Molecular mechanisms and clinical management of cancer bone metastasis

As one of the most common metastatic sites of malignancies,bone has a unique microenvironment that allows metastatic tumor cells to grow and flourish.The fenestrated capillaries in the bone,bone matrix,and bone cells,including osteoblasts and osteoclasts,together maintain the homeostasis of the bone microenvironment.In contrast,tumor-derived factors act on bone components,leading to subsequent bone resorption or excessive bone formation.The various pathways involved also provide multiple targets for therapeutic strategies against bone metastases.In this review,we summarize the current understanding of the mechanism of bone metastases.Based on the general process of bone metastases,we specifically highlight the complex crosstalk between tumor cells and the bone microenvironment and the current management of cancer bone metastases.

Nucleic acids and analogs for bone regeneration

With the incidence of different bone diseases increasing, effective therapies are needed that coordinate a combination of various technologies and biological materials. Bone tissue engineering has also been considered as a promising strategy to repair various bone defects. Therefore, different biological materials that can promote stem cell proliferation, migration, and osteoblastic differentiation to accelerate bone tissue regeneration and repair have also become the focus of research in multiple fields. Stem cell therapy, biomaterial scaffolds, and biological growth factors have shown potential for bone tissue engineering; however, off-target effects and cytotoxicity have limited their clinical use. The application of nucleic acids(deoxyribonucleic acid or ribonucleic acid)and nucleic acid analogs(peptide nucleic acids or locked nucleic acids), which are designed based on foreign genes or with special structures, can be taken up by target cells to exert different effects such as modulating protein expression, replacing a missing gene, or targeting specific gens or proteins. Due to some drawbacks, nucleic acids and nucleic acid analogs are combined with various delivery systems to exert enhanced effects, but current studies of these molecules have not yet satisfied clinical requirements. In-depth studies of nucleic acid or nucleic acid analog delivery systems have been performed, with a particular focus on bone tissue regeneration and repair. In this review, we mainly introduce delivery systems for nucleic acids and nucleic acid analogs and their applications in bone repair and regeneration. At the same time, the application of conventional scaffold materials for the delivery of nucleic acids and nucleic acid analogs is also discussed.

Ammonia promotes the proliferation of bone marrow-derived mesenchymal stem cells by regulating the Akt/mTOR/S6k pathway

Ammonia plays an important role in cellular metabolism.However,ammonia is considered a toxic product.In bone marrow-derived mesenchymal stem cells,multipotent stem cells with high expression of glutamine synthetase(GS)in bone marrow,ammonia and glutamate can be converted to glutamine via glutamine synthetase activity to support the proliferation of MSCs.As a major nutritional amino acid for biosynthesis,glutamine can activate the Akt/mTOR/S6k pathway to stimulate cell proliferation.The activation of mTOR can promote cell entry into S phase,thereby enhancing DNA synthesis and cell proliferation.Our studies demonstrated that mesenchymal stem cells can convert the toxic waste product ammonia into nutritional glutamine via GS activity.Then,the Akt/mTOR/S6k pathway is activated to promote bone marrow-derived mesenchymal stem cell proliferation.These results suggest a new therapeutic strategy and potential target for the treatment of diseases involving hyperammonemia.

Colony-stimulating factor-1 receptor inhibition combined with paclitaxel exerts effective antitumor effects in the treatment of ovarian cancer

Ovarian cancer is the tumor with the highest mortality among gynecological malig-nancies.Studies have confirmed that paclitaxel chemoresistance is associated with increased infiltration of tumor-associated macrophages(TAMs)in the microenvironment.Colony-stimu-lating factor 1(CSF-1)receptor(CSF-1R)plays a key role in regulating the number and differ-entiation of macrophages in certain solid tumors.There are few reports on the effects of targeted inhibition of CSF-1R in combination with chemotherapy on ovarian cancer and the tu-mor microenvironment.Here,we explored the antitumor efficacy and possible mechanisms of the CSF-1R inhibitor pexidartinib(PLX3397)when combined with the first-line chemothera-peutic agent paclitaxel in the treatment of ovarian cancer.We found that CSF-1R is highly ex-pressed in ovarian cancer cells and correlates with poor prognosis.Treatment by PLX3397 in combination with paclitaxel significantly inhibited the growth of ovarian cancer both in vitro and in vivo.Blockade of CSF-1R altered the macrophage phenotype and reprogrammed the immunosuppressive cell population in the tumor microenvironment.

