Polyphasic evaluation and cytotoxic investigation of isolated cyanobacteria with an emphasis on potent activities of a Scytonema strain.

Cyanobacteria are phototrophic organisms widely found in most types of natural habitats in the tropical regions of the world. In this study, we isolated and identified cyanobacterial strains from paddy soil in Hanoi (Vietnam) and investigated their cytotoxic activities. Five isolated cyanobacterial strains showed distinctive profiles of gene sequences (rRNA 16S and rbcL), phylogenetic placements, and morphological characteristics. Based on the polyphasic evaluation, they were classified as Scytonema bilaspurense NK13, Hapalosiphon welwitschii MD2411, Aulosira sp. XN1103, Desikacharya sp. NS2000, and Desmonostoc sp. NK1813. The cytotoxic screening revealed that the extract of strain Scytonema bilaspurense NK13 exhibited potent cytotoxic activities against four human cell lines of HeLa cells, OVCAR-8 cells, HaCaT cells, and HEK-293T cells, with IC50 values of 3.8, 34.2, 21.6, and 0.6 µg/mL, respectively. This is the first time a well-classified Scytonema strain from tropical habitat in Southeast Asia has been recognized as a potential producer of cytotoxic compounds.

Frequency and distribution of HLA-DQB1 alleles from 2076 cord blood samples of the Vietnamese cohort.

Human leucocyte antigen (HLA) alleles are very diverse and characterized by ethnicity. To date, information about the frequencies and distributions of HLA alleles among the Vietnamese population is still limited. In this study, HLA-DQB1 alleles of 2076 cord blood units from individuals belonging to Vietnam's Kinh ethnic people were genotyped using Luminex-based polymerase chain reaction sequence-specific oligonucleotide. The results of the study demonstrated that there were 23 alleles on the locus HLA-DQB1. Among those, there were six alleles with high frequencies of over 5%, including DQB1* 03:01 (35.9%), DQB1* 05:01 (12.8%), DQB1* 03:03 (12.2%); DQB1* 06:01 (7.20%), DQB1* 05:02 (6.62%) and DQB1* 02:01 (5.30%) and five rare alleles with low frequencies of below 0.1%. More importantly, this study for the first time reported the presence of two new rare alleles including DQB1* 01:01 and DQB1* 01:02. Conclusively, this study provided significant information about HLA-DQB1 alleles for further investigations and clinical applications.

Allele and Haplotype Frequencies of HLA-A, -B, -C, and -DRB1 Genes in 3,750 Cord Blood Units From a Kinh Vietnamese Population.

The frequencies and diversities of human leukocyte antigen (HLA) alleles and haplotypes are representative of ethnicities. Matching HLA alleles is essential for many clinical applications, including blood transfusion, stem cell transplantation, and tissue/organ transplantation. To date, the information about the frequencies and distributions of HLA alleles and haplotypes among the Kinh Vietnamese population is limited because of the small sample size. In this study, more than 3,750 cord blood units from individuals belonging to the Kinh Vietnamese population were genotyped using PCR sequence-specific oligonucleotide (PCR-SSO) for HLA testing. The results of the study demonstrated that the most frequently occurring HLA-A, -B, -C, and -DRB1 alleles were A*11:01 (25%), A*24:02 (12.3%), A*02:01 (11.2); A*03:03 (8.95%), A*02:03 (7.81%), A*29:01 (7.03%); B*15:02 (15.1%), B*46:01 (10.7%), B*58:01 (7.65%), B*38:02 (7.29%); C*08:01 (17.2), C*07:02 (16.2%), C*01:02 (15.2), C*03:02 (8.3%), C*15:05 (6.13); DRB1*12:02 (31.0%), DRB1*09:01 (10.47%), DRB1*15:02 (7.54%); DRB1*07:01 (6.68%), DRB1*10:01 (6.63%), respectively, with the highest allele diversity level observed in locus B (93 alleles). The most frequent haplotypes of two-locus combinations of HLA-A-B, HLA-A-C, HLA-A-DRB1, HLA-B-C, HLA-B-DRB1, and HLA-C-DRB1 haplotypes were A*11:01-B*15:02 (7.63%), A*11:01-C*08:01 (7.98%), A*11:01-DRB1*12:02 (10.56%), B*15:02-C*08:01 (14.0%), B*15:02-DRB1*12:02 (10.47%), and C*08:01-DRB1*12:02 (11.38%), respectively. In addition, the most frequent haplotypes of three- and four-locus sets of HLA-A-B-C, HLA-A-B-DRB1, HLA-A-C-DRB1, HLA-B-C-DRB1, and HLA-A-B-C-DRB1 were A*11:01-B*15:02-C*08:01 (7.57%), A*11:01-B*15:02-DRB1*12:02 (5.39%), A*11:01-C*08:01-DRB1*12:02 (5.54%), B*15:02-C*08:01-DRB1*12:02 (10.21%), and A*11:01-B*15:02-C*08:01-DRB1*12:02 (5.45%), respectively. This study provides critical information on the frequencies and distributions of HLA alleles and haplotypes in the Kinh Vietnamese population, accounting for more than 85% of Vietnamese citizens. It paves the way to establish an umbilical cord blood bank for cord blood transplantation programs in Vietnam.

