and biomedical sciences has revealed a wide range of contemporary therapies with intelligent features, adaptable functions, and modification potential. The development of numerous therapeutic techniques for the treatment of cancer is summarized in this article. Additionally, it can serve as a resource for oncology and immunology researchers.

Near-infrared photodynamic and photothermal co-therapy based on organic small molecular dyes

Near-infrared (NIR) organic small molecule dyes (OSMDs) are effective photothermal agents for photothermal therapy (PTT) due to their advantages of low cost and toxicity, good biodegradation, and strong NIR absorption over a wide wavelength range. Nevertheless, OSMDs have limited applicability in PTT due to their low photothermal conversion efficiency and inadequate destruction of tumor regions that are nonirradiated by NIR light. However, they can also act as photosensitizers (PSs) to produce reactive oxygen species (ROS), which can be further eradicated by using ROS-related therapies to address the above limitations of PTT. In this review, the synergistic mechanism, composition, and properties of photodynamic therapy (PDT)-PTT nanoplatforms were comprehensively discussed. In addition, some specific strategies for further improving the combined PTT and PDT based on OSMDs for cancer to completely eradicate cancer cells were outlined. These strategies include performing image-guided co-therapy, enhancing tumor infiltration, increasing H2O2 or O2 in the tumor microenvironment, and loading anticancer drugs onto nanoplatforms to enable combined therapy with phototherapy and chemotherapy. Meanwhile, the intriguing prospects and challenges of this treatment modality were also summarized with a focus on the future trends of its clinical application.

Impact of Surface Charge-Tailored Gold Nanorods for Selective Targeting of Mitochondria in Breast Cancer Cells Using Photodynamic Therapy

Herein, the impact of surface charge tailored of gold nanorods (GNRs) on breast cancer cells (MCF-7 and MDA-MB-231) upon conjugation with triphenylphosphonium (TPP) for improved photodynamic therapy (PDT) targeting mitochondria was studied. The salient features of the study are as follows: (i) positive (CTAB@GNRs) and negative (PSS-CTAB@GNRs) surface-charged gold nanorods were developed and characterized; (ii) the mitochondrial targeting efficiency of gold nanorods was improved by conjugating TPP molecules; (iii) the conjugated nanoprobes (TPP-CTAB@GNRs and TPP-PSS-CTAB@GNRs) were evaluated for PDT in the presence of photosensitizer (PS), 5-aminolevulinic acid (5-ALA) in breast cancer cells; (iv) both nanoprobes (TPP-CTAB@GNRs and TPP-PSS-CTAB@GNRs) induce apoptosis, damage DNA, generate reactive oxygen species, and decrease mitochondrial membrane potential upon 5-ALA-based PDT; and (v) 5-ALA-PDT of two nanoprobes (TPP-CTAB@GNRs and TPP-PSS-CTAB@GNRs) impact cell signaling (PI3K/AKT) pathway by upregulating proapoptotic genes and proteins. Based on the results, we confirm that the positively charged (rapid) nanoprobes are more advantageous than their negatively (slow) charged nanoprobes. However, depending on the kind and degree of cancer, both nanoprobes can serve as efficient agents for delivering anticancer therapy.

Hydrogen Sulfide Responsive Phototherapy Agents: Design Strategies and Biological Applications

Hydrogen sulfide (H2S) is one of the critical gasotransmitters, which play important roles in regular physiological processes, especially in vital signaling pathways. However, fluctuations in endogenous H2S concentration can be linked to serious health problems, such as neurodegenerative diseases, cancer, diabetes, inflammation, cardiovascular diseases, and hypertension. Thus, it has attracted a great deal of attention in therapeutic applications, specifically in the field of phototherapy. Photodynamic therapy (PDT) and photothermal therapy (PTT) are two subclasses of phototherapy, which utilize either reactive oxygen species (ROS) or local temperature increase upon irradiation of a photosensitizer (PS) to realize the therapeutic action. Phototherapies offer unique advantages compared to conventional methods; thus, they are highly promising and popular. One of the design principles followed in new generation PSs is to build activity-based PSs, which stay inactive before getting activated by disease-associated stimuli. These activatable PSs dramatically improve the selectivity and efficacy of the therapy. In this review, we summarize small molecule and nanomaterial-based PDT and PTT agents that are activated selectively by H2S to initiate their cytotoxic effect. We incorporate single mode PDT and PTT agents along with synergistic and/or multimodal photosensitizers that can combine more than one therapeutic approach. Additionally, H2S-responsive theranostic agents, which offer therapy and imaging at the same time, are highlighted. Design approaches, working principles, and biological applications for each example are discussed in detail.

