Targeting doublecortin-like kinase 1 reveals a novel strategy to circumvent chemoresistance and metastasis in ovarian cancer

Targeting the PI3K/AKT/mTOR pathway offer a promising therapeutic strategy for cholangiocarcinoma patients with high doublecortin-like kinase 1 expression

BACKGROUND

Cholangiocarcinoma (CCA), characterized by high heterogeneity and extreme malignancy, has a poor prognosis. Doublecortin-like kinase 1 (DCLK1) promotes a variety of malignant cancers in their progression. Targeting DCLK1 or its associated regulatory pathways can prevent the generation and deterioration of several malignancies. However, the role of DCLK1 in CCA progression and its molecular mechanisms remain unknown. Therefore, we aimed to investigate whether and how DCLK1 contributes to CCA progression.

METHODS

The expression of DCLK1 in CCA patients was detected using Immunohistochemistry (IHC). We established DCLK1 knockout and DCLK1 overexpression cell lines for Colony Formation Assay and Transwell experiments to explore the tumor-promoting role of DCLK1. RT-PCR, Western blot and multiple fluorescent staining were used to assess the association between DCLK1 and epithelial-mesenchymal transition (EMT) markers. RNA sequencing and bioinformatics analysis were performed to identify the underlying mechanisms by which DCLK1 regulates CCA progression and the EMT program.

RESULTS

DCLK1 was overexpressed in CCA tissues and was associated with poor prognosis. DCLK1 overexpression facilitated CCA cell invasion, migration, and proliferation, whereas DCLK1 knockdown reversed the malignant tendencies of CCA cells, which had been confirmed both in vivo and in vitro. Furthermore, we demonstrated that DCLK1 was substantially linked to the advancement of the EMT program, which included the overexpression of mesenchymal markers and the downregulation of epithelial markers. For the underlying mechanism, we proposed that the PI3K/AKT/mTOR pathway is the key process for the role of DCLK1 in tumor progression and the occurrence of the EMT program. When administered with LY294002, an inhibitor of the PI3K/AKT/mTOR pathway, the tumor's ability to proliferate, migrate, and invade was greatly suppressed, and the EMT process was generally reversed.

CONCLUSIONS

DCLK1 facilitates the malignant biological behavior of CCA cells through the PI3K/AKT/mTOR pathway. In individuals with cholangiocarcinoma who express DCLK1 at high levels, inhibitors of the PI3K/AKT/mTOR signaling pathway may be an effective therapeutic approach.

BET inhibition decreases HMGCS2 and sensitizes resistant pancreatic tumors to gemcitabine

Efforts to develop targetable molecular bases for drug resistance for pancreatic ductal adenocarcinoma (PDAC) have been equivocally successful. Using RNA-seq and ingenuity pathway analysis we identified that the superpathway of cholesterol biosynthesis is upregulated in gemcitabine resistant (gemR) tumors using a unique PDAC PDX model with resistance to gemcitabine acquired in vivo. Analysis of additional in vitro and in vivo gemR PDAC models showed that HMG-CoA synthase 2 (HMGCS2), an enzyme involved in cholesterol biosynthesis and rate limiting in ketogenesis, is overexpressed in these models. Mechanistic data demonstrate the novel findings that HMGCS2 contributes to gemR and confers metastatic properties in PDAC models, and that HMGCS2 is BRD4 dependent. Further, BET inhibitor JQ1 decreases levels of HMGCS2, sensitizes PDAC cells to gemcitabine, and a combination of gemcitabine and JQ1 induced regressions of gemR tumors in vivo. Our data suggest that decreasing HMGCS2 may reverse gemR, and that HMGCS2 represents a useful therapeutic target for treating gemcitabine resistant PDAC.

Deciphering a GPCR-lncrna-miRNA nexus: Identification of an aberrant therapeutic target in ovarian cancer

Ovarian cancer ranks as a leading cause of mortality among gynecological malignancies, primarily due to the lack of early diagnostic tools, effective targeted therapy, and clear understanding of disease etiology. Previous studies have identified the pivotal role of Lysophosphatidic acid (LPA)-signaling in ovarian cancer pathobiology. Our earlier transcriptomic analysis identified Urothelial Carcinoma Associated-1 (UCA1) as an LPA-stimulated long non-coding RNA (lncRNA). In this study, we elucidate the tripartite interaction between LPA-signaling, UCA1, and let-7 miRNAs in ovarian cancer progression. Results show that the elevated expression of UCA1 enhances cell proliferation, invasive migration, and therapy resistance in high-grade serous ovarian carcinoma cells, whereas silencing UCA1 reverses these oncogenic phenotypes. UCA1 expression inversely correlates with survival outcomes and therapy response in ovarian cancer clinical samples, underscoring its prognostic significance. Mechanistically, UCA1 sequesters let-7 miRNAs, effectively neutralizing their tumor-suppressive functions involving key oncogenes such as Ras and c-Myc. More significantly, intratumoral delivery of UCA1-specific siRNAs inhibits the growth of cisplatin-refractory ovarian cancer xenografts, demonstrating the therapeutic potential of targeting LPAR-UCA1-let-7 axis in ovarian cancer. Thus, our results identify LPAR-UCA1-let-7 axis as a novel avenue for targeted treatment strategies.

Shake It Up Baby Now: The Changing Focus on TWIST1 and Epithelial to Mesenchymal Transition in Cancer and Other Diseases

TWIST1 is a transcription factor that is necessary for healthy neural crest migration, mesoderm development, and gastrulation. It functions as a key regulator of epithelial-to-mesenchymal transition (EMT), a process by which cells lose their polarity and gain the ability to migrate. EMT is often reactivated in cancers, where it is strongly associated with tumor cell invasion and metastasis. Early work on TWIST1 in adult tissues focused on its transcriptional targets and how EMT gave rise to metastatic cells. In recent years, the roles of TWIST1 and other EMT factors in cancer have expanded greatly as our understanding of tumor progression has advanced. TWIST1 and related factors are frequently tied to cancer cell stemness and changes in therapeutic responses and thus are now being viewed as attractive therapeutic targets. In this review, we highlight non-metastatic roles for TWIST1 and related EMT factors in cancer and other disorders, discuss recent findings in the areas of therapeutic resistance and stemness in cancer, and comment on the potential to target EMT for therapy. Further research into EMT will inform novel treatment combinations and strategies for advanced cancers and other diseases.