Predominant HLA Alleles and Haplotypes in Mild Adverse Drug Reactions Caused by Allopurinol in Vietnamese Patients with Gout.

Allopurinol (ALP) is commonly used as a drug for gout treatment. However, ALP is known to cause cutaneous adverse reactions (CARs) in patients. The HLA-B*58:01 allele is considered a biomarker of severe CAR (SCAR) in patients with gout, with symptoms of Stevens Johnson syndrome, and with toxic epidermal necrolysis. However, in patients with gout and mild cutaneous adverse drug reactions (MCARs), the role of HLA-allele polymorphisms has not been thoroughly investigated. In this study, 50 samples from ALP-tolerant patients and ALP-induced MCARs patients were genotyped in order to examine the polymorphisms of their HLA-A and HLA-B alleles. Our results showed that the frequencies of HLA-A*02:01/HLA-A*24:02 and HLA-A*02:01/HLA-A*29:01, the dual haplotypes in HLA-A, in patients with ALP-induced MCARs were relatively high, at 33.3% (7/21), which was HLA-B*58:01-independent, while the frequency of these dual haplotypes in the HLA-A locus in ALP-tolerant patients was only 3.45% (1/29). The HLA-B*58:01 allele was detected in 38% (8/21) of patients with ALP-induced MCARs, and in 3.45% (1/29) of ALP-tolerant patients. Notably, although HLA-B*58:01 may be a cause for the occurrence of MCARs in patients with gout, this correlation was not as strong as that previously reported in patients with SCAR. In conclusion, in addition to the HLA-B*58:01 allele, the presence of the dual haplotypes of HLA-A*02:01/HLA-A*24:02 and/or HLA-A*02:01/HLA-A*29:01 in the HLA-A locus may also play an important role in the appearance of ALP-induced MCARs in the Vietnamese population. The obtained primary data may contribute to the development of suitable treatments for patients with gout not only in Vietnam but also in other Asian countries.

Toxicity and Anti-Proliferative Properties of Anisomeles indica Ethanol Extract on Cervical Cancer HeLa Cells and Zebrafish Embryos.

