New insights on the role of autophagy in the pathogenesis and treatment of melanoma.

Despite the depth of knowledge concerning the pathogenesis of melanoma, the most aggressive type of skin cancer, the prognosis and survival of patients still remain a challenge. In addition, responses to chemotherapy and immunotherapy are still poor, which underscore an urgent need in the development of new therapeutic strategies for the treatment of melanoma. Recently, the dynamic role of autophagy has gained considerable interest in the pathogenesis and treatment of melanoma. Whereas a decrease in autophagy activity promotes melanoma formation by increasing oncogene-induced tumorigenesis and DNA damage accumulation, an enhanced level of autophagy sustains melanoma cell viability and contributes to drug resistance. Obviously, the understanding of autophagy regulation may lead to a better defining melanoma pathogenesis and the progression toward new treatment options. In this review, we present new insights into a dual role of autophagy during melanoma tumorigenesis. In addition to summarizing current therapeutics for treating melanoma, we discuss how autophagy manipulation may improve the patients' outcome. Finally, autophagy-modulating drugs and nanoparticles, alone or in combination with current therapeutics, are proposed for possible clinical use in melanoma management.

Effects of Dendritic Cell Vaccine Activated with Components of Lieshmania Major on Tumor Specific Response.

BACKGROUND: Dendritic cells (DCs) contribute essentially to the outset and course of immune responses. So in patients with malignancy, there have been considerable interests in use of these cells in different interventions. OBJECTIVE: To evaluate the impact of Leishmania major's components on DC maturation and their use as a therapeutic agent against tumor cells. METHODS: The cancer model was induced by injection of WEHI-164 cells (BALB/c derived fibrosarcoma cell line) subcutaneously in the right flank of animals. Bone-marrow derived DCs (BMDCs) were cultured with granulocyte-macrophage colony-stimulating factor (GM-CSF) and IL-4. After 5 days, tumor lysate, Leishmania major's lysate, and Lipopolysaccharide (LPS) were added to the culture and incubated for 2 days. IL-12 production in DCs was measured by ELISA. For Immunotherapy, Mice received DCs subcutaneously around the tumor site. Two weeks after DCs injection, cytotoxicity assay and infiltration of CD8+ lymphocytes were evaluated. RESULTS: Our results showed that immunotherapy with dendritic cells exposed to Leishmania extract led to producing a higher amount of IL-12, compare to the control group. A considerable increment in specific cytotoxic T cells activity, diminished tumor growth rate and improved survival of immunized animals were seen. CONCLUSION: This study indicates that the use of Leishmania major extract, as well as LPS, can enhance the efficiency of DC-based vaccines and provides a basis for the use of Leishmania major in DC-targeted clinical therapies.

The Opposite Effects of DNA and Protein Components of Listeria Monocytogenes and Toxoplasma gondii on Immunologic Characteristics of Dendritic Cells.

The innate immune system utilizes pattern recognition receptors (PRRs) to recognize microbes. Pathogens contain various molecules with diverse effects on immune response. In this study, we evaluated the effect of DNA and protein components derived from two intracellular microorganisms including Listeria monocytogenes (L. monocytogenes) and Toxoplasma gondii (T. gondii) on dendritic cells (DCs) activation and ensuing adaptive immune responses. DNA and protein components of L. monocytogenes and T. gondii were prepared using relevant kits. DNA and protein components of these two pathogens were added to immature DCs (iDCs). Subsequently, co-stimulatory expression and cytokine production by DCs were measured. Finally, we evaluated the stimulatory capacity of mature DCs (mDCs) in DC-T cells co-culture. The results showed that protein matured-DCs produced higher level of IL (Interleukin)-12p70. There was also a significant increase in Interferon-Gamma (IFN-γ) production and proliferative capacity in T cells co-cultured with protein matured-DCs. On the other hand, DNA matured-DCs produced significantly higher amounts of Transforming growth factor-beta (TGF-ß). Collectively, these results imply a regulatory nature for DNA and potent stimulatory character for protein components of these two intracellular microorganisms.

The effect of aqueous cinnamon extract on the apoptotic process in acute myeloid leukemia HL-60 cells.

BACKGROUND: Acute promyelocytic leukemia (APL) is an acute leukemia diagnosed by translocation of chromosomes 15 and 17 [T (15,17)] and aggregation of neoplastic promyelocytes which are incapable of being converted into mature cells. Today, many tend to use medicinal herbs in studies and clinical applications for treatment of cancers. Cinnamon with scientific name "cinnamomumzelanicum" is a shrub of Laurales order, lauraceae family with cinnamomum genus. It is a medicinal shrub with anti-proliferation effect on tumor cells. This study was conducted to determine the effects of aqueous cinnamon extract on HL-60 cells as a model for APL. MATERIALS AND METHODS: In this in vitro experimental study, HL-60 cell line was cultured under the influence of cinnamon extract's concentrations of 0.01, 0.1, 1, and 2 mg/ml in with intervals of 24, 48, and 72 h. Growth inhibition and toxic effects of cinnamon extract were evaluated through tetrazolium salt reduction. The effect of this herb on the cell cycle was studied by flow cytometry. The Hoechst stain was used to detect apoptotic cell nuclei. RESULTS: Cinnamon extract inhibited the growth of HL-60 cells as correlated with concentration and time. After 72 h of treating HL-60 cells with 0.01 mg/l cinnamon extract, the growth of cells was inhibited by 90.1%. Cinnamon extract stopped the cell cycle in G1 phase and the Hoechst staining verified the apoptotic process in those cells. CONCLUSION: Considering the inhibitory property of cinnamon extract, we recommend it as a single drug or besides other medications for treating promyelocytic leukemia.

