Cancer Letters

The use of immunodeficient mice for human tumor engraftment is an essential model of human cancer, with uses ranging from basic science to translational research. However, low engraftment rates, slow growth, and smaller tumor volumes can be limitations. Previously, we reported a highly immunodeficient rat strain with the functional deletion of both the Rag2 and Il2rg genes on the Sprague-Dawley background (SRG RAT(R)), which lacks B, T, and NK cells. Here, we subcutaneously engrafted two cell-derived xenograft (CDX) and seven patient-derived xenograft (PDX) models, including prostate, lung, ovarian, and uterine cancer models, into the SRG rat or NSG mouse models and tracked tumor growth. In all cases, the engraftment and tumor growth rates were better supported in the SRG rat compared to the NSG mouse. Interestingly, the SRG rat is not more immunocompromised than the NSG mouse, suggesting alternative mechanisms leading to the supportive growth in the SRG rat. Therefore, we explored potential differences in the tumor microenvironment (TME) between models grown in the two host animals. Lung PDX models grown in SRG rats showed enhanced formation of vasculature and stroma and were morphologically more consistent with the originating patient tumors. IHC analysis of the NCI-H660 CDX model showed differences in the tumors stroma, vasculature, and macrophages when grown in the two host species. Single-cell spatial imaging of engrafted tumors showed upregulation of the human CXCL2 and TCIM in NCI-H660 tumors grown in the SRG rat versus the NSG mouse, both of which have been linked to poor prognosis in cancer. Combined, our data demonstrate that the SRG rat supports the growth of multiple human cancer types and displays enhanced tumor microenvironment interactions compared to NSG mice.

Stereotactic Radiosurgery (SRS) is one of the leading treatment modalities for oligo brain metastasis (BM), however no comprehensive genomic data assessing the effect of radiation on BM in humans exist. Leveraging a unique opportunity, as part of the clinical trial (NCT03398694), we collected post-SRS, delivered via Gamma-knife or LINAC, tumor samples from core and peripheral-edges of the resected tumor to characterize the genomic effects of overall SRS as well as the SRS delivery modality. Using these rare patient samples, we show that SRS results in significant genomic changes at DNA and RNA levels throughout the tumor. Mutations and expression profiles of peripheral tumor samples indicated interaction with surrounding brain tissue as well as elevated DNA damage repair. Central samples show GSEA enrichment for cellular apoptosis while peripheral samples carried an increase in tumor suppressor mutations. There are significant differences in the transcriptomic profile at the periphery between Gamma-knife vs LINAC.

Deregulation of glycolysis is common in non-small cell lung cancer (NSCLC). Hexokinase (HK) enzymes catalyze the phosphoryl-group-transfer in glucose metabolism. There are a very few studies that have begun to reveal the connections between glucose metabolism and splicing programs. Unlike HK2 gene, which is expressed as a single transcript, there are several transcripts of the HK1 gene due to alternative splicing. However, the functional differential roles of HK1 isoforms in glucose metabolism and tumor progression are still elusive. Here, we show that primary NSCLC patient tumor cells metabolically differ from the normal lung epithelium where they display predominant expression of one of the HK1 transcripts, hexokinase1b (HK1b). We utilized CRISPR-Cas9 system to selectively target specific HK1b isoform in NSCLC and show that silencing HK1b in NSCLC cells inhibits tumorigenesis through diminishing glycolysis and proliferation. Our findings constitute the first demonstration of the first biochemical distinction between the HK1 splice variants. Finally, HK1b deletion sensitizes NSCLC cells to standard-of-care, cisplatin treatment, and the combination therapy synergistically increases both apoptotic cell death by cisplatin and autophagic cell death by increased formation of LC3-II associated autophagic vesicles and myelinoid bodies. Notably, loss of HK1b leads to cellular DNA damage, further combination with cisplatin therapy showed significantly increased levels of DNA damage. Importantly, we showed that glycolysis and cisplatin resistance can be restored by adding-back HK1b in HK1b knock-out cells. Our findings reveal that targeting HK1b isoform alone or in combination with cisplatin may represent a novel strategy for NSCLC patients.