Isoliensinine augments the therapeutic potential of paclitaxel in multidrug-resistant colon cancer stem cells and induced mitochondria-mediated cell death

Previously we have reported the isoliensinine (ISO) potentates the therapeutic potential of cisplatin in cisplatin resistant colorectal cancer stem cells. The present study evaluates the chemo-sensitizing potential of the combinatorial regimen of ISO and Paclitaxcel (PTX) on multidrug-resistant (MDR)-HCT-15 cells to reduce the dose requirement of both ISO and PTX. The results of the present study suggest that treatment with the combinatorial regimen of ISO and PTX enhanced the cytotoxic effect with resultant increase in apoptosis in MDR-HCT-15 cells as evident from the altered cellular morphology, G2/M cell cycle arrest, propidium iodide uptake, Annexin V, increased intracellular Ca2+ accumulation, decreased mitochondrial membrane potential, diminished ATP production, PARP-1 cleavage, altered expression of ERK1/2, and apoptotic proteins. Treatment with combinatorial regimen of ISO and PTX also modulated the expression of the transcription factors SOX2, OCT4 which determine the stemness of cancer cells. Thus, results of the present study suggest that ISO and PTX combination regimen induces apoptosis in MDR-HCT-15 in a synergistic manner.

Imaging and photodynamic therapy of prostate cancer using a theranostic PSMA-targeting ligand

PURPOSE

Incomplete resection of prostate cancer (PCa) results in increased risk of disease recurrence. Combined fluorescence-guided surgery with tumor-targeted photodynamic therapy (tPDT) may help to achieve complete tumor eradication. We developed a prostate-specific membrane antigen (PSMA) ligand consisting of a DOTA chelator for 111In labeling and a fluorophore/photosensitizer IRDye700DX (PSMA-N064). We evaluated the efficacy of PSMA-tPDT using PSMA-N064 in cell viability assays, a mouse xenograft model and in an ex vivo incubation study on fresh human PCa tissue.

METHODS

In vitro, therapeutic efficacy of PSMA-N064 was evaluated using PSMA-positive LS174T cells and LS174T wild-type cells. In vivo, PSMA-N064-mediated tPDT was tested in immunodeficient BALB/c mice-bearing PSMA-positive LS174T xenografts. Tumor growth and survival were compared to control mice that received either NIR light or ligand injection only. Ex vivo tPDT efficacy was evaluated in excised fresh human PCa tissue incubated with PSMA-N064.

RESULTS

In vitro, tPDT led to a PSMA-specific light- and ligand dose-dependent loss in cell viability. In vivo, tPDT-induced tumor cell apoptosis, delayed tumor growth, and significantly improved survival (p = 0.004) of the treated PSMA-positive tumor-bearing mice compared with the controls. In fresh ex vivo human PCa tissue, apoptosis was significantly increased in PSMA-tPDT-treated samples compared to non-treated control samples (p = 0.037).

CONCLUSION

This study showed the feasibility of PSMA-N064-mediated tPDT in cell assays, a xenograft model and excised fresh human PCa tissue. This paves the way to investigate the impact of in vivo PSMA-tPDT on surgical outcome in PCa patients.

Combinations of Photodynamic Therapy with Other Minimally Invasive Therapeutic Technologies against Cancer and Microbial Infections

