Kwan-Hwa Chi

Combination of conformal radiotherapy and intratumoral injection of adoptive dendritic cell immunotherapy in refractory hepatoma.

A phase 1 study was conducted to assess the safety and immunologic response induced by direct injection of autologous immature dendritic cells (DCs) into tumor under radiotherapy in advanced hepatoma patients. Patients with advanced/metastatic stage hepatoma not suitable for surgery or transarterial embolization were enrolled. Groups of patients received two vaccinations. Each vaccination consisted of intratumoral injections of autologous immature DCs in four dose cohorts of 5 × 106, 1.5 × 107, 3 × 107, and 5 × 107 cells 2 days after a single fraction of conformal radiotherapy of 8 Gy. The second vaccination was performed 3 weeks later. Of the 14 patients entered, 12 completed two cycles of vaccination. The treatment was well tolerated at any of the dose levels. Six patients had mild transient fever (grade 1-2) with chill reactions, three patients developed grade 1 fatigue, and one patient developed mild myalgia and arthralgia after DC injections. There was no evidence of clinically manifested autoimmune disease. There were two partial responses and four minor responses. A decrease in the alpha-fetoprotein (AFP) level of more than 50% was found in three patients. Ten patients had completed immunologic response evaluation 2 weeks after the second cycle of vaccination. The AFP-specific immune response was evident in eight patients examined by cytokine release assay and in seven patients by ELISPOT assay. Six patients showed an increased NK cell cytotoxic activity after vaccination. These data suggest that the combination of intratumoral injection of DCs and conformal radiotherapy is safe and can induce tumor-specific and innate immunity.

ANGIOGENIC BLOCKADE AND RADIOTHERAPY IN HEPATOCELLULAR CARCINOMA

PURPOSE We report our preliminary experience of combining sunitinib and helical tomotherapy in patients with advanced HCC. METHODS AND MATERIALS Records of patients with advanced hepatocellular carcinoma (HCC) treated with helical tomotherapy and sunitinib after radiation therapy (RT) from March 2007 to August 2008 were retrospectively reviewed. We report acute toxicities, radiologic response, serial alpha-fetoprotein (AFP) kinetics, and survival. RESULTS Of 23 evaluable patients, 60% had >or=2 hepatic lesions, extrahepatic disease was present in 5 (21.7%), and all received 2 tablets (25 mg) of sunitinib at least 1 week before, during, and 2 weeks after RT. Thirteen patients continued maintenance sunitinib after RT until disease progression. Hypofractionated RT with a median target dose of 52.5 Gy/15 fractions was delivered. An objective response was achieved in 74% of patients. The 1-year survival rate was 70%, with median survival of 16 months. Multivariate analysis showed that maintenance sunitinib was the most significant factor for survival. The time to progression was 10 months in the maintenance group compared with 4 months in the control group. Eighteen out of 21 patients with elevated AFP (85.7%) had >or=50% decline of AFP within 2 months after RT. There were three episodes of upper gastrointestinal bleeding and one episode of pancreatitis; 10 patients had >or=Grade 2 elevation of liver enzymes, and 15 had >or=Grade 2 thrombocytopenia. CONCLUSIONS These preliminary results suggest that sunitinib and helical tomotherapy yield high Response Evaluation Criteria in Solid Tumors (RECIST) and AFP response rates in advanced HCC with an acceptable safety profile. Maintenance sunitinib after RT potentially prolongs survival. A randomized trial is warranted.

Biological characterization of cetuximab-conjugated gold nanoparticles in a tumor animal model

Gold nanoparticles (AuNPs) are widely applied to the diagnosis and treatment of cancer and can be modified to contain target-specific ligands via gold-thiolate bonding. This study investigated the pharmacokinetics and microdistribution of antibody-mediated active targeting gold nanoparticles in mice with subcutaneous lung carcinoma. We conjugated AuNPs with cetuximab (C225), an antibody-targeting epidermal growth factor receptor (EGFR), and then labeled with In-111, which created EGFR-targeted AuNPs. In vitro studies showed that after a 2 h incubation, the uptake of C225-conjugated AuNPs in high EGFR-expression A549 cells was 14.9-fold higher than that of PEGylated AuNPs; furthermore, uptake was also higher at 3.8-fold when MCF7 cells with lower EGFR-expression were used. MicroSPECT/CT imaging and a biodistribution study conducted by using a A549 tumor xenograft mouse model provided evidence of elevated uptake of the C225-conjugated AuNPs into the tumor cells as a result of active targeting. Moreover, the microdistribution of PEGylated AuNPs revealed that a large portion of AuNPs remained in the tumor interstitium, whereas the C225-conjugated AuNPs displayed enhanced internalization via antibody-mediated endocytosis. Our findings suggest that the anti-EGFR antibody-conjugated AuNPs are likely to be a plausible nano-sized vehicle for drug delivery to EGFR-expressing tumors.

