Molecular Cancer Therapeutics最新文献

Despite notable progress in the treatment of advanced head and neck squamous cell carcinoma (HNSCC), survival remains poor in patients with recurrent and/or metastatic (R/M) human papillomavirus (HPV)-negative HNSCC. Worse outcomes in the HPV-negative patients may be partly related to loss of cell-cycle regulators and tumor suppressors as well as a noninflamed and hypoxic tumor microenvironment, both of which contribute to treatment resistance and disease progression. Anti-programmed cell death protein 1-based regimens as current standard-of-care treatment for R/M HNSCC are associated with durable responses in a limited number of patients. The anti-epidermal growth factor receptor (EGFR) monoclonal antibody, cetuximab, has antitumor activity in this treatment setting, but responses are short-lived and inevitably curtailed due to treatment resistance. Crosstalk between the EGFR and hepatocyte growth factor (HGF)-dependent mesenchymal-epithelial transition (c-MET) receptor tyrosine kinase pathway is a known mechanism of resistance to cetuximab. Dual targeting of EGFR and c-MET pathways may overcome resistance to cetuximab in patients with HPV-negative HNSCC. Here, we review clinical data of treatments evaluated in patients with R/M HPV-negative HNSCC and highlight the potential role of combining HGF/c-MET and EGFR pathway inhibitors to overcome cetuximab resistance in this population.

Targeting synthetic lethal interactions between genes has emerged as a promising strategy for cancer therapy. This study explores the intricate interplay between terminal uridyltransferase 4 (TUT4) and terminal uridyltransferase 7 (TUT7), the 3'-5' exoribonuclease DIS3L2, and the SKI complex-interacting factor Focadhesin (FOCAD) in the context of cancer vulnerability. Using CRISPR and public functional genomics data, we show impairment of cell proliferation upon knockout of TUT7 or DIS3L2, but not TUT4, on cancer cells with FOCAD loss. Moreover, we report the characterization of the first potent and selective TUT4/7 inhibitors that substantially reduce uridylation and demonstrate in vitro and in vivo antiproliferative activity specifically in FOCAD-deleted cancer. FOCAD deficiency post-transcriptionally disrupts the stability of the SKI complex, whose role is to safeguard cells against aberrant RNA. Re-introduction of FOCAD restores the SKI complex and makes these cells less sensitive to TUT4/7 inhibitors, indicating that TUT7 dependency is FOCAD loss-driven. We propose a model where, in absence of FOCAD, TUT7 and DIS3L2 function as a salvage mechanism that degrades aberrant RNA, and genetic or pharmacological inhibition of this pathway leads to cell death. Our findings underscore the significance of FOCAD loss as a genetic driver of TUT7 vulnerability and provide insights into the potential utility of TUT4/7 inhibitors for cancer treatment.

Oxidative phosphorylation (OXPHOS) is an essential metabolic process for cancer proliferation and therapy resistance. The ClpXP complex maintains mitochondrial proteostasis by degrading misfolded proteins. Madera Therapeutics has developed a class of highly potent and selective small-molecule activators (TR compounds) of the ClpXP component caseinolytic peptidase proteolytic subunit (ClpP). This approach to cancer therapy eliminates substrate recognition and activates non-specific protease function within mitochondria, which has shown encouraging preclinical efficacy in multiple malignancies. The class-leading compound, TR-107, has demonstrated significantly improved potency in ClpP affinity and activation and enhanced pharmacokinetic properties over the multi-targeting clinical agent ONC201. In this study, we investigate the in vitro efficacy of TR-107 against human colorectal cancer (CRC) cells. TR-107 inhibited CRC cell proliferation in a dose- and time-dependent manner and induced cell cycle arrest at low nanomolar concentrations. Mechanistically, TR-107 downregulated the expression of proteins involved in the mitochondrial unfolded protein response (UPRmt) and mtDNA transcription and translation. TR-107 attenuated oxygen consumption rate and glycolytic compensation, confirming inactivation of OXPHOS and a reduction in total cellular respiration. Multi-omics analysis of treated cells indicated a downregulation of respiratory chain complex subunits and an upregulation of mitophagy and ferroptosis pathways. Further evaluation of ferroptosis revealed a depletion of antioxidant and iron toxicity defenses that could potentiate sensitivity to combinatory chemotherapeutics. Together, this study provides evidence and insight into the subcellular mechanisms employed by CRC cells in response to potent ClpP agonism. Our findings demonstrate a productive approach to disrupting mitochondrial metabolism, supporting the translational potential of TR-107.

An insufficient quantity of functional T cells is a likely factor limiting the clinical activity of T-cell bispecific antibodies, especially in solid tumor indications. We hypothesized that XmAb24306 (efbalropendekin alfa), a lymphoproliferative interleukin (IL)-15/IL-15 receptor α (IL-15Rα) Fc-fusion protein, may potentiate the activity of T-cell dependent (TDB) antibodies. The activation of human peripheral T cells by cevostamab, an anti-FcRH5/CD3 TDB, or anti-HER2/CD3 TDB resulted in the upregulation of the IL-2/15Rβ (CD122) receptor subunit in nearly all CD8+ and majority of CD4+ T cells, suggesting that TDB treatment may sensitize T cells to IL-15. XmAb24306 enhanced T-cell bispecific antibody-induced CD8+ and CD4+ T-cell proliferation and expansion. In vitro combination of XmAb24306 with cevostamab or anti-HER2/CD3 TDB resulted in significant enhancement of tumor cell killing, which was reversed when T-cell numbers were normalized, suggesting that T-cell expansion is the main mechanism of the observed benefit. Pretreatment of immunocompetent mice with a mouse-reactive surrogate of XmAb24306 (mIL-15-Fc) resulted in a significant increase of T cells in the blood, spleen, and tumors and converted transient anti-HER2/CD3 TDB responses to complete durable responses. In summary, our results support the hypothesis that the number of tumor-infiltrating T cells is rate limiting for the activity of solid tumor-targeting TDBs. Upregulation of CD122 by TDB treatment and the observed synergy with XmAb24306 and T-cell bispecific antibodies support clinical evaluation of this novel immunotherapy combination.

