Highly potent monomethyl auristatin E prodrug activated by caspase-3 for the chemoradiotherapy of triple-negative breast cancer

Strategies for the development of stimuli-responsive small molecule prodrugs for cancer treatment

Approved anticancer drugs typically face challenges due to their narrow therapeutic window, primarily because of high systemic toxicity and limited selectivity for tumors. Prodrugs are initially inactive drug molecules designed to undergo specific chemical modifications. These modifications render the drugs inactive until they encounter specific conditions or biomarkers in vivo, at which point they are converted into active drug molecules. This thoughtful design significantly improves the efficacy of anticancer drug delivery by enhancing tumor specificity and minimizing off-target effects. Recent advancements in prodrug design have focused on integrating these strategies with delivery systems like liposomes, micelles, and polymerosomes to further improve targeting and reduce side effects. This review outlines strategies for designing stimuli-responsive small molecule prodrugs focused on cancer treatment, emphasizing their chemical structures and the mechanisms controlling drug release. By providing a comprehensive overview, we aim to highlight the potential of these innovative approaches to revolutionize cancer therapy.

A polymeric nanocarrier that eradicates breast cancer stem cells and delivers chemotherapeutic drugs

BACKGROUND

Drug nanocarriers can markedly reduce the toxicities and side effects of encapsulated chemotherapeutic drugs in the clinic. However, these drug nanocarriers have little effect on eradicating breast cancer stem cells (BCSCs). Although compounds that can inhibit BCSCs have been reported, these compounds are difficult to use as carriers for the widespread delivery of conventional chemotherapeutic drugs.

METHODS

Herein, we synthesize a polymeric nanocarrier, hyaluronic acid-block-poly (curcumin-dithiodipropionic acid) (HA-b-PCDA), and explore the use of HA-b-PCDA to simultaneously deliver chemotherapeutic drugs and eradicate BCSCs.

RESULTS

Based on molecular docking and molecular dynamics studies, HA-b-PCDA delivers 35 clinical chemotherapeutic drugs. To further verify the drug deliver ability of HA-b-PCDA, doxorubicin, paclitaxel, docetaxel, gemcitabine and camptothecin are employed as model drugs to prepare nanoparticles. These drug-loaded HA-b-PCDA nanoparticles significantly inhibit the proliferation and stemness of BCSC-enriched 4T1 mammospheres. Moreover, doxorubicin-loaded HA-b-PCDA nanoparticles efficiently inhibit tumor growth and eradicate approximately 95% of BCSCs fraction in vivo. Finally, HA-b-PCDA eradicates BCSCs by activating Hippo and inhibiting the JAK2/STAT3 pathway.

CONCLUSION

HA-b-PCDA is a polymeric nanocarrier that eradicates BCSCs and potentially delivers numerous clinical chemotherapeutic drugs.

A Versatile Platform to Generate Prodrugs with Rapid and Precise Albumin Hitchhiking and High Cargo Loading for Tumor-Targeted Chemotherapy

Due to its tumor homing and long serum half-life, albumin is an ideal drug carrier for chemotherapy. For endogenous albumin hitchhiking with high cargo loading, a trimeric albumin-binding domain (ABD), i.e., ABD-Tri is designed by fusing an ABD with high specificity and affinity for albumin to a self-trimerizing domain (Tri) with an additional cysteine residue. ABD-Tri is highly (40 mg L-1 ) expressed as soluble and trimeric proteins in Escherichia coli (E. coli). Once mixed together, ABD-Tri rapidly and specifically forms a stable complex with albumin under physiological conditions without obviously changing its receptor- and cell-binding and tumor-homing properties. Maleimide-modified prodrugs are highly effectively conjugated to ABD-Tri to produce homogenous ABD-Tri-prodrugs with triple cargo loading under physiological conditions by thiol-maleimide click chemistry. Unlike the maleimide moiety, which can only mediate time- and concentration-dependent albumin binding, ABD-Tri mediated fast (within several minutes) albumin binding of drugs even at extremely low concentrations (µg mL-1 ). Compared to maleimide-modified prodrugs, ABD-Tri-prodrugs exhibit better tumor homing and greater in vivo antitumor effect, indicating that conjugation of chemical drug to ABD-Tri outperforms maleimide modification for endogenous albumin hitchhiking. The results demonstrate that ABD-Tri may serve as a novel platform to produce albumin-binding prodrugs with high cargo-loading capacity for tumor-targeted chemotherapy.