The rapid rise in research and development following the discovery of photodynamic therapy to establish novel photosensitizers and overcome the limitations of the technology soon after its clinical translation has given rise to a few significant milestones. These include several novel generations of photosensitizers, the widening of the scope of applications, leveraging of the offerings of nanotechnology for greater efficacy, selectivity for the disease over host tissue and cells, the advent of combination therapies with other similarly minimally invasive therapeutic technologies, the use of stimulus-responsive delivery and disease targeting, and greater penetration depth of the activation energy. Brought together, all these milestones have contributed to the significant enhancement of what is still arguably a novel technology. Yet the major applications of photodynamic therapy still remain firmly located in neoplasms, from where most of the new innovations appear to launch to other areas, such as microbial, fungal, viral, acne, wet age-related macular degeneration, atherosclerosis, psoriasis, environmental sanitization, pest control, and dermatology. Three main value propositions of combinations of photodynamic therapy include the synergistic and additive enhancement of efficacy, the relatively low emergence of resistance and its rapid development as a targeted and high-precision therapy. Combinations with established methods such as chemotherapy and radiotherapy and demonstrated applications in mop-up surgery promise to enhance these top three clinical tools. From published in vitro and preclinical studies, clinical trials and applications, and postclinical case studies, seven combinations with photodynamic therapy have become prominent research interests because they are potentially easily applied, showing enhanced efficacy, and are rapidly translating to the clinic. These include combinations with chemotherapy, photothermal therapy, magnetic hyperthermia, cold plasma therapy, sonodynamic therapy, immunotherapy, and radiotherapy. Photochemical internalization is a critical mechanism for some combinations.

Photodynamic and Photothermal Therapies: Synergy Opportunities for Nanomedicine

Tumoricidal photodynamic (PDT) and photothermal (PTT) therapies harness light to eliminate cancer cells with spatiotemporal precision by either generating reactive oxygen species or increasing temperature. Great strides have been made in understanding biological effects of PDT and PTT at the cellular, vascular and tumor microenvironmental levels, as well as translating both modalities in the clinic. Emerging evidence suggests that PDT and PTT may synergize due to their different mechanisms of action, and their nonoverlapping toxicity profiles make such combination potentially efficacious. Moreover, PDT/PTT combinations have gained momentum in recent years due to the development of multimodal nanoplatforms that simultaneously incorporate photodynamically- and photothermally active agents. In this review, we discuss how combining PDT and PTT can address the limitations of each modality alone and enhance treatment safety and efficacy. We provide an overview of recent literature featuring dual PDT/PTT nanoparticles and analyze the strengths and limitations of various nanoparticle design strategies. We also detail how treatment sequence and dose may affect cellular states, tumor pathophysiology and drug delivery, ultimately shaping the treatment response. Lastly, we analyze common experimental design pitfalls that complicate preclinical assessment of PDT/PTT combinations and propose rational guidelines to elucidate the mechanisms underlying PDT/PTT interactions.

Identifying TOPK and Hypoxia Hallmarks in Esophageal Tumors for Photodynamic/Chemo/Immunotherapy and Liver Metastasis Inhibition with Nanocarriers

Although esophageal squamous cell carcinoma (ESCC) is one of the most lethal cancers, there are major bottlenecks in its therapeutic approaches, primarily the identification of clinically relevant targets and the lack of effective targeted therapeutics. Herein, we identified the hallmarks of ESCC, namely, high T-lymphokine-activated killer cell-originated protein kinase (TOPK) expression in human ESCC tumors and its correlation with poor patient prognosis and hypoxia in the tumor microenvironment. We developed hypoxia-sensitive nanoparticles encapsulating TOPK inhibitor OTS964 and photosensitizer chlorin e6 for the imaging-directed precision therapy of ESCC tumors. The sub-100 nm monodisperse nanoparticles efficiently delivered drugs into the human ESCC KYSE 150 cancer cells to kill the cells. The nanoparticles were selectively accumulated in the ESCC tumors after intravenous (i.v.) injection, thereby enabling the diagnosis and photoacoustic imaging-guided local laser irradiation of tumors. The combination of chemotherapy and photodynamic therapy effectively eradicated human ESCC KYSE 150 tumors and inhibited liver metastasis and recurrence by suppressing TOPK and inducing ESCC cell apoptosis. The nanoparticle-based therapies further stimulated high rates of natural killer cells in ESCC tumors, thereby exhibiting the potential of immunotherapy. This study identified important therapeutic targets of ESCC tumors and delineated an effective nanocarrier-based approach for tumor microenvironment and molecular targeted therapy.

