Dual inhibition of FGFR4 and BCL-xL inhibits multi-resistant ovarian cancer with BCL2L1 gain

CRISPR/Cas9 system: a novel approach to overcome chemotherapy and radiotherapy resistance in cancer

Cancer presents a global health challenge with rising incidence and mortality. Despite treatment advances in cancer therapy, radiotherapy and chemotherapy remained the most common treatments for all types of cancers. However, resistance phenotype in cancer cells leads to unsatisfactory results in the efficiency of therapeutic strategies. Therefore, researchers strive to propose effective solutions to overcome treatment failure, which requires a deep knowledge of treatment-resistant mechanisms. The progression and occurrence of tumors can be attributed to gene mutation. Over the past decade, the emergence of clustered regularly interspaced short palindromic repeats and CRISPR-associated protein 9 (CRISPR/Cas9) genome editing has revolutionized cancer research. This versatile technology enables cancer modeling, manipulation of specific DNA sequences, and genome-wide screening. CRISPR/Cas9 is an effective tool for identifying radio- and chemoresistance genes and offering potential adjunctive treatments to overcome tumor recurrence after chemo- and radiotherapy. This article aims to explain the potential of the CRISPR/Cas9 system in improving the effectiveness of chemo- and radiotherapy and ultimately overcoming treatment failure.

Both direct and indirect suppression of MCL1 synergizes with BCLXL inhibition in preclinical models of gastric cancer

Despite the progress of treatment in gastric cancer (GC), the overall outcomes remain poor in patients with advanced diseases, underscoring the urgency to develop more effective treatment strategies. BH3-mimetic drugs, which inhibit the pro-survival BCL2 family proteins, have demonstrated great therapeutic potential in cancer therapy. Although previous studies have implicated a role of targeting the cell survival pathway in GC, the contribution of different pro-survival BCL2 family proteins in promoting survival and mediating resistance to current standard therapies in GC remains unclear. A systematic study to elucidate the hierarchy of these proteins using clinically more relevant GC models is essential to identify the most effective therapeutic target(s) and rational combination strategies for improving GC therapy. Here, we provide evidence from both in vitro and in vivo studies using a broad panel of GC cell lines, tumoroids, and xenograft models to demonstrate that BCLXL and MCL1, but not other pro-survival BCL2 family proteins, are crucial for GC cells survival. While small molecular inhibitors of BCLXL or MCL1 exhibited some single-agent activity, their combination sufficed to cause maximum killing. However, due to the unsolved cardiotoxicity associated with direct MCL1 inhibitors, finding combinations of agents that indirectly target MCL1 and enable the reduction of doses of BCLXL inhibitors while maintaining their anti-neoplastic effects is potentially a feasible approach for the further development of these compounds. Importantly, inhibiting BCLXL synergized significantly with anti-mitotic and HER2-targeting drugs, leading to enhanced anti-tumour activity with tolerable toxicity in preclinical GC models. Mechanistically, anti-mitotic chemotherapies induced MCL1 degradation via the ubiquitin-proteasome pathway mainly through FBXW7, whereas HER2-targeting drugs suppressed MCL1 transcription via the STAT3/SRF axis. Moreover, co-targeting STAT3 and BCLXL also exhibited synergistic killing, extending beyond HER2-amplified GC. Collectively, our results provide mechanistic rationale and pre-clinical evidence for co-targeting BCLXL and MCL1 (both directly and indirectly) in GC. (i) Gastric cancer cells rely on BCLXL and, to a lesser degree, on MCL1 for survival. The dual inhibition of BCLXL and MCL1 with small molecular inhibitors acts synergistically to kill GC cells, regardless of their TCGA molecular subtypes or the presence of poor prognostic markers. While the effect of S63845 is mediated by both BAX and BAK in most cases, BAX, rather than BAK, acts as the primary mediator of BCLXLi in GC cells. (ii) Inhibiting BCLXL significantly synergizes with anti-mitotic and HER2-targeting drugs, leading to enhanced anti-tumour activity with tolerable toxicity in preclinical GC models. Mechanistically, anti-mitotic chemotherapies induce MCL1 degradation via the ubiquitin-proteasome pathway mainly through FBXW7, whereas HER2-targeting drugs suppress MCL1 transcription via the STAT3/SRF axis. The combination of the STAT3 inhibitor and BCLXL inhibitor also exhibits synergistic killing, extending beyond HER2-amplified GC.

