Solid tumors characteristically display higher levels of lactate production due to anaerobic metabolism of glucose. Meanwhile, the U.S. Food and Drug Administration (FDA) has approved virotherapy for use in cancer treatment; however systemic administration remains as a particular challenge. Here we report exploitation of tumor lactate production in designing a hypoxia-responsive carrier, self-assembled from hyaluronic acid (HA) conjugated with 6-(2-nitroimidazole)­hexylamine, for localized release of recombinant adeno-associated virus serotype 2 (AAV2). The carrier is loaded with lactate oxidase (LOX) and is permeable to small molecules such as the lactate that accumulates in the tumor. Subsequently, LOX oxidizes the lactate to pyruvate inside the carrier, accompanied by internal lowering of oxygen partial pressure. Bioreduction of the 2-nitroimidazole of the HA conjugated with 6-(2-nitroimidazole)­hexylamine converts it into a hydrophilic moiety and electrostatically dissociates the carrier and virus. Efficacious and specific delivery was proven by transduction of a photosensitive protein (KillerRed), enabling significant limitation in tumor growth in vivo with photodynamic therapy. An approximate 2.44-fold reduction in tumor weight was achieved after a 2-week course, compared with control groups. Furthermore, conjugation of the AAV2 with iron oxide nanoparticles (“magnetized” AAV2) facilitated magnetic resonance imaging tracking of the virus in vivo. Taken together, the solid tumor microenvironment promotes bioreduction of the lactate-responsive carrier, providing rapid and specific delivery of AAV2 for light-triggered virotherapy via systemic administration.

Deregulated proliferation of tumors is generally associated with altered energy metabolism. A high rate of anaerobic glycolysis in solid tumors contributes to an acidification of pH to ∼6.7–7.2 in the tumor microenvironment and lactate accumulation. Macrophages in the tumor microenvironment can be educated by tumor cells. Tumor-derived lactate induces the polarization of M2 macrophages and promotes tumor invasion and metastasis. However, a particular challenge is to sustain lactate depletion. We propose that the repolarization of the tumor-supportive M2 macrophage to the tumor-suppressive M1 macrophage after the depletion of lactate by lactate oxidase (LOX) released from the hydrogels in the tumor microenvironment may enhance the antitumor treatment efficacy.

Chemotherapy represents a conventional treatment for many cancers at different stages and is either solely prescribed or concomitant to surgery, radiotherapy, or both. However, treatment is tempered in instances of acquired drug resistance in response to either chemotherapy or targeted therapy, leading to therapeutic failure. To overcome this challenge, many studies focus on how cancer cells manipulate their genomes and metabolism to prevent drug influx and facilitate the efflux of accumulated chemotherapy drugs. Herein, we demonstrate magnetic adeno-associated virus serotype 2 (ironized AAV2) has an ability to be magnetically guided and transduce the photosensitive KillerRed protein to enable photodynamic therapy irrespective of drug resistance.

The US Food and Drug Administration (FDA) has approved the use of virotherapy. However, significant improvements are anticipated if effective localized infection can be achieved. Herein, we demonstrate magnetic lentivirus is guided by magnetic fields. Introduction of short hairpin RNA (shRNA) into the lentivirus genome enabled micro-scale RNA interference (RNAi) therapy. Although epidermal growth factor receptor (EGFR)-targeted therapies have successfully treated individuals with non-small cell lung cancer (NSCLC) cells, clinical therapeutic outcomes have been compromised by acquired resistance to first-generation tyrosine kinase inhibitors. We assess magnetic lentivirus with NSCLC cells using an in vitro model and achieve micro-scale RNAi through EGFR silencing. This proof-of-principle study demonstrates guided and highly localized micro-scale, RNAi virotherapy.

The characteristics of global prevalence and high recurrence of bladder cancer has led numerous efforts to develop new treatments. The spontaneous voiding and degradation of the chemodrug hamper the efficacy and effectiveness of intravesical chemotherapy following tumor resection. Herein, the externally thiolated hollow mesoporous silica nanoparticles (MSN‐SH(E)) is fabricated to serve as a platform for improved bladder intravesical therapy. Enhanced mucoadhesive effect of the thiolated nanovector is confirmed with porcine bladder. The permeation‐enhancing effect is also verified, and a fragmented distribution pattern of a tight junction protein, claudin‐4, indicates the opening of tight junction. Moreover, MSN‐SH(E)‐associated reprogramming of M2 macrophages to M1‐like phenotype is observed in vitro. The antitumor activity of the mitomycin C (MMC)‐loaded nanovector (MMC@MSN‐SH(E)) is more effective than that of MMC alone in both in vitro and in vivo. In addition, IHC staining is used to analyze IFN‐γ, TGF‐β1, and TNF‐α. These observations substantiated the significance of MMC@MSN‐SH(E) in promoting anticancer activity, holding the great potential for being used in intravesical therapy for non‐muscle invasive bladder cancer (NMIBC) due to its mucoadhesivity, enhanced permeation, immunomodulation, and prolonged and very efficient drug exposure.