In this study, we showed that crude extract of Anisomeles indica (AI-EtE) expressed its toxicity to HeLa cells with an IC50 dose of 38.8 µg/mL and to zebrafish embryos with malformations, lethality and hatching inhibition at 72-hpf at doses higher than 75 µg/mL. More interestingly, flow cytometry revealed that AI-EtE significantly promoted the number of cells entering apoptotic. Accordingly, the transcript levels of BAX, CASPASE-8, and CASPASE-3 in the cells treated with AI-EtE at IC50 dose were 1.55-, 1.62-, and 2.45-fold higher than those in the control cells, respectively. Moreover, treatment with AI-EtE caused cell cycle arrest at the G1 phase in a p53-independent manner. Particularly, percentages of AI-EtE-treated cells in G1, S, G2/M were, respectively 85%, 6.7% and 6.4%; while percentages of control cells in G1, S, G2/M were 64%, 15% and 19%, respectively. Consistent with cell cycle arrest, the expressions of CDKN1A and CDNK2A in AI-EtE-treated cells were up-regulated 1.9- and 1.64-fold, respectively. Significantly, treatment with AI-EtE also decreased anchorage-independent growth of HeLa cells. In conclusion, we suggest that Anisomeles indica can be considered as a medicinal plant with a possible use against cervical cancer cells; however, the used dose should be carefully monitored, especially when applying to pregnant women.

Anticancer Activities of Ricin-Liposome Complexes on SKMEL-28 Cells.

Background: Ricin has been reported as a potential chemical for cancer treatment. However, so far, the application of ricin in cancer treatment is very limited because of its non-specificity. Methods: In this study, ricin were conjugated/ encapsulated with DOTAP/DOPE liposome to form ricin-liposome complexes (ricin-lipososme1, ricin-liposome2, ricin-liposome3 and ricin-liposome4). Characteristics of ricin-liposome complexes were analyzed and their effects on survival, apoptosis, migration, invasion and tumor formation of SKMEL-28 melanoma cells were examined by carrying out the MTT assay, apoptosis assay, scratch wound healing assay, invasion assay and soft-agar colony formation assay, respectively. Results: Ricin-liposome complexes had even size-distribution with average size of around 340 nm. These ricin-liposome complexes were able to penetrate into the cells via endocytosis with the highest ability of the ricinliposome3. It also showed that ricin-liposome3 expressed very high toxicity with the IC50 of 62.4 ng/mL and followed by ricin-liposome4 (286.4 mg/mL), ricin-liposome2 (417.5 ng/mL), and ricin-liposome1 (604.3 ng/mL) to SKMEL-28 cells at 36 hours post treatment. At the concentrations of IC10 (10.1 ng/mL), ricin-liposome3 strongly induced necrosis and apoptosis of SKMEL-28 cells up to 25.6% and 11.4%, respectively. Moreover, ricin-liposome3 expressed great anticancer properties by decreasing the migration, invasion and tumor formation abilities of SKMEL-28 cells of 7.5 folds, 4.3 folds and 5.9 folds, respectively, compared with those of control SKMEL-28 cells. Conclusion: The obtained results from our study suggest that although ricin is listed as one of the most poisonous substances in nature, it can be used in the complex forms with liposome to increase its specificity to apply in treatment of melanoma and other cancers.

Melanin-embedded materials effectively remove hexavalent chromium (CrVI) from aqueous solution.

BACKGROUND: Currently, it is recognized that water polluted with toxic heavy metal ions may cause serious effects on human health. Therefore, the development of new materials for effective removal of heavy metal ions from water is still a widely important area. Melanin is being considered as a potential material for removal of heavy metal from water. METHODS: In this study, we synthesized two melanin-embedded beads from two different melanin powder sources and named IMB (Isolated Melanin Bead originated from squid ink sac) and CMB (Commercial Melanin Bead originated from sesame seeds). These beads were of globular shape and 2-3 mm in diameter. We investigated and compared the sorption abilities of these two bead materials toward hexavalent-chromium (CrVI) in water. The isotherm sorption curves were established using Langmuir and Freundlich models in the optimized conditions of pH, sorption time, solid/liquid ratio, and initial concentration of CrVI. The FITR analysis was also carried out to show the differences in surface properties of these two beads. RESULTS: The optimized conditions for isotherm sorption of CrVI on IMB/CMB were set at pH values of 2/2, sorption times of 90/300 min, and solid-liquid ratios of 10/20 mg/mL. The maximum sorption capacities calculated based on the Langmuir model were 19.60 and 6.24 for IMB and CMB, respectively. However, the adsorption kinetic of CrVI on the beads fitted the Freundlich model with R2 values of 0.992 for IMB and 0.989 for CMB. The deduced Freundlich constant, 1/n, in the range of 0.2-0.8 indicated that these beads are good adsorption materials. In addition, structure analysis data revealed great differences in physical and chemical properties between IMB and CMB. Interestingly, FTIR analysis results showed strong signals of -OH (3295.35 cm- 1) and -C=O (1608.63 cm- 1) groups harboring on the IMB but not CMB. Moreover, loading of CrVI on the IMB caused a shift of broad peaks from 3295.35 cm- 1 and 1608.63 cm- 1 to 3354.21 cm- 1 and 1597.06 cm- 1, respectively, due to -OH and -C=O stretching. CONCLUSIONS: Taken together, our study suggests that IMB has great potential as a bead material for the elimination of CrVI from aqueous solutions and may be highly useful for water treatment applications.

