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Combination therapy, integrating multiple merits of monotherapy into one platform for enhanced antitumor efficacy while eliminating the likelihoods of tumor recurrence and metastasis, is of particular interest in clinical application. Hydrogels self-assembled by biologically-based building blocks can be used as promising platforms for incorporation of one or more therapeutic drugs to gain additive or synergistic therapeutic functions. Herein, antitumor combination therapy based on injectable collagen/alginate hydrogels is achieved by simultaneous encapsulation of the photothermal drug methylene blue (MB) and immunological agent imiquimod (R837). The resulting hybrid hydrogel (Gel-MB-R837) with shear-thinning and self-healing properties is applicable for localized delivery and prolonged release of therapeutic drugs. The antitumor efficacy can be significantly enhanced by combinatorial photothermal therapy (PTT) and immunotherapy treatments through the synergy of MB and R837. Moreover, the initial PTT not only eradicates primary tumors, but also generates tumor-associated antigens (TAA), which combines with R837 to trigger immune response for further inhibiting tumor recurrence and metastasis. Therefore, the biocompatible hybrid hydrogels starting from naturally-occurring biomacromolecules offer promising prospects for combinatorial photothermal and immuno tumor therapy.

The morbidity and mortality of melanoma which accounts for 90% of cutaneous neoplasm-related deaths is growing over the last few decades. Common treatments for melanoma are limited to poor tissue selectivity, high toxicity and drug resistance. Photodynamic therapy (PDT) is an effective adjuvant therapy and could be a promising therapy for melanoma. Multiple mechanisms are involved in PDT2 and programmed cell death (PCD) which comprises of autophagy and apoptosis is likely to be a critical one. Whereas, the molecular mechanism and subsequent effect of PDT-induced autophagy in melanoma are still unclear. In this study, we first analyzed gene expression data in the TCGA3 and GEO4 databases to clarify that PDT-induced-autophagy improved the prognosis of melanoma. The expression of FOS which generally defined as an immediate-early gene (IEG) and related to cell autophagy was found significantly elevated after PDT. To further investigate whether FOS played a key role in PDT-induced-autophagy of melanoma, we first determined the optimum concentration of ICG solution for autophagy observation. Then, relative FOS expression was detected at mRNA and protein level and cell autophagy was observed by western blot and flow cytometry. We found that ICG-PDT treatment could significantly elevate FOS expression in SKCM5 B16 cells, and FOS promoted ICG-PDT-induced cell autophagy. To sum up, our data indicated that FOS was involved in ICG-PDT-induced-autophagy in melanoma and furthermore improved the prognosis of melanoma.

Multimodality imaging-guided therapy can improve the diagnostics and therapeutics efficiency of cancer. Herein, we developed a light-responsive nanotheranostic agent based on the indocyanine green (ICG) conjugated mesoporous silica coated gold nanobipyramid (GNB@SiO2) (denoted as GNB@SiO2-ICG) for simultaneous fluorescence (FL)/photoacoustic (PA) imaging-guided photothermal therapy (PTT). The GNB@SiO2 with excellent photostability was used for PA imaging as well as PTT. The loaded ICG promised FL imaging and PTT. The feasibility of the cancer theranostic capability of GNB@SiO2-ICG was evaluated from cancer cells to mice. Under the guidance of FL/PA imaging, GNB@SiO2-ICG exhibited remarkably enhanced therapeutic efficacy, which could eliminate the tumor tissues completely without tumor recurrence. This well-defined nanotheranostic nanoplatform that intelligently integrates dual-modality imaging and phototherapy provides an efficient nanoplatform for cancer nanotheranostics.

Cancer nanotheranostics, integrating both diagnostic and therapeutic functions into nanoscale agents, are advanced solutions for cancer management. Herein, a light-responsive biodegradable nanorattle-based perfluoropentane-(PFP)-filled mesoporous-silica-film-coated gold nanorod (GNR@SiO2 -PFP) is strategically designed and prepared for enhanced ultrasound (US)/photoacoustic (PA) dual-modality imaging guided photothermal therapy of melanoma. The as-prepared nanorattles are composed of a thin mesoporous silica film as the shell, which endows the nanoplatform with flexible morphology and excellent biodegradability, as well as large cavity for PFP filling. Upon 808 nm laser irradiation, the loaded PFP will undergo a liquid-gas phase transition due to the heat generation from GNRs, thus generating nanobubbles followed by the coalescence into microbubbles. The conversion of nanobubbles to microbubbles can improve the intratumoral permeation and retention in nonmicrovascular tissue, as well as enhance the tumor-targeted US imaging signals. This nanotheranostic platform exhibits excellent biocompatibility and biodegradability, distinct gas bubbling phenomenon, good US/PA imaging contrast, and remarkable photothermal efficiency. The results demonstrate that the GNR@SiO2 -PFP nanorattles hold great potential for cancer nanotheranostics.