Recent Advances in Hydrogel-Based Phototherapy for Tumor Treatment

Phototherapeutic agent-based phototherapies activated by light have proven to be safe modalities for the treatment of various malignant tumor indications. The two main modalities of phototherapies include photothermal therapy, which causes localized thermal damage to target lesions, and photodynamic therapy, which causes localized chemical damage by generated reactive oxygen species (ROS). Conventional phototherapies suffer a major shortcoming in their clinical application due to their phototoxicity, which primarily arises from the uncontrolled distribution of phototherapeutic agents in vivo. For successful antitumor phototherapy, it is essential to ensure the generation of heat or ROS specifically occurs at the tumor site. To minimize the reverse side effects of phototherapy while improving its therapeutic performance, extensive research has focused on developing hydrogel-based phototherapy for tumor treatment. The utilization of hydrogels as drug carriers allows for the sustained delivery of phototherapeutic agents to tumor sites, thereby limiting their adverse effects. Herein, we summarize the recent advancements in the design of hydrogels for antitumor phototherapy, offer a comprehensive overview of the latest advances in hydrogel-based phototherapy and its combination with other therapeutic modalities for tumor treatment, and discuss the current clinical status of hydrogel-based antitumor phototherapy.

Inhibition of melanoma using a nanoceria-based prolonged oxygen-generating phototherapy hydrogel

Tumor hypoxic environment is an inevitable obstacle for photodynamic therapy (PDT) of melanoma. Herein, a multifunctional oxygen-generating hydrogel loaded with hyaluronic acid-chlorin e6 modified nanoceria and calcium peroxide (Gel-HCeC-CaO2) was developed for the phototherapy of melanoma. The thermo-sensitive hydrogel could act as a sustained drug delivery system to accumulate photosensitizers (chlorin e6, Ce6) around the tumor, followed by cellular uptake mediated by nanocarrier and hyaluronic acid (HA) targeting. The moderate sustained oxygen generation in the hydrogel was produced by the reaction of calcium peroxide (CaO2) with infiltrated H2O in the presence of catalase mimetic nanoceria. The developed Gel-HCeC-CaO2 could efficiently alleviate the hypoxia microenvironment of tumors as indicated by the expression of hypoxia-inducible factor -1α (HIF-1α), meeting the “once injection, repeat irradiation” strategy and enhanced PDT efficacy. The prolonged oxygen-generating phototherapy hydrogel system provided a new strategy for tumor hypoxia alleviation and PDT.

Photodynamic Priming Overcomes Per- and Polyfluoroalkyl Substance (PFAS)-Induced Platinum Resistance in Ovarian Cancer†

Per- and polyfluoroalkyl substances (PFAS) are widespread environmental contaminants linked to adverse outcomes, including for female reproductive biology and related cancers. We recently reported, for the first time, that PFAS induce platinum resistance in ovarian cancer, potentially through altered mitochondrial function. Platinum resistance is a major barrier in the management of ovarian cancer, necessitating complementary therapeutic approaches. Photodynamic therapy (PDT) is a light-based treatment modality that reverses platinum resistance and synergizes with platinum-based chemotherapy. The present study is the first to demonstrate the ability of photodynamic priming (PDP), a low-dose, sub-cytotoxic variant of PDT, to overcome PFAS-induced platinum resistance. Comparative studies of PDP efficacy using either benzoporphyrin derivative (BPD) or 5-aminolevulinic acid-induced protoporphyrin IX (PpIX) were conducted in two human ovarian cancer cell lines (NIH:OVCAR-3 and Caov-3). BPD and PpIX are clinically approved photosensitizers that preferentially localize to, or are partly synthesized in, mitochondria. PDP overcomes carboplatin resistance in PFAS-exposed ovarian cancer cells, demonstrating the feasibility of this approach to target the deleterious effects of environmental contaminants. Decreased survival fraction in PDP + carboplatin treated cells was accompanied by decreased mitochondrial membrane potential, suggesting that PDP modulates the mitochondrial membrane, reducing membrane potential and re-sensitizing ovarian cancer cells to carboplatin.

Photochemical Targeting of Mitochondria to Overcome Chemoresistance in Ovarian Cancer †

Ovarian cancer is the most lethal gynecologic malignancy with a stubborn mortality rate of ~65%. The persistent failure of multiline chemotherapy, and significant tumor heterogeneity, has made it challenging to improve outcomes. A target of increasing interest is the mitochondrion because of its essential role in critical cellular functions, and the significance of metabolic adaptation in chemoresistance. This review describes mitochondrial processes, including metabolic reprogramming, mitochondrial transfer and mitochondrial dynamics in ovarian cancer progression and chemoresistance. The effect of malignant ascites, or excess peritoneal fluid, on mitochondrial function is discussed. The role of photodynamic therapy (PDT) in overcoming mitochondria-mediated resistance is presented. PDT, a photochemistry-based modality, involves the light-based activation of a photosensitizer leading to the production of short-lived reactive molecular species and spatiotemporally confined photodamage to nearby organelles and biological targets. The consequential effects range from subcytotoxic priming of target cells for increased sensitivity to subsequent treatments, such as chemotherapy, to direct cell killing. This review discusses how PDT-based approaches can address key limitations of current treatments. Specifically, an overview of the mechanisms by which PDT alters mitochondrial function, and a summary of preclinical advancements and clinical PDT experience in ovarian cancer are provided.