Synergistic anti-tumor effect of combination radio- and immunotherapy by electro-gene therapy plus intra-tumor injection of dendritic cells

Interleukin-2 (IL-2) and granulocyte-macrophage colony stimulating factor (GM-CSF) facilitate the maturation and functioning of injected DC. We developed a method of in situ electroporation using IL-2 and GM-CSF genes (EGT/cytokines), followed by intra-tumoral (i.t.) immature DC to determine the immune response at the tumor site using prostate-specific antigen-transfected CT26 cells. Three cycles of EGT/cytokines and i.t. DC inhibited tumor growth most effectively, but not superior to EGT/cytokines alone. However, the role of i.t. DC became significant when radiation was given after immunotherapy, which may have clinical implications on achieving better local control and prevention of systemic relapse.

Apolipoprotein C1 (APOC1) as a novel diagnostic and prognostic biomarker for lung cancer: A marker phase I trial

Tumor cells continuously evolve over time in response to host pressures. However, explanations as to how tumor cells are influenced by the inflammatory tumor microenvironment over time are, to date, poorly defined. We hypothesized that prognostic biomarkers could be obtained by exploring the expression of inflammation‐associated genes between early and late stage lung cancer tumor samples.

Simultaneous activation and inhibition of autophagy sensitizes cancer cells to chemotherapy.

While combined chemotherapy (CT) with an autophagy inducer and an autophagy inhibitor appears paradoxical, it may provide a more effective perturbation of autophagy pathways. We used two dissimilar cell lines to test the hypothesis that autophagy is the common denominator of cell fate after CT. HA22T cells are characterized by CT-induced apoptosis and use autophagy to prevent cell death, while Huh7.5.1 cells exhibit sustained autophagic morphology after CT. Combined CT and rapamycin treatment resulted in a better combination index (CI) in Huh7.5.1 cells than combined CT and chloroquine, while the reverse was true in HA22T cells. The combination of 3 drugs (triplet drug treatment) had the best CI. After triplet drug treatment, HA22T cells switched from protective autophagy to mitochondrial membrane permeabilization and endoplasmic reticulum stress response-induced apoptosis, while Huh7.5.1 cells intensified autophagic lethality. Most importantly, both cell lines showed activation of Akt after CT, while the triplet combination blocked Akt activation through inhibition of phospholipid lipase D activity. This novel finding warrants further investigation as a broad chemosensitization strategy.

Reciprocal Complementation of the Tumoricidal Effects of Radiation and Natural Killer Cells

The tumor microenvironment is a key determinant for radio-responsiveness. Immune cells play an important role in shaping tumor microenvironments; however, there is limited understanding of how natural killer (NK) cells can enhance radiation effects. This study aimed to assess the mechanism of reciprocal complementation of radiation and NK cells on tumor killing. Various tumor cell lines were co-cultured with human primary NK cells or NK cell line (NK-92) for short periods and then exposed to irradiation. Cell proliferation, apoptosis and transwell assays were performed to assess apoptotic efficacy and cell viability. Western blot analysis and immunoprecipitation methods were used to determine XIAP (X-linked inhibitor of apoptosis protein) and Smac (second mitochondria-derived activator of caspase) expression and interaction in tumor cells. Co-culture did not induce apoptosis in tumor cells, but a time- and dose-dependent enhancing effect was found when co-cultured cells were irradiated. A key role for caspase activation via perforin/granzyme B (Grz B) after cell-cell contact was determined, as the primary radiation enhancing effect. The efficacy of NK cell killing was attenuated by upregulation of XIAP to bind caspase-3 in tumor cells to escape apoptosis. Knockdown of XIAP effectively potentiated NK cell-mediated apoptosis. Radiation induced Smac released from mitochondria and neutralized XIAP and therefore increased the NK killing. Our findings suggest NK cells in tumor microenvironment have direct radiosensitization effect through Grz B injection while radiation enhances NK cytotoxicity through triggering Smac release.