X-Ray-Induced Drug Release for Cancer Therapy

Drug delivery systems (DDSs) are designed to deliver therapeutic agents to specific target sites while minimizing systemic toxicity. Recent developments in drug-loaded DDSs have demonstrated promising characteristics and paved new pathways for cancer treatment. Light, a prevalent external stimulus, is widely utilized to trigger drug release. However, conventional light sources primarily concentrate on the ultraviolet (UV) and visible light regions, which suffer from limited biological tissue penetration. This limitation hinders applications for deep-tissue tumor drug release. Given their deep tissue penetration and well-established application technology, X-rays have recently received attention for the pursuit of controlled drug release. With precise spatiotemporal and dosage controllability, X-rays stand as an ideal stimulus for achieving controlled drug release in deep-tissue cancer therapy. This article explores the recent advancements in using X-rays for stimulus-triggered drug release in DDSs and delves into their action mechanisms.

Current research status of anti-cancer peptides: Mechanism of action, production, and clinical applications

The escalating rate of cancer cases, together with treatment deficiencies and long-term side effects of currently used cancer drugs, has made this disease a global burden of the 21st century. The number of breast and lung cancer patients has sharply increased worldwide in the last few years. Presently, surgical treatment, radiotherapy, chemotherapy, and immunotherapy strategies are used to cure cancer, which cause severe side effects, toxicities, and drug resistance. In recent years, anti-cancer peptides have become an eminent therapeutic strategy for cancer treatment due to their high specificity and fewer side effects and toxicity. This review presents an updated overview of different anti-cancer peptides, their mechanisms of action and current production strategies employed for their manufacture. In addition, approved and under clinical trials anti-cancer peptides and their applications have been discussed. This review provides updated information on therapeutic anti-cancer peptides that hold great promise for cancer treatment in the near future.

A self-cascaded unimolecular prodrug for pH-responsive chemotherapy and tumor-detained photodynamic-immunotherapy of triple-negative breast cancer

Despite the success of immune checkpoint blockade (ICB) therapy in cancer management, ICB-based immunotherapy of triple-negative breast cancer (TNBC) still suffers from immunosuppressive tumor microenvironment (ITM). To break through the bottleneck of TNBC immunotherapy, a self-cascaded unimolecular prodrug consisting of an acidic pH-activatable doxorubicin and an aggregation-induced emission luminogen (AIEgen) photosensitizer coupled to a caspase-3-responsive peptide was engineered. The generated prodrug, could not only release doxorubicin initiatively in acidic tumor microenvironment, but also activate apoptosis-related caspase-3. The activated caspase-3 could in turn trigger release and in situ aggregation of photosensitizers. Importantly, the unimolecular prodrug exhibits a renal clearance pathway similar to small molecules in vivo, while the aggregated AIEgens prolong tumor retention for long-term fluorescence imaging and repeatable photodynamic therapy (PDT) by only one single-dose injection. Furthermore, the tumor-detained PDT boosts both immunogenic cell death of TNBC cells and maturation of dendritic cells. Finally, the combination of repeatable PDT with ICB therapy further promotes the proliferation and intratumoral infiltration of cytotoxic T lymphocytes, and effectively suppresses tumor growth and pulmonary metastasis. This prodrug is a proof-of-concept that confirms the first self-cascaded chemo-PDT strategy to reverse the ITM and boost the ICB-mediated TNBC immunotherapy.

Emerging Strategies in Stimuli-Responsive Prodrug Nanosystems for Cancer Therapy

Prodrugs are chemically modified drug molecules that are inactive before administration. After administration, they are converted in situ to parent drugs and induce the mechanism of action. The development of prodrugs has upgraded conventional drug treatments in terms of bioavailability, targeting, and reduced side effects. Especially in cancer therapy, the application of prodrugs has achieved substantial therapeutic effects. From serendipitous discovery in the early stage to functional design with pertinence nowadays, the importance of prodrugs in drug design is self-evident. At present, studying stimuli-responsive activation mechanisms, regulating the stimuli intensity in vivo, and designing nanoscale prodrug formulations are the major strategies to promote the development of prodrugs. In this review, we provide an outlook of recent cutting-edge studies on stimuli-responsive prodrug nanosystems from these three aspects. We also discuss prospects and challenges in the future development of such prodrugs.