ABT‑737 increases cisplatin sensitivity through the ROS‑ASK1‑JNK MAPK signaling axis in human ovarian cancer cisplatin‑resistant A2780/DDP cells

Ovarian cancer is a gynecological malignant tumor with the highest mortality rate, and chemotherapy resistance seriously affects patient therapeutic outcomes. It has been shown that the high expression of anti‑apoptotic proteins Bcl‑2 and Bcl‑xL is closely related to ovarian cancer chemotherapy resistance. Therefore, reducing Bcl‑2 and Bcl‑xL expression levels may be essential for reversing drug resistance in ovarian cancer. ABT‑737 is a BH3‑only protein mimetic, which can effectively inhibit the expression of the anti‑apoptotic proteins Bcl‑xL and Bcl‑2. Although it has been shown that ABT‑737 can increase the sensitivity of ovarian cancer cells to cisplatin, the specific molecular mechanism remains unclear and requires further investigation. In the present study, the results revealed that ABT‑737 can significantly increase the activation levels of JNK and ASK1 induced by cisplatin in A2780/DDP cells, which are cisplatin‑resistant ovarian cancer cells. Inhibition of the JNK and ASK1 pathway could significantly reduce cisplatin cytotoxicity increased by ABT‑737 in A2780/DDP cells, while inhibiting the ASK1 pathway could reduce JNK activation. In addition, it was further determined that ABT‑737 could increase reactive oxygen species (ROS) levels in A2780/DDP cells induced by cisplatin. Furthermore, the inhibition of ROS could significantly reduce JNK and ASK1 activation and ABT‑737‑mediated increased cisplatin cytotoxicity in A2780/DDP cells. Overall, the current data identified that activation of the ROS‑ASK1‑JNK signaling axis plays an essential role in the ability of ABT‑737 to increase cisplatin sensitivity in A2780/DDP cells. Therefore, upregulation the ROS‑ASK1‑JNK signaling axis is a potentially novel molecular mechanism by which ABT‑737 can enhance cisplatin sensitivity of ovarian cancer cells. In addition, the present research can also provide new therapeutic strategies and new therapeutic targets for patients with cisplatin‑resistant ovarian cancer with high Bcl‑2/Bcl‑xL expression patterns.

Rational design of small-sized peptidomimetic inhibitors disrupting protein-protein interaction

Protein-protein interactions are fundamental to nearly all biological processes. Due to their structural flexibility, peptides have emerged as promising candidates for developing inhibitors targeting large and planar PPI interfaces. However, their limited drug-like properties pose challenges. Hence, rational modifications based on peptide structures are anticipated to expedite the innovation of peptide-based therapeutics. This review comprehensively examines the design strategies for developing small-sized peptidomimetic inhibitors targeting PPI interfaces, which predominantly encompass two primary categories: peptidomimetics with abbreviated sequences and low molecular weights and peptidomimetics mimicking secondary structural conformations. We have also meticulously detailed several instances of designing and optimizing small-sized peptidomimetics targeting PPIs, including MLL1-WDR5, PD-1/PD-L1, and Bak/Bcl-xL, among others, to elucidate the potential application prospects of these design strategies. Hopefully, this review will provide valuable insights and inspiration for the future development of PPI small-sized peptidomimetic inhibitors in pharmaceutical research endeavors.

Genome-wide CRISPR screen reveals the synthetic lethality between BCL2L1 inhibition and radiotherapy

Radiation therapy (RT) is one of the most commonly used anticancer therapies. However, the landscape of cellular response to irradiation, especially to a single high-dose irradiation, remains largely unknown. In this study, we performed a whole-genome CRISPR loss-of-function screen and revealed temporal inherent and acquired responses to RT. Specifically, we found that loss of the IL1R1 pathway led to cellular resistance to RT. This is in part because of the involvement of radiation-induced IL1R1-dependent transcriptional regulation, which relies on the NF-κB pathway. Moreover, the mitochondrial anti-apoptotic pathway, particularly the BCL2L1 gene, is crucially important for cell survival after radiation. BCL2L1 inhibition combined with RT dramatically impeded tumor growth in several breast cancer cell lines and syngeneic models. Taken together, our results suggest that the combination of an apoptosis inhibitor such as a BCL2L1 inhibitor with RT may represent a promising anticancer strategy for solid cancers including breast cancer.

