Can we negotiate with a tumor?

Recent progress in deciphering the molecular portraits of tumors promises an era of more personalized drug choices. However, current protocols still follow standard fixed-time schedules, which is not entirely coherent with the common observation that most tumors do not grow continuously. This unpredictability of the increases in tumor mass is not necessarily an obstacle to therapeutic efficiency, particularly if tumor dynamics could be exploited.

Interaction between Gambogic acid and dihydrofolate reductase and synergistic lethal effects with methotrexate on hepatoma cells.

Gambogic acid (GA), a natural xanthone, has a wide spectrum of pharmacological activities, including repression of telomerase expression and induction of apoptosis of cancer cells. GA has also been reported to reduce the steady-state level of thymidylate synthetase mRNA in a gastric carcinoma cell line. Therefore, it has recently emerged as a candidate for use in cancer treatment.

Neutropenia dynamics in a case of T-LGL lymphoproliferation illustrate rapid turnover of granulocyte progenitors.

Objectives: To elucidate the natural history of T-cell large granular lymphocyte (T-LGL) lymphoproliferation, we followed changes in associated fluctuating neutropenia for 3 years in an untreated patient presenting with the disease.

Materials And Methods: We report a nonlinear mathematical analysis of irregular neutrophil fluctuation, using iterative data maps, to detect long-term regulation of the neutrophil population.

Results: This geometric analysis indicated that variations of this sequence of neutrophil counts followed bounded deterministic dynamics around a fixed low level equilibrium, a situation similar to that previously observed for cultured mouse early bone marrow progenitor cells.

Unmasking chaotic attributes in time series of living cell populations.

Background: Long-range oscillations of the mammalian cell proliferation rate are commonly observed both in vivo and in vitro. Such complicated dynamics are generally the result of a combination of stochastic events and deterministic regulation. Assessing the role, if any, of chaotic regulation is difficult.

Sinusoidal swinging dynamics of the telomere repair and cell growth activation functions of telomerase in rat liver cancer cells.

Telomerase is a multimolecular complex of reverse transcriptase, RNA template, and regulatory proteins. It has two known functions: catalysis of the addition of [TTAGGG] repeats to telomeric DNA and the activation of various genes controlling cell proliferation. The possible coordination of these two functions is a key issue in understanding the growth of cancer cells.