Feedback amplification of senolysis using caspase-3-cleavable peptide-doxorubicin conjugate and 2DG

Therapy-induced senescence (TIS), a common outcome of current cancer therapy, is a known cause of late recurrence and metastasis and thus its eradication is crucial for therapy success. In this study, we introduced a conceptually novel strategy combining radiation-induced apoptosis-targeted chemotherapy (RIATC) with an effective glycolysis inhibitor, 2-deoxy-d-glucose (2DG) to target TIS. RIATC releases cytotoxic payload by amplification, continually increasing TIS, and this can be targeted by 2DG that stimulates an intrinsic apoptotic pathway in senescent cells, the senolysis; the senolytic 2DG also sensitizes cancer cells to chemo/radiation treatment. Anti-tumor efficacy of RIATC was investigated in numerous tumor models, and various cancer types were screened for TIS. Furthermore, in vitro evaluations of molecular markers of senescence, such as senescence-associated β-galactosidase (SA-β-Gal) assay, were performed to confirm that TIS was induced by RIATC therapy in MCF-7 cells. The combination therapy with 2DG proved to be effective in MCF-7 tumor-bearing mice that demonstrated feedback amplification of senolysis and successful inhibition of tumor growth. Our findings suggest that RIATC, when given together with 2DG, can overcome therapy-induced senescence and this combination is a promising strategy that enhances the therapeutic benefit of anti-cancer cytotoxic therapy.

Caspase-3 mediated switch therapy of self-triggered and long-acting prodrugs for metastatic TNBC

Triple-negative breast cancer (TNBC) is characterized by its highly heterogeneous microenvironment and propensity for aggressive behavior, both of which represent, along with poor prognosis and high incidence of relapse, the main challenges of curing the disease. Although recent progress in targeted chemotherapy combinations has shown promising outcomes, conventional targeted chemotherapeutic approaches have relied on exploiting the expression of certain molecules or proteins overexpressed on cancer cells as drug targets, which have demonstrated limited clinical benefit against metastatic cancers. Here, we describe a tumoral caspase-3 mediated peptide-doxorubicin conjugates (PDC) switch therapy that adopts two different caspase-3 cleavable PDCs, RGDEVD-DOX (TPD1) and EMC-KGDEVD-DOX (MPD1), for targeting metastatic triple-negative breast cancer (mTNBC). First, using TPD1, an integrin αVβ₃ based targeted strategy was utilized to target tumor cells or tumor vasculature associated with the highly malignant progression of mTNBC. TPD1 triggered the tumor cell-specific initial apoptosis and the induction of caspase-3 expression in the target tumor site. Then MPD1 was administered sequentially, which is an albumin-binding prodrug, and activated by induced caspase-3 in order to maintain the tumoral caspase-3 level and release the cytotoxic payload. The PDC switch therapy markedly accumulated doxorubicin in the tumor site and augmented tumor-specific in situ amplification of apoptosis. Importantly, the PDC switch therapy exerted a bystander killing effect on the neighboring cancer cells thus demonstrating potent therapeutic efficacy against both local and metastatic cancers. Given the limited therapeutic outcomes with conventional targeted therapies, our strategy of regulating the expression of caspase-3 level as a drug target could provide as a more durable and effective alternative in the treatment of highly heterogeneous mTNBC.

Targeted Chemoradiotherapy of Prostate Cancer Using Gold Nanoclusters with Protease Activatable Monomethyl Auristatin E

Combined radiotherapy (RT) and chemotherapy are prescribed to patients with advanced prostate cancer (PCa) to increase their survival; however, radiation-related side effects and systematic toxicity caused by chemotherapeutic drugs are unavoidable. To improve the precision and efficacy of concurrent RT and chemotherapy, we have developed a PCa-targeted gold nanocluster radiosensitizer conjugated with a highly potent cytotoxin, monomethyl auristatin E, PSMA-AuNC-MMAE, for RT and chemotherapy of PCa. This approach resulted in enhanced uptake of NCs by PSMA-positive cancer cells, targeted chemotherapy, and increased efficacy of RT both in vitro and in vivo. In addition, the combination of gold and MMAE further increased the efficacy of either of the agents delivered alone or simultaneously but not covalently linked. The PSMA-AuNC-MMAE conjugates improve the specificity and efficacy of radiation and chemotherapy, potentially reducing the toxicity of each therapy and making this an attractive avenue for clinical treatment of advanced PCa.