The drug efficacy testing in 3D cultures platform identifies effective drugs for ovarian cancer patients

Most patients with advanced ovarian cancer (OC) relapse and progress despite systemic therapy, pointing to the need for improved and tailored therapy options. Functional precision medicine can help to identify effective therapies for individual patients in a clinically relevant timeframe. Here, we present a scalable functional precision medicine platform: DET3Ct (Drug Efficacy Testing in 3D Cultures), where the response of patient cells to drugs and drug combinations are quantified with live-cell imaging. We demonstrate the delivery of individual drug sensitivity profiles in 20 samples from 16 patients with ovarian cancer in both 2D and 3D culture formats, achieving over 90% success rate in providing results six days after operation. In this cohort all patients received carboplatin. The carboplatin sensitivity scores were significantly different for patients with a progression free interval (PFI) less than or equal to 12 months and those with more than 12 months (p < 0.05). We find that the 3D culture format better retains proliferation and characteristics of the in vivo setting. Using the DET3Ct platform we evaluate 27 tailored combinations with results available 10 days after operation. Notably, carboplatin and A-1331852 (Bcl-xL inhibitor) showed an additive effect in four of eight OC samples tested, while afatinib and A-1331852 led to synergy in five of seven OC models. In conclusion, our 3D DET3Ct platform can rapidly define potential, clinically relevant data on efficacy of existing drugs in OC for precision medicine purposes, as well as provide insights on emerging drugs and drug combinations that warrant testing in clinical trials.

Omentum provides a special cell microenvironment for ovarian cancer

BACKGROUND

Ovarian cancer seriously threatens women's health because of its poor prognosis and high mortality. Due to the lack of efficient early detection and screening methods, when patients seek doctors' help with complaints of abdominal distension, back pain and other nonspecific signs, the clinical results always hint at the widespread metastasis of disease. When referring to the metastasis of this disease, the omentum always takes precedence.

RECENT FINDINGS

The distinguishing feature of the omentum is adipose tissue, which satisfies the energy demand of cancer cells and supplies a more aggressive environment for ovarian cancer cells. In this review, we mainly focus on three important cell types: adipocytes, macrophages, and mesenchymal stem cells. Besides, several mechanisms underlying cancer-associated adipocytes (CAA)-facilitated ovarian cancer cell development have been revealed, including their capacities for storing lipids and endocrine function, and the release of hormones, growth factors, and adipokines. Blocking the reciprocity among cancer cells and various cells located on the omentum might contribute to ovarian cancer therapy. The inhibition of hormones, growth factors and adipokines produced by adipocytes will be a novel therapeutic strategy. However, a sufficient number of trials has not been performed. In spite of this, the therapeutic potential of metformin and the roles of exercise in ovarian cancer will be worth mentioning.

CONCLUSION

It is almost impossible to overcome completely ovarian cancer at the moment. What we can do is trying our best to improve these patients' prognoses. In this process, adipocytes may bring promising future for the therapy of ovarian cancer.

Anti-apoptotic protein BCL-XL as a therapeutic vulnerability in gastric cancer

BACKGROUND

New therapeutic targets are needed to improve the outcomes for gastric cancer (GC) patients with advanced disease. Evasion of programmed cell death (apoptosis) is a hallmark of cancer cells and direct induction of apoptosis by targeting the pro-survival BCL2 family proteins represents a promising therapeutic strategy for cancer treatment. Therefore, understanding the molecular mechanisms underpinning cancer cell survival could provide a molecular basis for potential therapeutic interventions.

METHOD

Here we explored the role of BCL2L1 and the encoded anti-apoptotic BCL-XL in GC. Using Droplet Digital PCR (ddPCR) technology to investigate the DNA amplification of BCL2L1 in GC samples and GC cell lines, the sensitivity of GC cell lines to selective BCL-XL inhibitors A1155463 and A1331852, pan-inhibitor ABT-263, and VHL-based PROTAC-BCL-XL was analyzed using (CellTiter-Glo) CTG assay in vitro. Western Blot (WB) was used to detect the protein expression of BCL2 family members in GC cell lines and the manner in which PROTAC-BCL-XL kills GC cells. Co-immunoprecipitation (Co-IP) was used to investigate the mechanism of A1331852 and ABT-263 kills GC cell lines. DDPCR, WB, and real-time PCR (RTPCR) were used to investigate the correlation between DNA, RNA, protein levels, and drug activity.

RESULTS

The functional assay showed that a subset of GC cell lines relies on BCL-XL for survival. In gastric cancer cell lines, BCL-XL inhibitors A1155463 and A1331852 are more sensitive than the pan BCL2 family inhibitor ABT-263, indicating that ABT-263 is not an optimal inhibitor of BCL-XL. VHL-based PROTAC-BCL-XL DT2216 appears to be active in GC cells. DT2216 induces apoptosis of gastric cancer cells in a time- and dose-dependent manner through the proteasome pathway. Statistical analysis showed that the BCL-XL protein level predicts the response of GC cells to BCL-XL targeting therapy and BCL2L1 gene CNVs do not reliably predict BCL-XL expression.

