In vitro and in vivo effect of IFNα on B16F10 melanoma in two models: Subcutaneous (C57BL6J mice) and lung metastasis (Swiss mice)

New Evidence on the Antiproliferative Activity of Campomanesia Adamantium (Cambess.) O. Berg Extracts in Melanoma Lung Metastasis

Given the importance of discovering plant species from the Brazilian Cerrado biome with anticancer potential, this study evaluated the antitumor activity of two extracts of Campomanesi adamantium fruits in in vitro and in vivo models of melanoma lung metastasis. Pulp and peel extracts (DEGPU and DEGPE, respectively) were extracted from fresh fruit using dichloromethane as a solvent. As cytotoxicity parameter, concentration values that inhibited 50% cell growth (GI50), total growth inhibition (TGI), and selectivity index (SI) were established. The melanoma lung metastasis model was obtained by injecting 5 × 105/50 μL B16-F10 cells via the tail vein of mice, which received treatment on the 15th day. Metastatic lungs were collected for fluorescence analysis with the IR-780 marker and also macro- and microscopic assessment. In vitro analyses showed that DEGPU was active in K562 (GI50 32.99; TGI 47.93) and U-251 (GI50 32.10; TGI 249.92), whereas DEGPE showed better cytotoxicity results for all tumor cell lines, but was more efficient in K562 (GI50 27.42; TGI 40.20) and U-251 (GI50 4.89; TGI 12.77). Both showed a cytocidal effect on B16F10 at the highest concentration tested, with approximately 25% (DEGPU) and 88% (DEGPE) of cell death. In vivo analyzes showed that both extracts showed significant activity in metastatic lung. Fluorescence images showed differences in intensity between groups owing to greater tumor involvement. Macro- and microscopic images showed that treatments with extracts limited tumor growth and prevented proliferation. The extracts tested have promising activity, thus requiring further research on their active compounds.

Analysis of the antimelanogenic activity of zinc and selenium in vitro

Melasma is an acquired chronic condition characterized by hyperchromic patches in photo-exposed areas. The search for new compounds for the treatment of melasma without side effects is constant. In this context, the aim of this study was to investigate the in vitro cytotoxic and antimelanogenic effects of the trace elements Zinc (Zn) and Selenium (Se). In this study, we evaluated the effects of 30 µM hydroquinone, this concentration did not alter mitochondrial function (MTT assay), but increased the percentage of necrotic cells and levels of reactive species. Furthermore, it showed no influence on tyrosinase activity and melanin content. Unlike hydroquinone, exposure for 48 h to 100 µM Zn and 1 and 5 µM Se had no significant influence on the analysis of reactive species, as well as on the percentage of necrotic cells. Still, specifically in relation to 100 µM Zn, it decreased the melanin content. Given the above, the trace elements Zn and Se did not show toxicity at the concentrations tested and Zn showed a promising effect, however, the mechanism needs to be better explored in order to contribute to new and updated research in the fight against melasma with a perspective of therapeutic use.

The Melding of Drug Screening Platforms for Melanoma

The global incidence of cancer is rising rapidly and continues to be one of the leading causes of death in the world. Melanoma deserves special attention since it represents one of the fastest growing types of cancer, with advanced metastatic forms presenting high mortality rates due to the development of drug resistance. The aim of this review is to evaluate how the screening of drugs and compounds for melanoma has been performed over the last seven decades. Thus, we performed literature searches to identify melanoma drug screening methods commonly used by research groups during this timeframe. In vitro and in vivo tests are essential for the development of new drugs; however, incorporation of in silico analyses increases the possibility of finding more suitable candidates for subsequent tests. In silico techniques, such as molecular docking, represent an important and necessary first step in the screening process. However, these techniques have not been widely used by research groups to date. Our research has shown that the vast majority of research groups still perform in vitro and in vivo tests, with emphasis on the use of in vitro enzymatic tests on melanoma cell lines such as SKMEL and in vivo tests using the B16 mouse model. We believe that the union of these three approaches (in silico, in vitro, and in vivo) is essential for improving the discovery and development of new molecules with potential antimelanoma action. This workflow would provide greater confidence and safety for preclinical trials, which will translate to more successful clinical trials and improve the translatability of new melanoma treatments into clinical practice while minimizing the unnecessary use of laboratory animals under the principles of the 3R's.

Obesity and intermittent hypoxia increase tumor growth in a mouse model of sleep apnea

BACKGROUND

Intermittent hypoxia and obesity which are two pathological conditions commonly found in patients with obstructive sleep apnea (OSA), potentially enhance cancer progression.

