Tumor hypoxia is known to be one of critical reasons that limit the efficacy of cancer therapies, particularly photodynamic therapy (PDT) and radiotherapy (RT) in which oxygen is needed in the process of cancer cell destruction. Herein, taking advantages of the great biocompatibility and high oxygen dissolving ability of perfluorocarbon (PFC), we develop an innovative strategy to modulate the tumor hypoxic microenvironment using nano-PFC as an oxygen shuttle for ultrasound triggered tumor-specific delivery of oxygen. In our experiment, nanodroplets of PFC stabilized by albumin are intravenously injected into tumor-bearing mice under hyperoxic breathing. With a low-power clinically adapted ultrasound transducer applied on their tumor, PFC nanodroplets that adsorb oxygen in the lung would rapidly release oxygen in the tumor under ultrasound stimulation, and then circulate back into the lung for reoxygenation. Such repeated cycles would result in dramatically enhanced tumor oxygenation and thus remarkably improved therapeutic outcomes in both PDT and RT treatment of tumors. Importantly, our strategy may be applied for different types of tumor models. Hence, this work presents a simple strategy to promote tumor oxygenation with great efficiency using agents and instruments readily available in the clinic, so as to overcome the hypoxia-associated resistance in cancer treatment.

Theranostics for in vivo cancer diagnosis and treatment generally requires well-designed nanoscale platforms with multiple integrated functionalities. In this study, we uncover that functionalized iron oxide nanoparticles (IONPs) could be self-assembled on the surface of two-dimensional MoS2 nanosheets via sulfur chemistry, forming MoS2-IO nanocomposites, which are then modified with two types of polyethylene glycol (PEG) to acquire enhanced stability in physiological environments. Interestingly, 64Cu, a commonly used positron-emitting radioisotope, could be firmly adsorbed on the surface of MoS2 without the need of chelating molecules, to enable in vivo positron emission tomography (PET) imaging. On the other hand, the strong near-infrared (NIR) and superparamagnetism of MoS2-IO-PEG could also be utilized for photoacoustic tomography (PAT) and magnetic resonance (MR) imaging, respectively. Under the guidance by such triple-modal imaging, which uncovers efficient tumor retention of MoS2-IO-(d)PEG upon intravenous injection, in vivo photothermal therapy is finally conducted, achieving effective tumor ablation in an animal tumor model. Our study highlights the promise of constructing multifunctional theranostic nanocomposites based on 2D transitional metal dichalcogenides for multimodal imaging-guided cancer therapy.

Hypoxia, a common feature within many types of solid tumors, is known to be closely associated with limited efficacy for cancer therapies, including radiotherapy (RT) in which oxygen is essential to promote radiation-induced cell damage. Here, an artificial nanoscale red-blood-cell system is designed by encapsulating perfluorocarbon (PFC), a commonly used artificial blood substitute, within biocompatible poly(d,l-lactide-co-glycolide) (PLGA), obtaining PFC@PLGA nanoparticles, which are further coated with a red-blood-cell membrane (RBCM). The developed PFC@PLGA-RBCM nanoparticles with the PFC core show rather efficient loading of oxygen, as well as greatly prolonged blood circulation time owing to the coating of RBCM. With significantly improved extravascular diffusion within the tumor mass, owing to their much smaller nanoscale sizes compared to native RBCs with micrometer sizes, PFC@PLGA-RBCM nanoparticles are able to effectively deliver oxygen into tumors after intravenous injection, leading to greatly relieved tumor hypoxia and thus remarkably enhanced treatment efficacy during RT. This work thus presents a unique type of nanoscale RBC mimic for efficient oxygen delivery into solid tumors, favorable for cancer treatment by RT, and potentially other types of therapy as well.

Recently, photothermal therapy (PTT) has attracted tremendous attention because of its high efficacy in tumor ablation and minimal damage to normal tissues. While many inorganic nanomaterials, especially various gold nanostructures and nanocarbons, have been extensively explored for near-infrared (NIR) light triggered PTT in the past decade, a variety of organic photothermal agents have also emerged in recent years, aiming at replacing their inorganic counterparts which usually are not biodegradable. In this mini-review, we will summarize several typical classes of recently developed NIR-absorbing organic PTT nanoagents, which include NIR dye-containing micelles, porphysomes, protein-based agents, conjugated polymers, and organic/inorganic nanocomposites. The development of imaging-guided PTT and combination therapy will be introduced as well. Finally, the perspectives and challenges in the future development of PTT will be discussed.

Oral squamous cell carcinoma is a challenging oncology problem. A reliable biomarker for metastasis or high-risk prognosis in oral cancer patients remains undefined. Using quantitative immunohistochemistry, we examined the expression of vimentin, E-cadherin, and b-catenin in 83 oral squamous cell carcinoma patients, and the relationships between the expression of these markers and specific clinicopathological features were analysed. The high expression of vimentin was observed in 23 of 43 (53%) tumours from patients who eventually developed a recurrent tumour and was associated with recurrence and death (Po0.001 and o0.001, respectively). The decreased expression of E-cadherin was observed in 36 of 43 (84%) tumours from patients who eventually developed a recurrent tumour and was also associated with recurrence and death (Po0.001 and o0.001, respectively). Although no correlation between b-catenin expression in whole-tumour sections and clinicopathological features was observed, decreased b-catenin expression at the tumour invasive front was closely associated with recurrence and death (P ¼ 0.002 and 0.002, respectively). The expression of vimentin and that of E-cadherin were associated with survival and were independent prognostic factors in univariate and multivariate analyses. Our data show that the overexpression of vimentin was closely associated with recurrence and death in oral squamous cell carcinoma patients. The combination of the upregulation of vimentin and aberrant expression of E-cadherin/b-catenin complexes at the tumour invasive front may provide a useful prognostic marker in oral squamous cell carcinoma. Modern Pathology (2010) 23, 213-224; doi:10.1038/modpathol.2009 published online 13 November 2009 Keywords: vimentin; oral squamous cell carcinoma; immunohistochemistry Oral cancer is the sixth most frequently occurring cancer worldwide, accounting for 3-5% of all malignancies in both sexes.1,2 Over 90% of all oral carcinomas are classified as oral squamous cell carcinoma, which remains a challenging oncology problem.3 Although early-stage oral squamous cell carcinoma can be treated or cured, the prognosis for advanced oral squamous cell carcinoma (stage III and IV) is poor. The treatment of oral squamous cell carcinoma is usually based on surgery or radiation, with or without concomitant chemotherapy. Despite these advanced therapeutic strategies, the 5-year survival rate of oral squamous cell carcinoma (B50%) has not increased over the past four decades.3-5 Local or regional relapse and cervical lymph node metastasis are the most prevalent