Shuang Cai

Lymphatic drug delivery using engineered liposomes and solid lipid nanoparticles.

The lymphatic system plays a crucial role in the immune systems recognition and response to disease, and most solid cancers initially spread from the primary site via the tumors surrounding lymphatics before hematological dissemination. Hence, the lymphatic system is an important target for developing new vaccines, cancer treatments, and diagnostic agents. Targeting the lymphatic system by subcutaneous, intestinal, and pulmonary routes has been evaluated and subsequently utilized to improve lymphatic penetration and retention of drug molecules, reduce drug-related systemic toxicities, and enhance bioavailability of poorly soluble and unstable drugs. Lymphatic imaging is an essential tool for the detection and staging of cancer. New nano-based technologies offer improved detection and characterization of the nodal diseases, while new delivery devices can better target and confine treatments to tumors within the nodal space while sparing healthy tissues. This manuscript reviews recent advances in the field of lymphatic drug delivery and imaging and focuses specifically on the development of liposomes and solid lipid nanoparticles for lymphatic introduction via the subcutaneous, intestinal, and pulmonary routes.

Localized doxorubicin chemotherapy with a biopolymeric nanocarrier improves survival and reduces toxicity in xenografts of human breast cancer.

Patients with metastatic breast cancer have a five-year survival rate of 27% compared to 98% for localized cancer, and the presence of even a few cancer cells in lymph nodes, known as isolated tumor cells or nanometastases, significantly increases the risk of relapse in the absence of aggressive treatment. Therefore, diagnosis and treatment of lymphatic metastases in early breast cancer plays an important role in patient survival. Here, we demonstrate the first description of a delivery system for localized doxorubicin chemotherapy to the breast tissue. The hyaluronan-doxorubicin nanoconjugate exhibits a sustained release characteristic in vitro and in vivo in the breast tissues of rodents bearing human breast cancer xenografts. In addition, the conjugate reduces dose-limiting cardiac toxicity with minimal toxicity observed in normal tissues. Finally, the conjugate dramatically inhibits breast cancer progression in vivo, leading to an increased survival rate. Thus, localized chemotherapy to the breast lymphatics with a nanocarrier may represent an improved strategy for treatment of early stage breast cancers.

Intralymphatic chemotherapy using a hyaluronan-cisplatin conjugate.

BACKGROUND Breast cancers typically spread to regional lymph nodes once they disseminate from the primary tumor, thus adequate evaluation and treatment of the axillary lymph nodes is paramount in early stage disease. One significant problem with current therapy is the side effects chemotherapy agents create systemically, either alone or in combination. The purpose of this study is to determine whether lymphatically targeted cisplatin carriers will increase the localized dose in lymphatic metastases without systemic toxicities. METHODS Hyaluronan (HA) is a highly biocompatible polymer that follows lymphatic drainage from the interstitial spaces. We formed complexes of HA and cisplatin by non-covalent conjugation. Complexes were injected subcutaneously into the upper mammary fat pad of female rats, and the tissue distribution determined. RESULTS Cisplatin-HA contained up to 0.25 w/w of Pt and released drug with a half-life of 10 h in saline. Cisplatin-HA conjugates had high anti-tumor activity in vitro similar to the free drug: cisplatin-HA IC50 7 microg/mL in MCF7 and MDA-MB-231 human breast cancer cells (free cisplatin IC50 7 microg/mL). Cisplatin-HA conjugates were well tolerated in rodents with no signs of injection site morbidity or major organ toxicity after 96 h. The area-under-the-curve of cisplatin in the axially lymph nodes after injection with cisplatin-HA increased 74% compared with normal cisplatin. CONCLUSIONS This study demonstrates a novel intralymphatic drug delivery method in breast cancer to preferentially treat at-risk regional lymph nodes and avoid systemic toxicities. Further in vivo testing related to efficacy of this approach with regard to survival, toxicity, and pharmacokinetics is warranted to support its use in human trials.

