Analysis of Hypoxia and the Hypoxic Response in Tumor Xenografts

Tumor microenvironment-responsive nanoformulations for breast cancer

Nanomedicine, the most promising approach for regulated and targeted drug delivery, is frequently applied in cancer treatment. Essentially, accumulating evidence indicates that nanomedicine has positive results in the treatment of breast cancer (BC), with many BC patients benefiting from nanomedicine-related treatments. Currently, nanodrug delivery systems based on stimulus responses are gaining popularity because of their additional ability to manage drug release depending on the interior environment of the cancer. This review includes a synopsis of several types of internal (pH, redox, enzyme, reactive oxygen species, and hypoxia) stimuli-responsive nanoparticle drug delivery systems as well as perspectives for forthcoming times. Stimulus-responsive nanoparticles can remain stable under physiological conditions while being rapidly activated to release drugs in response to specific stimuli, prolonging blood circulation and increasing cancer cellular uptake, resulting in excellent therapeutic performance and improved biosafety. In this paper, we discuss tumor microenvironment responsive Nanoformulation for breast cancer treatment.

Glutamate dehydrogenase1 supports HIF-1α stability to promote colorectal tumorigenesis under hypoxia

Tumor cells surviving hypoxic stress acquire the ability to drive cancer progression. To explore the contribution of dehydrogenases to the low oxygen concentration response, we used siRNAs targeting 163 dehydrogenase-coding genes and discovered that glutamate dehydrogenase 1 (GDH1) plays a critical role in regulating colorectal cancer (CRC) cell survival under hypoxia. We observed that GDH1 deficiency had an inhibitory effect on CRC occurrence and impaired hypoxia-inducible factor 1-alpha (HIF-1α) stability even under hypoxia. Mechanistically, hypoxia triggered p300 recruitment to GDH1, promoting its acetylation at K503 and K527. GDH1 acetylation at K527 induced the formation of a GDH1 complex with EGLN1/HIF-1α; in contrast, GDH1 acetylation at K503 reinforced its affinity for α-ketoglutarate (αKG), and glutamate production. In line with this view, αKG is a product of GDH1 under normoxia, but hypoxia stimulation reversed GDH1 enzyme activity and αKG consumption by the EGLN1/HIF-1α complex, increasing HIF-1α stability and promoting CRC progression. Clinically, hypoxia-modulated GDH1 AcK503/527 can be used as a biomarker of CRC progression and is a potential target for CRC treatment.

Considerations for Whole-Slide Analysis of Murine Xenografts Experiments

Histochemistry of tumor sections is a widely employed technique utilized to examine cell death in preclinical xenograft animal models of cancer. However, this is under the assumption that tumors are homogeneous, leading to practices such as automatic cell counting across the entire section. We have noted that in our experiments the core of the tumor is largely or partially necrotic, and lacks evidence of vascularization (in contrast to the outer areas of the tumor). We note that this can bias and confound immunohistochemical analyses that do not take care to sample areas of interest in a way to take this into account. Design-based stereology with image analysis techniques is an alternative process that could be used to measure the volume of the necrotic region compared to the volume of the whole tumor.

Tumor microenvironment-responsive nanoparticles for cancer theragnostic applications

BACKGROUND

Cancer is one of the deadliest threats to human health. Abnormal physiochemical conditions and dysregulated biosynthetic intermediates in the tumor microenvironment (TME) play a significant role in modulating cancer cells to evade or defend conventional anti-cancer therapy such as surgery, chemotherapy and radiotherapy. One of the most important challenges in the development of anti-tumor therapy is the successful delivery of therapeutic and imaging agents specifically to solid tumors.

MAIN BODY

The recent progresses in development of TME responsive nanoparticles offers promising strategies for combating cancer by making use of the common attributes of tumor such as acidic and hypoxic microenvironments. In this review, we discussed the prominent strategies utilized in the development of tumor microenvironment-responsive nanoparticles and mode of release of therapeutic cargo.

CONCLUSION

Tumor microenvironment-responsive nanoparticles offers a universal approach for anti-cancer therapy.