Studies of gene-targeted mice identified the roles of the different pro-survival BCL-2 proteins during embryogenesis, but less is known about the roles of these proteins in adults, including in the response to cytotoxic stresses, such as treatment with anti-cancer agents. We investigated the role of BCL-XL in adult mice using a strategy where prior bone marrow transplantation allowed for loss of BCL-XL exclusively in non-hematopoietic tissues to prevent anemia caused by BCL-XL-deficiency in erythroid cells. Unexpectedly, the combination of total-body {gamma}-irradiation (TBI) and genetic loss of Bcl-x caused secondary anemia resulting from chronic renal failure due to apoptosis of renal tubular epithelium with secondary obstructive nephropathy. These findings identify a critical protective role of BCL-XL in the adult kidney and inform on the use of BCL-XL inhibitors in combinations with DNA damage-inducing drugs for cancer therapy. SummaryThe inducible loss of BCL-XL in all cells of adult mice causes primary anemia due to apoptosis of erythroid and megakaryocytic cell populations. In contrast {gamma}-radiation plus loss of BCL-XL in all cells except hematopoietic cells causes secondary anemia resulting from kidney damage.

The tumor microenvironment (TME) provides a niche for immune evasion and immunotherapy resistance, in part, by recruiting pro-tumor M2-like macrophages. In the present study, using heterospheroids consisting of cancer cells and macrophages, we identified TAM activators, which are compounds that reprogram M2-like tumor-associated macrophages (TAMs) toward the antitumor M1-like phenotype. THP-1- or human peripheral monocyte-derived macrophages were co-cultured with liver cancer cells in an ultra-low attachment dish to generate heterospheroids. Cell surface marker expression and macrophage infiltration into the heterospheroids were assessed by flow cytometry and fluorescence microscopy, respectively. Lipopolysaccharide (LPS) and interferon-{gamma} (IFN{gamma})-induced M1 marker expression was observed on the macrophages in the homospheroids; however, this induction was suppressed in heterospheroids. Microscopic imaging revealed that macrophage infiltration into the heterospheroids was decreased in the presence of LPS and IFN{gamma}, which prompted us to develop a high-content imaging screen. We identified two compounds [alprostadil (prostaglandin E1) and HX531] with TAM-activating activity. RNA-seq analysis revealed that HX531 modulated the immune and IFN response in cancer cells and cell division in macrophages. Moreover, alprostadil promoted the M1-like polarization of TAMs, increased tumor-infiltrating CD8+ T cells, and enhanced anti-PD-1 antibody therapeutic efficacy in a syngeneic mouse xenograft model. In conclusion, the heterospheroid culture recapitulates the immunosuppressive TME, which prevents the M1 polarization of TAMs. It provides a new platform for screening TAM activators and will enable the development of novel cancer immunotherapeutics when combined with high-content imaging analysis.

CD40, a member of the tumor necrosis factor (TNF) receptor superfamily, plays an important role not only in the immune system, but also in tumor progression. CD40 ligation reportedly promotes autophagy in immune cells. However, the effects of CD40 ligation on autophagy and its mechanism in solid tumor cells are still unclear. In this study, we find that CD40 ligation promotes autophagosome formation, and consequently promotes autophagic flux in cervical cancer cells. Mechanically, this effect relies on that ERK contributes to CD40 ligation-induced ATG13 upregulation by p53. Furthermore, we demonstrates that CD40 ligation-induced autophagy increases the radiosensitivity of cervical cancer cells. Taken together, our results provide new evidence for involvement of the CD40 pathway in autophagy and radiotherapy in cervical cancer cells.