Pulmonary delivery of cisplatin–hyaluronan conjugates via endotracheal instillation for the treatment of lung cancer

Cisplatin (CDDP) intravenous treatments suffer several dose-limiting toxicity issues. Hyaluronan (HA), a naturally occurring biopolymer in the interstitium, is primarily cleared by the lymphatic system. An alteration in input rate and administration route through pulmonary delivery of hyaluronan-cisplatin (HA-Pt) conjugate may increase local lung CDDP concentrations and decrease systemic toxicity. Sprague-Dawley rats were split into four groups: i.v. CDDP (3.5 mg/kg), i.v. HA-Pt conjugate (3.5 mg/kg equivalent CDDP), lung instillation CDDP and lung instillation HA-Pt conjugate. Total platinum level in the lungs of the HA-Pt lung instillation group was 5.7-fold and 1.2-fold higher than the CDDP intravenous group at 24 and 96 h, respectively. A 1.1-fold increase of Pt accumulation in lung draining nodes for the HA-Pt lung instillation group was achieved at 24h relative to the CDDP i.v. group. In the brain and kidneys, the CDDP i.v. group had higher tissue/plasma ratios compared to the HA-Pt lung instillation group. Augmented tissue distribution from CDDP i.v. could translate into enhanced tissue toxicity compared to the altered input rate and distribution of the intrapulmonary nanoformulation. In conclusion, a local pulmonary CDDP delivery system was developed with increased platinum concentration in the lungs and draining nodes compared to i.v. therapy.

A novel intralymphatic nanocarrier delivery system for cisplatin therapy in breast cancer with improved tumor efficacy and lower systemic toxicity in vivo

BACKGROUND A lymphatically delivered nanoconjugate of cisplatin was evaluated in an orthotopic mouse model of locoregionally metastatic breast cancer (LABC) to determine if it can overcome some of the limitations of standard cisplatin therapy such as high systemic toxicity. METHODS Human breast cancer cells (10(7) MDA-MB-468LN) were injected into the mammary fat pad of female nu/nu mice. Once tumor volume reached 50 mm(3), intravenous cisplatin or subcutaneous hyaluronan-cisplatin (HA-cisplatin) nanoconjugate was given 1/week x 3 weeks at 3.3 mg/kg (platinum basis). RESULTS Nanoconjugates colocalized with the tumors after subcutaneous peritumoral injection and showed improved efficacy to intravenous cisplatin. After 1 month, renal tubular hemorrhage and edema were more prevalent in the intravenous formulation compared with subcutaneous HA-cisplatin nanoconjugates. CONCLUSIONS This nanocarrier delivery platform focuses on delivering drugs to the areas in which tumor burden is greatest, potentially reducing systemic toxicity, and has future applicability as a neoadjuvant or adjuvant therapy for LABC.

Pharmacokinetics and disposition of a localized lymphatic polymeric hyaluronan conjugate of cisplatin in rodents

Cisplatin (CDDP) is an effective anticancer agent for many solid tumors but has significant systemic toxicity limiting its use in many patients. We have designed a loco-regional delivery system to increase platinum levels in the lymphatics, where early metastasis is most likely to occur, while reducing systemic toxicities. CDDP was conjugated to a biocompatible polymer hyaluronan (HA), with a conjugation degree of approximately 20% (w/w). Conjugates were delivered via subcutaneous injection into the mammary fat pad of rats. Intravenous hyaluronan-cisplatin (HA-Pt) exhibited an increased plasma area under the curve (AUC) 2.7-fold compared to conventional CDDP but with a reduced peak plasma level (C(max)), and HA-Pt increased the ipsilateral lymph node AUC by 3.8-fold compared to CDDP. Urine creatinine was unchanged over 30 days following dosing of HA-Pt. This study demonstrates that intralymphatic drug delivery with polymer-conjugated platinum may provide greater tissue and systemic plasma concentrations of platinum than intravenous CDDP. In addition, localized particle delivery augmented distribution in the loco-regional tissue basin where tumor burden predominates, while renal toxicity compared to standard intravenous CDDP was significantly reduced.

Multi-arm polymeric nanocarrier as a nitric oxide delivery platform for chemotherapy of head and neck squamous cell carcinoma

Nitric oxide is a cell signaling molecule that can be a potent inducer of cell death in cancers at elevated concentrations. However, NO is also toxic to normal tissues and chronic exposure at low levels can induce tumor growth. We have designed a polymeric carrier system to deliver nitric oxide locoregionally to tumorigenic tissues at micromolar concentrations. A highly water solubility and biodegradable multi-arm polymer nanocarrier, sugar poly-(6-O-methacryloyl-d-galactose), was synthesized using MADIX/RAFT polymerization, and utilized to deliver high concentrations of nitric oxide to xenografts of human head and neck squamous cell carcinoma (HNSCC). The in vitro release of the newly synthesized nitric oxide donor, O(2)-(2,4-dinitrophenyl) 1-[4-(2-hydroxy)ethyl]-3-methylpiperazin-1-yl]diazen-1-ium-1,2-diolate and its corresponding multi-arm polymer-based nanoconjugate demonstrated a 1- and 2.3-fold increase in half-life, respectively, compared to the release half-life of the nitric oxide-donor prodrug JS-K. When administered to tumor-bearing nude mice, the subcutaneously injected multi-arm polymer nitric oxide nanoparticles resulted in 50% tumor inhibition and a 7-week extension of the average survival time, compared to intravenous JS-K therapy. In summary, we have developed an effective nitric oxide anti-cancer chemotherapy that could be administered regionally to provide the local disease control, improving prognosis for head and neck cancers.

