Chemoradiation therapy in the management of gastrointestinal malignancies

AQ4N nanocomposites for hypoxia-associated tumor combination therapy

Hypoxia in solid tumors increases their invasiveness and resistance to therapy, presenting a formidable obstacle in tumor therapy. The hypoxia prodrug banoxantrone (AQ4N) undergoes conversion into its topoisomerase II inhibitor form AQ4 under hypoxic conditions, which inhibits tumor cells while leaving normal cells unharmed. Numerous studies have found that AQ4N significantly enhances the tumor effect while minimizing toxicity to normal tissues when combined with other drugs or therapeutic approaches. Thus, to maximize AQ4N's effectiveness, co-delivery of AQ4N with other therapeutic agents to the tumor site is paramount, leading to the development of multifunctional multicomponent AQ4N nanocomposites thereby emerging as promising candidates for combination therapy in tumor treatment. However, currently there is a lack of systematic analysis and reviews focusing on AQ4N. Herein, this review provides a comprehensive retrospect and analysis of the recent advancements in AQ4N nanocomposites. Specifically, we discuss the synergistic effects observed when AQ4N is combined with chemotherapeutic drugs, radiotherapy, phototherapy, starvation, sonodynamic therapy and immunotherapy in preclinical models. Moreover, the advantages, limitations, and future perspectives of different AQ4N nanocomposites are highlighted, providing researchers from diverse fields with novel insights into tumor treatment.

Efficacy of pembrolizumab and comprehensive CD274/PD-L1 profiles in patients previously treated with chemoradiation therapy as radical treatment in bladder cancer

Background

Chemoradiation therapy (CRT) has been increasingly reported as a possible alternative to total cystectomy (TC) for localized bladder cancer (BC). Pembrolizumab is the standard of care for platinum-refractory metastatic urothelial carcinoma, although it is unknown whether the efficacy of pembrolizumab in patients previously treated with curative CRT varies from the results of benchmark trials.

Methods

We retrospectively assessed whether the survival benefit of pembrolizumab differs between patients previously treated with TC or CRT as radical treatment. A total of 212 patient records were collected for a logistic regression propensity score model. An independent dataset with next-generation sequencing (n=289) and PD-L1 Combined Positive Score (CPS: n=266) was analyzed to assess whether CRT-recurrent tumor harbors distinct CD274/PD-L1 profiles.

Results

Propensity score matching was performed using putative clinical factors, from which 30 patients in each arm were identified as pair-matched groups. There was no significant difference in overall survival from the initiation of pembrolizumab (p=0.80) and objective response rate (p=0.59) between CRT and TC treatment groups. In the independent 289 BC cohort, 22 samples (7.6%) were collected as CRT-recurrent tumors. There was no significant difference in CD274 mRNA expression level between CRT-naïve and CRT-recurrent tumors. The compositions of CD274 isoforms were comparable among all isoforms detected from RNAseq between CRT-naïve (n=267) and CRT-recurrent (n=22) tumors. No actionable exonic mutation in CD274 was detected in CRT-recurrent tumors. PD-L1 CPS was positively correlated with CD274 mRNA expression level, and PD-L1 CPS was comparable between CRT-naïve and CRT-recurrent tumors.

Conclusions

The efficacy of pembrolizumab for patients previously treated with CRT was similar to those treated with TC. The enhanced tumor regression by combining programmed cell death protein 1/PD-L1 inhibitor and CRT might be expected only in the concurrent administration.

Increased BUB1B/BUBR1 expression contributes to aberrant DNA repair activity leading to resistance to DNA-damaging agents

There has been accumulating evidence for the clinical benefit of chemoradiation therapy (CRT), whereas mechanisms in CRT-recurrent clones derived from the primary tumor are still elusive. Herein, we identified an aberrant BUB1B/BUBR1 expression in CRT-recurrent clones in bladder cancer (BC) by comprehensive proteomic analysis. CRT-recurrent BC cells exhibited a cell-cycle-independent upregulation of BUB1B/BUBR1 expression rendering an enhanced DNA repair activity in response to DNA double-strand breaks (DSBs). With DNA repair analyses employing the CRISPR/cas9 system, we revealed that cells with aberrant BUB1B/BUBR1 expression dominantly exploit mutagenic nonhomologous end joining (NHEJ). We further found that phosphorylated ATM interacts with BUB1B/BUBR1 after ionizing radiation (IR) treatment, and the resistance to DSBs by increased BUB1B/BUBR1 depends on the functional ATM. In vivo, tumor growth of CRT-resistant T24R cells was abrogated by ATM inhibition using AZD0156. A dataset analysis identified FOXM1 as a putative BUB1B/BUBR1-targeting transcription factor causing its increased expression. These data collectively suggest a redundant role of BUB1B/BUBR1 underlying mutagenic NHEJ in an ATM-dependent manner, aside from the canonical activity of BUB1B/BUBR1 on the G2/M checkpoint, and offer novel clues to overcome CRT resistance.

Cyclopamine-loaded core-cross-linked polymeric micelles enhance radiation response in pancreatic cancer and pancreatic stellate cells

Pancreatic ductal adenocarcinoma (PDAC) is one of the most lethal cancers. Cyclopamine (CPA), a potent inhibitor for sonic hedgehog pathway (SHH), shows great promises in PDAC treatment, including the disruption of tumor-associated stroma, and enhancement of radiation therapy. However, CPA is insoluble in water and therefore requires a nanometric delivery platform to achieve satisfactory performance. We herein encapsulated CPA in a core-cross-linked polymeric micelle system (M-CPA). M-CPA was combined with Cs-137 radiation and evaluated in vitro in PDAC cell lines and a human pancreatic stellate cell line. The results showed that M-CPA had higher cytotoxicity than CPA, abolished Gli-1 expression (a key component of SHH), and enhanced the radiation therapy of Cs-137. M-CPA radiosensitization correlated with its ability to disrupt the repair of radiation-induced DNA damage. These findings indicate that the combination therapy of M-CPA and radiation is an effective strategy to simultaneously treat pancreatic tumors and tumor-associated stroma.

Giant adenocarcinoma of unknown origin penetrating from the pelvic cavity to subcutaneous tissue: A case report and review of the literature

In this study, we present a case of a 43-year-old female patient who was admitted to our hospital due to a giant mass on the left buttock. Imaging tests revealed that the mass was a solid-cystic tumor with a large size of 143×430×180 mm, penetrating from the pelvic cavity to the subcutaneous tissue. Pathology tests indicated a metastatic mucinous adenocarcinoma which was most likely of gastrointestinal origin. However, there was no evidence to confirm the existence of malignant changes in the gastrointestinal tract.