Effects of rapamycin in combination with fludarabine on primary chronic lymphocytic leukemia cells

Systemic inflammatory Th1 cytokines during Trypanosoma cruzi infection disrupt the typical anatomical cell distribution and phenotypic/functional characteristics of various cell subsets within the thymus

The thymus plays a crucial role in T cell differentiation, a complex process influenced by various factors such as antigens, the microenvironment and thymic architecture. The way the thymus resolves infections is critical, as chronic persistence of microbes or inflammatory mediators can obstruct the differentiation. Here, we illustrate that following inflammatory T helper 1 infectious processes like those caused by Candida albicans or Trypanosoma cruzi, single positive thymocytes adopt a mature phenotype. Further investigations focused on T. cruzi infection, reveal a substantial existence of CD44+ cells in both the cortical and medullary areas of the thymus at the onset of infection. This disturbance coincides with heightened interferon gamma (IFNγ) production by thymocytes and an increased cytotoxic capacity against T. cruzi-infected macrophages. Additionally, we observe a reduced exportation capacity in T. cruzi-infected mice. Some alterations can be reversed in IFNγ knockout mice (KO). Notably, the majority of these effects can be replicated by systemic expression of interleukin (IL)-12+IL-18, underlining the predominantly inflammatory rather than pathogen-specific nature of these phenomena. Understanding the mechanisms through which systemic inflammation disrupts normal T cell development, as well as subsequent T cell exportation to secondary lymphoid organs (SLO) is pivotal for comprehending susceptibility to diseases in different pathological scenarios.

Combined Effects of Fludarabine and Interferon Alpha on Autophagy Regulation Define the Phase of Cell Survival and Promotes Responses in LLC-MK2 and K562 Cells

Autophagy is a known mechanism of cells under internal stress that regulates cellular function via internal protein recycling and the cleaning up of debris, leading to healthy live cells. However, the stimulation of autophagy by external factors such as chemical compounds or viral infection mostly tends to induce apoptosis/cell death. This study hypothesizes that manipulation of the autophagy mechanism to the pro-cell survival and/or decreased pro-viral niche can be a strategy for effective antiviral and anticancer treatment. Cells susceptible to viral infection, namely LLC-MK2, normal monkey epithelium, and K562, human immune-related lymphocyte, which is also a cancer cell line, were treated with fludarabine nucleoside analog (Fdb), interferon alpha (IFN-α), and a combination of Fdb and IFN-α, and then were evaluated for signs of adaptive autophagy and STAT1 antiviral signaling by Western blotting and immunolabeling assays. The results showed that the low concentration of Fdb was able to activate an autophagy response in both cell types, as demonstrated by the intense immunostaining of LC3B foci in the autophagosomes of living cells. Treatment with IFN-α (10 U/mL) showed no alteration in the initiator of mTOR autophagy but dramatically increased the intracellular STAT1 signaling molecules in both cell types. Although in the combined Fdb and IFN-α treatment, both LLC-MK2 and K562 cells showed only slight changes in the autophagy-responsive proteins p-mTOR and LC3B, an adaptive autophagy event was clearly shown in the autophagosome of the LLC-MK2 cell, suggesting the survival phase of the normal cell. The combined effect of Fdb and IFN-α treatment on the antiviral response was identified by the level of activation of the STAT1 antiviral marker. Significantly, the adaptive autophagy mediated by Fdb was able to suppress the IFN-α-mediated pSTAT1 signaling in both cell types to a level that is appropriate for cellular function. It is concluded that the administration of an appropriate dose of Fdb and IFN-α in combination is beneficial for the treatment of some types of cancer and viral infection.

Increased Expression of Autophagy Protein LC3 in Two Patients With Progressing Chronic Lymphocytic Leukemia

Chronic lymphocytic leukemia (CLL) is the most common type of adult leukemia in the western hemisphere. It is characterized by a clonal proliferation of a population of CD5+ B lymphocytes that accumulate in the secondary lymphoid tissues, bone marrow, and blood. Some CLL patients remain free of symptoms for decades, whereas others rapidly become symptomatic or develop high-risk disease. Studying autophagy, which may modulate key protein expression and cell survival, may be important to the search for novel prognostic factors and molecules. Here, we applied flow cytometry technology to simultaneously detect autophagy protein LC3B with classical phenotypical markers used for the identification of tumoral CLL B cell clones. We found that two patients with progressing CLL showed increased expression of the autophagy protein LC3B, in addition to positive expression of CD38 and ZAP70 and unmutated status of IGHV. Our data suggest that activation of autophagy flux may correlate with CLL progression even before Ibrutinib treatment.