Cobalamin (Vitamin B12) in Anticancer Photodynamic Therapy with Zn(II) Phthalocyanines

Photodynamic therapy (PDT) is a curative method, firstly developed for cancer therapy with fast response after treatment and minimum side effects. Two zinc(II) phthalocyanines (3ZnPc and 4ZnPc) and a hydroxycobalamin (Cbl) were investigated on two breast cancer cell lines (MDA-MB-231 and MCF-7) in comparison to normal cell lines (MCF-10 and BALB 3T3). The novelty of this study is a complex of non-peripherally methylpyridiloxy substituted Zn(II) phthalocyanine (3ZnPc) and the evaluation of the effects on different cell lines due to the addition of second porphyrinoid such as Cbl. The results showed the complete photocytotoxicity of both ZnPc-complexes at lower concentrations (<0.1 μM) for 3ZnPc. The addition of Cbl caused a higher phototoxicity of 3ZnPc at one order lower concentrations (<0.01 μM) with a diminishment of the dark toxicity. Moreover, it was determined that an increase of the selectivity index of 3ZnPc, from 0.66 (MCF-7) and 0.89 (MDA-MB-231) to 1.56 and 2.31, occurred by the addition of Cbl upon exposure with a LED 660 nm (50 J/cm²). The study suggested that the addition of Cbl can minimize the dark toxicity and improve the efficiency of the phthalocyanines for anticancer PDT applications.

X-ray Activated Nanoplatforms for Deep Tissue Photodynamic Therapy

Photodynamic therapy (PDT), the use of light to excite photosensitive molecules whose electronic relaxation drives the production of highly cytotoxic reactive oxygen species (ROS), has proven an effective means of oncotherapy. However, its application has been severely constrained to superficial tissues and those readily accessed either endoscopically or laparoscopically, due to the intrinsic scattering and absorption of photons by intervening tissues. Recent advances in the design of nanoparticle-based X-ray scintillators and photosensitizers have enabled hybridization of these moieties into single nanocomposite particles. These nanoplatforms, when irradiated with diagnostic doses and energies of X-rays, produce large quantities of ROS and permit, for the first time, non-invasive deep tissue PDT of tumors with few of the therapeutic limitations or side effects of conventional PDT. In this review we examine the underlying principles and evolution of PDT: from its initial and still dominant use of light-activated, small molecule photosensitizers that passively accumulate in tumors, to its latest development of X-ray-activated, scintillator-photosensitizer hybrid nanoplatforms that actively target cancer biomarkers. Challenges and potential remedies for the clinical translation of these hybrid nanoplatforms and X-ray PDT are also presented.

The Coming of Age of Neodymium: Redefining Its Role in Rare Earth Doped Nanoparticles

Among luminescent nanostructures actively investigated in the last couple of decades, rare earth (RE³⁺) doped nanoparticles (RENPs) are some of the most reported family of materials. The development of RENPs in the biomedical framework is quickly making its transition to the ∼800 nm excitation pathway, beneficial for both in vitro and in vivo applications to eliminate heating and facilitate higher penetration in tissues. Therefore, reports and investigations on RENPs containing the neodymium ion (Nd³⁺) greatly increased in number as the focus on ∼800 nm radiation absorbing Nd³⁺ ion gained traction. In this review, we cover the basics behind the RE³⁺ luminescence, the most successful Nd³⁺-RENP architectures, and highlight application areas. Nd³⁺-RENPs, particularly Nd³⁺-sensitized RENPs, have been scrutinized by considering the division between their upconversion and downshifting emissions. Aside from their distinctive optical properties, significant attention is paid to the diverse applications of Nd³⁺-RENPs, notwithstanding the pitfalls that are still to be addressed. Overall, we aim to provide a comprehensive overview on Nd³⁺-RENPs, discussing their developmental and applicative successes as well as challenges. We also assess future research pathways and foreseeable obstacles ahead, in a field, which we believe will continue witnessing an effervescent progress in the years to come.