Improvement of a dendritic cell-based therapeutic cancer vaccine with components of Toxoplasma gondii.

The use of dendritic cells (DCs) as a cellular adjuvant is a promising approach to the immunotherapy of cancer. It has previously been demonstrated that DCs pulsed ex vivo with Toxoplasma gondii antigens trigger a systemic Th1-biased specific immune response and induce protective and specific antitoxoplasma immunity. In the present study, we demonstrate that tumor antigen-pulsed DCs matured in the presence of Toxoplasma gondii components induce a potent antitumor response in a mouse model of fibrosarcoma. Bone-marrow derived DCs (BMDCs) were cultured in the presence of granulocyte-macrophage colony-stimulating factor and interleukin-4. After 5 days, tumor lysates with or without the T. gondii lysate were added to the culture for another 2 days. The cytokine production in the BMDC culture and the coculture supernatants of DCs and splenic cells was evaluated. For immunization, 7 days after tumor challenge, different groups of BALB/c mice received different kinds of DCs subcutaneously around the tumor site. Tumor growth was monitored, and 2 weeks after DC immunotherapy, the cytotoxic activity and the infiltration of CD8(+) T cells were monitored in different groups. According to the findings, immunotherapy with T. gondii-matured DCs led to a significant increase in the activity of cytotoxic T cells and decreased the rate of growth of the tumor in immunized animals. Immature DCs did not cause any change in cytotoxic activity or the tumor growth rate compared to that in the healthy controls. The current study suggests that a specific antitumor immune response can be induced by DCs matured with T. gondii components and provide the basis for the use of T. gondii in DC-targeted clinical therapies.

Listeria monocytogenes activated dendritic cell based vaccine for prevention of experimental tumor in mice.

BACKGROUND: The use of dendritic cells (DCs) as a cellular adjuvant provides a promising approach in immunotherapy of cancer. It has been demonstrated that Listeria monocytogenes activated DCs pulsed ex vivo with tumor antigens trigger a systemic Th1-biased specific immune response and a single dose of this vaccine will cause a considerable anti tumor immunity. OBJECTIVE: The present study was designed to evaluate the ability of multiple doses of tumor antigen-pulsed DCs, matured in the presence of Listeria monocytogenes components in induction of a potent anti-tumor response and the prevention of tumor formation in an experimental model. METHODS: Bone-marrow derived DCs (BMDCs) were cultured in the presence of GM-CSF and IL-4. After 5 days, tumor lysates with/without Listeria monocytogenes lysate were added to the culture media for another 2 days. Mice received mature and tumor antigen pulsed dendritic cells subcutaneously in 3 groups. Tumor growth was monitored and two weeks after immunotherapy, cytotoxic activity of CD8+ T cells was evaluated in different groups. RESULTS: According to the findings, repeated doses of vaccine did not lead to a significant increase in the activity of cytotoxic T cells and decreased tumor growth of immunized animals. CONCLUSION: The current study suggests that increased doses of vaccine do not have sufficient efficiency for prevention of tumor induction. Generation of T regulatory responses upon repeated doses of such vaccines should be considered in future investigations.

Dendritic cell maturation with CpG for tumor immunotherapy.

BACKGROUND: Bacterial DNA has immunostimulatory effects on different types of immune cells such as dendritic cells (DCs). Application of DCs as a cellular adjuvant represents a promising approach in the immunotherapy of infectious disease and cancers. OBJECTIVE: To investigate the effect of tumor antigen pulsed DCs in the presence of CpG-1826 in treatment of a murine model of cancer. METHODS: WEHI-164 cells (Balb/c derived fibrosarcoma cell line) were injected subcutaneously in the right flank of mice. Bone marrow cells were cultured in the presence of GM-CSF and IL-4. After 5 days, tumor lysate, CpG-1826, and oligodeoxynucleosides, as control, were added to the culture media and incubated for 2 days. Cytokine production in DCs culture media was measured by ELISA. Then DCs were injected subcutaneously around the tumor site in the right flank of mice. Tumor growth rate was monitored in case and control groups. Two weeks after DCs immunotherapy, cytotoxic assay was conducted using various amounts of effector (splenic T cells) and target cells (WEHI-164 or CT26) for 6 h. RESULTS: Immunotherapy with DCs treated with CpG led to a significant increase in the activity of cytotoxic T cells and decreased tumor growth in immunized mice. In the control group which received DCs without CpG treatment, no change in cytotoxic activity and tumor growth rate was detected. CONCLUSION: The current study suggests that specific anti tumor immune responses can be induced by DCs matured with CpG and proposes CpG usage in DCs targeted clinical strategies.