Anti-CD47 antibody synergizes with cisplatin against laryngeal cancer by enhancing phagocytic ability of macrophages

Biomimetic mineralized DCPA/ anti-CD47 containing thermo-sensitive injectable hydrogel for bone-metastatic prostate cancer treatment

Strategies that leverage the phagocytic capabilities of M1 macrophages against tumor cells are currently being investigated for cancer treatment. However, the clinical application of these strategies is significantly hampered by the severe side effects associated with conventional M1 macrophage activators. In this study, biomimetic mineralized dicalcium phosphate anhydrous (MDCPA) was synthesized using Zein as an organic template, aiming to promote M1 macrophage polarization effectively while minimizing side effects. In vitro experiments demonstrated that MDCPA can be engulfed by macrophages and induce M1 macrophage polarization. By combining the stimulation of MDCPA with a commonly used immune checkpoint inhibitor, anti-CD47 (aCD47), the macrophages exhibited the highest phagocytic activity toward prostate cancer cells. Further in vivo experiments illustrated significant tumor suppression and reduced bone resorption in a prostate cancer bone metastasis model utilizing MDCPA/aCD47-containing thermos-sensitive injectable hydrogels (MDCPA/aCD47 TSI gel). Mechanistic studies indicated that the MDCPA/aCD47 TSI gel promotes tumor cell apoptosis not only through the phagocytosis of tumor cells mediated by M1 macrophages, but also by activating anti-tumor CD8-positive T cells. Consequently, this composite gel platform presents an effective theragnostic strategy for treating prostate cancer bone metastasis without the associated side effects, facilitated by biomimetic minerals that mediate anti-tumor immunity.

GULP1 as a Downstream Effector of the Estrogen Receptor-β Modulates Cisplatin Sensitivity in Bladder Cancer

BACKGROUND/AIM

Precise molecular mechanisms underlying resistance to cisplatin-based chemotherapy remain unclear, while the activity of estrogen receptor-β (ERβ) has been suggested to be associated with chemosensitivity in urothelial cancer. We aimed to determine if GULP1, an adapter protein known to facilitate phagocytosis, could represent a downstream effector of ERβ and thereby modulate cisplatin sensitivity in bladder cancer.

MATERIALS AND METHODS

GULP1 expression and cisplatin cytotoxicity were compared in bladder cancer lines. Immunohistochemistry was used to determine the expression of GULP1 and ERβ in two sets of tissue microarray (TMA) consisting of transurethral resection specimens.

RESULTS

The levels of GULP1 expression were considerably higher in ERβ-knockdown sublines than in the respective control ERβ-positive sublines. Estradiol treatment reduced GULP1 expression in ERα-negative/ERβ-positive lines, which was restored by the anti-estrogen tamoxifen. Chromatin immunoprecipitation assay revealed the binding of ERβ to the GULP1 promoter in bladder cancer cells. Moreover, GULP1 knockdown sublines were significantly more resistant to cisplatin treatment, but not to other chemotherapeutic agents, including gemcitabine, methotrexate, vinblastine, and doxorubicin. In the first set of TMA (n=129), the expression of ERβ and GULP1 was inversely correlated (p=0.023), and ERβ(-)/GULP1(+) in 51 muscle-invasive tumors was associated with significantly lower risk of disease progression and cancer-specific mortality. Similarly, in the second set (n=43), patients with ERβ(-)/GULP1(+) muscle-invasive disease were significantly (p=0.021) more likely to be responders to cisplatin-based neoadjuvant chemotherapy before radical cystectomy.

CONCLUSION

ERβ activation was found to reduce the expression of GULP1 as a direct downstream target in bladder cancer cells, resulting in the induction of cisplatin resistance.

Bionic lipoprotein loaded with chloroquine-mediated blocking immune escape improves antitumor immunotherapy

Tumor immunotherapy hold great promise for eradicating tumors. However, immune escape and the immunosuppressive microenvironment of tumor usually limit the efficiency of tumor immunotherapy. Therefore, simultaneously blocking immune escape and improving immunosuppressive microenvironment are the current problems to be solved urgently. Among them, CD47 on cancer cells membrane could bind to signal regulatory protein α (SIRPα) on macrophages membrane and sent out "don't eat me" signal, which was an important pathway of immune escape. The large number of M2-type macrophages in tumor microenvironment was a significant factor contributing to the immunosuppressive microenvironment. Here, we present a drug loading system for enhancing cancer immunotherapy, comprising CD47 antibody (aCD47) and chloroquine (CQ) with Bionic lipoprotein (BLP) carrier (BLP-CQ-aCD47). On the one hand, as drug delivery carrier, BLP could allow CQ to be preferentially taken up by M2-type macrophages, thereby efficiently polarized M2-type tumor-promoting cells into M1-type anti-tumor cells. On the other hand, blocking CD47 from binding to SIRPα could block the "don't eat me" signal, and improve the phagocytosis of macrophages to tumor cells. Taken together, BLP-CQ-aCD47 could block immune escape, improve immunosuppressive microenvironment of tumor, and induce a strong immune response without substantial systemic toxicity. Therefore, it provides a new idea for tumor immunotherapy.