Polygonum multiflorum root extract as a potential candidate for treatment of early graying hair.

Despite Polygonum multiflorum (PM) has been experiencely used as a drug to treat early graying hair phenomenon in Asian countries for a long time, there is limited study examined the real biological effects of PM on hair graying in vitro and in vivo. In this study, we investigated the effects of PM root extract (PM-RE) on melanin synthesis in human melanoma SKMEL-28 cells and embryos/larvae of wild-type strain AB zebrafish. We also preliminary revealed the molecular mechanism of early hair graying phenomenon in both in vitro and in vivo models. Our results showed that PM-RE significantly induced melanin synthesis in melanin-producing SKMEL-28 melanoma cells and also in zebrafish embryos/larvae at 4-day postfertilization through activation of MC1R/MITF/tyrosinase-signaling pathway. We also investigated the differences in genotype between graying hair follicle and black hair follicle of young peoples and found that early hair graying phenomenon may be related to downregulation of MC1R/MITF/tyrosinase pathway. Taken together, we suggested that PM-RE at safe doses could be used as a potential agent for the treatment of early hair graying and other loss pigmentation-related diseases.

Translocation of BBAP from the cytoplasm to the nucleus reduces the metastatic ability of vemurafenib-resistant SKMEL28 cells.

To the best of our knowledge, the present study is the first to demonstrate that treatment of vemurafenib-resistant SKMEL28 (SKMEL28-R) cells with paclitaxel leads to a shift in localization of the E3-ligase BBAP from the cytoplasm to the nucleus, consequently decreasing the metastatic ability of this cell line. The present study revealed that the movement of BBAP from the cytoplasm to nucleus initiated a change in cell morphology. In addition, the translocation of BBAP led to a decrease of metastatic characteristics in SKMEL28­R cells, including migration and invasion via downregulation of the phosphorylated form of focal adhesion kinase and N­cadherin, as well as an upregulation of p21 and E-cadherin. The results of the present study suggested that BBAP may not only be a novel biomarker for melanoma, but also a novel therapeutic target for treatment of metastatic melanoma.

Limited effectiveness of household sand filters for removal of arsenic from well water in North Vietnam.

Since well water utilized for domestic purposes in the Red River Delta of North Vietnam has been reported to be polluted by arsenic, barium, iron, and manganese, household sand filters consisting of various components are used. Information regarding the effectiveness of various sand filters for removal of the four toxic elements in well water is limited. In this study, arsenic levels in 13/20 of well water samples and 1/7 of tap water samples exceeded World Health Organization (WHO) health-based guideline value for drinking water. Moreover, 2/20, 6/20, and 4/20 of well water samples had levels exceeding the present and previous guideline levels for barium, iron, and manganese, respectively. Levels of iron and manganese, but not arsenic, in well water treated by sand filters were lower than those in untreated water, although previous studies showed that sand filters removed all of those elements from water. A low ratio of iron/arsenic in well water may not be sufficient for efficient removal of arsenic from household sand filters. The levels of barium in well water treated by sand filters, especially a filter composed of sand and charcoal, were significantly lower than those in untreated water. Thus, we demonstrated characteristics of sand filters in North Vietnam.

