Adoptive cell therapy with T cells reprogrammed to express chimeric antigen receptors (CAR-T cells) has been highly successful in patients with hematological neoplasms. However, its therapeutic benefits have been limited in solid tumor cases. Even those patients who respond to this immunotherapy remain at risk of relapse due to the short-term persistence or non-expansion of CAR-T cells; moreover, the hostile tumor microenvironment (TME) leads to the dysfunction of these cells after reinfusion. Some research has shown that, in adoptive T-cell therapies, the presence of less differentiated T-cell subsets within the infusion product is associated with better clinical outcomes. Naive and memory T cells persist longer and exhibit greater antitumor activity than effector T cells. Therefore, new methods are being studied to overcome the limitations of this therapy to generate CAR-T cells with these ideal phenotypes. In this paper, we review the characteristics of T-cell subsets and their implications in the clinical outcomes of adoptive therapy with CAR-T cells. In addition, we describe some strategies developed to overcome the reduced persistence of CAR T-cells and alternatives to improve this therapy by increasing the expansion ability and longevity of modified T cells. These methods include cell culture optimization, incorporating homeostatic cytokines during the expansion phase of manufacturing, modulation of CAR-T cell metabolism, manipulating signaling pathways involved in T-cell differentiation, and strategies related to CAR construct designs.

Background: The heat stress suffered by Leishmania sp during its digenetic life-cycle is a key trigger for its stage differentiation. In Leishmania subgenera two classes of HSP70 genes differing in their 3' UTR were described. Although the presence of HSP70-I genes was previously suggested in Leishmania (Viannia) braziliensis, HSP70-II genes had been reluctant to be uncovered. Results: Here, we report the existence of two types of HSP70 genes in L. braziliensis and the genomic organization of the HSP70 locus. RT-PCR experiments were used to map the untranslated regions (UTR) of both types of genes. The 3' UTR-II has a low sequence identity (55-57%) when compared with this region in other Leishmania species. In contrast, the 5' UTR, common to both types of genes, and the 3' UTR-I were found to be highly conserved among all Leishmania species (77-81%). Southern blot assays suggested that L. braziliensis HSP70 gene cluster may contain around 6 tandemly-repeated HSP70-I genes followed by one HSP70-II gene, located at chromosome 28. Northern blot analysis indicated that levels of both types of mRNAs are not affected by heat shock. Conclusions: This study has led to establishing the composition and structure of the HSP70 locus of L. braziliensis, complementing the information available in the GeneDB genome database for this species. L. braziliensis HSP70 gene regulation does not seem to operate by mRNA stabilization as occurs in other Leishmania species.

The receptor tyrosine kinase-like orphan receptor 1 (ROR1) is a membrane receptor that plays a key role in development. It is highly expressed during the embryonic stage and relatively low in some normal adult tissues. Malignancies such as leukemia, lymphoma, and some solid tumors overexpress ROR1, making it a promising target for cancer treatment. Moreover, immunotherapy with autologous T-cells engineered to express a ROR1-specific chimeric antigen receptor (ROR1 CAR-T cells) has emerged as a personalized therapeutic option for patients with tumor recurrence after conventional treatments. However, tumor cell heterogeneity and tumor microenvironment (TME) hinder successful clinical outcomes. This review briefly describes the biological functions of ROR1 and its relevance as a tumor therapeutic target, as well as the architecture, activity, evaluation, and safety of some ROR1 CAR-T cells used in basic research and clinical trials. Finally, the feasibility of applying the ROR1 CAR-T cell strategy in combination with therapies targeting other tumor antigens or with inhibitors that prevent tumor antigenic escape is also discussed.Clinical trial registration: https://clinicaltrials.gov/, identifier NCT02706392

The COVID-19 pandemic, caused by severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2), emerged in 2019 following prior outbreaks of coronaviruses like SARS and MERS in recent decades, underscoring their high potential of infectivity in humans. Insights from previous outbreaks of SARS and MERS have played a significant role in developing effective strategies to mitigate the global impact of SARS-CoV-2. As of January 7, 2024, there have been 774,075,242 confirmed cases of COVID-19 worldwide. To date, 13.59 billion vaccine doses have been administered, and there have been 7,012,986 documented fatalities (https://www.who.int/)