Hypofractionated radiotherapy for primary or secondary oligometastatic lung cancer using Tomotherapy

BackgroundTo retrospectively review the outcome of patients with primary or secondary oligometastatic lung cancer, treated with hypofractionated Tomotherapy.MethodsBetween April 2007 and June 2011, a total of 33 patients with oligometastatic intrapulmonary lesions underwent hypofractionated radiotherapy by Tomotherapy along with appropriate systemic therapy. There were 24 primary, and 9 secondary lung cancer cases. The radiation doses ranged from 4.5 to 7.0 Gy per fraction, multiplied by 8–16 fractions. The median dose per fraction was 4.5 Gy (range, 4.5-7.0 Gy), and the median total dose was 49.5 Gy (range, 45–72 Gy). The median estimated biological effective dose at 10 Gy (BED10) was 71.8 Gy (range, 65.3–119.0 Gy), and that at 3 Gy (BED3) was 123.8 Gy (range, 112.5–233.3 Gy). The mean lung dose (MLD) was constrained mainly under 1200 cGy. The median gross tumor volume (GTV) was 27.9 cm3 (range: 2.5–178.1 cm3).ResultsThe median follow-up period was 25.8 months (range, 3.0–60.7 months). The median overall survival (OS) time was 32.1 months for the 24 primary lung cancer patients, and >40 months for the 9 metastatic lung patients. The median survival time of the patients with extra-pulmonary disease (EPD) was 11.2 months versus >50 months (not reached) in the patients without EPD (p < 0.001). Those patients with smaller GTV (≦27.9 cm3) had a better survival than those with larger GTV (>27.9 cm3): >40 months versus 12.85 months (p = 0.047). The patients with ≦2 lesions had a median survival >40 months, whereas those with ≧3 lesions had 26 months (p = 0.065). The 2-year local control (LC) rate was 94.7%. Only 2 patients (6.1%) developed ≧grade 3 radiation pneumonitis.ConclusionUsing Tomotherapy in hypofractionation may be effective for selected primary or secondary lung oligometastatic diseases, without causing significant toxicities. Pulmonary oligometastasis patients without EPD had better survival outcomes than those with EPD. Moreover, GTV is more significant than lesion number in predicting survival.

Trimodality bladder-sparing approach without neoadjuvant chemotherapy for node-negative localized muscle-invasive urinary bladder cancer resulted in comparable cystectomy-free survival

BackgroundTo retrospectively review the efficacy and organ preservation experience for muscle-invasive bladder cancer by trimodality therapy at our institution.MethodsBetween July 2004 and February 2012, seventy patients (M/F = 55/15; median age = 69 years) of lymph node negative localized muscle-invasive bladder cancer were treated primarily with trimodality approach including transurethral resection of bladder tumor (TURBT) prior to combined chemotherapy and radiotherapy (CCRT). Radiotherapy consisted of initial large field size irradiation with 3D conformal technique (3D-CRT), followed by cone-down tumor bed boost with intensity modulated radiotherapy (IMRT) technique. The median total doses delivered to bladder tumor bed and whole bladder were 59.4Gy and 40.0Gy, respectively. No patient received neoadjuvant chemotherapy (NAC). Weekly cisplatin was administered during radiotherapy. Toxicity was scored according to the RTOG criteria. Tumor response was evaluated both cystoscopically and radiographically 3 months after treatment.ResultsThe numbers of patients with T2, T3 and T4 lesions were 41, 16 and 13, respectively. Overall survival (OS) and progression-free survival (PFS) at 2 and 5 year were 65.7%, 51.9% and 50.8%, 39.9%, respectively, after a median follow-up time of 24 months. Local-regional control and distant metastasis free survival at 2 year were 69.8% and 73.5%, respectively. Complete response (CR) rate assessed three month after CCRT was 78.1%. Ten patients (20%) had local recurrence after initial CR (n = 50), 3 of them were superficial recurrence. One patient underwent radical cystectomy after recurrence. The overall 5-year bladder intact survival was 49.0% (95% CI, 35.5% to 62.5%). Acute toxicities were limited to grade 1-2. One patient developed late grade 3 GU toxicity.ConclusionsOur result suggested that trimodality bladder-sparing approach without NAC or dose-intensification could be well-tolerated with a high CR rate and bladder preserving rate for muscle-invasive bladder cancer.

Improving Radioresponse Through Modification of the Tumor Immunological Microenvironment

Radioresponse is influenced by factors apart from the targeted cancer cells; in fact, endothelial cells and infiltrating immune cells within the tumor microenvironment (TME) are the two main components affecting the outcome of radiotherapy. The benefits of fractionated radiotherapy are attenuated through the upregulation of hypoxia inducible factor-1 α and vascular endothelial growth factor. The therapeutic effect of antiangiogenic agents is counteracted by the mobilization of endogenous proangiogenic cells to the TME. This study highlights the importance of radiation timing within a vascular normalization window and discusses the importance of immune cells that comprise the microenvironment. A balance between favorable tumor-infiltrating immune cells, including cytotoxic T cells, natural killer cells, and dendritic cells, and the unfavorable cells, such as tumor-associated macrophages and regulatory T cells, determines the final tumor-control probability. The reciprocal complementation between combinations of radiotherapy and immunotherapy strategies through modulation of the tumor immunological microenvironment may yield promising results in the future.