Carcinogenic risk of chromium, copper and arsenic in CCA-treated wood.

We showed that 2.1% of 233 pieces of lumber debris after the Great East Japan Earthquake was chromated copper arsenate (CCA)-treated wood. Since hexavalent chromium (Cr), copper (Cu) and pentavalent arsenic (As) in the debris may be diffused in the air via incineration, we exposed human lung normal (BEAS-2B) and carcinoma (A549) cells to Cr, Cu and As at the molar ratio in a representative CCA-treated wood. Co-exposure to 0.10 µM Cr and 0.06 µM As, which solely had no effect on colony formation, synergistically promoted colony formation in BEAS-2B cells, but not A549 cells, with activation of the PI3K/AKT pathway. Sole exposure and co-exposure to Cu showed limited effects. Since previous reports showed Cr and As concentrations to which human lungs might be exposed, our results suggest the importance to avoid diffusion of Cr and As in the air via incineration of debris including CCA-treated wood after the disaster.

Deltex-3-like (DTX3L) stimulates metastasis of melanoma through FAK/PI3K/AKT but not MEK/ERK pathway.

Deltex-3-like (DTX3L), an E3 ligase, is a member of the Deltex (DTX) family and is also called B-lymphoma and BAL-associated protein (BBAP). Previously, we established RFP/RET-transgenic mice, in which systemic hyperpigmented skin, benign melanocytic tumor(s) and melanoma(s) develop stepwise. Here we showed that levels of Dtx3l/DTX3L in spontaneous melanoma in RFP/RET-transgenic mice and human melanoma cell lines were significantly higher than those in benign melanocytic cells and primarily cultured normal human epithelial melanocytes, respectively. Immunohistochemical analysis of human tissues showed that more than 80% of the melanomas highly expressed DTX3L. Activity of FAK/PI3K/AKT signaling, but not that of MEK/ERK signaling, was decreased in Dtx3l/DTX3L-depleted murine and human melanoma cells. In summary, we demonstrated not only increased DTX3L level in melanoma cells but also DTX3L-mediated regulation of invasion and metastasis in melanoma through FAK/PI3K/AKT but not MEK/ERK signaling. Our analysis in human BRAFV600E inhibitor-resistant melanoma cells showed about 80% decreased invasion in the DTX3L-depleted cells compared to that in the DTX3L-intact cells. Thus, DTX3L is clinically a potential therapeutic target as well as a potential biomarker for melanoma.

Treatment of vemurafenib-resistant SKMEL-28 melanoma cells with paclitaxel.

Vemurafenib has recently been used as drug for treatment of melanomas with BRAFV600E mutation. Unfortunately, treatment with only vemurafenib has not been sufficiently effective, with recurrence after a short period. In this study, three vemurafenib-resistant BRAFV600E melanoma cell lines, A375PR, A375MR and SKMEL-28R, were established from the original A375P, A375M and SKMEL-28 cell lines. Examination of the molecular mechanisms showed that the phosphorylation levels of MEK and ERK, which play key roles in the RAS/RAF/MEK/ERK signaling pathway, were reduced in these three cell lines, with increased phosphorylation levels of pAKTs limited to SKMEL-28R cells. Treatment of SKMEL-28R cells with 100 nM paclitaxel resulted in increased apoptosis and decreased cellular proliferation, invasion and colony formation via reduction of expression levels of EGFR and pAKTs. Moreover, vemurafenib-induced pAKTs in SKMEL-28R were decreased by treatment with an AKT inhibitor, MK-2206. Taken together, our results revealed that resistance mechanisms of BRAFV600E-mutation melanoma cells to vemurafenib depended on the cell type. Our results suggested that paclitaxel should be considered as a drug in combination with vemurafenib to treat melanoma cells.