OBJECTIVE

To investigate whether obesity and/or intermittent hypoxia (IH) mimicking OSA affect tumor growth.

METHODS

A subcutaneous melanoma was induced in 40 mice [22 obese (40-45g) and 18 lean (20-25g)] by injecting 10(6) B16F10 cells in the flank. Nineteen mice (10 obese/9 lean) were subjected to IH (6h/day for 17days). A group of 21 mice (12 obese/9 lean) were kept under normoxia. At day 17, tumors were excised, weighed and processed to quantify necrosis and endothelial expression of vascular endothelial growth factor (VEGF) and CD-31. VEGF in plasma was also assessed.

RESULTS

In lean animals, IH enhanced tumor growth from 0.81±0.17 to 1.95±0.32g. In obese animals, a similar increase in tumor growth (1.94±0.18g) was observed under normoxia, while adding IH had no further effect (1.69±0.23g). IH only promoted an increase in tumoral necrosis in lean animals. However, obesity under normoxic conditions increased necrosis, VEGF and CD-31 expression in tumoral tissue. Plasma VEGF strongly correlated with tumor weight (ρ=0.76, p<0.001) in the whole sample; it increased in lean IH-treated animals from 66.40±3.47 to 108.37±9.48pg/mL, p<0.001), while the high baseline value in obese mice (106.90±4.32pg/mL) was unaffected by IH.

CONCLUSIONS

Obesity and IH increased tumor growth, but did not appear to exert any synergistic effects. Circulating VEGF appeared as a crucial mediator of tumor growth in both situations.

Interferon-alpha modulates the chemosensitivity of CD133-expressing pancreatic cancer cells to gemcitabine

Pancreatic cancer is a lethal disease as current chemotherapies with gemcitabine (GEM) are still insufficient. Accumulating evidence suggests that cancer stem cells (CSC) are responsible for chemoresistance and that CD133 is one of the CSC markers in pancreatic cancer. Interferon-alpha (IFN-α), a cytokine with pleiotropic effects, has direct cytotoxic and cytostatic effects on tumor cells. The aim of the present study was to investigate whether IFN-α can modulate the chemosensitivity of a human pancreatic cancer cell line, Capan-1, to GEM. Cell cycles were evaluated for response to GEM with and without IFN-α by BrdU assay. GEM inhibited Capan-1 cell growth in a dose-dependent manner. GEM (IC(50); 100 ng/mL) treatment reduced the number of both CD133(+) and CD133(-) cells in the S phase, induced apoptosis of CD133(-) cells more than that of CD133(+) cells and increased accumulation of CD133(+) cells into the G0/G1 phase. These results infer that CD133(+) cells take shelter into the G0/G1 phase from GEM treatment. IFN-α modulated CD133(+) cells from the G0/G1 phase to the S phase. Consequently, apoptosis was accelerated in both CD133(+) and CD133(-) cells after IFN-α combined with GEM treatment. Furthermore, GEM combined with IFN-α treatment showed a significant tumor suppressive effect in the in vivo study. Importantly, CD133(+) cells showed CSC-like properties, such as generation of spheres, highly invasive ability and high tumorigenesis. These results suggest that IFN-α, as a modulator, could contribute to the treatment of CD133(+) cancer cells and be effective in combined chemotherapies with GEM for pancreatic cancer stem-like cells.

Histopathological follow-up by tissue micro-array in a survival study after melanoma treated by nanosecond pulsed electric fields (nsPEF)

A recent study has shown that nanosecond pulsed electric fields (nsPEF) can affect the intracellular structures of melanoma within weeks. nsPEF is a non-drug, non-thermal treatment using ultrashort, intense pulsed electric fields with nanosecond durations. In the current study we followed up melanoma histopathology and metastasis with tissue micro-array 5 months post-nsPEF. After nsPEF treatment, tumor growth, tumor histology, metastasis, peri-tumor vessel and micro-vessel density were examined for the effect of nsPEF treatment on melanoma in vivo. The 17 nsPEF-treated mice were tumor-free for 169 days, significantly longer than those 19 control mice bearing melanoma without nsPEF. Histopathology follow-up showed that melanoma did not recur to the primary injection place after complete elimination. Compared with the control tumor, nsPEF-treated tumors present decreased micro-vessel density in a time-course manner in this survival study. Treatment with nsPEF caused continuous histopathological changes in melanomas, eliminated melanoma without recurrence at the primary site and prolonged animal survival time by inhibiting tumor blood supply and leading to tumor infarction. Thus, nsPEF could be applied in a non-ionizing therapeutic approach, without other agents, to locally treat tumors within a defined boundary.