Intranasal boosting with RBD-HR protein vaccine elicits robust mucosal and systemic immune responses

The emergence of severe acute respiratory syndrome coronavirus 2(SARS-CoV-2)variants has decreased the efficacy of SARs-CoV-2 vaccines in containing coronavirus disease 2019(CoVID-19)over time,and booster vaccination strategies are urgently necessitated to achieve sufficient protection.Intranasal immunization can improvemucosal immunity,offer-ing protection against the infection and sustaining the spread of SARS-CoV-2.In this study,an intranasal booster of the RBD-HR vaccine after two doses of the mRNA vaccine significantly increased the levels of specific binding antibodies in serum,nasal lavage fluid,and bronchoal-veolar lavage fluid compared with only two doses of mRNA vaccine.After intranasal boosting with the RBD-HR vaccine,the levels of serum neutralizing antibodies against prototype and variant strains of SARS-Cov-2 pseudoviruses weremarkedly higher than those in mice receiving mRNA vaccine alone,and intranasal boosting with the RBD-HR vaccine also inhibited the bind-ing of RBD to hACE2 receptors.Furthermore,the heterologous intranasal immunization regimen promoted extensive memory T cell responses and activated CD103+dendritic cells in the respiratory mucosa,and potently enhanced the formation of T follicular helper cells and germinal center B cells in vital immune organs,including mediastinal lymph nodes,inguinal lymph nodes,and spleen.Collectively,these data infer that heterologous intranasal boosting with the RBD-HR vaccine elicited broad protective immunity against SARS-CoV-2 both locallyandsystemically.

Targeting RAS-RAF-MEK-ERK signaling pathway in human cancer:Current status in clinical trials

Molecular target inhibitors have been regularly approved by Food and Drug Administration(FDA)for tumor treatment,and most of them intervene in tumor cell proliferation and metabolism.The RAS-RAF-MEK-ERK pathway is a conserved signaling pathway that plays vital roles in cell proliferation,survival,and differentiation.The aberrant activation of the RAS-RAF-MEK-ERK signaling pathway induces tumors.About 33%of tumors harbor RAS mutations,while 8%of tumors are driven by RAF mutations.Great efforts have been dedicated to targeting the signaling pathway for cancer treatment in the past decades.In this review,we summarized the development of inhibitors targeting the RAS-RAF-MEK-ERK pathway with an emphasis on those used in clinical treatment.Moreover,we discussed the potential combinations of inhibitors that target the RAS-RAF-MEK-ERK signaling pathway and other signaling pathways.The inhibitors targeting the RAS-RAF-MEK-ERK pathway have essentially modified the therapeutic strategy against various cancers and deserve more attention in the current cancerresearchandtreatment.

A novel heterologous receptor-binding domain dodecamer universal mRNA vaccine against SARS-CoV-2 variants

There are currently approximately 4000 mutations in the SARS-CoV-2 S protein gene and emerging SARS-CoV-2 variants continue to spread rapidly worldwide.Universal vaccines with high efficacy and safety urgently need to be developed to prevent SARS-CoV-2 variants pandemic.Here,we described a novel self-assembling universal mRNA vaccine containing a heterologous receptorbinding domain(HRBD)-based dodecamer(HRBD^(dodecamer))against SARS-CoV-2 variants,including Alpha(B.1.1.7),Beta(B.1.351),Gamma(B.1.1.28.1),Delta(B.1.617.2)and Omicron(B.1.1.529).HRBD containing four heterologous RBD(Delta,Beta,Gamma,and Wild-type)can form a stable dodecameric conformation under T4 trimerization tag(Flodon,FD).The HRBD^(dodecamer)-encoding mRNA was then encapsulated into the newly-constructed LNPs consisting of a novel ionizable lipid(4N4T).The obtained universal mRNA vaccine(4N4T-HRBD^(dodecamer))presented higher efficiency in mRNA transfection and expression than the approved ALC-0315 LNPs,initiating potent immune protection against the immune escape of SARS-CoV-2 caused by evolutionary mutation.These findings demonstrated the first evidence that structure-based antigen design and mRNA delivery carrier optimization may facilitate the development of effective universal mRNA vaccines to tackle SARS-CoV-2 variants pandemic.

