New approaches to cancer therapy

Streptomyces hygroscopicus UFPEDA 3370: A valuable source of the potent cytotoxic agent nigericin and its evaluation against human colorectal cancer cells

Streptomyces hygroscopicus UFPEDA 3370 was fermented in submerged cultivation and the biomass extract was partitioned, obtaining a fraction purified named EB1. After purification of EB1 fraction, nigericin free acid was obtained and identified. Nigericin presented cytotoxic activity against several cancer cell lines, being most active against HL-60 (human leukemia) and HCT-116 (human colon carcinoma) cell lines, presenting IC₅₀ and (IS) values: 0.0014 μM, (30.0) and 0.0138 μM (3.0), respectively. On HCT-116, nigericin caused apoptosis and autophagy. In this study, nigericin was also screened both in vitro and in silico against a panel of cancer-related kinases. Nigericin was able to inhibit both JAK3 and GSK-3β kinases in vitro and its binding affinities were mapped through the intermolecular interactions with each target in silico.

Dextran-Curcumin Nanoparticles as a Methotrexate Delivery Vehicle: A Step Forward in Breast Cancer Combination Therapy

With the aim to effectively deliver methotrexate (MTX) to breast cancer cells, we designed a nanocarrier system (DC) derived from the self-assembly of a dextran-curcumin conjugate prepared via enzyme chemistry with immobilized laccase acting as a solid biocatalyst. Nanoparticles consisted of homogeneously dispersed nanospheres with a mean diameter of 290 nm, as characterized by combined transmission electron microscopy and dynamic light scattering investigations. DC was able to control the MTX release overtime (t_1/2 value of 310 min), with cell internalization studies proving its presence inside MCF-7 cytoplasm. Finally, improved MTX efficacy was obtained in viability assays, and attributed to the synergy of curcumin moieties and loaded MTX as underlined by a combination index (CI) < 1.

Combination therapy in combating cancer

Combination therapy, a treatment modality that combines two or more therapeutic agents, is a cornerstone of cancer therapy. The amalgamation of anti-cancer drugs enhances efficacy compared to the mono-therapy approach because it targets key pathways in a characteristically synergistic or an additive manner. This approach potentially reduces drug resistance, while simultaneously providing therapeutic anti-cancer benefits, such as reducing tumour growth and metastatic potential, arresting mitotically active cells, reducing cancer stem cell populations, and inducing apoptosis. The 5-year survival rates for most metastatic cancers are still quite low, and the process of developing a new anti-cancer drug is costly and extremely time-consuming. Therefore, new strategies that target the survival pathways that provide efficient and effective results at an affordable cost are being considered. One such approach incorporates repurposing therapeutic agents initially used for the treatment of different diseases other than cancer. This approach is effective primarily when the FDA-approved agent targets similar pathways found in cancer. Because one of the drugs used in combination therapy is already FDA-approved, overall costs of combination therapy research are reduced. This increases cost efficiency of therapy, thereby benefiting the “medically underserved”. In addition, an approach that combines repurposed pharmaceutical agents with other therapeutics has shown promising results in mitigating tumour burden. In this systematic review, we discuss important pathways commonly targeted in cancer therapy. Furthermore, we also review important repurposed or primary anti-cancer agents that have gained popularity in clinical trials and research since 2012.

Cancer mortality in Europe, 1995-1999, and an overview of trends since 1960

Mortality data, abstracted from the World Health Organization database, are presented in tabular form for 26 cancer sites or groups of sites, plus total cancer mortality, in 36 European countries during the period 1995-1999. Trends in mortality are also given in graphic form for 23 major countries plus the European Union as a whole over the period 1960-1999. In the European Union, total cancer mortality declined by 7% for both sexes over the last 5 years considered. The fall since the late 1980s was 10% in both sexes, corresponding to the avoidance of over 90000 deaths per year, as compared to the rates of the late 1980s. For the first time, over the last few years, some leveling of mortality was reported also in the Russian Federation, the Czech Republic, Poland, Hungary and other Eastern European countries, although cancer rates in those areas remain exceedingly high. The overall favorable pattern of cancer mortality over recent years is largely driven by the decline of tobacco-related cancer mortality in men. However, important components of the trends are also the persistence of substantial falls in gastric cancer, mainly in Russia and Eastern Europe, the recent decline in intestinal cancer in both sexes and of breast cancer in women, together with the long-term falls in uterine (cervical) cancer, leukemias, Hodgkin's disease and other neoplasms amenable to advancements in diagnosis and treatment. Female lung cancer mortality has been declining in the Russian Federation, but is still rising in other areas of the continent. Thus, urgent intervention is needed to bring under control the tobacco-related lung cancer epidemic in European women before it reaches the high level observed in North America. Supplementary material for this article can be found on the International Journal of Cancer website at http://www.interscience.wiley.com/jpages/0020-7136/suppmat/index.html