Hypoxia-Triggered Bioreduction of Poly(N-oxide)-Drug Conjugates Enhances Tumor Penetration and Antitumor Efficacy.

PEGylation prolongs the blood circulation time of drugs; however, it simultaneously reduces the tumor penetration of drugs due to the nonfouling function and bulky hydrodynamic volume of PEG, leading to unsatisfactory outcomes in the treatment of solid tumors. Herein, we report the in situ growth of a bioreducible polymer of poly(N-oxide) from an important protein drug of interferon alpha (IFN) to generate site-specific IFN-poly(N-oxide) conjugates with higher bioactivity than a clinically used PEGylated IFN of PEGASYS. An IFN-poly(N-oxide) conjugate is screened out to have a circulating half-life as long as 51 h, which is similar to that of PEGASYS but 96-fold greater than that of IFN. However, the conjugate greatly outperforms PEGASYS and IFN in tumor penetration and antitumor efficacy in mice bearing melanoma. This enhanced tumor penetration is ascribed to the adsorption-mediated transcytosis of the conjugate whose poly(N-oxide) is biologically reduced into poly(tertiary amine), under hypoxia, which can be further protonated in the acidic tumor microenvironment. These novel findings demonstrate that poly(N-oxide)s are not only long-circulating but also bioreducible under hypoxia and are of great promise as next-generation carriers to deliver drugs into the interior of solid tumors to enhance their antitumor efficacy.

MiR-770 promotes oral squamous cell carcinoma migration and invasion by regulating the Sirt7/Smad4 pathway.

Oral squamous cell carcinoma (OSCC) is a common malignant cancer with unfavorable prognosis, and the epithelial-to-mesenchymal transition (EMT) is a critical contributor to OSCC metastasis. Recently, we have shown that sirtuin 7 (Sirt7) is associated with EMT and OSCC metastasis by acetylating small mother against decapentaplegic 4 (Smad4). Nonetheless, the mechanism of Sirt7 downregulation in OSCC cells remains unknown. This study analyzed the potential microRNAs that were predicted to regulate Sirt7 expression by online databases. We identified miR-770 as an upstream regulator of Sirt7 that targets its 3'-untranslated region. The expression of miR-770 was observed to be negatively correlated with the mRNA expression of Sirt7 in metastatic OSCC tumors, and higher miR-770 expression was correlated with poorer OSCC patient survival. Our in vitro data indicated that miR-770 promoted OSCC cell migration and invasion, and this process was dependent on Sirt7/Smad4 signaling. Furthermore, in vivo metastasis experiments indicated that miR-770 overexpression led to more prominent OSCC metastasis and downregulated Sirt7 expression. Collectively, our results revealed a new role of Sirt7 downregulation in metastatic OSCC and suggested that miR-770 is a potential target in counteracting OSCC metastasis.

Thermoresponsive Polypeptide Fused L-Asparaginase with Mitigated Immunogenicity and Enhanced Efficacy in Treating Hematologic Malignancies.

L-Asparaginase (ASP) is well-known for its excellent efficacy in treating hematological malignancies. Unfortunately, the intrinsic shortcomings of ASP, namely high immunogenicity, severe toxicity, short half-life, and poor stability, restrict its clinical usage. Poly(ethylene glycol) conjugation (PEGylation) of ASP is an effective strategy to address these issues, but it is not ideal in clinical applications due to complex chemical synthesis procedures, reduced ASP activity after conjugation, and pre-existing anti-PEG antibodies in humans. Herein, the authors genetically engineered an elastin-like polypeptide (ELP)-fused ASP (ASP-ELP), a core-shell structured tetramer predicted by AlphaFold2, to overcome the limitations of ASP and PEG-ASP. Notably, the unique thermosensitivity of ASP-ELP enables the in situ formation of a sustained-release depot post-injection with zero-order release kinetics over a long time. The in vitro and in vivo studies reveal that ASP-ELP possesses increased activity retention, improved stability, extended half-life, mitigated immunogenicity, reduced toxicity, and enhanced efficacy compared to ASP and PEG-ASP. Indeed, ASP-ELP treatment in leukemia or lymphoma mouse models of cell line-derived xenograft (CDX) shows potent anti-cancer effects with significantly prolonged survival. The findings also indicate that artificial intelligence (AI)-assisted genetic engineering is instructive in designing protein-polypeptide conjugates and may pave the way to develop next-generation biologics to enhance cancer treatment.

HOXC13-AS accelerates cell proliferation and migration in oral squamous cell carcinoma via miR-378g/HOXC13 axis.