Influence of phytochemicals in piper betle linn leaf extract on wound healing.

BACKGROUND: Wound healing has being extensively investigated over the world. Healing impairment is caused by many reasons including increasing of free-radicals-mediated damage, delaying in granulation tissue formation, reducing in angiogenesis and decreasing in collagen reorganization. These facts consequently lead to chronic wound healing. Piper betle Linn (Betle) leaves have been folklore used as an ingredient of drugs for cutaneous wound treatment. However, the effect of betle leaf on wound healing is not yet well elucidated. In this study, we aimed to investigate the healing efficacy of methanol leaf extract of Piper betle Linn on proliferation of fibroblast NIH3T3 cells as well as full-thickness burn and excision wounds in swiss mice. METHODS: Scratch wound healing assays were conducted to examine the effects of betle leaf extract on healing activity of fibroblast cells. Burn and excision wounds on swiss mouse skins were created for investigating the wound healing progress caused by the betle leaf extract. Malondialdehyde (MDA) was also evaluated to examine the products of lipid hydroperoxide (LPO) under conditions of with or without betle leaf extract treatment. RESULTS: The results of this study showed that Piper betle Linn leaf extract in methanol increased proliferation of NIH3T3 cells and promoted wound healing in vitro and in vivo with both burn wound and excision wound models. In addition, this extract significant decreased level of malondialdehyde (MDA) in liver of treated-mice compared with that in non-treated mice. CONCLUSIONS: Our results suggest that Piper betle Linn can be used as an ingredient in developing natural origin drugs for treatment of cutaneous wounds.

Bidirectional functions of arsenic as a carcinogen and an anti-cancer agent in human squamous cell carcinoma.

Bidirectional cancer-promoting and anti-cancer effects of arsenic for cancer cells have been revealed in previous studies. However, each of these effects (cancer-promoting or anti-cancer) was found in different cells at different treated-concentration of arsenic. In this study, we for the first time indicated that arsenic at concentration of 3 µM, equal to average concentration in drinking water in cancer-prone areas in Bangladesh, simultaneously expressed its bidirectional effects on human squamous cell carcinoma HSC5 cells with distinct pathways. Treatment with 3 µM of arsenic promoted cell invasion via upregulation of expression of MT1-MMP and downregulation of expression of p14ARF and simultaneously induced cell apoptosis through inhibition of expression of N-cadherin and increase of expression of p21(WAF1/CIP1) at both transcript and protein levels in HSC5 cells. We also showed that inhibition of MT1-MMP expression by NSC405020 resulted in decrease of arsenic-mediated invasion of HSC5 cells involving decrease in phosphorylated extracellular signal-regulated kinases (pERK). Taken together, our biological and biochemical findings suggested that arsenic expressed bidirectional effects as a carcinogen and an anti-cancer agent in human squamous cell carcinoma HSC5 cells with distinct pathways. Our results might play an important scientific evident for further studies to find out a better way in treatment of arsenic-induced cancers, especially in squamous cell carcinoma.

RAS/RAF/MEK/ERK and PI3K/PTEN/AKT Signaling in Malignant Melanoma Progression and Therapy.

Cutaneous malignant melanoma is one of the most serious skin cancers and is highly invasive and markedly resistant to conventional therapy. Melanomagenesis is initially triggered by environmental agents including ultraviolet (UV), which induces genetic/epigenetic alterations in the chromosomes of melanocytes. In human melanomas, the RAS/RAF/MEK/ERK (MAPK) and the PI3K/PTEN/AKT (AKT) signaling pathways are two major signaling pathways and are constitutively activated through genetic alterations. Mutations of RAF, RAS, and PTEN contribute to antiapoptosis, abnormal proliferation, angiogenesis, and invasion for melanoma development and progression. To find better approaches to therapies for patients, understanding these MAPK and AKT signaling mechanisms of melanoma development and progression is important. Here, we review MAPK and AKT signaling networks associated with melanoma development and progression.

A novel hairless mouse model for malignant melanoma.