Patients with breast cancer brain metastases (BCBM) exhibit dismal prognosis, largely due to the insufficient biological understanding of BCBM and the scarcity of therapeutics that can penetrate the blood-brain barrier. This study was focused on Rearranged during transfection (RET) receptor tyrosine kinase that has been implicated in tumorigenesis and metastatic progression of several solid tumor types including, non-small cell lung cancer (NSCLC), thyroid carcinomas, and luminal breast cancer subtypes. FDA-approved selective RET inhibitors, pralsetinib and selpercatinib, have demonstrated potent intracranial activity in brain metastases from NSCLC and thyroid cancer; however, their efficacy in BCBM has not been investigated. Here, we report that RET activation is elevated in brain metastases of breast cancer patients compared to matched primary tumors (N=30), and in three brain-tropic breast cancer cell lines compared to the parental lines. High RET pathway activation is associated with shorter overall metastasis-free survival and brain metastasis-free survival in patients with HER2-enriched and triple-negative breast cancer (TNBC). Using isogenic TNBC cells lines RET overexpression, we demonstrated that RET strongly promotes their preferential metastasis to the brain in mice with intracardiac injections to tumors cells. Using intracranial tumor implantation of the isogenic lines, we further found that RET significantly enhances the formation and progression of brain tumors in vivo. Moreover, we report that selective RET inhibition using pralsetinib and selpercatinib significantly reduces cell viability, enhances apoptosis, and attenuates migration of brain-tropic breast cancer cells in vitro. Using two mouse studies that model multi-organ metastases and breast tumor formation in the brain, we observed that RET inhibition significantly prevented the circulating tumor cells from forming brain metastases and suppressed the growth of intracranially implanted tumor cells, but did not significantly inhibit the progression of well-established brain metastases. Together, our findings demonstrated that RET is highly activated in BCBM and functioning as a novel mediator of BCBM, and that RET plays a new role as a viable therapeutic target for BCBM.

Despite the widespread deregulation of CDK4/6 activity in non-small cell lung cancer (NSCLC), the clinical trials with CDK4/6 inhibitors (CDK4/6is) as a monotherapy have shown poor antitumor activity. However, our preclinical studies have revealed a significant potential for CDK4/6is to collaborate by influencing DNA damage repair pathways during radiotherapy. Given the considerable upregulation of PARP1 expression in NSCLC, we analyzed the efficacy of combined PARP and CDK4/6 inhibition in NSCLC models. Our findings demonstrate that CDK4/6is synergize with PARP inhibitors (PARPis) to inhibit the clonogenic growth of RB-proficient NSCLC models. This synergy is associated with increased accumulation of DNA damage, interrupted cell-cycle checkpoints, and enhanced apoptotic cell death. We showed that CDK4/6is mechanically promote PARP1 protein degradation, leading to decreased availability of DNA repair factors involved in homologous recombination and suppression of DNA repair competency. Furthermore, we showed that PARP trapping is required for this synergy. We then confirmed that combining PARPi and CDK4/6i blocked the growth of NSCLC xenografts in vivo and patient-derived explant models ex vivo. These findings reveal a previously uncharacterized impact of CDK4/6i on PARP1 levels in RB-proficient NSCLC models and the requirement of PARP trapping to render synergy between CDK4/6i and PARPi. Our research suggests that combining CDK4/6i with PARPi could be a promising therapeutic strategy for patients with RB-proficient NSCLC, potentially opening up new and more effective avenues for treatment.

Leucine-rich repeat containing, G protein-coupled receptor 4, 5, and 6 (LGR4/5/6) are three homologous receptors that are co-expressed or alternately expressed at high levels in tumor cells of colorectal cancer (CRC) and high-risk neuroblastoma (NB). Simultaneous targeting of all three receptors may provide increased efficacy or overcome drug resistance due to tumor heterogeneity and cancer cell plasticity. LGR4/5/6 all bind to R-spondins (RSPOs) with high affinity and potentiate Wnt/{beta}-catenin signaling in response. Previously, we showed that a peptibody based on a mutant RSPO4 furin domain that bound to LGR4/5/6 without potentiating Wnt/{beta}-catenin signaling was able to deliver cytotoxins into cancer cells that express any of the three receptors. We have now generated a mutant RSPO2 furin domain that retains high affinity binding to LGR4/5/6 without signaling activity. Peptibodies based on this RSPO2 furin mutant were conjugated with either pyrrolobenzodiazepine dimer (PBD) or camptothecin derivative (CPT2), and the resulting peptibody-drug conjugates (PDCs) showed potent and specific cytotoxic activity in NB and CRC cell lines expressing any of LGR4/5/6 in vitro and robust anti-tumor activity in vivo. The results support the potential of RSPO2-based PDCs for the treatment of CRC, high-risk NB, and other cancers that express any of LGR4/5/6.