Oral squamous cell carcinoma (OSCC) is an aggressive cancer type in head and neck. A number of long non-coding RNAs (lncRNAs) are discovered to serve regulatory roles in OSCC. HOXC13 antisense RNA (HOXC13-AS) has been proved to behave as a tumor-facilitator in nasopharyngeal carcinoma, but its regulatory role in OSCC has never been investigated. In this study, GEPIA indicated that HOXC13-AS and its neighbor gene HOXC13 were upregulated in HNSC samples, and we consistently unveiled their upregulation in OSCC tissues and cell lines. Silencing HOXC13-AS abrogated OSCC cell proliferation, migration, and epithelial-to-mesenchymal transition (EMT). Moreover, HOXC13 overexpression rescued the influences of HOXC13-AS silence on OSCC cellular processes and in vivo tumor growth. Mechanistically, HOXC13-AS upregulated HOXC13 expression in OSCC through sequestering miR-378g, which was proved to exert suppressive functions in the malignant behaviors of OSCC cells. Further, HOXC13 was revealed to be positively correlated with HOXC13-AS and negatively with miR-378g in expression in OSCC samples. In sum, our findings suggested that HOXC13-AS functioned as a ceRNA to accelerate the malignant behaviors of OSCC cells via miR-378g/HOXC13 axis, shedding a new light on the lncRNA-targeted treatment for OSCC.

Assessment of Quality of Life of Free Anterolateral Thigh Flap for Reconstruction of Tissue Defects of Total or Near-Total Glossectomy.

BACKGROUND: The aim of this study was to evaluate quality of life of free anterolateral thigh flap (ALTFF) for reconstruction of tissue defects of total or near-total glossectomy. METHODS: Quality of life was assessed by means of the University of Washington Quality of Life (UW-QOL) and the 14-item Oral Health Impact Profile (OHIP-14), after 12 months postoperatively. RESULTS: 65 of 79 questionnaires were returned (82.27%). In the UW-QOL, the best-scoring domain was "shoulder," whereas the lowest scores were for "chewing" and "pain." In the OHIP-14, the lowest-scoring domain was "handicap," followed by "Social disability" and "Psychological disability." CONCLUSION: Free anterolateral thigh perforator flaps for reconstruction of total or near-total glossectomy defects after cancer resection would have significantly influenced the patients' oral functions and quality of life.

[Finite-element analysis of mandibular first molar with two marginal designs of endocrown for the repair of different defects].

OBJECTIVE: This study aimed to evaluate the stress distribution of the mandibular first molar with different thicknesses and heights of the axial wall restored by the endocrown with two marginal designs and thus provide a theoretical basis for selecting clinical preparation through the finite-element method. METHODS: Two marginal endocrowns of the mandibular first molar with different axial-wall thicknesses (t=1, 2, 3 mm) and heights (h=2, 3, 4 mm) were established. Group A was the butt-joint design, whereas group B was the shoulder-surrounded design. After applying vertical and oblique loads , the size and distribution of the maximum principal stress and equivalent stress of residual tooth tissue were recorded. RESULTS: The maximum principal stress and equivalent stress distribution of residual tooth tissue were similar among different models. Group A showed a lower maximum principal stress and equivalent stress than group B at the same thickness and height under vertical load. Meanwhile, under oblique load, the maximum principal stress values of groups A and B decreased with increased thickness at constant height. Group A showed lower equivalent stress than group B at the same thickness and height of 2 and 3 mm. However, when the height was 4 mm, the trend was reversed. CONCLUSIONS: In mastication, when bearing the vertical force, the retention of the butt-joint marginal endocrown preferred to the shoulder-surrounded one. Given the higher axial wall of the shoulder-surrounded marginal endocrown, it showed better ability to bear the oblique force than the butt-joint one.

An ultra-long-acting L-asparaginase synergizes with an immune checkpoint inhibitor in starvation-immunotherapy of metastatic solid tumors.

Metastasis stands as the primary contributor to mortality associated with tumors. Chemotherapy and immunotherapy are frequently utilized in the management of metastatic solid tumors. Nevertheless, these therapeutic modalities are linked to serious adverse effects and limited effectiveness in preventing metastasis. Here, we report a novel therapeutic strategy named starvation-immunotherapy, wherein an immune checkpoint inhibitor is combined with an ultra-long-acting L-asparaginase that is a fusion protein comprising L-asparaginase (ASNase) and an elastin-like polypeptide (ELP), termed ASNase-ELP. ASNase-ELP's thermosensitivity enables it to generate an in-situ depot following an intratumoral injection, yielding increased dose tolerance, improved pharmacokinetics, sustained release, optimized biodistribution, and augmented tumor retention compared to free ASNase. As a result, in murine models of oral cancer, melanoma, and cervical cancer, the antitumor efficacy of ASNase-ELP by selectively and sustainably depleting L-asparagine essential for tumor cell survival was substantially superior to that of ASNase or Cisplatin, a first-line anti-solid tumor medicine, without any observable adverse effects. Furthermore, the combination of ASNase-ELP and an immune checkpoint inhibitor was more effective than either therapy alone in impeding melanoma metastasis. Overall, the synergistic strategy of starvation-immunotherapy holds excellent promise in reshaping the therapeutic landscape of refractory metastatic tumors and offering a new alternative for next-generation oncology treatments.