Therapeutic strategies for gastric cancer targeting immune cells: Future directions

Gastric cancer (GC) is a malignancy with a high incidence and mortality, and the emergence of immunotherapy has brought survival benefits to GC patients. Compared with traditional therapy, immunotherapy has the advantages of durable response, long-term survival benefits, and lower toxicity. Therefore, targeted immune cells are the most promising therapeutic strategy in the field of oncology. In this review, we introduce the role and significance of each immune cell in the tumor microenvironment of GC and summarize the current landscape of immunotherapy in GC, which includes immune checkpoint inhibitors, adoptive cell therapy (ACT), dendritic cell (DC) vaccines, reduction of M2 tumor-associated macrophages (M2 TAMs), N2 tumor-associated neutrophils (N2 TANs), myeloid-derived suppressor cells (MDSCs), effector regulatory T cells (eT_regs), and regulatory B cells (B_regs) in the tumor microenvironment and reprogram TAMs and TANs into tumor killer cells. The most widely used immunotherapy strategies are the immune checkpoint inhibitor programmed cell death 1/programmed death-ligand 1 (PD-1/PD-L1) antibody, cytotoxic T lymphocyte–associated protein 4 (CTLA-4) antibody, and chimeric antigen receptor T (CAR-T) in ACT, and these therapeutic strategies have significant anti-tumor efficacy in solid tumors and hematological tumors. Targeting other immune cells provides a new direction for the immunotherapy of GC despite the relatively weak clinical data, which have been confirmed to restore or enhance anti-tumor immune function in preclinical studies and some treatment strategies have entered the clinical trial stage, and it is expected that more and more effective immune cell–based therapeutic methods will be developed and applied.

Therapeutic targets and biomarkers of tumor immunotherapy: response versus non-response

Cancers are highly complex diseases that are characterized by not only the overgrowth of malignant cells but also an altered immune response. The inhibition and reprogramming of the immune system play critical roles in tumor initiation and progression. Immunotherapy aims to reactivate antitumor immune cells and overcome the immune escape mechanisms of tumors. Represented by immune checkpoint blockade and adoptive cell transfer, tumor immunotherapy has seen tremendous success in the clinic, with the capability to induce long-term regression of some tumors that are refractory to all other treatments. Among them, immune checkpoint blocking therapy, represented by PD-1/PD-L1 inhibitors (nivolumab) and CTLA-4 inhibitors (ipilimumab), has shown encouraging therapeutic effects in the treatment of various malignant tumors, such as non-small cell lung cancer (NSCLC) and melanoma. In addition, with the advent of CAR-T, CAR-M and other novel immunotherapy methods, immunotherapy has entered a new era. At present, evidence indicates that the combination of multiple immunotherapy methods may be one way to improve the therapeutic effect. However, the overall clinical response rate of tumor immunotherapy still needs improvement, which warrants the development of novel therapeutic designs as well as the discovery of biomarkers that can guide the prescription of these agents. Learning from the past success and failure of both clinical and basic research is critical for the rational design of studies in the future. In this article, we describe the efforts to manipulate the immune system against cancer and discuss different targets and cell types that can be exploited to promote the antitumor immune response.

Anti-CD47 antibody synergizes with cisplatin against laryngeal cancer by enhancing phagocytic ability of macrophages

Cisplatin is mainly used in late-stage or recurrent laryngeal cancer patients. However, the effect of the chemotherapy is limited due to cisplatin resistance. Therefore, we explored the synergized role of immunosuppressive mediator with cisplatin in laryngeal cancer. Cancer cells isolated from tissues of patients with laryngeal cancer were treated with cisplatin to screen the potential immunosuppressive mediator, whose synergized effects with cisplatin were explored both in vivo and in vitro. CD47 was selected for its high expression in cisplatin-treated laryngeal cancer cells. Blocking CD47 expression using its neutralizing antibody (aCD47) synergized with cisplatin to increase macrophage phagocytosis in a co-culture system of human epithelial type 2 (Hep-2) cancer cells with tumor-associated macrophages (TAMs). Moreover, aCD47 together with cisplatin prevented tumor growth by inhibiting proliferation of cancer cells and the secretion of proinflammatory cytokines, as well as by inducing the apoptosis of cancer cells and phagocytosis of TAMs in a Hep-2-implanted mouse tumor model. aCD47 synergized with cisplatin against laryngeal cancer by enhancing the phagocytic ability of TAMs, and the combined therapy of cisplatin and aCD47 might serve as a novel therapeutic strategy against laryngeal cancer.