MicroRNA-129-3p Inhibits Colorectal Cancer Proliferation

MicroRNA-129-3p plays a pro-cancer role in colorectal cancer by down-regulating BIM. This study intends to assess its role in colorectal cancer cells. A total of 30 colorectal cancers and 10 paracancerous samples were obtained to measure MicroRNA-129-3p expression by PCR. Colorectal cancer cells were transfected with miR-129-3p mimic or inhibitor followed by analysis of cell growth, apoptosis. miR-129-3p expression was significantly lower in colorectal cancer tissues than that in cancer adjacent tissues (P <0.05). miR-129-3p overexpression after mimic transfection significantly inhibited cancer cell viability and promoted apoptosis (P < 0.05). Moreover, it also significantly downregulated E2F5, BIM and FoxO3a in colorectal cancer cells. Furthermore, E2F5 was targeted by miR-129-3p. In conclusion, miR-129-3p inhibits colorectal cancer cell proliferation via targeting E2F5 to downregulate BIM, indicating that it might be a target for treating colorectal cancer.

Photodynamic therapy with zinc phthalocyanine enhances the anti-cancer effect of tamoxifen in breast cancer cell line: Promising combination treatment against triple-negative breast cancer?

Photodynamic therapy (PDT) is a light-based anti-neoplastic therapeutic approach. Growing evidence indicates that combining conventional anti-cancer therapies with PDT can be a promising approach to treat malignancies. Herein, we aimed to investigate anti-cancer effects of the combination treatment of zinc phthalocyanine (ZnPc)-PDT with tamoxifen (TA) on MDA-MB-231 cells (as a triple-negative breast cancer (TNBC) cell line). For this purpose, we investigated the cytotoxicity of TA and ZnPc-PDT on MDA-MB-231 cells performing the MTT assay. The effect of TA and ZnPc-PDT on the apoptosis of MDA-MB-231 cells was studied using Annexin V/PI and DAPI staining. The wound-healing assay, and colony formation assay were performed to study the effect of TA and ZnPc-PDT on the migration, and clonogenicity of MDA-MB-231 cells, respectively. The qRT-PCR was done to study the gene expression of caspase-8, caspase-9, caspase-3, ZEB1, ROCK1, SNAIL1, CD133, CD44, SOX2, and ABCG2 (ATP-binding cassette sub-family G member 2). Based on our results, monotherapies with TA and ZnPc-PDT can remarkably increase cell cytotoxicity effects, stimulate apoptosis via downregulating Bcl-2 and upregulating caspase-3 and caspase-9, inhibit migration via downregulating SNAIL1 and ZEB1, and suppress clonogenicity via downregulating SOX2 and CD44 in MDA-MB-231 cells. Besides, these monotherapies can downregulate the expression of ABCG2 in MDA-MB-231 cells. Nevertheless, the combination treatment can potentiate the above-mentioned anti-cancer effects compared to monotherapy with TA. Of interest, the combined treatment of TA with ZnPc-PDT can synergically increase cell cytotoxicity effects on MDA-MB-231 cells. In fact, synergistic effects were estimated by calculation of Combination Index (CI); that synergistic outcomes were observed in all groups. Also, this combination treatment can significantly upregulate the caspase-8 gene expression and downregulate ROCK1 and CD133 gene expression in MDA-MB-231 cells. Overall, our results show that ZnPc-PDT can more sensitize the MDA-MB-231 cells to TA treatment. Based on our knowledge and experiment, the synergistic effects of ZnPc-PDT and TA deserve further evaluation in cancer research.

Photodynamic therapy improves the clinical efficacy of advanced colorectal cancer and recruits immune cells into the tumor immune microenvironment

OBJECTIVE

Although photodynamic therapy (PDT) has been proven effective in various tumors, it has not been widely used as a routine treatment for colorectal cancer (CRC), and the characteristics of changes in the tumor microenvironment (TME) after PDT have not been fully elucidated. This study evaluated the efficacy of PDT in patients with advanced CRC and the changes in systemic and local immune function after PDT.