Head and neck squamous cell carcinoma (HNSCC) is an aggressive malignancy with high mortality rates, often exhibiting resistance to conventional treatments such as radiotherapy (RT) or a combination of chemotherapy and radiotherapy (CRT). The nerve growth factor receptor (NGFR, also known as p75NTR or CD271) is a well-established cancer stem cell marker in melanoma, where it has been linked to resistance to multiple therapies. In HNSCC, NGFR has been reported as a poor prognostic marker, with its overexpression associated with disease progression. However, its contribution to therapy resistance in HNSCC remains unknown. Here, we show in a cohort of RT/CRT-treated patients that NGFR expression identifies individuals with poor prognosis and increased risk of recurrence following standard RT/CRT. Moreover, we found that NGFR is upregulated in the human Detroit 562 cisplatin (CDDP)-resistant HNSCC cell line in vitro and in vivo. Functional studies demonstrated that genetic knock out of NGFR in these cisplatin-resistant cells restored sensitivity to CDDP in vivo. These results indicate that NGFR contributes to cisplatin resistance in HNSCC. NGFR is upregulated in tumors from patients with poorer prognosis and an increased risk of recurrence after standard radiotherapy and/or RT/CRT, as well as in cisplatin-resistant models. Altogether, our findings open the way to consider NGFR as a new potential therapeutic target to overcome or mitigate cisplatin resistance in HNSCC.

IntroductionBased on our earlier finding that cell-free chromatin particles (cfChPs) released from dying cancer cells are potentially oncogenic, we hypothesised that metastases arise as new cancers from the cells of target organs transformed by cfChPs released from dying cancer cells. MethodsWe fluorescently dually-labelled MDA-MB-231 human breast cancer cells and A-375 human melanoma cells in their DNA with BrdU and in their histones with CellLight(R) Histone 2BGFP. One hundred thousand dually-labelled cells were intravenously injected into SCID mice. In other experiments unlabelled cells were injected for detection of lung metastasis. Also intravenously injected were 700 ng of purified cfChPs isolated from radiation-killed MDA-MB-231 cells. ResultsWe observed that the fluorescently dually-labelled MDA-MB-231 and A-375 cells died upon reaching the lungs and released dually-labelled fluorescent chromatin particles that accumulated in the nuclei of lung cells at 48 h. Injection of unlabelled cfChPs led to the activation of 10 hallmarks of cancer and immune checkpoints in lung cells at 72 h, suggesting that the lung cells had rapidly transformed into incipient cancer cells. Fluorescent in situ hybridisation analysis of lung metastases that subsequently developed using mouse and human specific DNA probes revealed that the tumour cells contained both mouse and human DNA in almost equal proportions. Similarly, immune-fluorescence analysis using species specific mAbs revealed that the tumour cells co-expressed mouse and human specific proteins. Metaphase preparations and single-cell clones developed from cell cultures of lung metastases were found to contain chimeric chromosomes containing both mouse and human DNA, and the cells to co-express both human- and mouse-specific proteins. The Intravenously injected purified cfChPs isolated from radiation-killed MDA-MB-231 cells also induced lung metastasis which predominantly contained mouse DNA strongly suggesting that the metastatic tumours had arisen from the mouse lung cells. ConclusionThese results provide strong evidence that cfChPs released from dying cancer cells integrate into genomes of target lung cells to transform them into new cancers that masquerade as metastasis. They support our hypothesis that metastases arise from the cells of target organs and not from those of the primary tumour. These findings have implications for the principles of cancer therapy.

Radiotherapy is a commonly used cancer treatment; however, patients with high serum squamous cell carcinoma antigen (SCCA1/SERPINB3) are associated with resistance and poor prognosis. Despite being a strong clinical biomarker, the modulation of SERPINB3 in tumor immunity is poorly understood. We investigated the microenvironment of SERPINB3 high tumors through RNAseq of primary cervix tumors and found that SERPINB3 was positively correlated with CXCL1/8, S100A8/A9 and myeloid cell infiltration. Induction of SERPINB3 in vitro resulted in increased CXCL1/8 and S100A8/A9 production, and supernatants from SERPINB3-expressing cultures attracted monocytes and MDSCs. In murine tumors, the orthologue mSerpinB3a promoted MDSC, TAM, and M2 macrophage infiltration contributing to an immunosuppressive phenotype, which was further augmented upon radiation. Radiation-enhanced T cell response was muted in SERPINB3 tumors, whereas Treg expansion was observed. A STAT-dependent mechanism was implicated, whereby inhibiting STAT signaling with ruxolitinib abrogated suppressive chemokine production. Patients with elevated pre-treatment serum SCCA and high pSTAT3 had increased intratumoral CD11b+ myeloid cell compared to patients with low SCCA and pSTAT3 cohort that had overall improved cancer specific survival after radiotherapy. These findings provide a preclinical rationale for targeting STAT signaling in tumors with high SERPINB3 to counteract the immunosuppressive microenvironment and improve response to radiation.