HSP70 protein is involved in Leishmania differentiation, apoptosis, antimony-resistance and host-immune response. Therefore, this protein and the regulatory mechanisms of HSP70 gene expression are promising targets for therapeutic intervention against leishmaniasis. The regulation of mRNA expression in trypanosomatids operates mostly through the interaction of trans-acting proteins, and elements located in the untranslated regions of mRNAs. The aim of this work was to identify protein factors interacting specifically with the Leishmania braziliensis HSP70 mRNAs. Thus, the 5' UTR and the two types of 3' UTRs (UTR-I and UTR-II) from L. braziliensis HSP70 genes were used as baits in pull down assays using total protein extracts from parasites cultured at 26 or 35°C. The captured proteins were resolved by two-dimensional gel electrophoresis (2-DE) and identified by mass spectrometry (MS) analysis. As a result, 52 different proteins were identified based on their binding to the L. braziliensis HSP70-mRNAs. As expected, several of the identified proteins were related to RNA metabolism (27%) and translation process (7%). In addition, five hypothetical conserved proteins having motifs related with RNA interaction were also identified (9.6%). Nevertheless, unexpected proteins, apparently unrelated to the mRNA expression, were also identified. The biological significance of these and others L. braziliensis detected proteins, including the HSP70 itself, is discussed. For the first time, a riboproteomic analysis of the proteins interacting with the untranslated regions of the heat shock protein 70 (HSP70) mRNA from Leishmania braziliensis was carried out. This work provides new insights related to protein factors putatively involved in the regulation of HSP70 gene expression in L. braziliensis, and thereby, contributes to a better understanding of the parasite biology, and ultimately to the development of novel therapeutic interventions for controlling the important diseases caused by this parasite.

Background: Alpha tubulin is a fundamental component of the cytoskeleton which is responsible for cell shape and is involved in cell division, ciliary and flagellar motility and intracellular transport. Alpha tubulin gene expression varies according to the morphological changes suffered by Leishmania in its life cycle. However, the objective of studying the mechanisms responsible for the differential expression has resulted to be a difficult task due to the complex genome organization of tubulin genes and to the non-conventional mechanisms of gene regulation operating in Leishmania. Results: We started this work by analyzing the genomic organization of α-tubulin genes in the Leishmania braziliensis genome database. The genomic organization of L. braziliensis α-tubulin genes differs from that existing in the L. major and L. infantum genomes. Two loci containing α-tubulin genes were found in the chromosomes 13 and 29, even though the existence of sequence gaps does not allow knowing the exact number of genes at each locus. Southern blot assays showed that α-tubulin locus at chromosome 13 contains at least 8 gene copies, which are tandemly organized with a 2.08-kb repetition unit; the locus at chromosome 29 seems to contain a sole α-tubulin gene. In addition, it was found that L. braziliensis α-tubulin locus at chromosome 13 contains two types of α-tubulin genes differing in their 3′ UTR, each one presumably containing different regulatory motifs. It was also determined that the mRNA expression levels of these genes are controlled by post-transcriptional mechanisms tightly linked to the growth temperature. Moreover, the decrease in the α-tubulin mRNA abundance observed when promastigotes were cultured at 35°C was accompanied by parasite morphology alterations, similar to that occurring during the promastigote to amastigote differentiation. Conclusions: Information found in the genome databases indicates that α-tubulin genes have been reorganized in a drastic manner along Leishmania speciation. In the L. braziliensis genome database, two loci containing α-tubulin sequences were found, but only the locus at chromosome 13 contains the prototypic α-tubulin genes, which are repeated in a head-to-tail manner. Also, we determined that the levels of α-tubulin mRNAs are down-regulated drastically in response to heat shock by a post-transcriptional mechanism which is dependent upon active protein synthesis.