METHODS

Patients with stage III-IV CRC diagnosed in our hospital from November 2020 to July 2021 were retrospectively analyzed to compare the survival outcomes among each group. Subsequently, short-term efficacy, systemic and local immune function changes, and adverse reactions were assessed in CRC patients treated with PDT.

RESULTS

A total of 52 CRC patients were enrolled in this retrospective study from November 2020 to July 2021, and the follow-up period ended in March 2022. The overall survival (OS) of the PDT group was significantly longer than that of the non-PDT group (p=0.006). The objective response rate (ORR) and disease control rate two months after PDT were 44.4% and 88.9%, respectively. Differentiation degree (p=0.020) and necrosis (p=0.039) are two crucial factors affecting the short-term efficacy of PDT. The systemic immune function of stage III patients after PDT decreased, whereas that of stage IV patients increased. Local infiltration of various immune cells such as CD3+ T cells, CD4+ T cells, CD8+ T cells, CD20+ B cells and macrophages in the tumor tissue were significantly increased. No severe adverse reactions associated with PDT were observed.

CONCLUSION

PDT is effective for CRC without significant side effects according to the available data. It alters the TME by recruiting immune cells into tumor tissues.

Spotlight on Photoactivatable Liposomes beyond Drug Delivery: An Enabler of Multitargeting of Molecular Pathways

The potential of photoactivating certain molecules, photosensitizers (PS), resulting in photochemical processes, has long been realized in the form of photodynamic therapy (PDT) for the management of several cancerous and noncancerous pathologies. With an improved understanding of the photoactivation process and its broader implications, efforts are being made to exploit the various facets of photoactivation, PDT, and the associated phenomenon of photodynamic priming in enhancing treatment outcomes, specifically in cancer therapeutics. The parallel emergence of nanomedicine, specifically liposome-based nanoformulations, and the convergence of the two fields of liposome-based drug delivery and PDT have led to the development of unique hybrid systems, which combine the exciting features of liposomes with adequate complementation through the photoactivation process. While initially liposomes carrying photosensitizers (PSs) were developed for enhancing the pharmacokinetics and the general applicability of PSs, more recently, PS-loaded liposomes, apart from their utility in PDT, have found several applications including enhanced targeting of drugs, coloading multiple therapeutic agents to enhance synergistic effects, imaging, priming, triggering drug release, and facilitating the escape of therapeutic agents from the endolysosomal complex. This review discusses the design strategies, potential, and unique attributes of these hybrid systems, with not only photoactivation as an attribute but also the ability to encapsulate multiple agents for imaging, biomodulation, priming, and therapy referred to as photoactivatable multiagent/inhibitor liposomes (PMILS) and their targeted versions─targeted PMILS (TPMILS). While liposomes have formed their own niche in nanotechnology and nanomedicine with several clinically approved formulations, we try to highlight how using PS-loaded liposomes could address some of the limitations and concerns usually associated with liposomes to overcome them and enhance their preclinical and clinical utility in the future.

Complexation Nanoarchitectonics of Carbon Dots with Doxorubicin toward Photodynamic Anti-Cancer Therapy

Carbon dots (Cdots) are known as photosensitizers in which the nitrogen doping is able to improve the oxygen-photosensitization performance and singlet-oxygen generation. Herein, the characteristics of nanoconjugates of nitrogen-doped Cdots and doxorubicin were compared with the property of nitrogen-doped Cdots alone. The investigation was performed for the evaluation of pH-dependent zeta potential, quantum yield, photosensitization efficiency and singlet-oxygen generation, besides spectroscopy (UV-visible absorption and fluorescence spectra) and cytotoxicity on cancer model (HeLa cells). Encapsulation efficiency, drug loading, and drug release without and with light irradiation were also carried out. These investigations were always pursued under the comparison among different nitrogen amounts (ethylenediamine/citric acid = 1-5) in Cdots, and some characteristics strongly depended on nitrogen amounts in Cdots. For instance, surface charge, UV-visible absorbance, emission intensity, quantum yield, photosensitization efficiency and singlet-oxygen generation were most effective at ethylenediamine/citric acid = 4. Moreover, strong conjugation of DOX to Cdots via π-π stacking and electrostatic interactions resulted in a high carrier efficiency and an effective drug loading and release. The results suggested that nitrogen-doped Cdots can be considered promising candidates to be used in a combination therapy involving photodynamic and anticancer strategies under the mutual effect with DOX.