Sodium alginate coating simultaneously increases the biosafety and immunotherapeutic activity of the cationic mRNA nanovaccine

The extraordinary advantages associated with mRNA vaccines,including their high efficiency,relatively low severity of side effects,and ease of manufacture,have enabled them to be a promising immunotherapy approach against various infectious diseases and cancers.Nevertheless,most mRNA delivery carriers have many disadvantages,such as high toxicity,poor biocompatibility,and low efficiency in vivo,which have hindered the widespread use of mRNA vaccines.To further characterize and solve these problems and develop a new type of safe and efficient mRNA delivery carrier,a negatively charged SA@DOTAP-mRNA nanovaccine was prepared in this study by coating DOTAP-mRNA with the natural anionic polymer sodium alginate(SA).Intriguingly,the transfection efficiency of SA@DOTAP-mRNA was significantly higher than that of DOTAP-mRNA,which was not due to the increase in cellular uptake but was associated with changes in the endocytosis pathway and the strong lysosome escape ability of SA@DOTAP-mRNA.In addition,we found that SA significantly increased the expression of LUC-mRNA in mice and achieved certain spleen targeting.Finally,we confirmed that SA@DOTAP-mRNA had a stronger antigen-presenting ability in E.G7-OVA tumor-bearing mice,dramatically inducing the proliferation of OVA-specific CLTs and ameliorating the antitumor effect.Therefore,we firmly believe that the coating strategy applied to cationic liposome/mRNA complexes is of potential research value in the field of mRNA delivery and has promising clinical application prospects.

SARS-CoV-2 variants,immune escape,COVID-19 vaccine,and therapeutic strategies

The global pandemic of coronavirus disease 2019(COVID-19) caused by severe acute respiratory syndrome coronavirus2(SARS-CoV-2) has brought considerable challenges to worldwide public health and the economy. Over 535 million confirmed cases and 6.3 million deaths of COVID-19 were reported as of June 17, 2022(https://covid19.who.int/).

Low levels of neutralizing antibodies against XBB Omicron subvariants after BA.5 infection

The COVID-19 response strategies in Chinese mainland were recently adjusted due to the reduced pathogenicity and enhanced infectivity of Omicron subvariants.In Chengdu,China,an infection wave was predominantly induced by the BA.5 subvariant.It is crucial to determine whether the hybrid anti-SARS-CoV-2 immunity following BA.5 infection.

Nanovaccines for cancer immunotherapy:Current knowledge and future perspectives

Cancer immunotherapy harnesses the immune system to attack tumors and has received extensive attention in recent years.Cancer vaccines as an important branch of immunotherapy are designed for delivering tumor antigens to antigen-presenting cells(APCs)to stimulate a strong immune response to against tumors,representing a potentially therapeutic and prophylactic effect with the long-term anticancer benefits.Nevertheless,the disappointing outcomes of their clinical use might be attributed to dilemma in antigen selection,immunogenicity,lymph nodes(LNs)targeting ability,lysosomal escape ability,immune evasion,etc.Nanotechnology,aiming to overcome these barriers,has been utilized in cancer vaccine development for decades.Numerous preclinical and clinical studies demonstrate positive results in nanomaterials-based cancer vaccines with considerable improvement in the vaccine efficacy.In this review,we systematically introduced the characteristics of nanovaccines and highlighted the different types of nanomaterials used for cancer vaccine design.In addition,the opportunities and challenges of the emerging nanotechnology-based cancer vaccines were discussed.