Emerging Albumin-Binding Anticancer Drugs for Tumor-Targeted Drug Delivery: Current Understandings and Clinical Translation

Albumin has shown remarkable promise as a natural drug carrier by improving pharmacokinetic (PK) profiles of anticancer drugs for tumor-targeted delivery. The exogenous or endogenous albumin enhances the circulatory half-lives of anticancer drugs and passively target the tumors by the enhanced permeability and retention (EPR) effect. Thus, the albumin-based drug delivery leads to a potent antitumor efficacy in various preclinical models, and several candidates have been evaluated clinically. The most successful example is Abraxane, an exogenous human serum albumin (HSA)-bound paclitaxel formulation approved by the FDA and used to treat locally advanced or metastatic tumors. However, additional clinical translation of exogenous albumin formulations has not been approved to date because of their unexpectedly low delivery efficiency, which can increase the risk of systemic toxicity. To overcome these limitations, several prodrugs binding endogenous albumin covalently have been investigated owing to distinct advantages for a safe and more effective drug delivery. In this review, we give account of the different albumin-based drug delivery systems, from laboratory investigations to clinical applications, and their potential challenges, and the outlook for clinical translation is discussed. In addition, recent advances and progress of albumin-binding drugs to move more closely to the clinical settings are outlined.

Albumin metabolism targeted peptide-drug conjugate strategy for targeting pan-KRAS mutant cancer

Despite recent breakthroughs in the development of direct KRAS inhibitors and modulators, no drugs targeting pan-KRAS mutant cancers are clinically available. Here, we report a novel strategy to treat pan-KRAS cancers using a caspase-3 cleavable peptide-drug conjugate that exploits enhanced albumin metabolism in KRAS altered cancers to deliver a cytotoxic agent that can induce a widespread bystander killing effect in tumor cells. Increased albumin metabolism in KRAS mutant cancer cells induced apoptosis via the intracellular uptake of albumin-bound MPD1. This allowed caspase-3 upregulation activated MPD1 to release the payload and exert the non-selective killing of neighboring cancer cells. MPD1 exhibited potent and durable antitumor efficacy in mouse xenograft models with different KRAS genotypes. An augmentation of anti-cancer efficacy was achieved by the bystander killing effect derived from the caspase-3 mediated activation of MPD1. In summary, albumin metabolism-induced apoptosis, together with the bystander killing effect of MPD1 boosted by caspase-3 mediated activation, intensified the efficacy of MPD1 in KRAS mutant cancers. These findings suggest that this novel peptide-drug conjugate could be a promising breakthrough for the treatment in the targeting of pan-KRAS mutant cancers.

[89Zr]ZrDFO-CR011 positron emission tomography correlates with response to glycoprotein non-metastatic melanoma B-targeted therapy in triple negative breast cancer

There is a need for prognostic markers to select patients most likely to benefit from antibody drug conjugate (ADC) therapy. We quantified the relationship between pre-treatment positron emission tomography (PET) imaging of glycoprotein non-metastatic melanoma B (gpNMB) with 89Zr-labeled anti-gpNMB antibody ([89Zr]ZrDFO-CR011) and response to ADC therapy (CDX-011) in triple negative breast cancer (TNBC). First, we compared different PET imaging metrics and found that standardized uptake values (SUV) and tumor-to-heart SUV ratios (SUVR) were sufficient to delineate differences in radiotracer uptake in the tumor of four different cell- and patient-derived tumor models and achieved high standardized effect sizes. These tumor models with varying levels of gpNMB expression were imaged with [89Zr]ZrDFO-CR011 followed by treatment with a single bolus injection of CDX-011. The percent change in tumor volume relative to baseline (% CTV) was then correlated with SUVmean of [89Zr]ZrDFO-CR011 uptake in the tumor. All gpNMB-positive tumor models responded to CDX-011 over 6 weeks of treatment, except one patient-derived tumor re-grew after 4 weeks of treatment. As expected, the gpNMB-negative tumor increased in volume by 130 {plus minus} 59 % at endpoint. The magnitude of pre-treatment SUV had the strongest inverse correlation with the % CTV at 2 - 4 weeks after treatment with CDX-011 (Spearman ρ = -0.8). However, pre-treatment PET imaging with [89Zr]ZrDFO-CR011 did not inform on which tumor types will re-grow over time. Other methods will be needed to predict resistance to treatment.

Enzyme-activated Prodrugs and Their Release Mechanisms for Treatment of Cancer

Enzyme-activated prodrugs have received a lot of attention in recent years. These prodrugs have low toxicity to cells before they are activated, and when they interact with specific enzymes, they...