Cancer cells acquire stem cell and mesenchymal properties during epithelial-to-mesenchymal transition (EMT), facilitating metastasis and chemoresistance [1-6]. In this study, we find that mammary epithelial cells quickly develop mesenchymal phenotype in response to EMT-inducing signals; however, acquiring stemness takes several days and always requires a preceding mesenchymal program. In addition, we observe that carcinoma cells, over a period of time, switch their cell division from symmetrical differentiated type to symmetrical self-renewal type. Importantly, epithelial cells can gain mesenchymal properties without undergoing cell division, but cell disivion is vital for these cells to gain stem cell properties during EMT. The EMT-induced stemness signature (SC-sig) is capable of predicting progression-free and overall-survival of breast cancer patients but not the EMT-induced mesenchymal signature (M-sig). Collectively, our findings demonstrate that the use of mesenchymal markers alone is insufficient to identify tumors with metastatic and chemoresistance potential and emphasize that the markers of EMT-induced stem cell program are central for clinical prediction. Most importantly, our data, for the first time, demonstrate that acquisition of stem cell properties during EMT depends on cell division but not the mesenchymal program.

Effective treatment for Pancreatic Cancer remains a major challenge due to its resistance to radiation/chemotherapy and poor drug permeability. Moreover, treatment induced normal tissue toxicity, mainly to the duodenum and gastrointestinal epithelium, is common and is a dose limiting event, while toxicity to the pancreas is relatively rare1-3. Gastrointestinal toxicity, however, often results in interruption, reduction or premature withdrawal of anti-cancer therapy which is a very significant factor impacting the overall survival of patients being treated. Therefore, development of a therapeutic strategy to selectively sensitize tumor tissue without inducing normal tissue toxicity is important. In this manuscript, we show that the novel small molecule BCN057 can modulate chemo-sensitivity of oncogenic RAS pancreatic cancer cells while conversely protecting normal intestinal epithelium from off target toxicity. In particular, BCN 057 protects Lgr5 positive intestinal stem cells, thereby preserving barrier function. Further, it is demonstrated that BCN057 inhibits GSK3{beta} and thereby induces a pro-apoptotic phosphorylation pattern on c-Jun in KRAS G12D mutant pancreatic cancer cells (Panc-1) leading to the restoration of PTEN expression and consequent apoptosis. This appears to be a new mechanistic observation for the oncogenic RAS phenotype. Lastly, concurrent with its GSK3{beta} inhibition, BCN057 is a small molecule inhibitor of PD-1 expression on human T-lymphocytes co-cultured with human pancreatic cancer cells. In summary, BCN057 can promote synthetic lethality specifically to malignant cells and therefore should be considered to improve the therapeutic ratio in pancreatic and epithelial cancer treatment in conjunction with chemotherapy and radiation.

The cellular programs that mediate therapy resistance are often important drivers of metastasis, a phenomenon that needs to be understood better to improve screening and treatment options for cancer patients. Although this issue has been studied extensively for chemotherapy, less is known about a causal link between resistance to radiation therapy and metastasis. We investigated this problem in triple-negative breast cancer (TNBC) and established that radiation resistant tumor cells have enhanced metastatic capacity, especially to bone. Resistance to radiation increases the expression of integrin {beta}3 (ITG{beta}3), which promotes enhanced migration and invasion. Bioinformatic analysis and subsequent experimentation revealed an enrichment of RNA metabolism pathways that stabilize ITG{beta}3 transcripts. Specifically, the RNA binding protein heterogenous nuclear ribonucleoprotein L (HNRNPL), whose expression is regulated by Nrf2, mediates the formation of circular RNAs (circRNAs) that function as competing endogenous RNAs (ceRNAs) for the family of let-7 microRNAs that target ITG{beta}3. Collectively, our findings identify a novel mechanism of radiation-induced metastasis that is driven by alterations in RNA metabolism.