Tripterin liposome relieves severe acute respiratory syndrome as a potent COVID-19 treatment

For coronavirus disease 2019(COVID-19),caused by severe acute respiratory syndrome coronavirus 2(SARS-CoV-2),15–30%of patients are likely to develop COVID-19-related acute respiratory distress syndrome(ARDS).There are still few effective and well-understood therapies available.Novel variants and short-lasting immunity are posing challenges to vaccine efficacy,so finding antiviral and antiinflammatory treatments remains crucial.Here,tripterin(TP),a traditional Chinese medicine,was encapsulated into liposome(TP lipo)to investigate its antiviral and antiinflammatory effects in severe COVID-19.By using two severe COVID-19 models in human ACE2-transgenic(hACE2)mice,an analysis of TP lipo’s effects on pulmonary immune responses was conducted.Pulmonary pathological alterations and viral burden were reduced by TP lipo treatment.TP lipo inhibits SARS-CoV-2 replication and hyperinflammation in infected cells and mice,two crucial events in severe COVID-19 pathophysiology,it is a promising drug candidate to treat SARS-CoV-2-induced ARDS.

A small-molecule pan-HER inhibitor alone or in combination with cisplatin exerts efficacy against nasopharyngeal carcinoma

The abnormal activation of HER family kinase activity is closely related to the development of human malignancies.In this study,we used HER kinases as targets for the treatment of nasopharyngeal carcinoma(NPC)and explored the anti-tumor effects of the novel pan-HER inhibitor HM781-36B,alone or in combination with cisplatin.We found that HER family proteins were positively expressed in tumor tissues of some NPC patients,and the high levels of those proteins were significantly related to poor prognosis.HM781-36B inhibited NPC in vitro and in vivo.HM781-36B exerted synergistic effects with cisplatin on inhibiting proliferation and promoting apoptosis of NPC cells.In NPC xenograft models in nude mice,HM781-36B and cisplatin synergistically inhibited tumor growth.Downregulating the activity of HER family proteins and their downstream signaling pathways and regulating tumor microenvironment may explain the synergistic anti-tumor effects of HM781-36B and cisplatin.In conclusion,our study provides evidence for HER family proteins as prognostic biomarkers and potential therapeutic targets for NPC.The pan-HER inhibitor HM781-36B alone or in combination with cisplatin represents promising therapeutic effects for the treatment of NPC patients,which provides a new idea for the comprehensive treatment of NPC.

Multifunctional regulatory protein connective tissue growth factor (CTGF):A potential therapeutic target for diverse diseases

Connective tissue growth factor(CTGF),a multifunctional protein of the CCN family,regulates cell proliferation,differentiation,adhesion,and a variety of other biological processes.It is involved in the disease-related pathways such as the Hippo pathway,p53 and nuclear factor kappa-B(NF-κB)pathways and thus contributes to the developments of inflammation,fibrosis,cancer and other diseases as a downstream effector.Therefore,CTGF might be a potential therapeutic target for treating various diseases.In recent years,the research on the potential of CTGF in the treatment of diseases has also been paid more attention.Several drugs targeting CTGF(monoclonal antibodies FG3149 and FG3019)are being assessed by clinical or preclinical trials and have shown promising outcomes.In this review,the cellular events regulated by CTGF,and the relationships between CTGF and pathogenesis of diseases are systematically summarized.In addition,we highlight the current researches,focusing on the preclinical and clinical trials concerned with CTGF as the therapeutic target.

CCL5/CCR5 axis in human diseases and related treatments

To defense harmful stimuli or maintain the immune homeostasis, the body produces and recruits a superfamily of cytokines such as interleukins, interferons, chemokines etc. Among them, chemokines act as crucial regulators in defense systems. CCL5/CCR5 combination is known for facilitating inflammatory responses, as well as inducing the adhesion and migration of different T cell subsets in immune responses. In addition, recent studies have shown that the interaction between CCL5 and CCR5 is involved in various pathological processes including inflammation, chronic diseases, cancers as well as the infection of COVID-19. This review focuses on how CCL5/CCR5 axis participates in the pathological processes of different diseases and their relevant signaling pathways for the regulation of the axis. Moreover, we highlighted the gene therapy and chemotherapy studies for treating CCR5-related diseases, including the ongoing clinical trials. The barriers and perspectives for future application and translational research were also summarized.