Recent advances in self-immolative linkers and their applications in polymeric reporting systems

Interest in self-immolative chemistry has grown over the past decade with more research groups harnessing the versatility to control the release of a compound from a larger chemical entity, given...

Cathepsin B-Overexpressed Tumor Cell Activatable Albumin-Binding Doxorubicin Prodrug for Cancer-Targeted Therapy

Prodrugs are bioreversible medications that should undergo an enzymatic or chemical transformation in the tumor microenvironment to release active drugs, which improve cancer selectivity to reduce toxicities of anticancer drugs. However, such approaches have been challenged by poor therapeutic efficacy attributed to a short half-life and low tumor targeting. Herein, we propose cathepsin B-overexpressed tumor cell activatable albumin-binding doxorubicin prodrug, Al-ProD, that consists of a albumin-binding maleimide group, cathepsin B-cleavable peptide (FRRG), and doxorubicin. The Al-ProD binds to in situ albumin, and albumin-bound Al-ProD indicates high tumor accumulation with prolonged half-life, and selctively releases doxorubicin in cathepsin B-overexpressed tumor cells, inducing a potent antitumor efficacy. Concurrently, toxicity of Al-ProD toward normal tissues with innately low cathepsin B expression is significantly reduced by maintaining an inactive state, thereby increasing the safety of chemotherapy. This study offers a promising approach for effective and safe chemotherapy, which may open new avenues for drug design and translational medicine.

Ultrasound augments on-demand breast tumor radiosensitization and apoptosis through a tri-responsive combinatorial delivery theranostic platform

Advanced inoperable triple-negative breast cancer (TNBC) comprises aggressive tumors with a modest pathological response to neoadjuvant chemotherapy. The concomitant use of chemoradiotherapy improves the pathological response rates. However, the dose-dependent systemic toxicity of clinical radiosensitizers with poor circulation half-life and limited passive bioavailability limits their clinical utility. We address these challenges by rationally designing a stealth and tumor microenvironment responsive nano-conjugate platform for the ultrasound-mediated on-demand spatio-temporal delivery of plant flavonoid curcumin as a combinatorial regimen with clinically approved paclitaxel for the neoadjuvant chemoradiotherapy of locally advanced triple-negative breast cancer (TNBC). Interestingly, the focused application of ultrasound at the orthotopic TNBC xenograft of NOD-SCID mice facilitated the immediate infiltration of nano-conjugates at the tumor interstitium, and conferred in vivo safety over marketed paclitaxel formulation. In addition, curcumin significantly potentiated the in vivo chemoradiotherapeutic efficacy of paclitaxel upon loading into nano-conjugates. This gets further enhanced by the concurrent pulse of ultrasound, as confirmed by PET-CT imaging, along with a significant improvement in the mice survival. The quadrapeutic apoptotic effect by the combination of paclitaxel, curcumin, radiation, and ultrasound, along with a reduction in the tumor microvessel density and cell proliferation marker, confers the broad chemo-radiotherapeutic potential of this regimen for radio-responsive solid tumors, as well as metastatic niches.

Stimulus-cleavable chemistry in the field of controlled drug delivery

This review comprehensively summarises stimulus-cleavable linkers from various research areas and their cleavage mechanisms, thus provides an insightful guideline to extend their potential applications to controlled drug release from nanomaterials.

Protease-activated prodrugs: strategies, challenges, and future directions

Proteases play critical roles in virtually all biological processes, including proliferation, cell death and survival, protein turnover, and migration. However, when dysregulated, these enzymes contribute to the progression of multiple diseases, with cancer, neurodegenerative disorders, inflammation, and blood disorders being the most prominent examples. For a long time, disease-associated proteases have been used for the activation of various prodrugs due to their well-characterized catalytic activity and ability to selectively cleave only those substrates that strictly correspond with their active site architecture. To date, versatile peptide sequences that are cleaved by proteases in a site-specific manner have been utilized as bioactive linkers for the targeted delivery of multiple types of cargo, including fluorescent dyes, photosensitizers, cytotoxic drugs, antibiotics, and pro-antibodies. This platform is highly adaptive, as multiple protease-labile conjugates have already been developed, some of which are currently in clinical use for cancer treatment. In this review, recent advancements in the development of novel protease-cleavable linkers for selective drug delivery are described. Moreover, the current limitations regarding the selectivity of linkers are discussed, and the future perspectives that rely on the application of unnatural amino acids for the development of highly selective peptide linkers are also presented.

