Although DNA damage repair plays a critical role in cancer chemotherapy, the function of lncRNAs in this process remains largely unclear. In this study, in silico screening identified H19 as an lncRNA that potentially plays a role in DNA damage response and sensitivity to PARP inhibitors. Increased expression of H19 is correlated with disease progression and with a poor prognosis in breast cancer. In breast cancer cells, forced expression of H19 promotes DNA damage repair and resistance to PARP inhibition, whereas H19 depletion diminishes DNA damage repair and increases sensitivity to PARP inhibitors. H19 exerted its functional roles via direct interaction with ILF2 in the cell nucleus. H19 and ILF2 increased BRCA1 stability via the ubiquitin-proteasome proteolytic pathway via the H19- and ILF2-regulated BRCA1 ubiquitin ligases HUWE1 and UBE2T. In summary, this study has identified a novel mechanism to promote BRCA1-deficiency in breast cancer cells. Therefore, targeting the H19/ILF2/BRCA1 axis might modulate therapeutic approaches in breast cancer.

Transcription-associated cyclin-dependent kinases (tCDKs) precisely control the gene transcription process (initiation, elongation, and termination) by mediating RNA polymerase II phosphorylation. In several cancers, disrupted transcriptional control is emerging as a hallmark. In this review we summarize research studies of tCDKs’ role in gastrointestinal (GI) tumors, particularly, in the biology of esophageal, gastric, pancreatic, and hepatobiliary cancers. Across these tumor types, tCDKs are implicated as activators of super enhancer (SE) regions and contribute to the “transcriptional addiction” that not only drives cancer cell growth but is also attributed to therapeutic vulnerabilities. Overall, expression of tCDKs is increased in GI tumor tissues, indicating a rational target for therapeutics. We further describe emerging approaches, including genetic manipulation, small-molecule inhibitors or targeted protein degradation that disrupt tCDK functions in GI malignancies. We conclude by describing key challenges in targeting tCDKs and future treatment directions.

Background: Dysregulation of the Hippo signaling pathway, characterized by aberrant activation of the transcriptional coactivators YAP1 and TAZ, drives tumor progression, immunosuppression, and metastasis. Hippo pathway components are emerging therapeutic targets in several solid tumors, however, the expression profiles of Hippo coactivators YAP1, TAZ, and their transcriptional factors TEAD1-4 in gastric cancer peritoneal metastases (GCPMs), and their therapeutic value, are unknown. In this study, we sought to determine the expression status of YAP1, TAZ, and TEAD1-4 in GCPMs and to evaluate whether dual targeting of YAP1 and TAZ provides superior antitumor activity compared with inhibition of either coactivator alone. Methods: Expression of YAP1, TAZ, and TEAD1–4 was examined in GCPMs by single-cell RNA sequencing and co-immunofluorescent staining. Functional studies using genetic knockout and antisense oligonucleotide (ASO) inhibition of YAP1 or TAZ were performed to assess antineoplastic effects in vitro and in vivo. Co-immunoprecipitation and luciferase reporter assays were used to characterize YAP1/TAZ interactions with TEADs and AP-1 components (JUN and FOSB) and to quantify transcriptional activity. Antitumor efficacy was validated in patient-derived xenograft (PDX) and KP-Luc2 syngeneic models. Results: YAP1, TAZ, and TEADs1-4 were highly coexpressed in GCPMs and correlated with poor survival. YAP1 inhibition alone elicited compensatory upregulation of TAZ, while combined inhibition of both coactivators maximally repressed cell proliferation and invasion in vitro, and tumor growth in vivo. Increased TAZ complexation with TEAD4 and AP-1 (c-JUN and FOSB) heterodimer was observed following YAP1 knockdown or pharmacological ASO inhibition. Dual inhibition of YAP1 and TAZ was required to maximally suppress YAP1/TAZ expression and reduce their nuclear accumulation, transactivation of TEAD, and activation of downstream genes. Conclusions: These findings show that combined YAP1 and TAZ inhibition holds promise for the treatment of GCPM, a highly lethal disease with an urgent need for novel treatment options.

Transcription-associated cyclin-dependent kinases (tCDKs) precisely control the gene transcription process (initiation, elongation, and termination) by mediating RNA polymerase II phosphorylation. In several cancers, disrupted transcriptional control is emerging as a hallmark. In this review we summarize research studies that explored tCDKs’ role in gastrointestinal (GI) tumors, particularly, in the biology of esophageal, gastric, pancreatic and hepatobiliary cancers. Across these tumor types, tCDKs are implicated as activators of super enhancer (SE) regions and contribute to the ‘transcriptional addiction’ that not only drives cancer cell growth but also attribute to therapeutic vulnerabilities. Overall, expression of tCDKs is increased in GI tumor tissues, indicating a rational target for therapeutics. We further describe emerging approaches including genetic manipulation, small-molecule inhibitors or targeted protein degradation that disrupt the functions of tCDK in GI malignancies. We conclude by describing key challenges in targeting tCDKs and future treatment directions.

Epigenetic dysregulation is a defining feature of solid tumors. Among epigenetic regulators, the nuclear receptor-binding SET domain (NSD) family of histone methyltransferases, comprising NSD1, NSD2, and NSD3, have emerged as critical mediators of oncogenic chromatin remodeling and transcriptional regulation. These enzymes primarily catalyze histone H3 lysine 36 (H3K36) methylation, thereby regulating chromatin accessibility, transcriptional programs, DNA damage repair, and genome stability. Aberrant expression, mutation, amplification, and chromosomal rearrangement of NSD family members have been identified across tumors, establishing them as key epigenetic drivers of malignancy. Accumulating evidence demonstrates that NSD proteins promote multiple hallmarks of cancer, including sustained proliferative signaling, invasion and metastasis, immune evasion, metabolic reprogramming, genome instability, and therapeutic resistance. Although NSD proteins share overlapping catalytic functions, each exhibit distinct biological roles and mechanisms of dysregulation in solid tumors. Advances in structural biology, medicinal chemistry, and targeted protein degradation have accelerated the development of selective NSD inhibitors, chromatin-reader antagonists, and proteolysis-targeting chimeras (PROTACs), establishing the feasibility of pharmacologically targeting NSD-dependent epigenetic pathways. In this review, we summarize the biological functions of the NSD family, discuss their oncogenic mechanisms in solid tumors, and highlight recent progress in therapeutic targeting.