Mitochondrial DNA in the regulation of innate immune responses

Mitochondrion is known as the energy factory of the cell, which is also a unique mammalian organelle and con. sidered to be evolved from aerobic prokaryotes more than a billion years ago. Mitochondrial DNA, similar to that of its bacterial ancestor＇s, consists of a circular loop and contains significant number of unmethylated DNA as CpG islands. The innate immune system plays an important role in the mammalian immune response. Recent research has demonstrated that mitochondrial DNA （mtDNA） activates several innate immune path- ways involving TLR9, NLRP3 and STING signaling, which contributes to the signaling platforms and results in effector responses. In addition to facilitating antibac- terial immunity and regulating antiviral signaling, mounting evidence suggests that mtDNA contributes to inflammatory diseases following cellular damage and stress. Therefore, in addition to its well-appreciated roles in cellular metabolism and energy production, mtDNA appears to function as a key member in the innate immune system. Here, we highlight the emerging roles of mtDNA in innate immunity.

Epigenetic regulation of macrophages: from homeostasis maintenance to host defense

Macrophages are crucial members of the innate immune response and important regulators.The differentiation and activation of macrophages require the timely regulation of gene expression,which depends on the interaction of a variety of factors,including transcription factors and epigenetic modifications.Epigenetic changes also give macrophages the ability to switch rapidly between cellular programs,indicating the ability of epigenetic mechanisms to affect phenotype plasticity.In this review,we focus on key epigenetic events associated with macrophage fate,highlighting events related to the maintenance of tissue homeostasis,responses to different stimuli and the formation of innate immune memory.Further understanding of the epigenetic regulation of macrophages will be helpful for maintaining tissue integrity,preventing chronic inflammatory diseases and developing therapies to enhance host defense.

The role of lysosome in regulated necrosis

Lysosome is a ubiquitous acidic organelle fundamental for the turnover of unwanted cellular molecules,particles,and organelles.Currently,the pivotal role of lysosome in regulating cell death is drawing great attention.Over the past decades,we largely focused on how lysosome influences apoptosis and autophagic cell death.However,extensive studies showed that lysosome is also prerequisite for the execution of regulated necrosis(RN).Different types of RN have been uncovered,among which,necroptosis,ferroptosis,and pyroptosis are under the most intensive investigation.It becomes a hot topic nowadays to target RN as a therapeutic intervention,since it is important in many patho/physiological settings and contributing to numerous diseases.It is promising to target lysosome to control the occurrence of RN thus altering the outcomes of diseases.Therefore,we aim to give an introduction about the common factors influencing lysosomal stability and then summarize the current knowledge on the role of lysosome in the execution of RN,especially in that of necroptosis,ferroptosis,and pyroptosis.

Targeting epigenetic regulators for cancer therapy: mechanisms and advances in clinical trials

Epigenetic alternations concern heritable yet reversible changes in histone or DNA modifications that regulate gene activity beyond the underlying sequence.Epigenetic dysregulation is often linked to human disease,notably cancer.With the development of various drugs targeting epigenetic regulators,epigenetic-targeted therapy has been applied in the treatment of hematological malignancies and has exhibited viable therapeutic potential for solid tumors in preclinical and clinical trials.In this review,we summarize the aberrant functions of enzymes in DNA methylation,histone acetylation and histone methylation during tumor progression and highlight the development of inhibitors of or drugs targeted at epigenetic enzymes.

The molecular mechanisms of MLKL-dependent and MLKL-independent necrosis

Necrosis,a type of unwanted and passive cell demise,usually occurs under the excessive external stress and is considered to be unregulated.However,under some special conditions such as caspase inhibition,necrosis is regulable in a well-orchestrated way.The term'regulated necrosis'has been proposed to describe such programed necrosis.Recently,several forms of necrosis,including necroptosis,pyroptosis,ferroptosis,parthanatos,oxytosis,NETosis,and Na^(+)/K^(+)ATPasimediated necrosis,have been identified,and some crucial regulators governing regulated necrosis have also been discovered.Mixed lineage kinase domain-like pseudokinase(MLKL),a core regulator in necroptosis,acts as an executioner in response to ligands of death receptor family.Its activation requires the receptor-interacting protein kinases,RIP1 and RIP3.However,MLKL is only involved in necroptosis,i.e.MLKL is dispensable for necrosis.Therefore,this review is aimed at summarizing the molecular mechanisms of MLKLdependent and MLKL-independent necrosis.