Up-regulation of DNA2 results in cell proliferation and migration in endometriosis

Ethyl Pyruvate as a Potential Therapeutic Agent for Endometriosis: A Perspective

Endometriosis is a disease where vascularised tissue similar to endometrium (the lining of the uterus) grows outside of the uterus. Its pathogenesis involves a complex interplay of inflammation, angiogenesis, cellular proliferation, reactive oxygen species (ROS) production, altered energy metabolism, and epithelial-to-mesenchymal transition (EMT).Even though endometriosis was described more than 150 years ago, we have been unable to find its effective therapy. Conservative treatment approaches like non-steroidal anti-inflammatory drugs or hormone therapy are available to date for the treatment of endometriosis. Anti-angiogenic inhibitors and immunomodulators like IFN-α, β, and TNF-α inhibitors are also potential treatment options. These treatments are inadequate as they either affect the symptoms only of endometriosis or target only one pathological pathway involved. Surgical excision of the endometriotic lesion is also possible, however, recurrence of the disease is reported in several cases. A single therapeutic agent targeting several pathological processes in endometriosis would always be a better option. Here we present our perspective on the pharmacological potential of Ethyl pyruvate and also propose it as a promising therapeutic agent for endometriosis as it inhibits inflammation, cell proliferation, angiogenesis, aerobic glycolysis, EMT, and ROS activity together.

RPA and Rad27 limit templated and inverted insertions at DNA breaks

Formation of templated insertions at DNA double-strand breaks (DSBs) is very common in cancer cells. The mechanisms and enzymes regulating these events are largely unknown. Here, we investigated templated insertions in yeast at DSBs using amplicon sequencing across a repaired locus. We document very short (most ∼5-34 bp), templated inverted duplications at DSBs. They are generated through a foldback mechanism that utilizes microhomologies adjacent to the DSB. Enzymatic requirements suggest a hybrid mechanism wherein one end requires Polδ-mediated synthesis while the other end is captured by nonhomologous end joining (NHEJ) or by alternative end joining (Alt-EJ). This process is exacerbated in mutants with low levels or mutated RPA (rtt105Δ; rfa1-t33) or extensive resection deficiency (sgs1Δ exo1Δ). Templated insertions from various distant genomic locations also increase in RPA mutants as well as in rad27Δ and originate from fragile regions of the genome. Among complex insertions, common events are insertions of two sequences, originating from the same locus and with inverted orientation. We propose that these inversions are also formed by microhomology-mediated template switching. Together, we propose that a shortage of RPA, typical in cancer cells, may be a factor that stimulates the formation of templated insertions.

N6-methyladenosine-modified circ_0000337 sustains bortezomib resistance in multiple myeloma by regulating DNA repair

Studies have shown that bortezomib resistance in multiple myeloma (MM) is mediated by the abnormalities of various molecules and microenvironments. Exploring these resistance mechanisms will improve the therapeutic efficacy of bortezomib. In this study, bone marrow tissues from three patients with MM, both sensitive and resistant to bortezomib, were collected for circRNA high-throughput sequencing analysis. The relationship between circ_0000337, miR-98-5p, and target gene DNA2 was analyzed by luciferase detection and verified by RT-qPCR. We first found that circ_0000337 was significantly upregulated in bortezomib-resistant MM tissues and cells, and overexpression of circ_0000337 could promote bortezomib resistance in MM cells. circ_0000337 may act as a miR-98-5p sponge to upregulate DNA2 expression, regulate DNA damage repair, and induce bortezomib resistance. Furthermore, it was determined that the increased circ_0000337 level in bortezomib-resistant cells was due to an increased N6-methyladenosine (m6A) level, resulting in enhanced RNA stability. In conclusion, the m6A level of circ_0000337 and its regulation may be a new and potential therapeutic target for overcoming bortezomib resistance in MM.

RPA and Rad27 limit templated and inverted insertions at DNA breaks

Formation of templated insertions at DNA double-strand breaks (DSBs) is very common in cancer cells. The mechanisms and enzymes regulating these events are largely unknown. Here, we investigated templated insertions in yeast at DSBs using amplicon sequencing across a repaired locus. We document very short (most ∼5-34 bp), templated inverted duplications at DSBs. They are generated through a foldback mechanism that utilizes microhomologies adjacent to the DSB. Enzymatic requirements suggest a hybrid mechanism wherein one end requires Polδ-mediated synthesis while the other end is captured by nonhomologous end joining (NHEJ). This process is exacerbated in mutants with low levels or mutated RPA ( rtt105 Δ; rfa1 -t33) or extensive resection mutant ( sgs1 Δ exo1 Δ). Templated insertions from various distant genomic locations also increase in these mutants as well as in rad27 Δ and originate from fragile regions of the genome. Among complex insertions, common events are insertions of two sequences, originating from the same locus and with inverted orientation. We propose that these inversions are also formed by microhomology-mediated template switching. Taken together, we propose that a shortage of RPA typical in cancer cells is one possible factor stimulating the formation of templated insertions.