CONCLUSION

We identified BCL-XL as a promising therapeutic target in a subset of GC cases with high levels of BCL-XL protein expression. Functionally, we demonstrated that both selective BCL-XL inhibitors and VHL-based PROTAC BCL-XL can potently kill GC cells that are reliant on BCL-XL for survival. However, we found that BCL2L1 copy number variations (CNVs) cannot reliably predict BCL-XL expression, but the BCL-XL protein level serves as a useful biomarker for predicting the sensitivity of GC cells to BCL-XL-targeting compounds. Taken together, our study pinpointed BCL-XL as potential druggable target for specific subsets of GC.

Molecular mechanism of the miR-7/BCL2L1/P53 signaling axis regulating the progression of hepatocellular carcinoma

Background

To investigate the roles of miR-7 and its potential mechanisms in hepatocellular carcinoma (HCC).

Methods

The functions of miR-7 were identified and measured by MTT [3-(4,5)-dimethylthiahiazo(-z-y1)-3,5-di-phenytetrazoliumromide], colony formation, transwell, and flow cytometry assays. A luciferase assay was applied to verify the direct binding of miR-7 on BCL2L1 3'untranslated region (3'UTR). An in vitro experiment was then used to investigate the biological effects of miR-7 and BCL2L1. A co-immunoprecipitation (COIP) assay was used to detect the protein interaction between BCL2L1 and P53.

Results

We found that miR-7 overexpression suppressed cell proliferation, migration, and invasion in HCC. BCL2L1 was also demonstrated as a direct target gene of miR-7. This study showed that BCL2L1 could partially rescue the inhibitory effect of miR-7 on the proliferation, migration, and invasion of HCC cells. Our research showed that miR-7 could inhibit the epithelial-mesenchymal transition (EMT) pathway by regulating BCL2L1. We also further confirmed that miR-7 inhibits the proliferation, migration, and invasion of Hep3B and Huh7 cells by targeting BCL2L1. Furthermore, we observed that the BCL2L1 protein interacts with the P53 protein and BCL2L1 affects the development of liver cancer through P53. We also found that BCL2L1 could promote the invasion and migration of liver cancer cells through P53 inhibition. BCL2L1 also inhibited the expression of Caspase 3/7 in hepatoma cells by inhibiting the expression of P53.

Conclusions

Our study demonstrated that miR-7/BCL2L1/P53 may serve as a regulatory molecular axis for HCC treatment. Our results suggest that miR-7/BCL2L1/P53 may have predictive value and represent a new treatment strategy for liver cancer.

Efficacy evaluation of multi-immunotherapy in ovarian cancer: From bench to bed

Ovarian cancer, one of the most common gynecological malignancies, is characterized by high mortality and poor prognosis. Cytoreductive surgery and chemotherapy remain the mainstay of ovarian cancer treatment, and most women experience recurrence after standard care therapies. There is compelling evidence that ovarian cancer is an immunogenic tumor. For example, the accumulation of tumor-infiltrating lymphocytes is associated with increased survival, while increases in immunosuppressive regulatory T cells are correlated with poor clinical outcomes. Therefore, immunotherapies targeting components of the tumor microenvironment have been gradually integrated into the existing treatment options, including immune checkpoint blockade, adoptive cell therapy, and cancer vaccines. Immunotherapies have changed guidelines for maintenance treatment and established a new paradigm in ovarian cancer treatment. Despite single immunotherapies targeting DNA repair mechanisms, immune checkpoints, and angiogenesis bringing inspiring efficacy, only a subset of patients can benefit much from it. Thus, the multi-immunotherapy investigation remains an active area for ovarian cancer treatment. The current review provides an overview of various clinically oriented forms of multi-immunotherapy and explores potentially effective combinational therapies for ovarian cancer.

Efficacy and Pharmacological Mechanism of Poria cocos-Based Formulas Combined With Chemotherapy for Ovarian Cancer: A Integrated Systems Pharmacology Study