BACKGROUND: An appropriate animal model for malignant melanoma could be a strong tool to develop biomarkers through analysis of melanomagenesis. OBJECTIVE: Development of a novel animal model that spontaneously develops malignant melanoma with a high percentage. METHODS: We crossed oncogenic RET (RFP-RET)-carrying transgenic mice of line 304/B6 (RET-mice) with hairless mice (hr/hr) and newly established hairless RFP-RET-transgenic mice of line 304-hr/hr (HL-RET-mice). RESULTS: The HL-RET-mice developed hyperpigmented skin and benign melanocytic tumors without exception. More importantly, 63.8% (46/72) of the benign tumors were transformed to malignant melanoma in the HL-RET-mice. Mean time until the development of benign melanocytic tumors (2.4 months; n = 102) in the HL-RET-mice was about half of that in the original RET-mice (4.6 months; n = 20). Mean life span in the HL-RET-mice (9.7 months; n = 38) was also significantly (p < 0.01) shorter than that in the original RET-mice (10.8 months; n = 20). Since early development of tumors could contribute to shortening of the research period, HL-RET-mice could be a useful model for analysis of melanomagenesis. We then found that the expression level of Mps one binder kinase activator-like-2B (Mobkl2b) in benign tumors was higher than that in malignant melanoma in HL-RET-mice. Expression level of MOBKL2B in malignant melanoma cell lines was also lower than that in non-malignant melanocytic cells in mice and humans, suggesting that MOBKL2B could be a novel marker for malignant melanoma. CONCLUSION: We established a novel hairless RET-transgenic mouse line spontaneously developing cutaneous malignant melanomas from benign melanocytic tumors. This mouse model may be useful to find new candidates of melanoma-related molecule.

Molecular Network Associated with MITF in Skin Melanoma Development and Progression.

Various environmental and genetic factors affect the development and progression of skin cancers including melanoma. Melanoma development is initially triggered by environmental factors including ultraviolet (UV) light, and then genetic/epigenetic alterations occur in skin melanocytes. These first triggers alter the conditions of numerous genes and proteins, and they induce and/or reduce gene expression and activate and/or repress protein stability and activity, resulting in melanoma progression. Microphthalmia-associated transcription factor (MITF) is a master regulator gene of melanocyte development and differentiation and is also associated with melanoma development and progression. To find better approaches to molecular-based therapies for patients, understanding MITF function in skin melanoma development and progression is important. Here, we review the molecular networks associated with MITF in skin melanoma development and progression.

Barium promotes anchorage-independent growth and invasion of human HaCaT keratinocytes via activation of c-SRC kinase.

Explosive increases in skin cancers have been reported in more than 36 million patients with arsenicosis caused by drinking arsenic-polluted well water. This study and previous studies showed high levels of barium as well as arsenic in the well water. However, there have been no reports showing a correlation between barium and cancer. In this study, we examined whether barium (BaCl(2)) may independently have cancer-related effects on human precancerous keratinocytes (HaCaT). Barium (5-50 µM) biologically promoted anchorage-independent growth and invasion of HaCaT cells in vitro. Barium (5 µM) biochemically enhanced activities of c-SRC, FAK, ERK and MT1-MMP molecules, which regulate anchorage-independent growth and/or invasion. A SRC kinase specific inhibitor, protein phosphatase 2 (PP2), blocked barium-mediated promotion of anchorage-independent growth and invasion with decreased c-SRC kinase activity. Barium (2.5-5 µM) also promoted anchorage-independent growth and invasion of fibroblasts (NIH3T3) and immortalized nontumorigenic melanocytes (melan-a), but not transformed cutaneous squamous cell carcinoma (HSC5 and A431) and malignant melanoma (Mel-ret) cells, with activation of c-SRC kinase. Taken together, our biological and biochemical findings newly suggest that the levels of barium shown in drinking well water independently has the cancer-promoting effects on precancerous keratinocytes, fibroblast and melanocytes in vitro.