BackgroundGlioblastoma (GBM) is an aggressive, therapy-resistant brain tumor with limited treatment options. Epidermal growth factor receptor (EGFR) is frequently amplified and activated in GBM, driving tumorigenesis through pro-oncogenic signaling and coordination of nuclear DNA repair. This study examines the anti-GBM efficacy and mechanism of ZYH005 (Z5), a brain-penetrant DNA intercalator exhibiting low systemic toxicity. MethodsAntitumor efficacy of Z5 was determined with GBM cell lines and patient-derived glioblastoma stem cells (GSCs) in vitro and in vivo. Target identification and mechanistic validation were performed using DNA microarray, surface plasmon resonance, immunoblot and siRNA silencing. The EGFR-WEE1 correlation was analyzed via public databases and confirmed by coimmunoprecipitation. ResultsZ5 significantly inhibits the proliferation of GBM cell lines and patient-derived GSCs, effectively suppresses tumor growth in orthotopic GSC-induced mouse models, prolongs survival, and shows no obvious toxicity. Mechanistically, Z5 exerts potent anti-GBM activity through a dual mechanism: DNA intercalation-induced damage and targeted inhibition of EGFR. By specifically inhibiting EGFR at E762, Z5 not only enhances DNA damage by suppressing the DNA damage response in the nucleus but also disrupts the interaction between nuclear EGFR and WEE1, leading to impaired WEE1/CDC2 signaling and G2/M checkpoint failure. Extranuclearly, Z5 further enhances its anti-GBM efficacy by inhibiting the canonical EGFR downstream pathways, mTOR and ERK. Together, these molecular events promote cell cycle arrest and mitotic catastrophe in GBM cells. ConclusionZ5 emerges as a promising brain-penetrant clinical candidate for treating GBM. It acts through a dual mechanism that synergistically targets both DNA and EGFR, inducing mitotic catastrophe while demonstrating a favorable safety profile. These compelling findings provide a strong rationale for advancing Z5 toward clinical translation, offering a novel therapeutic strategy for GBM patients.

Patients with triple-negative breast cancer (TNBC) experience high recurrence rates despite current interventions, which includes radiation therapy (RT). Tumor cells thought to be involved in recurrence survive in part due to their interactions with irradiated fibroblasts following treatment. How fibroblasts metabolically respond to RT and influence the behavior of TNBC cells is poorly understood. In this study, we demonstrate that irradiated fibroblasts undergo a mitochondrial stress response that is regulated by autophagy, resulting in a metabolic profile characterized by high levels of mitochondrial respiration and fatty acid oxidation. This stress response in fibroblasts induces an aggressive phenotype in TNBC cells that is mitigated when fibroblast autophagy is blocked. Our work reveals how a metabolic stress response in irradiated fibroblasts and crosstalk with TNBC cells leads to a microenvironment conducive to recurrence. Graphical Abstract O_FIG O_LINKSMALLFIG WIDTH=200 HEIGHT=140 SRC="FIGDIR/small/492249v3_ufig1.gif" ALT="Figure 1"> View larger version (39K): org.highwire.dtl.DTLVardef@181680aorg.highwire.dtl.DTLVardef@d58a1forg.highwire.dtl.DTLVardef@15f04eforg.highwire.dtl.DTLVardef@13cf5f9_HPS_FORMAT_FIGEXP M_FIG C_FIG

