Cancer cell bioenergetics and pH regulation influence breast cancer cell resistance to paclitaxel and doxorubicin

The multidrug resistance (MDR) phenotype, frequently observed during cancer treatment, is often associated with drug efflux pump activity. However, many other factors are also known to be involved. Cancer cells often rely on aerobic glycolysis for energy production; this is known as the “Warburg effect” and is used as a survival mechanism. Associated to this event, a reverse pH gradient across the cell membrane occurs, leading to cytosol alkalinization and extracellular acidification. In the present study, we investigated the role of different mechanisms involved in MDR, such as altered tumor microenvironment and energetic metabolism. The breast cancer cell line MCF-7, used as model, was exposed to two widely used antitumor drugs, paclitaxel (antimitotic agent) and doxorubicin (alkylating agent). Cancer pH regulation was shown to be crucial for malignant characteristics such as cell migration and drug resistance. Our results showed that a lower extracellular pH induced a higher migratory capacity and higher resistance to the studied chemotherapeutical compounds in MCF-7 cells. Besides the influence of the extracellular pH, the role of the tumor metabolism in the MDR phenotype was also investigated. Pre-treatment with different bioenergetic modulators led to cell ATP depletion and altered lactic acid production and glucose consumption, resulting in increased sensitivity to paclitaxel and doxorubicin. Overall, this study supports the potential use of compounds targeting cell metabolism and tumor microenvironment factors such as pH, as co-adjuvants in conventional chemotherapy.     

Symposium announcement and call for presentations

Symposium announcement and call for presentations     

Correction to: A New Species of Ctenomys (Rodentia: Ctenomyidae) from Patagonia Related to C. sociabilis

Journal of Mammalian Evolution -     

Role of adiponectin as a modulator of testicular function during aging in mice

The mechanisms by which testicular functions decline with aging remain largely speculative. Our recent finding showed the importance of adiponectin in the regulation of testicular functions, whereas its concentration declines during male infertility. Thus, the aim of present study was to explore the potential role of adiponectin during aging. The changes in adiponectin, adiponectin-receptors, and insulin receptor proteins expression in the testis were evaluated and compared with the testicular parameters, mass, and testosterone level in the mice from early post-natal to late senescence period. Further, the current study has examined the effect of exogenous adiponectin treatment on testicular functions in aged mice. The results showed a significant decline in adiponectin/adiponectin-receptors expression simultaneously with a significant decline in testicular mass, insulin receptor expression and testosterone synthesis in the testis of aged mice. Exogenous treatment of adiponectin to aged mice resulted in marked improvements in testicular mass, histological features (cells proliferation), insulin receptor expression, testicular glucose uptake, anti-oxidative enzymes activity and testosterone synthesis as compared with the control. Based on these findings, it may be concluded that a marked decline in adiponectin synthesis and action results in decreased insulin sensitivity (development of insulin resistance) and increased oxidative stress which consequently suppresses testicular functions during aging. This study further showed that treatment with adiponectin ameliorates reduced testicular functions by enhanced expression of insulin receptor in the testis of senescent mice. It is thus hypothesized that systemic adiponectin treatment could be a promising therapeutic strategy for improvement of testosterone production and sperm counts during aging.