Previous studies have shown that Poria cocos-based formulas combined with chemotherapy can improve the quality of life of ovarian cancer patients. However, the results are still controversial. We systematically searched the literature from eight databases to evaluate the efficacy and safety of Poria cocos-based formulas in combination with paclitaxel-carboplatin in treating ovarian cancer (OC). Subsequently, network pharmacology, molecular docking and cell experiments were performed to further verify the underlying molecular mechanism. Thirteen randomized controlled trials, including 922 patients with OC, were enrolled in the study. The results indicated that Poria cocos-based compounds combined with paclitaxel-carboplatin significantly improved patients' tumor response rate, traditional Chinese medicine syndrome score, Karnofsky Performance Scale, physical and social function, and reduced side effects of chemotherapy compared to the paclitaxel-carboplatin alone. According to the network pharmacological analysis, tumulosic acid were the most bioactive compounds of Poria cocos. BCL2L1 is highly expressed in OC and is associated with a worse prognosis which could become potential drug target. Functional enrichment analysis suggested that the anti-OC effect of Poria cocos may be related to PI3K-Akt signaling pathway. The molecular docking results indicated that tumulosic acid might inhibit OC by regulating BCL2L1. Vitro experiment confirmed tumulosic acid that induced cell apoptosis by modulating PI3K/AKT signaling and BCL2L1. Our study may provide a clinical basis and theoretical rationale for combining Poria cocos-based formulas with chemotherapy for OC. In addition, the integrated pharmacological strategy proposed in our study provides an excellent example for exploring the mechanism of complex formulas.

BTG2 Serves as a Potential Prognostic Marker and Correlates with Immune Infiltration in Lung Adenocarcinoma

Background

B-cell translocation gene 2 (BTG2) has been revealed to be involved in the occurrence and development of multiple cancers. However, the role of BTG2 in lung adenocarcinoma (LUAD) is still ambiguous. Thus, this study aims to investigate the prognostic value of BTG2 and its correlation with immune infiltration in LUAD.

Methods

The expression of BTG2 in LUAD was analyzed using the TIMER and UALCAN databases. The correlations between BTG2 expression and clinicopathological factors were investigated using the UALCAN databases. The Kaplan–Meier plotter, GEPIA, and TCGA databases were employed to assess the prognostic value of BTG2. The STRING database and Cytoscape software were used to construct an interaction network and mine co-expression genes. The TISIDB database was examined for a correlation between BTG2 and driver genes in LUAD. Enrichment analysis of co-expressed genes and BTG2 was performed using the LinkedOmics database. Finally, the correlations between BTG2 and immune infiltrates were investigated using the TIMER, GEO, and TISIDB database.

Results

BTG2 was significantly downregulated in LUAD. The decreased expression of BTG2 in LUAD was significantly correlated with higher cancer stages and shorter duration of overall survival. The expressions of BTG2-related co-expression genes were associated with the prognosis in LUAD. The expression of BTG2 was closely associated with the mutations of TP53 and ROS1. Enrichment analysis revealed that BTG2 was significantly correlated with immune‐associated signaling pathways and function. In addition, the expression of BTG2 was found to be closely related to immune infiltration, multiple gene markers of immune cells, chemokines, and chemokine receptors.

Conclusion

Our findings have effectively demonstrated that BTG2 expression was downregulated in LUAD, indicating poor prognosis. Closely relating to immune cell infiltration, BTG2 may be a promising immune-related biomarker and molecular target for patients with LUAD.

FGF/FGFR-Dependent Molecular Mechanisms Underlying Anti-Cancer Drug Resistance

Simple Summary

Deregulation of the FGF/FGFR axis is associated with many types of cancer and contributes to the development of chemoresistance, limiting the effectiveness of current treatment strategies. There are several mechanisms involved in this phenomenon, including cross-talks with other signaling pathways, avoidance of apoptosis, stimulation of angiogenesis, and initiation of EMT. Here, we provide an overview of current research and approaches focusing on targeting components of the FGFR/FGF signaling module to overcome drug resistance during anti-cancer therapy.

Abstract

Increased expression of both FGF proteins and their receptors observed in many cancers is often associated with the development of chemoresistance, limiting the effectiveness of currently used anti-cancer therapies. Malfunctioning of the FGF/FGFR axis in cancer cells generates a number of molecular mechanisms that may affect the sensitivity of tumors to the applied drugs. Of key importance is the deregulation of cell signaling, which can lead to increased cell proliferation, survival, and motility, and ultimately to malignancy. Signaling pathways activated by FGFRs inhibit apoptosis, reducing the cytotoxic effect of some anti-cancer drugs. FGFRs-dependent signaling may also initiate angiogenesis and EMT, which facilitates metastasis and also correlates with drug resistance. Therefore, treatment strategies based on FGF/FGFR inhibition (using receptor inhibitors, ligand traps, monoclonal antibodies, or microRNAs) appear to be extremely promising. However, this approach may lead to further development of resistance through acquisition of specific mutations, metabolism switching, and molecular cross-talks. This review brings together information on the mechanisms underlying the involvement of the FGF/FGFR axis in the generation of drug resistance in cancer and highlights the need for further research to overcome this serious problem with novel therapeutic strategies.