EGFR plays an essential role in cellular signaling pathways that regulate cell growth, proliferation, and survival and is often dysregulated in cancer. Several monoclonal IgG antibodies have been clinically tested over the years, which exert their function via blocking the ligand binding domain (thereby inhibiting downstream signaling) and inducing Fc-related effector functions, such as antibody-dependent cellular cytotoxicity (ADCC) and antibody-dependent cellular phagocytosis (ADCP). However, these IgG antibodies do not optimally recruit neutrophils, which are the most abundant white blood cell population in humans. Therefore, we reformatted six therapeutic EGFR antibodies (cetuximab, panitumumab, nimotuzumab, necitumumab, zalutumumab, and matuzumab) into the IgA3.0 format, which is an IgA2 isotype adapted for clinical application. Reformatting these antibodies preserved Fab-mediated functions such as EGFR binding, growth inhibition, and ligand blockade. In addition, whole leukocyte ADCC was significantly increased when using this panel of IgA3.0 antibodies compared with their respective IgG counterparts, with no major differences between IgA3.0 antibodies. In vivo, IgA3.0 matuzumab outperformed the other antibodies, resulting in the strongest suppression of tumor outgrowth in a long intraperitoneal model. We showed that neutrophils are important for the suppression of tumor outgrowth. IgA3.0 matuzumab exhibited reduced receptor internalization compared with the other antibodies, possibly accounting for its superior in vivo Fc-mediated tumor cell killing efficacy. In conclusion, reformatting EGFR antibodies into an IgA3.0 format increased Fc-mediated killing while retaining Fab-mediated functions and could therefore be a good alternative for the currently available antibody therapies.

Individuals with neurofibromatosis type 1, an autosomal dominant neurogenetic and tumor predisposition syndrome, are susceptible to developing low-grade glioma and less commonly high-grade glioma. These gliomas exhibit loss of the neurofibromin gene [neurofibromin type 1 (NF1)], and 10% to 15% of sporadic high-grade gliomas have somatic NF1 alterations. Loss of NF1 leads to hyperactive RAS signaling, creating opportunity given the established efficacy of MEK inhibitors in plexiform neurofibromas and some individuals with low-grade glioma. We observed that NF1-deficient glioblastoma neurospheres were sensitive to the combination of an MEK inhibitor (mirdametinib) with irradiation, as evidenced by synergistic inhibition of cell growth, colony formation, and increased cell death. In contrast, NF1-intact neurospheres were not sensitive to the combination, despite complete ERK pathway inhibition. No neurosphere lines exhibited enhanced sensitivity to temozolomide combined with mirdametinib. Mirdametinib decreased transcription of homologous recombination genes and RAD51 foci, associated with DNA damage repair, in sensitive models. Heterotopic xenograft models displayed synergistic growth inhibition to mirdametinib combined with irradiation in NF1-deficient glioma xenografts but not in those with intact NF1. In sensitive models, benefits were observed at least 3 weeks beyond the completion of treatment, including sustained phosphor-ERK inhibition on immunoblot and decreased Ki-67 expression. These observations demonstrate synergistic activity between mirdametinib and irradiation in NF1-deficient glioma models and may have clinical implications for patients with gliomas that harbor germline or somatic NF1 alterations.

Oncolytic virotherapy or immunovirotherapy is a strategy that utilizes viruses to selectively infect and kill tumor cells while also stimulating an immune response against the tumor. Early clinical trials in both pediatric and adult patients using oncolytic herpes simplex viruses (oHSV) have demonstrated safety and promising efficacy; however, combinatorial strategies designed to enhance oncolysis while also promoting durable T-cell responses for sustaining disease remission are likely required. We hypothesized that combining the direct tumor cell killing and innate immune stimulation by oHSV with a vaccine that promotes T cell-mediated immunity may lead to more durable tumor regression. To this end, we investigated the preclinical efficacy and potential synergy of combining oHSV with a self-assembling nanoparticle vaccine codelivering peptide antigens and Toll-like receptor 7 and 8 agonists (referred to as SNAPvax),which induces robust tumor-specific T-cell immunity. We then assessed how timing of the treatments (i.e., vaccine before or after oHSV) impacts T-cell responses, viral replication, and preclinical efficacy. The sequence of treatments was critical, as survival was significantly enhanced when the SNAPvax vaccine was given prior to oHSV. Increased clinical efficacy was associated with reduced tumor volume and increases in virus replication and tumor antigen-specific CD8+ T cells. These findings substantiate the criticality of combination immunotherapy timing and provide preclinical support for combining SNAPvax with oHSV as a promising treatment approach for both pediatric and adult tumors.