Visible light-induced apoptosis activatable nanoparticles of photosensitizer-DEVD-anticancer drug conjugate for targeted cancer therapy

The therapeutic efficacy of photodynamic therapy (PDT) in cancer treatment is attributed to the conversion of tumor oxygen into reactive singlet oxygen (¹O₂) using photosensitizers. However, poor tissue penetration and rapid oxygen depletion have limited the effectiveness of PDT. Therefore, we have developed visible light-induced apoptosis activatable nanoparticles of the photosensitizer (Ce6)-caspase 3 cleavable peptide (Asp-Glu-Val-Asp, DEVD)-anticancer drug monomethyl auristatin E (MMAE) conjugate, resulting in Ce6-DEVD-MMAE nanoparticles. The average size of self-assembled Ce6-DEVD-MMAE nanoparticles was 90.8 ± 18.9 nm. Compared with conventional PDT based on high-energy irradiation, the new therapy uses lower-energy irradiation to induce apoptosis of cancer cells, and activation of caspase 3 to successfully cleave the anticancer drug MMAE from the Ce6-DEVD-MMAE nanoparticles, resulting in strong cytotoxic effects in cancer cells. Notably, the one-time activation of MMAE in the Ce6-DEVD-MMAE nanoparticles further amplified the cytotoxic effect resulting in additional cell death in the absence of visible light irradiation. Furthermore, Ce6-DEVD-MMAE nanoparticles passively accumulated in the targeted tumor tissues via enhanced permeation and retention (EPR) effect in mice with squamous cell carcinoma (SCC7). The high levels of toxicity were retained after exposure to lower-energy irradiation. However, Ce6-DEVD-MMAE nanoparticles did not show any toxicity in the absence of exposure to visible light irradiation, in contrast to the toxicity of free MMAE (1-10 nM). Thus, the light-induced therapeutic strategy based on apoptotic activation of Ce6-DEVD-MMAE nanoparticles can be used to treat solid tumors inaccessible to conventional PDT.

Metal-Organic Framework Nanoparticle-Based Biomineralization: A New Strategy toward Cancer Treatment

Cancer treatment using functional proteins, DNA/RNA, or complex bio-entities is important in both preclinical and clinical studies. With the help of nano-delivery systems, these biomacromolecules can enrich cancer tissues to match the clinical requirements. Biomineralization via a self-assembly process has been widely applied to provide biomacromolecules exoskeletal-like protection for immune shielding and preservation of bioactivity. Advanced metal-organic framework nanoparticles (MOFs) are excellent supporting matrices due to the low toxicity of polycarboxylic acids and metals, high encapsulation efficiency, and moderate synthetic conditions. In this review, we study MOFs-based biomineralization for cancer treatment and summarize the unique properties of MOF hybrids. We also evaluate the outlook of potential cancer treatment applications for MOFs-based biomineralization. This strategy likely opens new research orientations for cancer theranostics.

The novel strategy for concurrent chemoradiotherapy by conjugating the apoptotic cell-binding moiety to caspase-3 activated doxorubicin prodrug

The selective targeting of cytotoxic agents to a tumor has shown limited success by difficulties in identifying the appropriate target molecules, and more importantly, by the phenotypically dynamic nature of the tumor cells and intratumoral heterogeneity. In an attempt to overcome these issues and efficiently deliver cytotoxic drugs to the tumor, we previously reported a strategy termed radiation-induced apoptosis-targeted chemotherapy (RIATC), which utilizes the radiotherapy for intentionally triggering the caspase-3 and in situ amplification of tumor apoptosis by caspase-3 activated prodrug. Herein, we propose an advanced form of RIATC prodrug, AP1-DEVD-S-DOX, that could more actively target to the ligands of radiation-induced tumor cells, which could accumulate more prodrugs, thereby allowing more effective in situ activation and amplification of tumor apoptosis, comparing to RIATC. Indeed, AP1-DEVD-S-DOX was able to exert improved doxorubicin (DOX) delivery to the tumor and anticancer effect than the RIATC prodrug that lacks apoptotic cell-binding property but having a similar degree of off-target distribution in the other organs. Accordingly, AP1-DEVD-S-DOX could be an efficient prodrug for concurrent chemoradiotherapy by selectively delivering doxorubicin to the tumor with less systemic cytotoxicity.