We present the results of a randomized, open-label pilot study investigating the combination of oral vancomycin and stereotactic body radiotherapy (SBRT) in early-stage non-small cell lung cancer (NSCLC). Our findings highlight vancomycins safety, evidenced by the absence of Grade 3 or 4 adverse events, and its potential to enhance the antitumor efficacy of SBRT. The observed enhancement is linked to vancomycins modulation of the gut microbiota, which triggers significant metabolic changes and immune activation, thereby contributing to improved progression-free survival (PFS) and overall survival (OS). Patients received vancomycin (125 mg, four times daily for five weeks, starting one week prior to SBRT), which induced restructuring of the gut microbiome and significant changes in the gut metabolome. Key changes included reductions in short-chain fatty acids (SCFAs) and shifts in other immunomodulatory metabolites. These metabolic shifts were associated with the activation of dendritic cells and T cells, creating a pro-inflammatory environment conducive to strengthening SBRTs antitumor efficacy. The combination of vancomycin and SBRT presents a novel, low-toxicity therapeutic approach for early-stage NSCLC, showing promising initial outcomes. While the results are encouraging, further research with larger cohorts is necessary to verify these findings and elucidate the underlying mechanisms that contribute to the observed clinical benefits. WHAT IS ALREADY KNOWN ON THIS TOPICRadiation therapy is a primary treatment for early-stage non-small cell lung cancer and offers excellent local control in early-stage NSCLC, the challenges of regional and distant failures which occur in up to 50% of patients, lead to increased morbidity and mortality. The gut microbiome is increasingly recognized in cancer immunotherapy. RT can induce Immunogenic Cell Death, activating the immune system and promoting abscopal effect to impact untreated lesions. Our previous preclinical studies have shown that antibiotics like vancomycin can modulate these immune effects and enhance RTs antitumor activity. WHAT THIS STUDY ADDSThis clinical study corroborates our previous preclinical findings by demonstrating the safety of vancomycin and its potential to enhance the antitumor effects of RT, despite the small cohort size. These findings suggest that vancomycin could be strategically used to improve RT outcomes. HOW THIS STUDY MIGHT AFFECT RESEARCH, PRACTICE OR POLICYOur findings prompt further investigation into this combined treatment in a larger patient cohort to confirm enhanced progression-free survival and overall survival. Exploring the impact on distal recurrences and applying this strategy to more advanced patient stages could significantly influence future research directions and clinical practices. This approach may also guide policy towards integrating microbiome modulation strategies in standard cancer treatment protocols.

Vitamin-D receptor (VDR) mRNA is enriched in malignant lung, ovarian and pancreatic tissues and showed poor prognoses. Calcitriol and stable or CRISPR-directed VDR upregulation increased PD-L1mRNA and protein expression in cancer cells in-vitro. A ChIP assay showed the binding of VDR with VDREPD-L1. Stattic, a STAT3 phosphorylation inhibitor blocked calcitriol or VDR overexpression induced PD-L1 upregulation. MeTC7, a VDR antagonist developed by us, reduced PD-L1 expression on macrophages, ovarian, lung, breast, and pancreatic cancer cells in-vitro. In radiotherapy inducible PD-L1 model of orthotopic MC38 murine colon cancer, MeTC7 decreased PD-L1 surface expression, suppressed inflammatory monocytes (IMs) population and increased intra-tumoral CD69+PD1+CD8+T-cells. Intriguingly, MeTC7 reduced TH-MYCN transgenic neuroblastoma tumor growth without affecting PD-L1 and tumor immune milieu. In summary, Vitamin-D/VDR drives PD-L1 expression on cancer cells via STAT-3. Inhibiting VDR exhibited anti-checkpoint effects in orthotopic colon tumors, whereas PDL1-independent and anti-VDR/MYCN effects controlled growth of transgenic neuroblastoma and xenografted tumors. SummaryVitamin-D/VDR induces PD-L1 expression on cancer cells via STAT-3; and targeting VDR by a novel small molecule antagonist MeTC7 exhibits both anti-PD-L1 and anti-VDR/MYCN effects in tumor models.

Epidermal growth factor receptor (EGFR) tyrosine kinase inhibitors (TKIs) have provided successful targeted therapies for patients with EGFR-mutant non-small-cell lung cancer (NSCLC). Osimertinib (AZD9291) is a third-generation irreversible EGFR TKI that has received regulatory approval for overcoming resistance mediated by the EGFR T790M mutation as well as a first-line treatment targeting EGFR activating mutations. However, a significant fraction of patients cannot tolerate the adverse effect associated with AZD9291. In addition, brain metastases are common in patients with NSCLN and remain a major clinical challenge. Here, we report the development of a novel third-generation EGFR TKI, CM93. Compared to AZD9291, CM93 exhibits improved lung cancer targeting and brain penetration and has demonstrated promising antitumor efficacy in mouse models of both EGFR-mutant NSCLC orthotopic and brain metastases. In addition, we find that CM93 confers superior safety benefits in mice. Our results demonstrate that further evaluations of CM93 in clinical studies for patients with EGFR-mutant NSCLC and brain metastases are warranted.