Carrier-based intralymphatic cisplatin chemotherapy for the treatment of metastatic squamous cell carcinoma of the head & neck

BACKGROUND Since head and neck squamous cell carcinoma (HNSCC) preferentially metastasizes to the locoregional lymphatics, treatment of the tumor-draining cervical lymph nodes is paramount. RESULTS We developed a hyaluronan-cisplatin (HA-Pt) nanoconjugate with prolonged lymphatic retention and greatly improved tumor tissue deposition for the treatment of metastatic HNSCC. We also developed an orthotopic metastatic xenograft model of HNSCC to examine the efficacy of the nanoconjugate. HNSCC (1/week x 3 weeks) were completely cured for 57% of the female mice in the HA-Pt treatment group, which demonstrated greatly hindered HNSCC progression compared with the standard cisplatin therapy (p < 0.05). CONCLUSION With this insight, we will be able to optimize the carriers for better uptake, penetration and retention within cancer cells.

Impact of Molecular Weight on Lymphatic Drainage of a Biopolymer-Based Imaging Agent

New lymphatic imaging technologies are needed to better assess immune function and cancer progression and treatment. Lymphatic uptake depends mainly on particle size (10–100 nm) and charge. The size of carriers for imaging and drug delivery can be optimized to maximize lymphatic uptake, localize chemotherapy to lymphatic metastases, and enable visualization of treatment deposition. Toward this end, female BALB/c mice were injected subcutaneously in the hind footpad or forearm with a series of six different molecular weight hyaluronan (HA) near-infrared dye (HA-IR820) conjugates (ca. 5–200 nm). Mice were imaged using whole body fluorescent imaging over two weeks. HA-IR820 fluorescence was clearly visualized in the draining lymphatic capillaries, and in the popliteal and iliac or axillary lymph nodes. The 74-kDa HA-IR820 had the largest lymph node area-under-the-curve. In contrast to prior reports, mice bearing limb tumors exhibited three-fold longer retention of 74-kDa HA-IR820 in the popliteal node compared to mice without tumors. HA conjugate kinetics and disposition can be specifically tailored by altering their molecular weight. The specific lymphatic uptake and increased nodal retention of HA conjugates indicate significant potential for development as a natural biopolymer for intralymphatic drug delivery and imaging.

Cellular uptake and internalization of hyaluronan-based doxorubicin and cisplatin conjugates.

Abstract Background: Hyaluronan (HA) is a ligand for the CD44 receptor which is crucial to cancer cell proliferation and metastasis. High levels of CD44 expression in many cancers have encouraged the development of HA-based carriers for anti-cancer therapeutics. Purpose: The objective of this study was to determine whether HA conjugation of anticancer drugs impacts CD44-specific HA-drug uptake and disposition by human head and neck cancer cells. Methods: The internalization and cellular disposition of hyaluronan-doxorubicin (HA-DOX), hyaluronan-cisplatin (HA-Pt), and hyaluronan-cyanine7 (HA-Cy7) conjugates were investigated by inhibiting endocytosis pathways, and by inhibiting the CD44-mediated internalization pathways that are known to mediate hyaluronan uptake in vitro. Results: Cellular internalization of HA was regulated by CD44 receptors. In mouse xenografts, HA conjugation significantly enhanced tumor cell uptake compared to unconjugated drugs. Discussion: The results suggested that the main mechanism of HA-based conjugate uptake may be active transport via CD44 in conjunction with a clathrin-dependent endocytic pathway. Other HA receptors, hyaluronan-mediated motility receptor (RHAMM) and lymphatic vessel endothelial hyaluronan receptor (LYVE-1), did not play a significant role in conjugate uptake. Conclusions: HA conjugation significantly increased CD44-mediated drug uptake and extended the residence time of drugs in tumor cells.